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The Importance of Solder Mask

When constructing a printable circuit board (PCB), copper wires form connections within a board and between boards. The points of contact are often coated with a polymer called Solder Mask. Including solder mask in the design process will improve both quality and reliability of the PCB.

Improved Functionality

Connectors on and between PCBs are designed to function only at points of contact. Due to the size and proximity of components, a connection can take place at an unintended location, causing potential malfunction or damage. Applying a solder mask significantly reduces the conductivity of a given component, lowering the risk of faulty connections and short circuits.

Improved Longevity

Solder mask help maximize the longevity of PCBs. This is accomplished, in part, by protecting delicate electrical components from dust and other particles in the air. Dust may land on the solder mask without causing as much interference as exposed components would experience. Similarly, solder mask protect components from oxidation and corrosion.

The application of solder mask can increase both the immediate and long-term reliability of a printed circuit board. Whether it be preventing undesired shorting or protecting from corrosion or every-day dust, including a solder mask is an important step to implement when fabricating PCBs.

BESTProto is a leader in PCB prototyping, PCB assembly, and PCB production. Contact us today for a quote on your project.  224-387-3283

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Best Practices for More Reliable PCB Assemblies

Printed circuit board assemblies (PCBAs) or PWB (Printed Wiring Boards) or CCAs (Circuit Card Assemblies) may vary in use, from remote controls to hospital equipment, extending even to airplanes. But the cost of a PCB failure is easy to predict: Loss of money and/or applications, as well as valuable time. It is important for quality engineering to be paired with good PCB layout design practices to create and deliver a robust and functional PCB assembly.

Quality Versus Reliability

When a PCB assembly is manufactured, the quality of the board is easily measured and can be tested according to a checklist of requirements related to technology and performance. The manufacturer has a variety of responsibilities related to quality and workmanship once the customer accepts the boards, and the customer expects the boards to perform and function properly.

There is no simple answer for determining reliability. Measured over the lifespan of the board, reliability is much more difficult to quantify than quality. Failure can occur after one year, five years, or ten. Below are design tips to help improve PCB reliability.

Maintaining Connectivity

If a board is highly reliable (as in IPC Class 3), all connections will remain intact for the lifespan of the device. Connections can be copper, silicon, gold, or other materials, and maybe fused by means of soldering, vias, or bonding wires. Quality design and workmanship will increase the probability of constant connectivity and improve the reliability of the board.

Matching Coefficient of Thermal Expansion

A PC Board has parts made of a range of materials. When the board or its components increase in temperature, each will expand at a different rate due to its composition. The rate of expansion for each material is known as the Coefficient of Thermal Expansion, or CTE. Designers are advised to use materials with matching CTEs to prevent uneven expansion. If components with differing CTEs are used, cracking or delamination may occur, rendering the PCB unusable and leading to potential failure.

Thermal Profile

Boards may be built using reflow soldering or wave soldering. For either type, it is important to calculate the best temperature at which the board will be processed. PCB components must be able to withstand the high temperatures required for lead-free soldering. While lead-free solder requires temperatures that are higher, the time will be shorter. Adjusting the reflow oven to the correct thermal profile will allow all parts to be effectively soldered.
Printed circuit board assemblies are crucial in important electronic devices, the failure of which can be catastrophic. Through implementing these best practices, designers can increase not only the quality of PCBs but also their reliability, improving the long-term value of the boards and, more importantly, allowing devices to function as expected. BESTProto uses advanced software for creating reliable PCB layouts. We will work with your organization to ensure all design rules are met and that high quality, the reliable layout is produced.

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pcb assembly

Methods for PCB Assembly Inspection and Verification

Inspection is a crucial part of the PCB production and assembly process. The inspection process is to ensure high quality and reliable printed circuit boards are assembled. The inspection process helps reveal any design flaws that may exist at different stages during manufacturing and the assembly procedure that must be eliminated. 

This blog post will inspect the leading inspection methods. Here is an overview of the various PCB assembly inspection methods. 

1. Visual Inspection

Manual visual inspection is the simplest form of PCB inspection. This inspection method can be used after most PCB assembly processes have been conducted. To perform this type of test, a worker looks over the board either with the naked eye or through magnification. Although visual inspection is a method commonly used, its validity depends on the capability of the inspection staff and how they apply the inspection standards.

2. Structural Process Test Inspection Systems

Structural process test inspection is often used for large volumes of production where accuracy and speed are extremely important. This inspection method uses some form of light emissions such as visible lights, lasers, and x-rays to acquire data through real-time image processing for locating and measuring defects related to solder joint quality. 

3. Automated Optical Inspection (AOI)

This method typically conducts an inspection using multiple visible light sources with programmable LEDs, one or more still or video cameras and computerized systems for inspecting solder joints.

An automatic optical inspection can find many of the same defects that a VMI can, including open circuits, solder thinning, missing components, displaced components and more.

4. Component Value Verification

BESTProto uses the latest technology to verify that not only the correct package size and types are being placed on a board but, we are also able to electrically test the individual components before placement to verify that the are the correct electrical value as well.

5. X-Ray System Inspection 

The X-ray method can be performed in two different ways: the X-ray fluoroscopic system and the X-ray lamination system. The fluoroscopic system produces a density image to accurately inspect solder joint distribution, thickness, and internal integrity. The lamination system, on the other hand, uses X-rays to generate focal planes of a horizontal sectional area of a PCB. 

Inspection is a crucial part of the PCB production and assembly process. There are five different types of manufacturers, and assemblers can use to inspect the PC board assemblies and help to eliminate workmanship defects. BESTProto ensures quality through our quality assurance program and continues our commitment from first articles through a disciplined approach to process control. Contact our team today to request a quote on your PCB Assembly project today.

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pcb assembly

Implementing Effective PCB Manufacturing Processes for 2020

There are four crucial stages for creating and implementing printed circuit boards, including design, manufacturing, testing, and, of course, PCB assembly. Traditional processes do not always incorporate all independent stages from the start; neither do they require the input of the contract manufacturer from the onset. Over the years, this practice has led to unnecessary hold-ups due to modifications in fabrication and design that expand the time to market. When we look at the future impacts of PCB, a more effective PCB manufacturing process must be implemented.

The Need for Change

In 2014, the market for bare PCBs surpassed $60.2 billion. By 2024, the PCB market is expected to exceed $79 billion. The demand explosion in the electronic market augments the growth witnessed in demand for PCBs. Therefore, PCB manufacturing industries must seize the opportunity by boosting productivity which is only possible with a more effective PCB manufacturing. 

Factors Impacting the Effectiveness of Your PCB Manufacturing Process

Every PCB manufacturing process needs an objective. Usually, the aim is to transform the PCB design into a quality, assembled product that can be reliably used for its intended purpose. While different PCB projects have their own costs and deadlines, the practices you implement can significantly improve your processes:

1. Select the Right BOM Materials

Making available crucial materials on your BOM can augment the PCB manufacturing process and prevent long lead-time or shortages. Therefore, it is essential to create a comprehensive list of suppliers that can deliver genuine components.

2. Using DFM Guidelines

Every PCB product has specific regulatory standards that must be met. Therefore, it is essential to consult with the contract manufacturer’s DFM (Design For Manufacturability) guidelines at the start. This ensures that the PCB layout meets standard industry specifications and tolerances and avoids wasting time and money in designing.

3. Consulting for PCB Assembly

It is recommended to consult with your EMS (Electronic Manufacturing Services) supplier or, contract manufacturer (CM), which provides access to valuable insights on how to maximize assembly efficiency and reduce assembly costs. The design files should also be made available to the CM in the preferred format to avoid errors.

4. Testing

Collaborating with the CM during testing ensures that an objective and independent assessment is made on your prototypes. This way, you can effectively locate and deal with all types of faults.

The bottom line is that with strategic CM and PCB assembly partners, you can effectively improve all stages of production. Finding the right partners will help you control costs and leverage current trends without sacrificing quality. BESTProto offers electronic assembly services for single or multi-layer flexible or rigid circuit boards. Contact us today to request a quote for your PCB project.

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pcb layout services

5 Common Mistakes for Printed Circuit Board Layouts

Printed circuit boards require keen attention to detail and meticulous design planning. One small mistake and the board won’t work properly. In our years of providing PCB layout services, we have seen similar mistakes made time and time again. Here are some of the most common PCB board layout errors.

1. Incorrect Landing Patterns

Many projects require you to work with electronic components above and beyond what is included in the libraries. On their own, the libraries have pre-designed schematic symbols, but when you add more components you have to manually draw schematic symbols and landing patterns. Being off by even a fraction of a millimeter can bring your project to a halt. 

2. Wireless Antenna Placement

The world has gone wireless and many PCBs require a wireless antenna, but it can’t just be placed anywhere. For best results, use a microstrip calculator to ensure that the antenna and transceiver are properly connected. This typically requires a 50-ohm microstrip transmission line, but use a calculator to be sure. You will also need an LC matching circuit to ensure maximum power transfer. 

3. Placement of Decoupling Capacitors

Decoupling capacitors can’t do their job unless they are placed as close as possible to the pin that requires power and voltage. You need power to transfer to the decoupling capacitor before going to the pin needle, otherwise voltage will not be stable. Power must then be transferred to the output capacitor, which means it must be placed close to the output pin.

4. PCB Trace Width

It is easy to miscalculate PCB trace width. For proper calculation you must factor in whether it is an internal or external layer and the thickness/weight of the trace copper. To be safe, aim for a 10C rise—but never more than 20C. To minimize error, use a trace width calculator. 

5. Improper Use of Vias

You must understand the difference between through, blind, and buried vias to connect the layers of your PCB. If you select the incorrect via, your board won’t be manufacturable. 

All the errors above are costly and time-consuming. To eliminate these common PCB mistakes, outsource your layout and design to BESTProto. This is one of the many PCB layout services we provide!

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pcb prototype

Considerations Before Sending Your PCB Prototype to Mass Production

You’ve designed an innovative new or updated circuit board for your smart technology, but now it’s time for a prototype. Here are a few things to keep in mind before sending your PCB prototype out for production.

Determine Your Top Priority

One of the first things you must determine is your top priority: board size, cost, or layout time. The larger the board, the higher the routing function, but the higher the cost. However, multiple layers on smaller boards are sometimes more expensive than larger prototypes. The smaller the board, the longer it takes to layout. 

Part Selection

If your design currently requires a sole-sourced part, consider if you can swap it out for something that is more widely available—if not for the long-term, for your prototypes. Otherwise, waiting for the part you need can cause a bottleneck in your launch date. While easy availability is ideal, also consider if there are any new parts that can improve your current design. And yes, this includes sole-source parts. Just be mindful of turnaround. If you are sending part kits with, create a checklist to double check all parts are accounted for.

Layout and Polarity Markings

If you haven’t yet, it’s time to ensure your board is laid out for maximum efficiency and has clear polarity markings. No large parts next to small parts that can interfere with solder function and no copper planes that overlap only on one side of small parts. Ensure that your polarity markings and reference designators are crystal clear. You know where everything is supposed to go, but if your markings aren’t clear your prototypes may come out incorrectly. The most common cause of incorrect PBC prototype completion is being sent outdated design files. Your prototype has likely evolved, so double check you send the correct version.

Don’t have a prototype partner yet? Reach out to BESTProto today for a quote.

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pcb panelization

PCB Assemblies: A Quick Tutorial

Electronics manufactured for everything from healthcare to space shuttles require a PCB Assembly. In fact, the invention of the PCB (Printed Circuit Board) and how it supports physical components and their wiring through copper tracks is remarkable. The components are fixed into position by drilling holes in the board, placing them, and then soldering them in place or, having pads to place on the surface in what’s called Surface Mount Technology (SMT). 

Panelization has brought high amounts of efficiency to PCB Assembly production, which wasn’t possible in the early days. Consequently, technicians can prototype a handful of project boards all in one simple swoop. 

Fortunately, with the proper PCB Assembly design software, PCB panelization has never been easier to implement. Let’s explore the simplicity of designing your own PCB panel with a quick tutorial.

1. Draw your board

It all starts with preparing the board layout. In this stage, you’ll need to draw your board. Schematics are important throughout this stage. The schematics are used for laying out the traces and placing the components on the PCB. 

Start by logging in to your software, and create a new project. Make sure that in the process of drawing your schematic, each schematic symbol you use has a PCB footprint associated with it. The PCB footprint will define the component’s physical dimensions and placement of the copper pads or through holes. This stage is great to decide which components you’ll be using. 

2. Draw your artwork

The next step is to transfer your schematic diagram into a drawing of your printed circuit board. Drawing PCBs can be a time-consuming process. Thankfully, most PCB layout software is equipped with tools that will help you draw your board from the schematic.

3. Placement of components

Do you prefer your circuit board to be in a box? Keep in mind that tall components might need to be flat to fit. You can test this by drawing your components on your board, then printing it out on a sheet of paper. This will help you know if it will fit in the box and if the connectors will fit properly.

4. Assembly of your PCB

When you have completed your drawing, it is time to get your PCB design ready for manufacturing. This step is all about finding a trusted PCB production and assembly specialist. Look for an organization who will work with you on prototyping, stands behind their work, and has an expert understanding of your industry. Contact BESTProto today to request a quote on your project.

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electronic assembly services

A Brief Introduction to Common Plating Methods

PCB finishing processes are a common aspect of electronic assembly services. However, finishing processes vary and one of those processes is plating. In electronic assembly services, the plating process uses a chemical to fuse all of the different layers of the PCB together. PCB production knows four main types of plating: gold finger-plated plating, through-hole plating, reel linkage selective plating, and brushing plating. This article will discuss these four different methods in more detail.

1. Gold finger plating

Gold fingers are electroplated edge-connectors the are generally used to connect PCBs to a motherboard. Since gold fingers are mainly used for plugging, the gold thickness should be between 3u“ to 50u“. The expectant cycles of gold fingers are approximately 1,000 before any repair is needed, however, that is only if the correct thickness is used and if the gold fingers are applied correctly.

2. Through-hole plating

Through-hole plating is a crucial step in the manufacturing process for drilling. This method is beneficial as it allows both sides of the printed circuit board to be used and connect to other layers of the board. This method uses copper plating to allow electrical conductivity to travel through the board. The thicker the copper plating, the longer it can go through this thermal cycling without cracking. The life of the printed circuit board is dependant on the thickness of the copper plating of the through-hole.

Through-holes without the copper plating lack conductivity and electricity, and is unable to connect to the other side or other boards.

3. Selective plating

Selective plating is the ultimate method for corrosion resistance and good contact resistance.  Selective plating is suitable for electronic components that use contact pins. The process of individually selecting the pins is extremely expensive so most electronic assembly services use batch welding. Selective plating only uses the portion of the metal copper foil plate that is selected, as the other part is coated with a resist film.

4. Brushing plating

Brushing plating is also a form of selective plating. It is a plating technique that only uses a select amount of parts of electrolyte during the plating process, thus only a limited portion gets plated. This plating method is commonly used by electronic assembly services when repairing waste boards.

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Understanding Selective Soldering

Defining Selective Soldering

In the world of electronic assembly services, one soldering process reigns supreme – selective soldering.

In the simplest of words, selective soldering is a way of soldering parts onto a printed circuit board in a fast and efficient amount of time, when compared to doing it by hand. It has become a go-to soldering method for many companies. In a more technical sense, selective soldering is an automated soldering process in that parts are soldered to a PCB in quick succession or all at once. In a sense, it sets up a template to make the process quicker.

Selective Soldering Processes

Laser Selective Soldering – The laser is what makes this process different. It uses the laser to perform the process, thus making it a precision-intensive option.

Miniature Wave Select Solder Fountains – Using a “wave,” the board is manipulated to solder in premeditated locations. You do not need the aperture tooling and masking for this method.

Selective Dip Solder Fountain – Relying on the solder fountain, this process works on exact points where the board is meant to be soldered. Once the board is dipped into the fountains, soldering components are sought out and correctly soldered, while other parts remain untouched.

Aperture Tooling Over Wave Soldering – The second “wave” process in which the board is pushed through a wave of solder which creates a molten solder pool. Un-soldered areas are masked for protection.

After any of these processes, the soldering machine is left to cool and the finished board continues through the manufacturing process.

Why Use a Selective Soldering System?

Because of its efficiency and accuracy, a selective soldering system has become the preferable way of soldering. Reflow ovens and hand soldering is still used and have their benefits, but mass production demands selective soldering. The question comes down to this – how many boards need to be produced, and will it be cost efficient for you to use a selective soldering system?

In conclusion, for many modern operations, selective soldering is the most efficient electronic assembly services for precision and speed. It does so without compromising the delicacy of the board. The companies that use them are able to create and deliver the products their customers seek out in the most effective way.

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Rigid Flex PCB Basic Layout Guidelines

As technology changes and evolves, the printed circuit boards that enable devices to work have to evolve as well. With this trend, investing in PCB layout service is more important than ever before as it can save you both time and money. Durable rigid flex PCBs are able to withstand today’s challenge of flawless performance, regardless of the application.

Rigid flex circuit boards are a hybrid of all the best qualities of the rigid and flex circuits boards. These hybrid circuits provide better quality control and more design options. Organizations that produce aerospace, medical, automotive, military, and consumer electronics, are increasingly utilizing the versatility of rigid-flex PCBs.

When designing and building a rigid-flex circuit board, there are a few basic layout guidelines that can help to ensure consistent quality, while still adhering to production timelines. Here is an overview of the guidelines to follow when building a rigid-flex PCB.

Insulate with Bondply: Take the time to insulate the rolled-up copper cladding that is used within the flex layers of a rigid-flex PCB. The bondply prevents the copper from becoming brittle over time.

Adjust Via Spacing: The best way for pliable flex materials to remain stable is to place vias 50 millimeters from the edge of the rigid area, adjacent to the flex ribbon. This distance is greater than that found in rigid-only stackups, but it is essential to retain stackup stability.

Alternate Flex Traces from Layer to Layer: For the PCB wiring to continue functioning as intended, ribbons need to remain flexible. In order for this to happen, traces cannot be positioned on top of each other, layer upon layer. Instead, stagger the traces vertically to allow for optimal ribbon flexibility.

Adapt Adhesive Application: Be aware of where adhesive is being placed. Do not apply adhesive to the bendable parts of circuits that have more than four flex layers.

At BESTProto we know the best practices when providing PCB layout services and assembling PCBs. If you are looking for PCB assembly services or want to know more, visit bestproto.net today.

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