Connect the Dots: Five Best Practices to Ensure Manufacturability

Optimizing your board using design for manufacturability (DFM) techniques just makes sense. But without formal training, this isn’t as straightforward as one would hope. Every day, our team receives designs that are too complex, too thick, incomplete, with components placed too close together, among other things.

When something like this happens, rejection of your design is a best-case scenario because it means your manufacturing partner has your back. If your design is just dropped into an automated queue without concern for manufacturability, quality, or functionality, the output can be a batch of unusable boards.

This doesn’t have to happen because you are in control of your vendor choice. While not a replacement for good design practice, carefully picking a manufacturing partner and service level that meet your needs will help you achieve a quality result.

Now, let’s examine five design best practices that will help reduce costs, increase yield, and improve manufacturability.

1. Always Double Check Your Design

It will save you time on the front end. Regardless of which partner or service level you choose, I strongly encourage you to be sure to review your design, taking a second look for issues, such as insufficient power trace widths or blind vias. Ditto if components are laid out too close together. It is easy to accidentally cut holes or route slots too close to pads or traces.

Copper thickness is another biggie. Higher current may require thicker copper and narrow traces probably should be thinner, so be specific about what you need to ensure your design will not fail. Check land patterns against the part supplier’s manufacturer data sheets (MDS) as well. Often, that’s all it takes to avoid common design issues.

2. Always Consider Your Environment

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.

To read this entire column, which appeared in the July 2019 issue of Design007 Magazine, click here.

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2019

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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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 I led 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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MakeHarvard 2019: Bigger and Better!

04-18-2019

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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Connect the Dots: Key Guidelines for Clean Schematic Designs

01-08-2019

The smoke has not even cleared, but they already know what the problem is. It was supposed to be a celebratory moment for the team, plugging in the first board from the initial shipment. Instead, the room is as silent as a morgue. The engineer knows that they put the capacitor in place. However, on closer examination, it is not close enough to the IC pad to make a difference. Everyone turns to the PCB designer. “But I put it right where the schematic said to!” they say. The fix is easily implemented. It takes 15 minutes to produce a new design. Unfortunately, the break room already has an ample supply of coasters, and that’s all this batch of boards can now be used for.

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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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