Powerful Prototypes: Manufacturing in an Uncertain World

In the best of times, electronics manufacturing is an exercise in taking chaos (in the form of data and information of multiple non-aligned forms and formats) and creating order (in the form of a working PCB). As I write this, it is not the best of times. The coronavirus has been declared a global pandemic, and the primary theme of the day is uncertainty.

Still, the world machine grinds on. As with any set of challenges, fear and doubt can be broken into parts and examined and responded to separately. You have your health concerns, as well as those of your friends, family members, neighbors, and coworkers. Then, you have your overall well-being, including food and shelter. Somewhere a bit further in the list comes your job and the projects you are trying your best to finish up and get built. I can’t advise on the former set, but I can on the last one.

I’m in the business of helping people get their boards built, and I’ve been doing it long enough to have been through recessions, wars, and natural disasters. The wise words of my brother always come to mind: “Do what you did the last time the world came to an end.” With that in mind, here are four things you can do to better ensure that your projects can be built and improve your habits.

1. Minimize Chaos

Remember how I started this column by talking about chaos? That wasn’t hyperbole. Around 70% or more of the file sets we get require some sort of clarification before we proceed to manufacturing. I would assume that what is true for us is true for most manufacturers.

Spend some extra time to ensure that all of those files are accurate and complete. The less time we spend clarifying, the more time we have to process and build.

Double-check your reference designators. It’s pretty common to add or subtract a bypass cap or resistor in the latter stages of design. Some designers also try to resequence the reference designators for clarity. Whether you resequence or not, it’s also pretty easy to end up duplicating a reference designator or causing a mismatch between the BOM and the PCB.

I did that on the last design I sent through our factory. The result was a phone call at the airport from our customer service folks, asking why I had two each of R20 and R21.

Create a checklist early on in the design phase and keep adding to it as you go. Anything that is referenced in more than one file is subject to this type of error. Before hitting “send,” go grab a coffee, donut, or maybe a carrot stick. Then, come back and slowly walk through the checklist.

2. Take Extra Care With All of Your Component Footprints

This is another common way to introduce error and chaos into the process. It’s also another error that I’m pretty familiar with, unfortunately. With so many variations in components and so many new components coming out, it’s just not reasonable to assume that your PCB design CAD software will have all of the footprints you need.

Some companies have dedicated librarians, and their job is to create and or manage all of the company footprints, but few of us in practice have that luxury. Sometimes, that librarian is busy enough that we need to go ahead and make our own footprints or be forced to wait a week.

If you have a big connector, 2.5 mm is not the same as 2.54 mm or 0.1 in. We see this way too often. For a 2 x 6 pin connector, it is usually close enough, but beyond that, through-hole connectors don’t fit, and surface-mount connectors risk bridging.

For super small parts, all of the layers in the footprint are critical. It’s common to let your CAD footprint editor just duplicate the copper layer for the solder paste layer. Don’t do this. Go to the component datasheet and use the exact dimensions and position specified for the paste layer. You may need to get out your calculator because of the way they often specify dimensions.

The copper layer is also critical with small parts. Some people will duplicate the pad on the bottom of the component. Again, that will likely not allow for proper paste spread. Take a look at my previous column titled “Powerful Prototypes: An Open-source Adventure” to see an example of what can happen when the copper pad is the wrong size.

3. Do Not Assume: Communicate and Eliminate Ambiguity

This one seems a little pedantic, but it is really important and is a cause of many issues. As a designer, you have all of the details of your design in your head (“your” is the watchword here). You know all of the subtleties, nuances, and details of your design. Even things that seem obvious to you are not obvious to others.

A good example would be the humble 0.1-uF, 6-volt bypass capacitor. In most cases, any 0.1-uF capacitor of the same package between 6 volts and 50 volts would work fine as a substitute. That may seem obvious. However, while many components land in that “close is close enough” realm, others do not. In a highly tuned RF design, the ESR, ISR, or other ratings may be critical design parameters. A manufacturer has no way of knowing that. Add a couple of alternates to your BOM so that no one in purchasing needs to guess.

Also, be available. We—and many other EMS companies—work 24 hours, 6 or 7 days a week. If we have questions, we may need to contact you at 3:00 a.m. on a Saturday. The sooner we can get an answer, the sooner we can get back to building your boards.

4. Don’t Panic

Always know where your towel is (and your hand sanitizer). Crises come and go. They are not good, nor should they be taken lightly—hence the word “crisis” —but we can come out of them stronger. Any work practices that you improve to get through this period will still apply long after the world is back to normal.

Duane Benson is marketing manager and CTO at Screaming Circuits.

 

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2020

Powerful Prototypes: Manufacturing in an Uncertain World

03-25-2020

In the best of times, electronics manufacturing is an exercise in taking chaos (in the form of data and information of multiple non-aligned forms and formats) and creating order (in the form of a working PCB). As I write this, the coronavirus has been declared a global pandemic, and the primary theme of the day is uncertainty. Duane Benson shares four things you can do to better ensure that your projects can be built and improve your habits.

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Powerful Prototypes: An Open-source Adventure

02-26-2020

Duane Benson describes the latest board design project he has been working on in his off-hours—a motion-sensitive lapel pin—including compromises, mistakes, and lessons learned

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Powerful Prototypes: Five Technological Shifts in the New Decade

01-08-2020

Depending on your perspective, we are either starting the last year of the old decade or starting the first year of the new decade. But regardless of what you call the decade, a lot of change is in store. Duane Benson shares five of the more significant technological shifts directly ahead of us and how to respond.

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2019

Powerful Prototypes: Cost Reduction in Design

12-11-2019

Getting custom electronics manufactured is not cheap, fast, or easy. Fortunately, there are ways to keep costs down and yields up without adding cost. Duane Benson shares six ways to keep costs down and yields up that you can do without a lot of effort.

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Powerful Prototypes: New PCB Fab Technology—What You Need to Know

11-20-2019

Exotic materials have been around for a while, but being “exotic,” most of us could safely ignore them. However, as clock speeds increase, and board sizes decrease, some of those exotic materials are getting close to mainstream. Duane Benson shares some of the newest terminology you might see in your daily electronics adventures and will need to be familiar with when venturing beyond a standard, rigid FR-4 PCB.

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Powerful Prototypes: Panelization—What Is It and Why Would You Want It?

10-30-2019

We see orders for a single board, and we see orders for thousands. “A few thousand” falls way outside the realm of “prototype,” but in the startup and open-source worlds, the lines are blurred. Once you order more than about 50 boards, a few things change; for example, you should consider ordering your boards in a panel, also called arrays or a palette, of multiple boards.

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Powerful Prototypes: Never Assume—A DFM Story

09-19-2019

I write a lot of words about DFM and best practices for PCB layout. Working for a manufacturer, I regularly see the results of not taking DFM seriously. DFM is something never to be taken for granted at any point in the design cycle, and I mean at any point in the process.

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Powerful Prototypes: 5 Common Myths About Solder Mask

08-14-2019

Before parts are added, a typical PCB has four ingredients: substrate, metal, solder mask, and silkscreen. Solder mask, in particular, seems to be looked at as a great place to cut when costs are tight, but Duane Benson disagrees. Read on as he dispels five common myths about solder mask.

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Powerful Prototypes: The Ideal Bill of Materials

07-10-2019

A good portion of a quality electronics build is simply the result of clear information. Not long ago, I wrote about the set of files containing the information required by your manufacturing partner to ensure a quality build.

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Powerful Prototypes: Moisture Sensitivity—What’s the Risk, and What Can You Do About It?

04-18-2019

I recently traveled to New Orleans, Louisiana, for a week of beignets, fried food, and urban exploration. It’s a good thing that parts of the exploration came in the form of walking as some level of exercise was needed to compensate for the lack of greens and heavy emphasis on the word “fried” that went along with most of the food.

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Proper PCB Storage: Top Three Hazards

03-28-2019

Overall, our modern world could not exist without PCBs; they are everywhere, but they aren’t items to be taken for granted. Like most technology, PCBs need proper handling and storage. PCBs don’t last forever and are even more vulnerable before the parts are soldered on. The solderable metal surface is very thin and subject to a number of potential problems, especially if not stored properly.

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Seven PCB Cost-reduction Design Tips

02-11-2019

Like everything else in the modern world, design decisions can have a pretty big impact on your manufacturing cost. Here's a list of seven design decisions that can make your manufacturing more affordable.

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Eight PCB Assembly Tips for 2019

01-17-2019

It's now 2019, and all I'll say on the coming year is that we are in for a wild ride. The last few years have been pretty crazy, and 2019 looks to continue that trend but amped up. While predictions might be fun to muse upon, they really won't help you get your job done. So, here's my top eight pieces of PCB assembly advice for the coming year to make up for that.

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2018

What Is Your Supply Chain Telling You About Components?

12-24-2018

Right now, many, many parts are in short supply, or unavailable with extraordinarily long lead times. Allocation is the word of the day and substitutions are your friend. Sure, electronics components shortage happens every now and then in this industry. It's a periodic nuisance, but what should you do for the long term? Read on.

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Electronic Manufacturing Files: What We Need for PCB Assembly

12-07-2018

As PCB assemblers, manufacturing is all about taking data and delivering good working circuit boards. It can be just data, as in full turn-key, data plus some parts, or a partial turn-key or a kitted job. Regardless of whether you're sending parts and boards or having us buy everything, PCB assemblers need good data, and a lot of it.

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The Future of PCB Designs

11-28-2018

Duane Benson designed his first PCB using tape and etch-resist pens from RadioShack. He penciled the schematic on graph paper, drew the layout directly onto the single-sided copper-plated board, and then etched it. At the time, commercial PCB design wasn’t too different. In his column, he talks about the advancements in PCB design and the key considerations when designing boards.

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Top 5 Things to Know When Moving from Hand Assembly to Robotic Assembly

11-14-2018

A lot of factors go into the decision to hand-build or outsource circuit boards. When the decision is to outsource, there are a few important things to consider. Some things that work fine when hand soldering may stand in the way of quality, repeatability, and reliability when machine assembling. Here are some of the most important considerations when changing from hand-build to outsourced.

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Top 5 Ways to Mitigate PCB Component Availability Problems

11-07-2018

The electronics design world is by now aware that we're in a very serious period of components shortages. Allocation and shortages hit every few years, but this one seems to be the worst in recent memory. It could be a problem until 2020 and the supply chain and world of components manufactures will likely be a different animal coming out of it. Here are five things you can do to minimize the effects.

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