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Printed circuit boards have found use in almost all the electronic gadgets that we see around the world. It is a new type of technology that has made the electronic industry take a new path to give satisfaction to its customers. This technology has brought about the miniaturization of electronic gadgets and improved the portability of the same devices. Today, most clients can walk around with their devices such as smartphones and tablets, which was not the case sometime back. Due to the high demand for electronic devices, the world has seen growth in the area of manufacturing due to the introduction of both small and large printed circuit boards fabrication houses. Both small and big manufacturing firms are trying their best to come up with quality work to meet clients’ demands. Though these firms can defer on how large their production is and maybe the quality of the produced boards, they both utilize almost similar technology and process of production. In this article, we are going to discuss the printed circuit board production fully.

We shall have a look at the various services that a good PCB fabrication house should offer to its clients. They include through-hole technology assembly, surface mount technology assembly, BGA assembly, assembly of rigid-flex PCBs, mixed assembly, etc. and they must also be compliant with the many set standards such as the class 2, IPC 610, and Class 3 standards. Now let us focus on the process of the surface mount technology soldering.

SMT soldering Process

The process is divided into several important steps that should be adhered to:

PCB design and output

The printed circuit board should be a copy of the designs produced using the design automation software. Such software includes KiCAD, Altium, Eagle, OrCAD, etc.

• The designers have to inform the PCB manufacturers about their intention and when they are given a go-ahead, they have to submit the design files in the format that has been specified by the manufacturer.
• The most common file that is used in the process of printed circuit board manufacturing is the Gerber file.
• The Gerber file is also known as IX274X.

Take note that different Electronic Design Automation software will involve different steps in the production of the Gerber files.

• The Gerber files carry very comprehensive data regarding the type of board being designed. They will have drill drawing, copper tracking layers, component notation, aperture, and many other options.
• At this point, all the aspects of the printed circuit board design will undergo checks.
• After proper checking and confirming that the design is of good quality, the designer will now forward it to the fabricators for the production process to start.
• All PB manufacturing houses need to run a DFM check to ensure that the board complies with all the design rules.

The printing

This is the first step in the process of printed circuit board printing. It involves printing the solder paste on the solder pad of the printed circuit board. The process is made possible by the use of a solder paste printing press machine and the process is done in preparation of the board for welding.

Dispense of adhesives

This process is made possible by the use of the glue dispenser machine. The machine does the precise spot injection of liquids such as glue paints to the given spot of the product being manufactured. The main idea here is to fix the required components onto the PCB when the soldering process using the wave solder is done.

Placement of the components

After the confirmation that the printed circuit board has the current amount of solder paste placed on its surface, it is moved to the next step which is the placement of the electrical components.

• A gripper or a vacuum nozzle is used to pick each component from where it is packaged.
• Then it is passed through the vision system for checking before it is placed at a high speed in a location that is programmed for it.
• When you search on the market, you will come across too many types of machines that have been designed for this process and it will now depend on the intention of your company to settle for which machine.
• For example, when purchasing these machines, companies that focus on large production quantities will tend to focus on machines that can do large placement rates within a short period.

Pre-reflow AOI

AOI is an abbreviation for Automated Optical Inspection. In this stage, we are thinking about the inspection of the printed circuit board after the components have been placed.

• Here, we have to confirm whether the connections of the components have been done correctly as described in the Gerber files delivered by the designer.
• The component’s connection can influence the functionality of the whole board.
• This is made possible by the use of the Automated Optical Inspection machine which will inspect whether the components are present, have well-connected polarity, and are of the correct expected value and type.

Reflow soldering

This is the process where electrical components are connected temporarily to respective contact pads before the entire printed circuit board is taken through a process of controlled heating to melt the solder and do a connection of the component permanently into the board.

• Solder paste is a mixture of powdered flux and solder and has the characteristic of stickiness.

This heating process can be achieved by taking the PCB through a reflow oven. Sometimes the process can be achieved through the use of infrared lamb or even doing the soldering of each joint by utilization of the pencil exposed to hot air.

• The reflow soldering has the advantage of being the most used method in soldering of the SMT components, although it is also usable in the THT components where a solder paste is filled on the drilled holes before the insertion of the components is done.
• In THT, reflow is not generally used since the wave soldering method is cheaper for such components.
• Sometimes you find we have boards that utilize both the THT and SMT components and therefore, in such a situation, we shall be forced to eliminate the wave soldering and utilize the reflow soldering method fully. This will drastically lower the cost of production and assembly.

Let us have a deeper look into the reflow process.

• Soldering oven: the first step is the board is taken into the reflow soldering oven using a conveyor.
• Pre-heat zone: this is the first part of the oven and it is where the board and its element temperature are raised systematically. The temperature rises slowly at a rate of 1 to 2 degrees Celcius until it hits a maximum of 140 to 160 degrees Celcius.
• Soak zone: this is a zone where the PCB is placed for about 80 seconds at a temperature of about 150 degrees Celcius.
• Reflow zone: here the board is then superheated to a temperature of about 220 degrees Celcius where this is done so that we can melt the tin that is mixed with the solder paste to bound the placed components into the PCB leads.
• Cooling zone: here we freeze the solder to avoid the defects that may arise due to high temperatures.

Removing excess copper

In the process of preparation of the copper tracks and soldering, there is poring of excess copper and other material. This has to be removed to avoid the effect it can induce on the functionality of the printed circuit board.

• We need to cover the needed copper with resistance and harden it then allow the board to proceed to the stage that follows which is the removal of the unwanted copper stage.
• A copper solvent is used to remove the excess copper that is exposed while the needed copper remains protected by the hardened photoresist material.
• After the process, the hardened photoresist is washed away and the needed copper is exposed.
• The washing away is done with a different type of solvent to make it possible.

Post reflow AOI

Again, we have to take the board through an AOI inspection to ensure that no single error has been made during the soldering process.

• This has to be done to ensure that the quality of the joint is up to satisfactory standards and that no defects can be detected and also ensure that the whole joints have been soldered during the process of reflow.
• Remember reflow process is sometimes accompanied by poor joint connections or incomplete connections.
• In the process, the components may encounter misplacements leading to shorts within the circuit.
• Therefore, it is a very significant practice to always take the board through an inspection process to ensure that such errors are eradicated and confirm that the board being manufactured is of quality standards.
• This process can be carried out using several methods as discussed below:

Manual checks:

• This process is done by visual inspection, where our experienced experts have to check for any noticeable defects to ensure that the printed circuit board is up to standard.

Automated x-ray inspections

• This type of inspection employs the same knowledge as the AOI whereby they utilize the principle of image capturing.
• The only existing difference is that AXI utilizes the X-rays while the AOI utilizes light to carry out the process.
• Every material has a different rate of X-ray absorption. From experience, we can notice that materials with heavy elements are capable of absorbing more portions of X-rays compared to those that are made out of lighter materials.
• Therefore, heavy materials will have a better darker display as compared to the lighter materials.
• This one is used when the components being inspected have hidden elements for example in BGAs pins tests.
• The image below has a comparison between the AOI and the AXI on how they perform matters inspection.

Automatic optical inspections:

• This one will find useful when the defects on the board are somehow easier to discover.
• Such defects will include solder shorts, open circuits, insufficient solder, and solder bridges.
• This makes utilization of light energy to carry out the process.

ICT

This is the most important equipment that is used in the electrical tests of PCBs.

• The device has a bed nail that comes into contact with the components that have been mounted on the board and then a specific amount of current and voltage is used to carry out the possible defects on the components such as parameter deviations, misplacements, displacements, solder joint bridging missing components, shorts, and open circuits.
• This method is good for mass production and simple PCBs because of the high-speed features it gives.
• Flying probe test is another good example of the ICT methods of PCB tests and this utilizes a large amount of flying probes to achieve its goals of carrying out printed circuit board electrical tests.
• Flying probe method is widely used in the assembly of the surface mount devices.

Conformal coating

In this process, we shall involve a thin polymeric material that is applied on top of the PCB to protect the components.

• The thickness of the polymeric film is between 25 to 250 um.
• It is purpose is to offer protection to a given board against dust, moisture, extreme temperatures, and chemicals spills.
• If you don’t protect your PCB components, then expect several failures within a short period meaning the functionality will be altered.
• In the modern manufacturing industry, most companies have opted to use transparent coating material such that it can allow easier inspection of the components.

Final inspection and testing of functionality

At this level, we need to test whether we can achieve the objectives of the design. An electrical test has to be carried out by a team of qualified experts to ensure that the functionality has been achieved as expected.

• The customers have to provide the test software and sometimes the manufacturing firm can construct test fixtures according to customers’ definitions.
• The PCB is simulated through the normal working conditions while the testers do the monitoring of the printed circuit board’s features and characteristics

Cleaning: washing and drying.

The production process has a lot of activities that are carried out by the machines. This machine utilizes oil as lubricants and they can also carry with them a lot of dirt which ends up getting into contact with the printed circuit boards being manufactured.

• A good example is during the process of adding soldering paste, you will notice that some visible content of the flux is left behind during the process of manufacturing humans can transfer oils and dirt into the PCB while handling them.
• This is what needs to be removed during this process to ensure that the PCB is very clean and ready for packaging.

Packaging and shipment

All the produced boards need to be packaged so that they can be delivered to respective clients. Packaging can be done in various ways one being anti-static packaging which can only be done if requested by the customers.

Shipment is done through various shipment agencies such as DHL, EMS, FedEx, and UPS. The customers are notified anytime the shipment has begun.

The extra components after the design process are also returned to either the customer or where they were ordered depending on the customer’s idea.

• There are very significant factors that you have to consider when doing the SMT placements of the components such as the spacing and tolerances.
• The most important factor is the coefficient of thermal expansion. This should not be too big between the materials making up the PCB since you will experience cracking of the solder joints.
• Another factor that determines the components placement process is the cost and size factor. Components that absorb more current requires greater electrical and thermal considerations. Such components will need ground flow so that it can be able to manage the heat flowing in them.

Conclusion

This is all about the surface mount devices soldering process. It is a comprehensive process that starts with the PCB design and output, the printing, dispense of adhesives, placement od components all the way to packaging of the finished product.

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Printed circuit boards

Printed circuit boards are in use in almost all electronic devices. Except for the smallest electronic devices, Printed circuit boards are found in all electronic devices. This article will discuss quality control in printed circuit boards to bring the reader to the understanding of quality control in PCBs, how printed circuit boards are manufactured, the materials used, and the justification.

Why laminate materials?

Circuit Board Manufacturing and PCB Quality Control Methods

What Is Quality Control, And Why Is It Important?

Quality control is a set of processes designed to ensure that a product or service is done in adherence to the defined quality standards for safety, optimum functionality, and cost-effectiveness.

Standards are often approved by a body approved nationally or internationally. For electronics, there are several bodies responsible for setting internationally acceptable standards.

• ISO (International Organization for Standardization), for ensuring standard processes in electronics design and product development.
• ITU (International Telecommunication Union) which regulates telecommunications
• IEC- International Electro technical Commission involved in testing and certifying electrical, electronic, and related products
• IPC (Association Connecting Electronics Industries) which is involved in electronic boards (PCB’s)

IPC standardization process

What is the implication of quality control on PCBs?

PCBs are the backbone of all electronic devices and, therefore, directly impact the quality of performance. PCBs determine the functions and performance of electronic devices. PCBs’ quality control is a continuous process, from the design to the manufacturing process. Now that we understand the design and functions of PCBs, we can now delve into quality control in PCBs and understand the dynamics therein.

There are various aspects of quality control that one can perform on PCBs. as noted earlier, quality control is an ongoing process and can be summarized into the following:

• Incoming quality control is done at the point of entry, where quality checks are done on supplies in line with the required standards and client specifications. There is also the constant review of supplier performance and taking corrective actions.
• In process quality control – refers to the continuous quality checks and procedures that ensure quality flops are caught and addressed before it is too late.
• Final quality control is done at the final stage before products are released to the consumers.

Quality Control in PCB Design

Quality control in design involves the following critical activities;

1. Ensuring the Validity of the PCB design file

A design file is a critical component in quality control, as it is the major communication tool between the fabricator and the designer. Various types of files can be sent to the fabricator containing information on the PCB design. The project leader has to confirm the validity of the design file as a measure of quality. The information contained in the design file translates to the materials that designers will need in manufacturing the particular PCB required. Errors in the design file will have a chain reaction on the entire process and compromise quality.

Types of PCB design files are;

• Gerber files – these are ASCII formatted files containing everything on the PCB layer image, and don’t require external files for extra information.

Gerber files

• IPC Netlist/ IPC – 356 – has instructions for PCB CAM software including net names, start and endpoints for the nets and nodes and locations.

IPC PCB Netlist

• Drill files NC format – these files contain PCB drilling and routing information
• Fab drawing
• BOM (Bill of materials) – this is a list containing information on all parts that are required for building a specific printed circuit board.
• IPC-2581
• Pick and Place files – this is a list of all the components with regard to the specific PCB design. Pick and place files also contain information on the respective x-y coordinates and rotation.

Pick and Place setup

It is also critical to check on;

• Design rule check-list
• Design for manufacturability

Design rule checklist

• Design rule checklist

The process of PCB design and manufacturing involves multiple components and connections. A lot goes on in designing quality PCBs, and given the central roles of PCBs in electronic devices, management of the process cannot be left to chance. A design rule checklist keeps track of all the requirements and dimensional tolerances meant for a specific board. The checklist allows the designer to double-check that every guideline in the design, assembly and manufacturing of PCBs aligns with the design files and the acceptable standards of the different PCBs.

• Design for manufacturability

The design for manufacturability (DFM) approach has become prominent in the quality control process. This is the process through which the design layout is done in a way that foresees and addresses problems in assembly and fabrication. DFM is critical in quality control designed to optimize costs in time for product development, repairs, wastages, and recalls. DFM has two critical components: a design for fabrication, which forecasts problems at the fabrication stage, and a design for assembly, covering issues at the design phase. The DFM process is an important quality control tool.

2. Guarantee the manufacturability of PCBs

PCB manufacturing comes with technological requirements that are governed by standard procedures. Once the design has been approved, quality control checks shift to the availability of the requisite technology to manufacture the specified design. In this phase, the technologist must possess the required skills to manufacture the specified design and possess the right tools for the manufacturing process. The manufacturer should communicate the requirements clearly and reasonably, and the machinery must meet the specified operations standards.

3. Guarantee the testability and normalization of PCBs

The testability and normalization of PCBs must conform to the laid down standards in the industry. The process requires checking and analyzing test points, dimensions, routing, structural style, and testability for manufacturing. Design for testability (DFT) happens before production and is meant to catch testing issues earlier on in the process. The process is meant to catch defective products before production.

Quality Control In Component Procurement

Quality control in procurement is an essential part of ensuring the production of high-quality PCBs. Each component used in PCB manufacturing needs to be of high quality if the resulting product meets quality standards. The following areas are critical in component procurement;

• Validation of the bill of materials (BOM) – the items listed on the bill must align with the final design file.
• Manufacturer part number (MPR) – this is a measure in procurement that allows the purchasing of the right part. The manufacturer gives an MPR
• Visual inspection is done once the components have been received, ensuring that the delivery matches the order.
• Supplier verification – suppliers must be credible and reliable, and their products must meet the industry-accepted standards and guidelines.

Quality Control in Production of PCB

• Manufacturers capability

Before embarking on a project, the designer must conduct thorough investigations on the manufacturer’s capability to deliver quality. The manufacturer must have complied with the standard operating procedures outlined by the regulating bodies.

• Constant checking and confirmations

Using the design rule checks, design files, and other tools available, the production team is responsible for conducting numerous checks and confirmations before production commences. Since the first design is not always perfect, and there is a need for multiple design files as consultations between the designer and manufacturer ensue, the production team is responsible for confirming the final design file before commencing production.

• Attention to key procedures

Quality control in production defines how key production procedures are carried out. Quality control in the design process is crucial to ensure that each step follows the accepted standards. Key procedures in PCB production are as follows;

• Design imaging is done using a specialized printer, producing photo negatives of the design file or schematic diagram.
• Printing the inner layers on copper
• Ultraviolet light blasting meant to harden the photo reactive photo chemicals
• Inner layer etching
• Aligning the layers
• Optical inspection
• Layer pressing and lamination
• drilling
• PCB plating
• Imaging the outer laying
• Etching the outer layer
• Solder mask application

Soldering mask application

• Silk screening
• Finishing
• Testing
• Profiling
• Final quality check
• Packaging and shipping

There are guidelines to every single process guaranteeing the quality of the final product. Quality control measures in production are a step-by-step process.

Quality Control in PCB Inspection

This is the process of monitoring and measuring PCBs, with strict adherence to quality standards. The final product must reflect the initial design outlined in the design file. There are acceptable quality standards in every industry and country, and quality PCBs must meet these standards in the context they will be in use. Quality control inspection is done in the following ways;

• Visual inspection
• Performance inspection
• Technological inspection

These methods are further broken down into:

• Visual inspection involves a thorough check of connections and other components of the PCBs with the use of the naked eye. This can be applicable where the volume of production is low.

PCB visual inspection

• Microscope – where the naked eye fails, microscopes, USB devices, and handheld visual tools provide a clearer, wider view of the components and possible quality issues.

Man using microscope for visual inspection

• In-Circuit Tests – this method uses electronic inspection methods, a bed of nails, and fixtureless. Bed of nails testing uses pogo pins arranged in a series, pressing into different test points to measure resistance. Fixtureless or flying-probe testing uses probes that are machine-operated. They check test points on the PCBs at breakneck speeds.
• X Rays use non-invasive technology to inspect quality issues in PCBs visually.
• Automated optical inspections use webcams and OpenCV to compare a perfect PCB and the finished product under inspection and point out the discrepancies.
• Functional testing involves full tests on the functionality of the PCB once it has been manufactured. Self-tests run on the PCBs as part of the trial tests.
• Inspection cameras are high-resolution cameras that produce high-quality images. These are projected on screens where operators can view the PCB components with the naked eye and perform necessary inspections.

What is the most reliable method of quality control before assembly?

Electrical testing is the more reliable testing method for PCBs before shipping. There are two major ways of testing PCBs before assembly;

• Universal grid test
• Flying probe test

Universal grid test/bed of nails

This method uses pins mounted on an epoxy surface, and these numerous pins are inserted into the holes. These are aligned into the testing point, allowing the testing to be done simultaneously.

Flying probe test

A generic board holder contains one or more that are controlled by software to test for opens and shorts, as well as test other things.

Quality Control Methods

There are several methods one can use to guarantee quality to their customers and reduce the cost of recalls, expensive lawsuits, and other negativities associated with low quality.

• IPC certification
• Component expertise
• Process controls
• Assembly checks
• Inspection and tests
• Functional workspace

IPC Certification

IPC standard is a globally recognized trade association that involves itself in standardizing the manufacturing of PCBs electronics components. These standards also regulate the assembly, protection of electronic equipment, training, research, and advocacy on public policy.

The IPC offers continuous development programs on PCB. IPC certification is based on industry standards, and practitioners in the field must be certified by the IPC for soldering, reworking, and assembly of PCBs. The certification must be up to date, and compliance with the industry standards must also be on display and up to date. IPC certification controls operations standards and ensures the same standards are maintained across the industry, leading to safe, reliable, and quality PCBs. IPC gives the following benefits of adherence to their quality standards and quality control measures:

• The product becomes reliable and high quality
• Reduced costs due to recalls, wastages and damage through faulty equipment
• Improved communications
• Better relations with customer and and management

IPC defines quality in the following three classes, that define the quality of the electronics (class 1 contains products with the least quality while class 3 has items with the highest quality;

• Class 1 – in this class, the major requirement is the functionality of the complete IPC assembly, and contains the equipment contained here are the general electronic equipment and everyday products
• Class 2 contains products like laptops. The equipment here are for dedicated service, and must have highly reliable and has extended life to qualify for this class.
• Class 3 contains high performance electronic products. These must perform on demand, sometimes with no equipment downtown. Some of the equipment belonging to class 3 are life support systems and other medical equipment.

IPC standards are meant to cover design, production and assembly of PCB as a measure to control quality. These standards are as listed;

• IPC-A-610 – it covers the acceptability of electronic components, and clearly outlines the prerequisites for acceptability.
• IPC-A-600 – is all about the acceptability of printed boards
• J-STD-001 – outlines the soldering requirements of electrical and electronic components
• IPC-7711/IPC-7721 instructs on how to rework electronic components/printed board, repair or modify electronic components.

Standards are built on conditions that define and justify the quality control process. IPC has the following conditions;

• Target Conditions – refers to goals that are set as a reference point for every PCB manufacturer. The objective is to ensure the manufacturers produce PCB that are as close as possible to the target products.
• Acceptable Conditions are the ideals which PCB products ought to meet in quality and in design. PCB manufacturers are meant to meet the conditions, with a negligible margin of error allowed.
• Defect Conditions address and define what is categorized as defective inPCB manufacturing. Defective products are reworked or rejected.
• Process Indicator Conditions don’t affect performance or quality of the end product. They however impact on selection of materials, design parameters, manufacturing and assembly.

Component Expertise

The engineering process and inspections should be in place to ensure the use of only the best parts for the job. The engineer should possess vast knowledge of the different components for producing the specific PCB. Some factors to consider when investigating the expertise of the engineer is how well they understand;

• Power consumption and alternatives parts that can help you stay within the budget without compromising on quality;
• Type of memory for your device
• Different internet protocols compatible with the device design
• Simulation protocols
• Mixed-signal design

Usually, understanding these different components, applicability, advantages, and disadvantages give you confidence in the quality of the product.

Process Controls

Process control entails the following;

• Documentation is an important part of process control. A professional will have documented procedures and processes that adhere to the standards of operation as guided by the regulating body. Documentation of processes is a great way to forecast results and detection of anomalies early enough.
• Constant monitoring during manufacturing regulates process control, and once any anomaly is detected, the process is immediately re-adjusted to the required cause. Process controls ensure process uniformity across all production units and uniformity of products.

Assembly checks

PCB assembly process

Assembly checks involve the checking of solder points before and after soldering. The process is as follows:

• Solder paste – solder paste is added to requisite areas before adding the components on the board. The solder paste amount is controlled to ensure only the right amount is used. ‘
• Pick and place – this is the process where the board with the solder paste is picked by a machine with a series of reels and placed at the right place on the board. The solder paste holds the components in place.

A pick and place machine

• Soldering – this is the process of passing the board through the soldering machine, mostly through reflow soldering techniques.
• Inspection – once the soldering process is done, the boards undergo inspection as part of quality control by automated inspection. The inspection process is automated to inspect boards for poor joints and misplaced components. In some cases, faulty components are detected during the inspection process.
• Testing – inspection is followed by testing. Testing is an integral part of all development of electronics and electrical components. The following are some of the popular instruments used in testing;

1. Multimeters,
2. analog and digital (DMM – digital multimeter),
3. Oscilloscopes,
4. spectrum analyzers

Inspection and testing

• A manufacturer should document inspection and testing methods and provide documented evidence on previous work done.
• The inspection and testing methods should align with the industry best practices and should be up to date. Inspection and testing procedures are inbuilt and part of every process.
• Functional workspace – quality standards reflect on the working space, evident in the assembly down and individual working space organization.

Quality control in workspaces is determined by;

• Building proper processes, done through documentation, clear labeling of equipment, organization, and smooth working procedures
• Clean workspaces
• Unscheduled equipment use tests – it ensures quality is maintained at all times, as surprise breakdowns of machinery are reduced to a minimum,
• They are identifying essential spare parts and ensuring their availability at all times.
• Proper staff training and refresher courses keep the staff updated on the latest industry standards and requirements.

Conclusion

PCBs are critical components of electronic devices and are expected to be of the highest quality standards achievable. Quality control processes are indispensable, especially in PCBs. Quality control ensures quality PCBs are produced in line with industry standards. Producers and consumers greatly benefit from quality control, as they avoid unnecessary costs in recalls and wastages brought about by faulty pieces of equipment. Adherence to quality standards guarantees a competitive advantage for manufacturers and customer satisfaction, a prerequisite for higher profits. High-quality PCBs guarantee the safety of electronic equipment around the world. The compromised safety of PCBs would pose a great danger to humanity.

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A printed circuit board (PCB) is a rigid board with electrical circuits known as traces. The present-day PCBs were first designed and produced around the 1930s however, in 1936 an Austrian inventor, Eisler Paul made the first printed circuit board to operate his radio system. This kind of printed circuit board (Rigid printed circuit board) can neither bend nor be forced out of its shape and is made with copper tracks. Alternatives of PCB are a wire wrap and point to pint construction. The board has lines and pads connecting different points. They were made through laborious point-to-point wiring which led to frequent wire failures and short circuits hence a significant advancing wire wrapping was made. A metal known as solder makes electrical connections between the PCB surface and electronic components since it’s a metal hence strong is composed of silkscreen, solder mask, copper, and substrate (FR4)

Silkscreen

• It’s applied on top of the solder mask layer and adds letters, numbers, and symbols to the PCB to allow easier assembly and ease human understanding of the board.
• The labels indicate each function of each pin, mostly the silkscreen is white though any ink color can be used.

Solder mask

• This is the layer on top of copper foil and gives the PCB its green color and is overlaid onto the copper layer to insulate the copper traces from coming into contact accidentally with other metal, solder, or conductive bits.

Copper –

• it’s laminated to the board with heat and adhesive. Double-sided PCBs copper has been applied on both sides of the substrates.
• the thickness of the copper is depended on the specified weight some PCBs that can handle very high power may use 2- or 3-ounce copper.
• They act in the same way as wire

Substrate (FR4)

• Its usual fiberglass and most historically and most common designator for this fiberglass is “FR4 which gives the PCB rigidity and thickness
• The designator for this fiberglass is “FR4”

Types of PCBs

• Single-sided PCB is the simplest and the lowest cost PCB and has been in existence since the 1950s and is only one single layer of the base substrate (fiberglass)and one single conductive layer which is made from copper.

• Double-sided PCB is a little and complex than single-sided PCBs as they have one single layer of the base substrate conductive layer on both sides of the board. The holes of electronic components have to be plated through for conductivity of both sides due to the double layers forming the circuit

• Multilayer PCB is a printed board with more than 2 layers and it must have 3 or more conductive layers whereby all these layers should be interconnected with copper-plated holes.

• High density interconnects (HDI) PCB –They take advantage of precision basing manufacturing technology to pack as much functionality small space through the use of many conductive layers.

Components of PCB

The transistor

• is a semiconductor device whose aim is to amplify electrical signals and power and are active components of integrated circuits.
• Transistors were invented in 1947-1948 by physicists John Bardeen, Walter H. Brattain, and William B. Shockley.
• It mainly works as both amplifier and a switch.
• The transistor works as an amplifier in the sense that it takes in a tiny electric current at a particular end and produces a bigger electric current through the output current by first boosting the current.
• Transistors are made from silicon which doesn’t conduct electricity as it’s a semiconductor.

Resistor

Its purpose is to monitor the flow of electrical current in the circuits which are mostly made from copper materials or carbon whose purpose is to make it hard for the electrical charges to flow through the circuit.

• The commonly used type of resistor is a carbon resistor which is suitable for lower-powered circuits.
• The resistors are used in protecting against voltage spikes as they ensure components receive proper voltage.

Inductor

It is also known as the coil and is a two-terminal electrical component for storing energy in magnetic when electric current flows through it.

• They are used as energy storage devices in switched-mode power devices to produce DC.it supplies energy to the circuits to maintain energy flow during the off-switching period.
• The capacity of inductors is controlled by the number of coils as the more the number of coils the more the inductance.
• The cross-sectional area of the coil whereby the more the area the more the inductance.

Capacitator

This is a device for storing electrical energy which consists of two conductors proximate and insulated from each other.

• They are mostly used in digital circuits so to store information in large computer memory is not lost during temporary power loss.
• Capacitator stores energy in the terminals hence when activated releases energy in a fraction of a second.

Light-emitting diode (LED)

This is a semiconductor light source emitting lite when current flows through it they convert electrical energy directly into the light and operates on a basic principle that electrons and holes in semiconductors recombine to emit protons under forwarding bias.

• It is applied in most cases due to its compact size, low consumption of energy, and extended lifetime.
• LEDs are used for TV backlighting it uses LEDs to give an efficient power reduction, using LEDs behind the display provides a better contrast hence it has resulted in them replacing CFLs and LCDs in the case of Tv backlighting.
• It is also used in the dimming of lights hence reduction of energy consumption

Potentiometer

This is a three-terminal resistor with a sliding contact forming an adjustable divider it is mostly used to measure the displacement in any direction it operates on a basic principle that the potential dropped across a segment of a wire of uniform cross-section carrying constant current is directly proportional to its length.

Electrical fuse

This is an electrical safety device operating to provide overcurrent protection of an electrical circuit it has a metal strip (wire) that melts when excess current flows through it, therefore, interrupting the current by stopping the flow of current. Fuses are of many types which include thermal fuses, mechanical fuses, blade fuses, expulsion fuses, and varistors.

• The fuse plays a very vital role as it’s the cheapest form of maintenance. Its operations are automated and require less time compared to circuit breakers.
• Despise the fuse playing a very vital role it has several cons such as being time-consuming, especially when replacing a worn-out fuse after its operation.

How to design a layout of PCB

Don’t rush to use the auto-router

Most printed circuit board software designs have an autoroute feature that automatically does the routing for you unfortunately auto-routing is not perfect as routing for oneself. There are a few scenarios suitable for auto-routing which include:

• Upon placement of all your components, one can use the autoroute tool for checking one’s completion rating. If the rating is anything below 85%, then one needs to adjust component placement.
• if you don’t know how to begin routing or you get stuck at some point, auto-routing can be used as an inspiration source.
• In some cases, bottlenecks and other critical connection points can fall through the cracks when routing hence one can easily identify these through the autoroute feature.

Auto routing is not recommended as it ignores symmetry hence manual routing is advocated due to accuracy and reliability.

Use sufficient trace width

Since copper traces faces resistance from electrical current hence voltage drop which results in power resistance hence the generation of heat.

• To avoid excess heat in your circuit, one should reduce the amount of heat should increase the width of the traces.
• The width of the trace is calculated through a width calculator as far as the width is in line with your manufacturer’s stipulations, one can use a larger trace width than the ones specified by the calculator.

Know the manufacturer’s specifications

Preferred manufacturer’s specifications are very crucial before designing a PCB one should familiarize with the specifications such as trace width, number of board layers, and trace spacing beforehand to avoid the printed circuit board not being functional. This avoids the frustration of having to reroute the whole design at the final stages and working on it for extra hours.

Component planning

This is a success key factor as for one to place properly the components making up a circuit has to understand their characteristics as their components which should be placed close to others. Propper placement also enhances convenience. it’s advisable to place heat-sensitive electrolytic capacitors away from heat-generating diodes, inductors, and resistors.

Rules for designing

• Be mindful of components with more pins since they will require more space. It’s a joint mistake to pack components together, thereafter realize that there is no space left for routing traces.
• Take respectively component’s function and its relation to other workings into consideration before placement.
• Ensure that the components are placed in the same orientation since components usually have standard pin numbering to help with this.

Proper trace angles (45⁰)

45° is the sweet spot since 90° angles at the corners can be entrenched narrower than they should be. Trance angles make it easier to weave between pads and still produce a beautiful design.

Create a ground plane

The shared ground is aimed at gauging voltage to give all your traces a single orientation, particularly in analog circuits.

Designing a circuit board

Schematic capture

The schematics show things such as components that are used in your circuit board design, how components are connected, and the relationships between groups of components in various schematics.

• Not only is circuit interconnectivity easier to describe and control, but adapting a schematic to a board layout is much easier than designing directly on the board.
• However, one can design own schematic symbols and form a footprint.

Create a Blank PCB layout

After creating a schematic one should use a schematic capture tool to import components into a blank PCB layout.

• If PCBs shapes have already been determined one can set them.
• Schematic data is made obtainable for the PcbDoc by compiling the SchDoc the process verification of design and generation of several project documents that allows one to inspect and correct design before transfer to the PcbDoc

Synchronize Schematics to Your PCB

All the tools in Altium Designer work in a united strategy environment, where the schematic, printed circuit board layout, and BOM are interconnected and can be accessed instantaneously. Other programs force you to manually accumulate your schematic facts, but Altium Designer will do this for you automatically while you create your design.

Designing Your PCB Stackup

Upon transferring one schematic information to the PcbDoc the component footprints as shown in addition to the board outline specified.

• Once you are working on a high-frequency design you can use the built-in impedance profiler to ensure resistance regulator in your board.
• Routing style should be decided before you start calculating impedances despite using differential pair routing design the impedance solver in the layer enables differential pair of the solution not forgetting single-ended to determine both requirements while routing.

Defining PCB Plan Rules and DFM Requirements

There are various rules of PCB design hence there is no need to use all these available rules hence you can select and deselect various rules by clicking on the rules from the list in the PCB Rules and constraints editor whereby categories are divided into:

• Approvals between objects in the PCB design, such as between traces and pads
• High speed and signal integrity limits such as overshoot
• Board fabrication limits and clearances such as edge clearance

One can create ne design rules by following the rules of Altium designers design wizard which treats your custom design rules just like the built-in design rules. Upon placement of components, drill holes, and traces designer will automatically check out the layout against these rules and thereafter flag you visually upon notice of violation.

Place Components

Altium Designer provides a great deal of flexibility which allows quick placement of components on your circuit board the items can be arranged manually or automatically these options can be used jointly to take advantage of the speed of auto-placement and ensure that the board is laid according to good component placement rules.

Insert Drill Holes

Drill holes are placed before rioting of traces. If the design is complicated there is a need to modify at least some of the via locations during trace routing, the preferences should be guided by the design for manufacturing (DFM) specifications of your PCB manufacturer.

Route Traces

Upon placement of component and mechanical elements, one is now in a position to route the traces. When routing aboard, one should arise with a strategy to finish significant routes first thereafter fill gaps with the remaining connections ss required. Among the important routes include power nets, impedance-controlled nets, and any noise-sensitive nets such as low-level analog signals

Add Labels and Identifiers

Addition of labels, identifiers, markings, or imagery to the board upon verification of circuit board. its good to also include reference designators for components as it assists in PCB assembly. The issue of polarity also should be kept into consideration for indication. The elements should be placed at the top overlay or bottom overlay layers in the PCB layout

Generate Design Output Files

This is done through a design rule check (DRC)for verification of circuit board layout which is done automatically by Altium Designer once the board has passed the final DRC there is a need to generate design files for the manufacturer to be clear on what to use. Using a systematic approthathich ensures that all aspects of your design are accounted for inherently whereby during the process there is minimal need to retrace the steps

Uses of PCB

• PCBs were used as insulating fluid in capacitors and transformers and also as hydraulic and lubricating fluids.
• They are also used in industrial electronics such as power equipment, Industrial Equipment, and control systems.
• They are mostly used in electronics and communication devices such as mobile, recording devices, entertainment systems, and computer electronics.
• In research and development, PCBs are used in testing machines, control boards, and scanning machines among others.
• In aerospace and defense, PCBs are used in monitoring types of equipment, security devices armored car satellites among others.

Mistakes to avoid in PCB design

The printed circuit board is the heart and soul of every electronic circuit it is the basic in the control of the cost of manufacturing costs can increase due to the mistakes made in the design phase some of the mistakes to be avoided include

Wrong trace geometry

The traces are responsible for the transmission of electrical signals between colorful factors of the circuit putting into consideration the speed, intensity, and frequency of the signal

Inadequate layout

Due to increased demand for small PCBs, the designers are forced to use components with smaller footprints and reduction of the distance between components. to ensure the desired functionality it’s important to adopt a layout suiting needs of particular circuits

Wrong position of decoupling capacitors

The capacitors are required on the PCB to supply power supply lines for a stable power supply free from transients to all the board components

Landing pattern errors

Landing pattern is the size of pads for each component which should have an area larger than the corresponding footprint even the slightest error in the pad-to-pad spacing can result in fatal soldering during the manufacturing process hence resulting in misalignments between components and PCB.

Over-reliance on the automatic routing

Automatic routing occupies a greater than desirable area of the PCB hence creating larger holes than those that could be achieved through manual routing.

Incorrect antenna layout

If PCB includes antennas for wireless communication should be very careful not to make layout mistakes hence impedance is adapted between the transceiver and the antenna.

Insufficient revision of the project

Periodic reviews of a project allow one to verify the conformity with the requirements of the project. this allows designers to avoid on advance errors that may fail the PCB

Advantages of the printed circuit board

PCBs are easy for diagnosing errors and repairs.

Compact size and saving of wire

PCBs have the capability of holding a large number of components which may be very small in size and therefore impossible to connect through wiring. PCBs help not only in connecting all the components through the copper tracks instead of wires hence making them intact.

Saves time by use of printed circuit board not only takes lesser time but also very convenient.

Ease in reparability in cases where PCB stops functioning correctly the problem is easily identified and repaired as all components are labeled using silkscreen.

It reduces the chances of short circuits the connections are made all through copper tracks hence a lesser chance of losing the connection that can result in short-circuiting the board.

There is less electronic noise is released in form of heat or radiation since the lengths are minimized since there is less emission of EM waves and radiation.

Lower cost since PCBs are mostly computerized systems hence saving layout of the schematic design.

Reliability PCBs ate very reliable as they are strictly checked for any errors as the process is fully automated.

Disadvantages of the printed circuit board

Damage is difficult to repair

Upon damage of PCBs, it’s nearly impossible to repair when damaged since there is only a single plate upon which all the parts are attached. It’s easier to replace a PCB rather than to repair it.

Not all machines can use them

A PCB should be designed in a way that should be compatible with the device since it is not automatic that the PCB will be compatible with the machine. They are also not for every situation or every type of device.

Etching is a great process for the board and is not eco-friendly hence not good for the planet as it uses chemicals hence producing negative effects on the environment.

In case one wants to modify the board after it is printed one is not able to and has to create a new board from the scratch.

It also uses a complex assembly process.

In the case of double-sided printed circuit boards are not ideal for conducting heavy current since the copper wires get heated up.

CONCLUSION

With the increased use of printed circuit boards, there is an increased need to familiarize ourselves with the basics of the PCBs as they are inclusive of various components such as resistors among others. In the design of PCB, the various stated factors should be kept into consideration for proper functionality. The impacts of the formation of PCBs should also be taken into consideration to avoid negative impacts.

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With the existence of the fourth industrial revolution, the Internet of Things has grown and evolved into a most significant movement from the birth of the dot-com. Internet of Things and its effects has been deeply woven into the framework of technology and daily life. Most consumers might not realize that Internet of Things Printed Circuit Boards are at the forefront of the internet of things infiltration into everyday tech and that the internet of things is playing an integral part in a shift in printed circuit board design and their manufacture. The demand for internet of things devices is rising each day. This makes the understanding of the interconnections between the IoT, flex, and HDI PCBs become increasingly crucial for printed circuit board designers.

This article will have a detailed look at the printed circuit boards and the internet of things. Everything that needs to be told we will have in this article.

What is the Internet of Things?

• Internet of things is the crossover between the physical and the digital world which is brought forth by the creation of other than PCs that connect to IP networks. The best example of an IoT is the smartphone. It is the most prominent but recently, apps that are controlling home utilities and appliances have been developed. There has been also the introduction of wearable tech and vehicles with data accessibility that are proving the potential of IoT being limitless.

• When it comes to IoT command for revolution, consumer electronics might be the first innovation that comes to one’s mind. However, the manufacturing, transportation, and health industries will top even personal cars and electronics for their command in the IoT revolution. As such, these large-scale industries need innovative printed circuit board design that gives flexibility and high-speed connectivity to streamline the processes on a global scale.

The Main Pillars for PCB Design in IoT Products

PCBs are currently found in a great percentage of IoT products, they are the core components. For one to have successful Internet of Things products they require well-designed printed circuit boards.

Therefore there are 4 main pillars for printed circuit board design that amount to successful Internet of Things products. The pillars are discussed below;

1. Form factor

Currently being the prior days of the Internet of Things development, there is already a good number of various form factors found in markets. Check out the comparisons between Philips Hue lighting, Ecobee4 Thermostats, Fitbit smartwatches even Ring doorbells.

With the form factor, there are challenges that one should take care of while selecting the form factor. They include;

• Lightweight: Most Internet of Things products are for consumer use and most users want something that is not heavy for them.
• Miniaturized: Internet of Things devices are designed to be carried anywhere and therefore they have to be very small in size as possible.
• Hard-wearing or ruggedized: You will realize that some of these products are designed for rough and tough uses hence they operate in very extreme conditions. Therefore, you have to design something capable of overcoming such
• Ergonomic: if you are building something that needs to be worn by the consumer again it should be very comfortable for them.

To overcome the above challenges, it is recommended and advisable to use these practices –MCAD/ECAD.

Why does MCAD/ ECAD collaborate?

Electrical and mechanical engineers must be great mates while working on the IoT product. When any change is experienced in the electrical it affects mechanical design, that’s why alignment should be maintained in every single step.

Working together is key if your device operates on battery. Consumption of power can be very demanding and hence the thermal output from the processors and the microcontrollers should be kept always in check. One needs to undertake a thermos-airflow simulation, which can only be achieved through MCAD tools. Take for example, if there is a manufacturing process of an IoT device that produces a lot of thermal output at maximum achievement if the collaboration between mechanical engineers and electrical engineers takes place mechanical people will help in the performance of simulation of the airflow that will ensure the design will minimize overheating.

Leveraging multiple board designs

The old horizontal printed circuit boards are not well suited to be user-friendly and miniaturized Internet of Things products.

• If a designer takes the advantage of the multiple PCB designs seriously, they can overcome the challenges of form factor.
• Among the approaches is building tinier modules and stacking them to reduce the general horizontal footprint.

2. Connectivity

There is the availability of so many wireless technologies that can be chosen when trying to come up with an internet of things product.

• The kind of connectivity that you choose will always determine the power utilization, certification, compatibility, and many other things.
• You are interested in making connectivity into account when making the architectural stage and the early you choose the right and best technology the safer you are.
• That means deciding if you require Zigbee, wifi, and Bluetooth.
• All the decisions that you come up with will have a perfect impact on the range and data rate of your internet of Things devices making the right decision is very important.
• The below layout practices which happen to be so common can help you ensure that you come up with an IoT product that is less affected by the noises;

1. The analysis of the power: the power consumption will have a fluctuation during the given period and therefore, you should come up with a way to ensure that that can be measured and have a formula that will ensure that the fluctuation is well catered for. Ensure that you come up with a projection of the required power over the lifetime of this product especially if the product is powered by a battery.
2. The stack-up of the PCB: this ae very necessary when it comes up to the RF performance and the thermal conductivity of the product. Ensure that you take a lot of time when trying to come up with the stack-up to ensure that you can avoid the problems associated with power delivery, signal transmission, and antennae feed.
3. Process of grounding: the ground surface is always limited for the tiny devices and therefore a lot of care must be taken so that proper grounding can be provided for better heat dissipation and RF better performances.
4. The stitching of the vias: when via stitching is done efficiently, we expect proper returns of the current and a great reduction of the interferences from noise. When it is well combined with the grounding process, you will have an effectively reduced noise and you can easily achieve high performance for the RF design being made.
5. The performance of the antenna: when doing the selection of the antenna directivity, form factor, orientation, and gain is very significant.

3. Cost

The price of the internet of things product that you have designed will always depend on the complexity. Let us take the following examples of how to frame our cost design challenges:

1. Research & Development: the time taken in the process of research and development will always depend on how complex the product is and it should take between months and years.
2. MSRP: ensure that the selling price of your product falls in the right price range which could be determined by the complexity and the functionality of the same product.
3. The certifications: sometimes the IoT products certification can prove to be so expensive here you could find yourself spending over 20000 dollars to fully protect and certify your printed circuit boards.
4. The non-recurring engineering fee: this is the money that is always used in the setting up of the production process. This usually involves the contraction of the manufacturer which may take a very long time to process.

Design for Manufacturing and Assembly

You are supposed to start planning with your CM at an early stage of your product development so that you don’t get surprises when the production process begins. The proper planning before manufacturing will hold the CM not to increase the production prices due to requests that are made at the last minute and in a hurried manner. The assembly and the production costs can be lowered also through:

• Reducing the number of the components used: ensure that you reduce the number of the components that would be bought in bulk.
• Building of the standard components: it is very easy to assemble parts that are common and when the common parts are used in the production lines, it is very easy to lower the costs of the production of the PCB.
• Relaxing designing tolerance: given design will always need strict adherence.
• Leveraging plastics: most electronic products will make use of metal materials for support purposes. If it is possible to make sure that you make a replacement of the metal parts with cheaper plastics.,

4. MARKETING TIME

When you are the first person to market your own IoT product can be advantageous to you for you will have the ability to establish your market base before other competitors come in.

Key Takeaways for Successful PCB Design in IoT Products

There is a lot to have in for each of the above pillars of successful PCB design. If one needs to start or focus on the path of the Internet of Things hardware development they should keep the following points in mind;

• They should do everything they are able for them to choose the right technologies earlier or in the prior stages.
• They should keenly collaborate with MCAD and ECAD and maximize this collaboration.
• They should always design for manufacturing and assembly.
• Always plan early for their certifications and manufacturing.
• Ensure they have shortened the design feedback loop and always do the testing early.
• They should know mistakes that happen will always consume time and will be costly.

Printed Circuit Board Applications That Are Controlled By IoT

PCBs are now in control of electronic devices and have ensured that electronics offer the IoT capabilities that are mostly available in smart applications or even on smartphones screens in vehicles’ dashboards. Also, the internet of things is still influencing the design of PCBs and apps to meet the high demand for new ways of utilizing the internet which include;

• Cameras and sensors in automobiles and residential applications to offer higher levels of convenience, efficiency, and proper security.
• Fitted trackers with data being analyzed away from the client.
• Color-changing bulbs that can create self-satisfying moods for various rooms, these can be managed from smartphones or even small smart devices or tablets.
• In shop centers or even amusement parks there are grid layouts.

Printed circuit boards have made almost every new or proposed idea to be possible, from the monitoring of train arrivals times and its maintenance schedule needs to creating reliable transportation schedules or even tracking real-time traffic which navigates through the car dashboards

Internet of Things Opportunity in the area of Flex and HDI Printed Circuit Boards

In the early computer and technology days, the shape, weight, and size of the computer depended on the inner components’ structure. Years later, technology has evolved and the industry is now all about the creation of optimal Internet of Things products that can function similarly no matter the form it undertakes. This has made it crucial to rethink the internal schematic to reflect this progress in methodology.

The functionality of the new form aspects of printed electronics is at the forefront in making sophisticated production possible. Flex printed circuit boards and HDI printed circuit boards ensure there is freedom for design, cater to very high-power demands in raising fastening printed circuit board spaces, and are suitable where electromagnetic interference is intense. This also offers tensile strength.

Flex PCBs and IoT Benefits

• Small size: Rigid PCBs being bulk limits freedom designs but they also tend to require too much space within the PCB. Flex PCBs occupy a small volume, this allows components like microphones, and batteries all to fit in a tiny package without disturbing capabilities for performance
• Great resistance: Material used in flex PCBs give improved durability, increasing their ability to resist stress caused by electromagnetic interference
• Clear wiring routes: Wiring methods have been simplified by flex PCBs with their abstinence of mechanical connections.

Materials used by flex PCBs are flexible and open up a world of opportunities for mobile gadgets and moving parts, this makes the undisputable tool for a wide range of IoT applications.

HDI PCBs and IoT Advantages

HDI is an indispensable tool for the tiny packaged PCBs we see in many electronics today. While facing the bigger picture of IoT, fabricators should consider the advantages of HDI boards, which includes their reliability and speed. The aspects they should put the effort into include;

• Reduced weight and size: HDI PCBs are commonly known for dense component holding capacity. They are identified with their small trace size and high density of the wires. Great courtesy of stacked micro Vias and other characteristics which help save the space on the board. Having a small board translates to a great application, making them perfect for use with the changing strategies in the field of IoT.
• Clean circuit route: High-density interconnect PCBs provide a versatile routing option, this is highly influenced by blind vias or buried Vias and micro Vias which forms the smooth dense parts of the circuit. This makes it possible for IoT optimization due to the small space performance of HDI printed circuit boards.
• Improvement of cost-effectiveness: Reduced layering and higher energy efficiency lead to a more cost-effective product to produce and implement.

The Changes in the Internet of Things PCB Design Process

The procedures and process of making IoT products start with the evaluation of the new form of possibilities and out of their transition into the stages of selecting printed circuit boards layouts and materials. The requirements for assembly into a finished product need to be considered throughout the product design flow.

The main aspect of industry rattling of IoT is a crossover between an electronic and the mechanical, between a product itself and its printed circuit board form.

CONCLUSION

Internet of Things Design Tips and Recommendations

While designing a printed circuit board that is perfect for IoT, one will come across a few key areas of design to pay attention to. Some of the areas with tips that help in making a PCB ideal for IoT include;

• Size requirements: Bigger devices are getting smaller. Printed circuit board designers no longer have extra PC board layout space in their routine placement of traces and tracks, components, and Vias. Currently, great flexibility and functionality in small areas are made possible via high-density interconnectivity and rigid-flex PCBs. With these tiny forms, it is important to ensure all IoT products are on the same stage from the very start of the design.

• Product fitting: After the size of the board, one will wish to do much prototyping virtually to ensure they easily include the shapes of their design into the IoT form it is intended for. Circuit boards in IoT will at some point fit on non-functional materials for better functionality, and one might find themselves opting for a plastic component in their designs that they never expect.

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The process of implementing ideas into concrete forms from written materials to digitalized forms by design teams is referred to as prototyping. With this process, one can improve and confirm their designs so that the right products are released. There are various ways of prototyping: rapid, competitive, parallel, and iterative. A good example of prototyping is the development of new of a robot. Prototyping is the transformation of a concept into reality.

On the other hand, the revolution PCBCBs designs have been enhanced by rapid prototyping. In a world full of competition in manufacturing electronics, speed is of the essence! The faster a company develops a concept stage to product, the more success is likely.

Rapid PCB prototyping

These are the methods of creating a prototype of a product quickly. The final product can be verified by these methods. A manufacturing approach is required in addition, unlike the subtractive approach which requires considerable rework. 3D printing technology enables the creation of product replicas by the addition of material layers. This is done by designers. STL file is converted from CAD file format which can be used printing 3D and hence prototyping.

Types of prototyping

• When it comes to prototyping thee major techniques are used. The most popular is additive manufacturing which is closely related to 3-dimensional printing. When you start with a block of material, trim or cut and grind the material until you form your product is called subtractive manufacturin Starting with a liquid material or semi-solid material and forcing it to the required shape after solidification is called compressive manufacturing. When dimensional accuracy is critical, computer numerical control (CNC) rapid prototyping is usually the best option for simple or metal parts.
• Additive manufacturing is popular because it is generally easy and it saves on cost. Its flexibility allows one to make adjustments throughout the process because aspects of the prototype can be added or subtracted until the final product is achieved. Another type of 3D printing is the stereolithographic apparatus (SLA); it is used for complex designs, the concept of models, and cosmetic prototypes. Stereo-lithography can make parts with designs and intricate angels with an excellent surface finish unlike the other types of additive manufacturing. Another type of additive manufacturing is selective laser sintering (SLS); this uses a nylon-based powder that is fused by a laser to form the final product. This process can be repeated until the product is created. The difference between stereolithographic apparatus (SLA) and selective laser sintering (SLS) is that selective laser sintering (SLS) can stand up to test better than stereolithographic apparatus (SLA) while stereolithographic apparatus (SLA) can produce a perfect finish compared to selective laser sintering (SLS).

Advantages of the rapid prototyping process

• Test of products

Verification of a product is of major importance in 3D PCB prototypes. Errors and expensive mistakes can be detected and necessary steps can be taken in time. Designers enjoy greater freedom to break manufacturing rules which are intrinsic in PCB manufacturing due to reduced development time.

• Cost economization

Optimization of cost is a result of technology. The affordability of 3D printers has enabled startups who are having limited budgets. One can improve the product before final production due to the quick realization of the product.

• Diversity in working materials

The addition of materials will increase the layers and the doubling prevents the board from limiting the circuits. Essential materials necessary for production are used in 3D circuit board manufacturing.

• Speed

Compound designs will consume a long time and extra cost but the speed can be improved. Development can reduce from weeks to minutes.

Steps Used When Prototyping

• Design

The first step is coming up with a design. There are different software that can create different designs.

• Schematic design

This includes important information that engineers and manufacturers will use in the process of production. All the requirements of production are included here.

• Bill of materials

All the materials and a list of gadgets necessary for production are detailed in this section.

• Routing design

The procedure is important since this is what will be used to connect the PCB. Factors such as signal noise, power level, and signal noise among others should always be considered.

• Checks –The design should be checked on regular performance issues. Evaluation should be made before moving to the fabrication phase
• Photo creation- This is done by use of a printer known as Plotter for every layer and solder mask of the board
• Print of inner layers

In this stage, the copper is up to the substrate material. It’s hardened using UV light.

• Layers alignment-This is done to multiple layers and ensures accuracy in registration holes. It’s difficult to perform correction of inner layers once they are combined.

• Layer fusion –The step of fusing the layer involves two stages that are: bonding and layer-up. The prepreg layer is placed over an aligned basin, the substrate layer is then stacked, more prepreg, copper sheet, and aluminum foil. These layers are fixed into pins on a steel table. The process of heating the stack is controlled by a bonding press computer. To get a PCB we remove the pressure plate and the pins.
• Holes drilling –Holes are drilled into the stack which will be used to add components. The drills are controlled by a computer that uses air-driven spindles with 150,000 revolutions per minute. The process can take a while despite the drill moving quickly.
• Plating the copper -Depositing a layer of copper is done using a chemical bath about one micron thick on the surface of a panel and the interior walls of the holes. This process is precisely controlled by computers.

• Imaging the outer layer -Another layer of photoresist is applied to the panel to image the outer layers with the PCB design. This process is creating an inversion of the inner layers and is similar to the one used earlier.
• Plating copper and tin -Another round of copper plating is done. The photoresist layer confirms that the desired parts of the boards are deposited with copper. The board is then platted using tin which protects the copper during the next stage.
• Final etching -Any excess copper is removed by a chemical solution, while the tin guards the copper that creates the conductive surfaces. Once this is done, the conductive connections are confirmed.
• Application of solder mask –The panel is then cleaned and an epoxy solder mask is applied. UV light is passed on the board, this hardens the film. Unhardened or covered parts are then removed.

• Application of surface finish –More plating is then deposited, in most cases silver or gold is used. To ensure the pads are uniform we use hot air leveling. The surface is then finished.
• Applying silkscreen –This is done using ink-jet writing which conveys critical information about the board to the surface of the PCB.
• Cutting –Once the final electrical test is conducted to confirm the board functions as expected, the board is separated from the larger panel using either a v-groove or a router. The boards can easily be popped out of the panel.
• Sourcing –For the preparation of the PCB assembly prototype stage, the source of all the components is required.
• Assembly –The next step is printed circuit board assembly, PCBA – in which the required components are placed on the board.
• Solder paste stenciling –Solder paste is applied to the board, this mixes with flux which helps the solder to melt thus bonding with the surface of the PCB. Stainless steel is placed over the PCB to ensure that the solder paste only applies to the areas where components will be in the finished PCB. It is evenly spread to the open areas. The stencil is then removed thus the solder paste is left in desired locations.
• Pick and place -A pick and place machine is used to place surface mount components on the PCB. The non-connector components are placed on top of the soldering paste in preprogrammed areas.
• Reflow soldering –The solder paste is solidified in this process, where the surface mounts are attached to the board. The PCB is placed on a conveyor belt that moves the board through a reflow oven. A series of heaters that slowly heat the board is placed in the oven. The temperature is reduced gradually when cooling and solidification take place and permanently attach the surface mount components to the board.
• Inspection and quality control –There are various ways of conducting an inspection such as manual checks, automatic optical inspection, and x-ray inspection. This is done to ensure there are no errors or risks.
• Conducting a functionality test-This stimulates the normal operating conditions that will be exposed to the PCB. This is the last step.

RAPID PROTOTYPE AS DESIGN

A new twist to the traditional prototype as the design process has been added by the recent coming of the latest rapid prototyping, computer-aided manufacturing (CAM) and computer, computer-aided design (CAD), and computer-aided engineering (CAE) technologies. The transformation is from prototype design to a rapid prototype design process. Engineers are now able to perform complex finite element analysis (FEA) calculations on their results; they can also test any structural or thermal problems and even simulate how plastic may flow through an injection molding tool during production with the help of new generation tools. Physical prototypes play a major role in product development as they are a means of revealing scale and realism in a way that paper drawings, and even computer 3D models, cannot. The translation of three-dimensional representations from two-dimensional is an important stage in product development.

The reliability of a physical product can be effectively achieved by a three-dimensional physical model. There is always a huge difference in perception between a user seeing a traditional Computer-aided design model only and then seeing a real physical working model.

Rapid prototyping accelerates the design process

Designers have been using rapid prototyping as a tool for over a decade, there has been an improvement in the technologies behind it. Traditional modeling techniques however have been replaced by these technologies in the final stages of product development to manufacturing. The earlier design process affects the potential for 3D modeling greatly where the superior designs are embraced while those which hinder development are laid down.

Product development can be greatly accelerated if rapid prototyping is properly used, this may lead to high quality and defect-free products. The conceptual modelers, 3D printers, and desktop modelers known as regeneration of rapid prototyping tools, fortunately, are much faster than the earlier versions. The engineers use them in office environments.

Tightening up the front end

Engineers can shorten the design cycle by the use of rapid prototyping; a prototype that would have taken a week without it can be made in 2 hours. Time-saving is of the essence on a percentage basis, but the week saved is inadequate comparing it to the 12-month development cycle save time, the process of product development will need to be updated by the managers and engineers to reflect the strength of next-generation rapid prototyping tools. Examining the lowest parts with an eye will assist in applying rapid prototyping ability to radically accelerate these activities. Most time is spent on approving the concept; companies need to save time at this stage.

Delayed decision making

Earlier stages consume a lot of time in deciding what action to take because relevant parties may not have a common base of communication. At a time the identity of the relevant parties remains unknown.

Lack of common decision-making channel

Those involved in an important decision such as marketers, manufacturing staff, or engineers might not have the same access to product information.

Poor communication

Investigation of the design process has too many or few possibilities of being investigated. It was recently found by a sensor company that the different sectors of its design team, which differ in geographical location, were each undertaking ideas deftly incompatible with other firms. The different branches grew apart for several months, it shocked two of the three groups when they were forced to redesign so that they would be compatible with the third.

Lack of consensus

Disagreement may occur among those involved in the design process on the way to follow. Most developers design strong ideas about a product to be considered. They are then constrained to debating relevant benefits based on computer-aided design drawings and 2D projections. A third party which in this case is the customer cannot be brought into the discussion to settle the argument because they usually don’t know drawings or projections. The process is then left for personal opinion; this may lead to the end of the project.

Rework and changes in the direction

Critical errors mostly end up unnoticed in digital models for weeks and can appear in the final stages of production. This may lead to reworking the whole project.

Difference making with the prototypes

Evaluation of tree-dimensional design is equally performed by the designers, managers, marketers, and manufacturing staff. All the different teams can touch, see and handle the model just like the esteemed customer will. Some companies go the extra mile by including the end-users in the process; use prototypes. Disciplines, spanning distances, and clarifying communication are done by the prototypes.

Rapid typing advice –

This is done to shorten and improve product development. Some of the suggestions, for helping other firms change their model styles or maybe improve them to take advantage of the rapid prototyping are found here.

Revolution of PCB design

Revolution is necessary when it comes to printed circuit boards. Designing tools must keep pace with the fast-changing technology; revolutionary is highly embraced by the PCB designer tools. PCB designers experience extremely difficult signal integrity challenges, thanks to innovations such as the multi-gigabit serial data-streaming technologies like serializes/deserializes (SERDES). Designers are likely to struggle to meet their timing requirements if their toolset is not up to speed.

With the ongoing trend towards the higher pin, all of the above can be combined to create an environment where PCB designers must have the right tools for the task at hand. There are different challenges facing PCB designers and they are handled differently by the design tools. They include:

Need For Speed

• Engineering is required in extremely high signal speeds drive throughout the board design process. Modern processors need modern buses and those buses carry very fast signals. A good example of a simulation tool that can handle the high-speed challenge is Cadence Allegro PCB SI 630.

• On a desktop it can simulate up to 10 Kbits/s and 1 Mbit/hour. This means that on a single day, it can run through multiple full-board simulations. Memory access is another speed issue, this makes the life of PCB designers difficult. Circuit designers are planning to move to double data rate (DDR) from SDRAM; current designers mostly make use of DDR2 with access rates of 800 MHz, it is clear that consumer electronics continue to favor DDR3.
• Increased adoption of advanced memory technologies and high-speed buses drives designers to become experts in signal integrity. In the past, what were termed “extremely exotic” board design elements came into existence. Technologies such as buried Vias and blind embedded passive components, made flex circuitry drop their niche tags. They are now part of designers’ tools thus designers must ensure their toolset can manage this technology efficiently.

A Holistic Approach

• The combination of large pin-count devices like field-programmable gate arrays (FPGAs) and high speeds pushes designers and EDA vendors toward taking a holistic view of the components they carry and the PCBs. The board designers are presented with a different scenario of the malleability that makes the field-programmable gate array (FPGAs) such a useful tool for designers.
• PCB/FPGA co-design is supported by Altiums designer 6.0. This enables the designers to fully exploit FPGAs as a system platform. FPGA pins are often assigned without regard to board layout; this is a major barrier for board designers. Additionally, board routing can wreak havoc with the dense packaging technology in large-scale field-programmable gate arrays (FPGAs).
• The idea of dynamic reassignment portrays an important feature of Altiums designer6.0. Field programmable gate array (FPGAs) pins can be swapped on the fly during PCB routing with this feature. Pre-routed subnets are dynamically reallocated by the tool and swap linked differential pairs of the signal.
• Combination of an automatic field-programmable gate array (FPGAs) pin-optimization engine with dynamic net reassignment, 6.0 enables designers to take full control of field-programmable gate array (FPGAs) pin programmability to optimize the routing of board-level

It’s important to take note that the recent IC package is becoming more like PCB.

Melding Design and Test

• Broadening the functionality in the design tools may be an added advantage to the PCB designers. The workbench design suite which is the latest release embodies national instruments response. The 9^th version of the suit aims at breaking down the artificial partitions between the benchtop, part selection, and desktop design work by faking tight integration between Lab View and version 9 of multiuse.

The Perils of Placement

• Today, the placement of components is among the top vexing aspects of PCB design. This is because, in the course of system design, the component net assists changes mostly. PCB design is similar to other aspects of system design; this makes it a global affair. Collaboration is necessary from all the design teams all over the world.

CONCLUSION

Rapid prototyping has revolutionized printed circuit boards. The direction of PCB design tools is seen. To fill the changing needs of designers, these tools must revolve. The improved computer-aided design (CAD), computer-aided engineering (CAE), and computer-aided manufacturing (CAM) technologies as well as the growth of low-cost rapid prototyping have facilitated the evolution of rapid prototype designs. Designers can produce high technology products at an increasing rate due to the emerging and existing technologies in the new product development process.

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A Printed Circuit Board (PCB) is truly an important aspect of electronic items that are applied in practically all components in various fields, from little to enormous, from PCs, broadcast communications to military equipment. PCB assumes a huge part in executing elements of electronic items.

However, it’s never a simple errand to design a circuit board. Relationships, between layers, parts, or hardware, must be appropriately managed. Despite the difficult trait of PCB design, a few issues that regularly happen can be summed up so that PCB designers can get to know them ahead of time and figure out how to manage them before the PCB manufacture stage.

In this article, we are going to discuss the following;

• Complexity in PCB design.
• Common PCB design software.
• What to consider when designing an ideal PCB.
• General challenges in the PCB design process.
• PCB Design Factors Affecting its Assembly.

Is designing Printed Circuit Boards Difficult?

Printed Circuit Boards’ design technology is constantly evolving with new complex designs moving into production. Thanks to the rapid advancement that has led to PCB designs that are powerful yet small in size. The demand for more modest and powerful gadgets has driven designers out of their comfort zone. Only skillful and clever PCB designers can comprehend the application needs of the Printed Circuit Board and propose changes or upgrades to the design of equipment.

PCB designing, Rewarding Career with Excellent Prospects

• Printed circuit board designing is a difficult and comprehensive industry. However, today is quite possibly the most rewarding calling.
• One of the new PCB design industry reviews shows that laborers in this industry are getting high salaries out of more significant compensations and rewards, expanded benefits and education opportunities, bigger staff numbers as well as better employer stability.
• All in all, the possibilities, concerning PCB designing, are fantastic. In addition, rigid, flex, and rigid-flex printed circuit board producers all around the world are searching for youthful designers for an enormous scope.

• The statistical analysis confirms that around 59% of Printed Circuit Board designers overall are beyond 50 years old, and with regards to the US, the numbers ascend to 66.5%.

• Nearly half of PCB designers fall between age 51 and 55 while 18% are under 40. This implies that the business is maturing, and a bigger number of designers are close to the furthest limit of their profession.

• More opportunities will therefore be available in the coming years in the PCB design industry. There are several opportunities for young and new designers around the world.

If you are fascinated with complex electronic circuits, then you belong in the PCB design industry.

What to consider when designing an ideal Printed Circuit Board

With regards to the manufacture of customized printed circuit boards, the 1^st thought anybody considers is the different types of custom PCB designs to browse.

However, for a knowledgeable individual in the PCB creation and customization process, it is vital to recognize that it needs to be thought of factors and not the kinds of custom PCB designs.

The kinds of PCB designs like double-sided, single-sided, rigid, flexible, rigid-flex, HDI, and so forth are significant considerations.

The determination of the type of PCB design is essentially affected by a few elements. This section will acquaint you with significant elements that impact the determination and execution of types of custom PCB designs.

Challenges in the Selection of Custom Printed Circuit Board Designs

Regardless of the type of PCB being manufactured, certain challenges might force limitations on creation. The contemplation of the following elements will limit or avoid restrictions on the manufacture of various types of custom PCBs.

1. Types of Interconnect:

• The custom PCB plans are becoming minimal with progressions in technology. It requires the utilization of small spaces by placing components in a confined space without imperiling productivity.

• In specific cases, generally, HDI (High-Density Interconnect) PCBs are taken on. This permits the packing of parts on a PCB for elite execution.

• Notwithstanding, the interconnect construction might hinder design as interconnects may go through edges, drills, and so on which in the long run impacts the adaptability or part mounting in double-sided PCBs

2. The Kinds of Vias:

• Vias are the associations/connections between the parts. These metal lines associate the parts and communicate the signal starting with one part then onto the next.

• In the customization of various types of PCBs, different vias types are taken on. For the board design types like single-sided or rigid PCBs, direct vias can be picked.

• Nonetheless, these direct vias may present limitations for rigid-flex and HDI sorts of PCBs. In such cases, buried or vias- in-pad are picked. For high-density, high-frequency PCBs extraordinary types of vias are picked.

3. Stack-up Parameters:

• The layer stack-up is a significant element in choosing a PCB plan. Regularly for multi-facet boards, the drill design, number of layers, the material of the substrate, and so forth, sway the design boundaries of the PCBs. Hence, these elements should be selected cautiously.

4. Drill Pattern:

• It is the design of openings made to embed part leads. The drill example ought not to have any drills on the edges or twisting locales of the board.

• On the off chance that the drill design is mind-boggling, the adaptability or format of vias might be limited which in the end impacts on types of custom circuit board designs.
• Alongside these previously mentioned factors, a couple of more factors need to be thought to guarantee the exhibition and productivity of the chosen type of circuit board design.

Exceptional Considerations

Considering the accompanying elements helps in enhancing the nature of PCB creation.

• Pick the plan that offers dependable and strong execution.
• Select dependable PCB manufacture, assembly, and testing methods.
• Decide on sans lead PCBs plan and advancement process assuming RoHS consistency is required or in any case.

Now that every one of the variables past the types of custom PCB plans is examined, it is suggested that you put resources into top-notch PCB creation companies from trusted dealers.

Printed Circuit Board (PCB) Design Factors Affecting its Assembly

The assembly process of PCB depends on the creation information of a PCB design and the specs of PCB manufacture. The great PCB configuration will work with ensuing PCB assembly handling, while the deficient design will influence the handling system and even influence the nature of the last PCB assembly item. So what are the PCB configuration factors that will influence PCB assembly handling/processing? Here are a few issues that PCB designers need to pay close attention to.

1. The soldering position should have no silkscreen. This will influence the assembly quality by forestalling solderability.

Image: Wrong PCB design that silkscreen on SMT PAD

• In any case, constantly the silkscreen sign of basic ICs is essential because it tends to be utilized to distinguish the deviation of solder quality (particularly for some high valuable QFN parts).

• Therefore the IC’s edge imprint can be put at the edges of the SMT region to abstain from any covering issues to soldering PAD.

Image: IC edge marking to prevent silkscreen on SMT

• The base distance between the copper foil and board edge is 0.5mm, the base distance between part and board edge is 5.0mm, and the base distance between the pads and board edge is 4.0mm.

3. Important of Fiducial imprint and Tooling openings:

• Fiducial imprint (red bolt in beneath picture) is important to be put in single PCB or board.
• It is utilized on assembly machines as the reference position for a paste printing machine or a pick-and-spot machine to guarantee exact electronic parts patching activity in the PCB assembly process.
• Normally the base distance across a roundabout fiducial imprint is 1.0 mm with a 3.0mm solder cover opening region.

• cooling openings (pin bolt in the above picture) likewise is a non-plated opening, which is with typical size 3.0mm with the amount of 3pcs basically to be put on the circuit board. This is used to fix the Printed circuit board for not unreservedly development during PCB in the creative interaction, for example, electronic test cycle or blueprint profile process. These are fundamental openings for accommodation to the PCB creation and assembling process.

4. While planning the twofold-sided board, focus on the parts of the metal shell. Whenever the shell is in touch with the printed board when DIP, the bind cushion on the top layer can’t be opened, and it should be covered with weld veil oil or silkscreen oil.

5. Try not to put the jumper track under the IC, engines, potentiometers, or different parts with enormous metal shells.
6. There should be no copper foil (aside from establishing required) and parts (or as expected by the primary drawing) inside 5mm of the screw opening span.
7. Electrolytic capacitors would not touch be able to warm producing parts, like high-power resistors, thermistors, transformers, radiators. The base distance between electrolytic capacitors and radiators is 10 mm, and the span between different parts and radiators is 2.0 mm.

7. Huge parts, (for example, transformers, electrolytic capacitors with a breadth of more than 15mm, attachments with enormous flows) should expand the cushion.

8. The base track width/dispersing: 0.1mm/0.1mm; it will take an additional test to PCB creation ability and its assembling cost will raise in like manner if the track width/dividing under 0.1/0.1mm. Assuming that your last electronic item is a high coordinated circuit plan and has the restricted actual size to PCB board, you need to think about less track width/dispersing and the assembling cost is at a sensible reach.

10. The cushion size (measurement) of the overall through-opening mounting part is two times the opening breadth. The base of the twofold-sided board is 1.5mm and the single-sided board is somewhere around 2.0mm. If round cushions are not accessible, midsection cushions can be utilized.

11. In the event that the middle distance of the cushion is under 2.5mm, the encompassing cushion ought to be wrapped with silkscreen oil, and the width of the silkscreen oil is 0.2mm.

12. For parts that should be fastened through the tin heater, the cushion ought to be opened away from the tin position. The heading of the cushion is inverse to that of the tin, which is 0.5mm to 1.0mm. This is predominantly utilized for the back-welded cushion in one side to abstain from hindering while passing the heater.

13. In the huge region PCB plan (more than around 500cm or more), to forestall the PCB board from twisting while going through the tin heater, a 5mm to 10mm hole should be left in the center of the PCB board without parts (can be steered) to be utilized to add bowing bars to forestall bowing while going through the tin heater.

14. To diminish short out-of-weld joints, all twofold-sided vias don’t open patch cover windows.

15. Keep sufficient actual separating between SMD parts or through opening welding parts, or, in all likelihood stay away from any potential edge-covered issues, which will take the additional difficulty to SMD get together process (the deviation fastening issues).

Common PCB designing Software

The following are the absolute most well-known PCB designing software. You can find out about these PCB plan programming here.

1. Eagle is one of the well-known and simplest PCB designing software. This software represents an Easily Applicable Graphical Layout Editor which has recently evolved by Cad Soft. For planning circuit graphs, EAGLE has a schematic proofreader. Eagles Board document extension is. BRD.

2. Multisim is powerful and simple learning software that incorporates microcontroller simulations (MultiMCU) and coordinated import trade elements to the PCB design software. This product is generally utilized by scholars and in the industry for circuit instruction.

3. EasyEDA is software that is utilized to plan and circuit simulations. It is an incorporated device for the schematic catch, SPICE circuit recreation, in view of Ngspice and PCB format.

The most significant benefit of this software is that it is an online design software and is utilized in the program window. Thus, it is independent of the operating system.

5. Altium Designer is software is created by an Australian programming organization. The principal component of this software is the schematic catch, 3D PCB plan, FPGA advancement, and delivery/information to the executives. This is the first programming that offers 3D representation and freedom checking of PCB straightforwardly from PCB proofreader.
6. Ki Cad is a creation of Jean-Pierre Charras. It has instruments that can make BoM (Bill of Material), work of art, and 3D perspective on PCB as well as all parts utilized in the circuit. A large number are accessible in the library of this software and there is include that client can add their custom parts. This product supports numerous human dialects.

Common PCB Design Problems

The most fundamental type of design for making as it applies to PCBs is the utilization of configuration rules and configuration rule checking in PCB design software.

Design rule checking (DRC) is the method involved with taking a look at a plan to check whether it adjusts to the assembling abilities of a PCB fabricator.

DRCs are generally coordinated with PCB design programming and are not commonly considered as extra services. Advanced designs for fabricating analysis software are additionally accessible to search for more complicated and more subtle design imperfections.

Regularly, DFM software checking is presented by PCB fabricators to clients as an additional service. The justification behind this differentiation is a direct result of the addition to the cost of very good quality DFM software and there is a need for more training on how to utilize it.

Let’s take a look at these common PCB design related problems;

1. Starved thermals: This happen when thermal relief traces associated with a pad are not well connected with the copper plane.

The space between the vias will regularly pass a fundamental design rule check. however, the joined thermal relief traces will be hindered and those vias that will be affected improperly separated from their designated pours. This problem is normally seen when several vias are set too close to one another.

2. Silvers:

Assuming tiny bits of a copper pour are simply connected to bigger bits of a similar copper pour through a limited or narrow trace, they are prone to break during manufacture, “float” to different parts of the board, and cause accidental shorts.

The issues introduced by silvers have been diminished lately by fabricators changing to the utilization of photo-actuated carving solutions. So while silvers are still to be kept away from in designs, they are not as overwhelming of an issue as they have been in the past.

3. Acid Traps: In the joint of 2 traces, it’s however conceivable that an etching solution used to eliminate copper from the board will get held at the intersections. This trap is usually alluded to be an acid trip.

4. Annular rings: Vias are always made by penetrating through pads by drilling one or the other side of a board followed by plating the walls of these openings to connect the different sides of the PC board.

5. Via in Pad: Periodically it very well might be advantageous to design via to be situated inside a PCB pad. Notwithstanding, via in pads can cause problems during the assembly process. The solder will be drawn away from pads by Via causing the part that is connected together with the pad not appropriately mounted.

The picture beneath shows contrasts between via in-pad PCB and typical PCB.

6. Copper being too near to the board’s edge:

Regularly discovered during the process of design rule checks, setting copper layers excessively near the periphery of a board can make those layers shot together when the board is cut to a close estimate during the manufacturing process.

Even though this kind of blunder ought to be found using DRC features, regularly accessible in PCB design automation software, a PCB manufacturer who does not use a DFM check can likewise get this challenge.

7. Missing solder masks in pads:

In tight pacing in little pin pitch gadgets, it is very normal for the spacing to be with no solder cover between pins because of the standard design layout settings. The exclusion of the solder mask may prompt solder spans framing all the more effectively when the well pin-pitched part is joined to the PCB during the assembly process.

The picture underneath shows a highly exact solder cover between 0.40 pitch the QFN pads.

8. Tombstoning:

Whenever little aloof surface mount parts are bound to the PCB assembly utilizing a reflow process, which is usual for them to lift toward one side and “tombstone”. Tombstoning can incredibly influence PCB outcomes and right away drive up creation costs. The wellspring of tombstoning may be wrong landing patterns and imbalanced heat relief to the stack of the gadget. Tombstoning may be successfully moderated by the utilization of the DFM checks.

Beneath the picture is the tombstoning test and its sketch of schematic.

Conclusion

Even though the area of PCB design is facing some challenges, quick solutions seem to be put in place to curb them. With the quickly evolving PCB technology, these challenges will be an issue in the past.

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PCBs boards are laminated composites made from non-conductive substrate materials with layers of copper circulatory buried on the internal or external surface. The substrate most commonly used in a printed circuit board is a glass fiber reinforced epoxy resin.

In this topic, we are going to discuss more of the materials used in the manufacturing of PCB boards.

Types of materials used

The primary materials used in the manufacture of PCBs boards are of importance. It’s essential to consider the materials in terms of temperature resistance, flexibility, tensile strength, dielectric constant, and many other factors. These materials include;

1. FR-4
2. PTFE(Teflon)
3. Resins
4. Polyimide
5. Kapton

1. FR-4

These are the most used substrates for Printed circuit boards. However, it does not refer to the type of material but refers to the grade of materials.

• FR-4 is a grade designation for glassed epoxy laminate material. Once all the materials are fixed to each other, the board is laminated with copper foil before going into the PCB manufacturing process.
• It is composed of fiberglass cloth and epoxy resin bind which is flame resistant. The glass epoxy of FR-4 is known to be adaptable high-pressure thermoset laminate with good strength to weight ratios.
• It is one of the most popular materials used in making PCBs. FR-4 stands for flame retardant where the number 4 effeminates materials from the same group. It stands for the grade used to make the laminated sheet. FR-4 is a fiberglass reinforced epoxy that looks like a thin sheet.

The FR-4 is the most popularly used due to its low cost and versatility of the material. FR-4 are electric insulators with high dielectric strength and also a high height strength weight ratio.

Subclasses of FR-4

FR4 materials are divided into several subclasses which are done according to their specifications:

1. High glass transition: also known as Tg and the temperature where fiberglass gets unstable.
2. Standard: Standard FR4 PCBs are made of a certain

• Halogen-free: this is an FR-4 board that is made with no toxic bromine.

Properties of FR4 PCB material

• Versatility: FR4 is used in different types of PCBs boards including single layer, multilayer, single-sided, and double-sided PCBs.
• Chemically resistant: This material is resistant to corrosion. Also, FR4 materials don’t absorb water as compared to other materials thus increasing their resistance to chemicals.
• Strength to weight ratio
• Dimensional stability: this material is is affected by vibrations and pressure hence they hold its physical shape very well.
• Good electric insulator: FR4 has good electrical properties which make it a better choice for man electrical engineering applications.

Limitations of FR4

Despite being the least expensive and providing enough electric insulation. When used in high-speed applications may cause the following problems;

1. Temperature stability – FR4 is not recommended for devices with high temperatures. They also do not support lead-free soldering because of the reflow temperatures
2. The insulating stability – FR4 being a great insulator has limits when exposed to high voltage if it reaches a certain limit more than required the properties will defect and start conducting electricity instead.
3. Controlled impedance – FR4 imposes challenges while maintaining the impedance value since FR4 does not offer, a uniform dielectric constant like high-speed board materials. FR4 material is not the preferred choice for controlled impedance boards
4. They have a low thermal conductivity: FR4 PCBs may have some trouble when it comes to heat dissipation hence affecting its thermal conductivity properties.

FR-4 is used in the PCB when they form a primary insulating backbone. Once the manufacturing company prepares the circuit, the FR4 board is laminated with layers of copper foil using heat adhesive.

Advantages of FR 4 materials

1. Costly friendly when compared to other materials resulting in lower production costs overall
2. Wide range of operating temperatures: FR4 materials can withstand high temperatures without losing their properties.
3. Compact and easy to design
4. Moisture resistance
5. Strong plastic fastener materials

Applications of FR-4

1. Low-frequency applications due to their compatibility and low cost.
2. DC board application: Due to excellent accessibility and performance most of the DC boards are completed with FR4. The low cost of the FR4 board compared to boards made from other materials is also a factor.
3. Digital applications: this digital application include consumer electronics appliances such as mobile phones and Television.

2. PTFE (Teflon)

Teflon is the highly useful plastic material polytetrafluoroethylene (PTFE) trading name. PTFE semi-crystalline polymer is made up of a carbon backbone surrounded by fluorine atoms. These fluorine atoms act as a barrier and are responsible for the high corrosion resistance. Teflon PCB material can resist high temperatures. Due to this, it is commonly used in high-frequency PCB.

PTFE exhibits different properties which we are going to look at below,

Properties of PTFE

• Low-temperature resistance: PTFE has a great mechanical toughness when at low temperatures below the standard it can remain elongated
• Non-stick: PTFE is a combination of carbon and fluorine atoms attached to every carbon atom. This nature makes it to be less reactive making it non-stick.
• Exceptional electric properties: this material offers volume resistivity and high breakdown voltage. It features high dielectric loss and dielectric constant over high frequency.
• Low water absorption rate: they have a low absorption rate and hence can be used in humid environments.
• Chemical resistants: PTFE material can withstand chemicals. Board made with PTFE can be used in a chemical reagent environment.
• Fluoropolymer or Polytetrafluoroethylene (PTFE) is used in products with high frequencies with low dielectric constant. Their performances can be demonstrated in the table below

Advantages of PTFE material

PTFE manufacturers add a variety of components into blends like carbon fiber, glass bronze, and many others to strengthen weak characteristics of materials. is useful material in the manufacture of PCB boards. Some of its advantages compared to other materials are;

1. Temperature resistant: Teflon substrate can maintain its properties in both cold and extreme conditions. This explains why the PCB board made of this substrate is used in the military.
2. Great dielectric strength: high dielectric strength makes it nonconductive. The insulating capability of this material protects equipment from electric breakdowns

• Durability: PTFE material can withstand oxidation and ultraviolet rays. It is a cost-effective option because of its long-lasting nature.

Disadvantages of PTFE material

there are some advantages of PTFE that give the products some limitations.

1. Produces toxic fumes when overheated
2. Price: PTFE is not a low-cost polymer
3. It can change shape under pressure

Teflon is one of the most commonly used materials in the electronic industry. PCB boards made of Teflon are used in several applications due to their benefits.

3. Resin

Resins are sticky substances that are converted into rigid polymers using the curing process. Resins are made synthetically. Synthetic resins are made up of several classes. Some are made by the esterification of the organic compounds

Some resins find used in PCB board manufacturing; the industry leader in demand on manufacturing platforms. In this article, we are going to discuss the types of resin and their properties.

Polyester resins

They are very flexible with good resistance to heat, flames, and chemicals

Polyamide resins

Polyamide resins are easily molded, strong and resistant, and lightweight. The resin polyamide has a low friction factor and is free from scrapping and resistant to the chemical.

Polypropylene resins

They have low density and good heat resistance. They can be sterilized. Polypropylene resins are also resistant to chemicals.

Epoxy resins

They have copper-clad laminate (CCL) as a substrate material used in PCBs. Epoxy resin both its structure and performance play an important role in determining the performance of CCL. With the fast development of the electronic industry PCB fabrication technology moves towards high density and multiple layers thus laying higher requirements on dimensional stability and dielectric loss bringing new demands on the performance of the epoxy resin.

Epoxy are materials that make up the green board that houses the components, resistors, and connections needed to run the entire operation.

Properties of epoxy resins

When two or more objects must adhere to every other over an extended period the simplest thanks to accomplishing this is often by use of epoxy. Epoxy exhibits both physical and chemical properties as discussed below

Chemical properties of epoxy resins

• Epoxy resin differs in mass. The relative molecular mass of a resin over 700 is brought up as a high molecular, while epoxy with a lower mass of under 700 is termed low molecular. Epoxy resins will be allergens. The lower the mass the lower the probability of allergies.
• A molecular epoxy glue with a median mass of 380 is liquid at hospital temperature, while an epoxy with a mean relative molecular mass of 1000 is solid at hospital temperature. The mass determines what the synthetic resin is often used for

Physical properties of epoxy glue

• Resins generally occur in an amorphous state
• They generally become soft at heating

Advantages of resins on PCBs

• Resins are employed in high voltage electronics and electronics which operate within the explosive environment to supply a dielectric layer to forestall arcing
• Protects the PCB against high humidity and condensation
• With good dielectric constancy, it acts as an insulator
• Epoxy coating prevents metal within the PCB from rusting and corrosion

Disadvantages of resins on PCBs

• While epoxy provides reliable exterior film protection for PCBs, its long-lasting surface durability also makes it very difficult to remodel and repair; repair costs are high compared to most conformal coating
• Extreme temperature during operation significantly lower epoxy’s stress resistance.
• Not recommended within the coating of components whose operating conditions are water, salt spray, and mist

4. Polyamide

Many companies consider the utilization of polyamide in the making of the computer circuit board. Several polyamide PCB materials’ properties fit well with the board application of their industries.

What is polyamide PCB material?

Polyamide is additionally referred to as polyimides. they’re polymers consisting of imide monomers, the varied groups of this polymer have various metals both natural and artificial. In PCB manufacturing the polyamides used are synthetically mass-produced.

Properties of polyamide PCB material

Polyimide is highly in demand, most notably thanks to the material’s strength. There are different considerations to think about when choosing the most effective application required for the PCB characteristics of your choice. They include

1. good tensile strength: even with the flexibleness of the polyamide material they’re strong and proof against wrapping which makes it a superb choice for many applications that will need some physical strength.
2. Flexible: rigid-flex computer circuit boards and other flexible boards are commonly produced with a polyimide material. because the fabric is exceptionally flexible.
3. iii. Highly durable: other than being proof against chemicals and warmth.
4. Temperature resistant: polyamide is far more stable in an environment of extremely high temperatures
5. immune to chemicals: meaning they can not corrode easily even if exposed to corrosion.

Applications of the polyimide printed circuit board materials.

Polyamide material can be found in consumer products, clothing, and vehicles. However, they are commonly known for their use in printed circuit boards. Specifically, polyamide boards are used to create flexible and rigid-flex PCBs, which are known widely.

Some of the wide range of applications in the PCB board manufacturing industry are discussed below

1. Military and aerospace electronics: Aerospace and military applications prefer polyamide materials for PCBs because of their reliability, thermal stability, and flexibility. This is both due to the frequent necessity for field repairs as well as the physical stressors involved in these industries which other PCBs material are less suited for.
2. Automotive electronics:
3. Consumer electronics: such as tablets and smartphones are made up of flex and rigid-flex PCBs which are made up of polyamide material.
4. Medical industry electronics: medical applications require some amount of flexibility in the electronics used, for example, implants, prosthetics, and imaging technology, which tend to require more movement.

4. Kapton

Kapton is a polyamide used in the manufacture of flexible printed circuit boards. A flexible printed circuit board is made by using a thin layer of the polymer film of Kapton with a conductive pattern of traces on the substrate.

Kapton is used in the manufacturing of electric devices due to heat exposure. Kapton is a flame retardant and highly versatile material which can withstand harsh conditions to offer effective circuit board labeling every time.

Advantages of Kapton PCB

1. Kapton circuit is flexible, it can be bent, move, and have a torsion effect also. And the conductivity would not be affected by this flexibility.
2. Kapton is designed in such a way it can meet higher and smaller density mountain designs and can improve flexibility.
3. Stability and strength can be enhanced by reinforcing the base material of the circuit. There is a solution is ranging from single base Kapton circuits to multilayer printed circuit boards.
4. Boards made of Kapton can reduce their size which is why are preferred in most applications such as laptops, aerospace, and other digital devices.

Properties of Kapton

• Highly durable: It has a higher level of resistance against temperature and many other chemicals which makes it highly durable.
• Excellent stability of thermal power: Kapton polyimide can deal with temperature exposures of electronic devices. Due to this, electronic devices made with Kapton board can work in high temperatures
• Highly flexible: Kapton printed boards can be moved and bend easily.

Characteristics of Kapton

1. Kapton is highly effective
2. It has good radiation a chemical resistance
3. It is stable even in the high range of temperature
4. Well suited for diverse applications
5. It has excellent mechanical, physical, and electric properties which make it an excellent choice for demanding industries

Conclusion

The printed circuit board has led to the manufacture and revolution of modern electric devices. This has been contributed by the properties of the substances used in the making of the PCBs substrate material, the low cost of the materials being one of the major factors. Circuits boards have contributed greatly to both mechanical and electrical features due to this they are essential for use in most applications.

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