Connect the Dots: Build Quality Into Your Boards and Processes

bob-tise.jpgTo the procurement clerk, a PCB may seem like it is just a line item on a bill of materials (BOM) or parts list during the production of an electronic device. At Sunstone, we know differently. The PCB is the building block for all of the components and parts in your electrical project.

Boards are more than the sum of their parts—the epoxy, glass, copper, polymers, and holes are not the board. The board is the custom-made end product for a designer, layout engineer, entrepreneur, or team who has taken hours, days, or even weeks of time crafting the perfect PCB design. If the design turns out to not be perfect or the manufacturer doesn’t produce quality boards, delay and cost over-runs are the result. In the worst-case scenario, the boards don’t function properly, and nobody needs that many PCB coasters!

Committing to quality and best practices at the outset will help you limit the potential for design errors or manufacturing problems during your PCB project. More than lip service, quality management should be integral to your process. Choosing reputable PCB manufacturers at the beginning of each design phase is critical and a great first step towards a high-quality outcome.

It is unlikely that one manufacturer will fit all of your PCB needs. We each have our sweet spots with respect to each type of manufacturing project. By performing due diligence with your manufacturers and designing to their individual sweet spots, you position yourself for effective collaboration on those cutting edge or capability-taxing pieces. This can pay dividends in the overall manufacturability and re-liability of your project.

We don’t hide what we are good at. Most every PCB manufacturer goes to great lengths to promote their sweet spot, as well as maxi-mum and minimum capabilities, to the marketplace. This makes it easier for you to choose the right manufacturing partner for each board. Of primary concern at the outset is to confirm that the manufacturer accepts industry-standard file formats, specifically Gerber files and/or ODB++.

Accurate Gerber files are mission-critical for smooth PCB manufacturing. Converting to Gerber files can reveal design issues ahead of the quote process and ensure your manufac-turer has everything needed to produce your boards correctly and on time. Of course, what you put in those files will determine the final outcome, so perform design rule checks before you convert. Just because your soft-ware will let you design a board in a certain way doesn’t make it easily man-ufacturable. Keep manufacturability at the forefront as you set up and perform your design rule check before converting to Gerber.

By confirming the number of board layers, proper spacing, drill hole to size and placement aspect ratio, spacing, and proper tolerances, you can be assured you are indeed de-signing a board that can be built by your manufacturer without delays or errors. Some manufacturers even offer a set of DRC settings that can be added directly to your software, saving you the time and effort to create these rules. By taking these into consideration early in the process, you are building the quality right into your PCB.

Assuming your manufacturers are prioritizing quality and you are producing files that are compatible with their process, look for other production elements that are important to you. Does the manufacturer have the capacity and capability to build your board as designed? Without the right technology, equipment, process, and key personnel, you might not get a quality product, and you might not get it delivered on time.

Quality PCBs require the best materials. Manufacturers sourcing cheaply not only produce a mediocre product but they can also leave you in a lurch with respect to safety. Make sure your manufacturing partner can de-liver a UL-marked board that confirms its safe operability.

The UL mark tells you that the boards have been carefully monitored and will withstand thermal stress without failure, within reasonable limits. UL certification will give you confidence that your boards can with-stand temperatures required for soldering, as well as some rework, without delamination or decomposition. You can also be sure your PCBs will not catch fire under reasonable, and sometimes even unreasonable, operating conditions. This is an important safety concern if your boards will be used in a commercial product.

Since no two projects or boards are exactly alike, you will need different levels of support for each. Look for partners with multiple service levels. Sometimes, you just need a quick turn for proof of concept or a fast prototype run to keep an established manufacturing pro-cess moving along. In other cases, like new product development, more collaboration can help you get the job done right the first time.

Once you submit your design to your chosen manufacturing partner, it is incumbent upon them to execute and deliver your boards. Hopefully, you have chosen one that has a proven track record for quality and on-time delivery and a demonstrated passion for your success.
 
Bob Tise is an engineer at Sunstone Circuits.
 
This article originally appeared in the October 2019 issue of Design007 Magazine.
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2019

Connect the Dots: Build Quality Into Your Boards and Processes

11-06-2019

To the procurement clerk, a PCB may seem like it is just a line item on a bill of materials (BOM) or parts list during the production of an electronic device. At Sunstone, we know differently. The PCB is the building block for all of the components and parts in your electrical project.

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Connect the Dots: A Proactive Approach to Controlled Impedance

10-09-2019

You can save time, money, and effort if you are aware of the impedance math when you sit down to design your board. Gain this awareness by using a good impedance calculator, and you can build the right tolerances into your design. Impedance testing becomes a double-check of your work instead of the tool you rely on to tell you if your documentation is correct. Documenting impedance requirements properly is more onerous than most people realize. Though it seems simple, PCB documentation is a details game that often leaves knowledge gaps for your manufacturer.

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Connecting the Dots: Managing Global Supply Chain Uncertainty

09-03-2019

We are well into the second year of tariff-centric trade policy, and one thing appears certain—uncertainty is here to stay. Though most of the media focus has been on cars and steel or consumer prices and corporate profits, the enduring challenge for both the electronics and PCB industries has been maintaining reliable global supply chains.

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Connect the Dots: Five Best Practices to Ensure Manufacturability

08-01-2019

When you send your design for manufacturing, your partner does not know what type of device the board will be part of nor the conditions in which it will have to perform. It’s common for harsh environments or exposure to mess up a board’s performance. If you call out materials that will not tolerate the end-product’s operating environment, bad things can happen—such as a smoking board, for example. Be sure your board can tolerate thermal stress or solder joints risk breaking and damaging components.

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Connect the Dots: The Future of PCB Manufacturing Doesn't Belong to Robots, but to the Users

07-09-2019

Is the world ready for the consequences of rapid automation? Will the use of robots displace entire categories of workers? Can artificial intelligence really “think”? How will manufacturing, including PCB manufacturing, be affected by all of these smart robots? These questions actually come from a pamphlet published in 1955: "The Age of Automation: Its Effects on Human Welfare."

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Connect the Dots: Accurate Gerber Files Are Mission-Critical for Smooth PCB Manufacturing

05-30-2019

Gerber files can reveal design issues ahead of the quote process and ensure your manufacturer has everything needed to produce your boards correctly. After consulting with Engineering Support Specialist Eric Haugen, we explored some best practices for making sure that Gerber files are accurate.

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Connect the Dots: Preparing for Tomorrow’s Technology Today

05-16-2019

At a recent Sunstone Circuits planning summit, Matt Stevenson, VP of sales and marketing, and Bob Tise had a wide-ranging discussion about emerging technologies and how they will impact PCB manufacturing. The following is an abridged transcript of this conversation.

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Connect the Dots: MakeHarvard 2019: Bigger and Better!

04-09-2019

Sunstone Circuits was eager to return to MakeHarvard as a sponsor and creator of a competition category this year, also serving as both mentors and competition judges. If you were there, you saw us—we were hard to miss in our bright orange vests. As mentors, we were out and about helping students and answering questions.

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Connect the Dots: Exploding PCBs: Don’t Lose Track of Voltage in Your Design

04-01-2019

Managing split planes? Your CAM tool will not do it for you. We see this almost every day—not exploding PCBs, which pretty rare—but rather problems created by having more than one voltage on a power plane layer. From where we sit, this is one of the more insidious and costly challenges facing PCB designers.

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Connect the Dots: Selecting the Right Board Thickness—A PCB Designer’s Balancing Act

02-21-2019

Choosing wisely is critical for PCB quality and performance, but it can be tricky depending on size constraints, functional requirements, and environmental factors. While we sometimes have a general idea about assembly requirements or how the board will be used, there can still be a lot of unanswered questions as we begin the manufacturing process. After all, there’s a big difference between a PCB going into a drone and a PCB that will be part of a submersible drone and needs to be the size of a tennis ball, withstand intense heat or cold, and function forty fathoms below the surface.

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2018

Connect the Dots: Six Tips to Ensure Parts Fit on Your Board

12-12-2018

One of the most frustrating mismatches with alternative through-hole parts occurs when the land pattern matches, but the pin size is off. If hole sizes are too tight, pins may not fit through the holes, or if they do go into the holes, they may not solder well. Solder will need to flow through the gap between the pin and the hole barrel. If there is not enough space to allow enough solder mass to flow through the hole, the circuit board will absorb heat from the molten solder and cause the solder to solidify partway up the hole. This is called a cold solder joint and can result in a premature failure of your circuit.

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Connect the Dots: New Landing Design to Reduce Thermal Pad Failure

11-16-2018

You’ve finally finished your design. All the traces are correct and the IC landings are to the manufacturer’s specifications. A short run of test boards performs perfectly. For best results, you select a reputable domestic board house for production and a quality assembly shop to do the soldering. When the finished boards arrive, everything looks great. You’re in high spirits and congratulate yourself on a job well done. Then the reports start coming in.

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