Rapid Prototyping and Manufacturing Tips from Electronics Expert Duane Benson
Judy Warner: Duane, please share briefly about your background in the electronics industry.
Duane Benson: I first burned my fingers with a soldering iron when I was about fourteen. Though I was formally trained and started my career in software development, my first love has always been electronics. My early hardware projects included an electronic stethoscope used to listen through walls for termites chewing on wood, and a caller ID device before caller ID was commercially available.
Duane Benson Technology Marketing
My career took me from software to product management and then into technology marketing and writing. All the while, I kept up with the chips. I’ve been building microcontroller boards, small robots, and experimenting with FPGAs as my after-hours avocation for about two decades now. More recently, I’ve been using these projects and experiences as raw material for articles and speaking subjects in technical and industry magazines, websites, and events.
Warner: Milwaukee Electronics and Screaming Circuits are both EMS companies. Can you tell us about the history of each and what makes one unique from the other?
Screaming Circuits Facility in Canby, Oregon (USA)
Benson: Milwaukee Electronics started in 1954 designing and building industrial controls for mining equipment. The company was purchased by Michael Stoehr in 1985 and broadened its clientele as a full-service contract manufacturer. Stoehr, with an electronics engineering background, brought a more customer-focused approach to manufacturing that guides the organization to this day.
The Screaming Circuits division was created in 2003 to address the emerging need for rapid prototyping and non-traditional manufacturing. With downsizing and increasing global competition, the old ways of waiting weeks for a prototype or only building to a forecast were no longer serving the needs of the engineer.
The main difference between Milwaukee Electronics and Screaming Circuits is in the way orders are quoted, taken, and processed. Milwaukee Electronics builds products based on long-term contracts, forecasts, and Kanban arrangements. Screaming Circuits builds products based on transactions. Quoting can be done online and each order, whether it’s for one board or a few thousand, comes in as an individual transaction. We may see many repeat orders, or we may never see the board again. This transactional manufacturing works very well for prototypes, R&D, high-end custom designs, and hardware startups.
Warner: What are a few key things you wish designers understood about board assembly that would make their lives (and your life) easier?
Benson: First and foremost, that component polarity is not obvious. It may seem easy since a diode can only go one of two ways, but the marking “standards” are anything but standard; especially with LEDs. Some manufacturers mark the cathode. Some mark the anode. Some LEDs, from the same manufacturer in the same family, use the same mark for the cathode on one part and the anode on the next part in the product line. One should never assume an assembly partner can easily figure it out.
Don’t trust a footprint if you don’t know the source. Crowdsourced footprints are nice, but people make mistakes. Quite often the zero degree rotation orientation doesn’t match the IPC standard, which can throw off automated equipment. Some components may have variants with different pinouts, and that isn’t always captured by the footprint designer. Your best bet is to always double check the pinout, package, orientation, paste, mask, and polarity/pin one marking before relying on a footprint.
Ambiguity is the enemy of quality and speed. In rapid prototyping and on-demand manufacturing settings, every minute counts. Ambiguous markings, unclear data, or incomplete documentation often leads to quality defects or late shipments.
Warner: Since solder paste applications account for 65% or more of anomalies in SMT assembly, what do you do to increase your yields and reliability?
Benson: Solder paste accounts for a much smaller incidence of issues here at Screaming Circuits. It has to do with experience and technique. Since we build so many different boards, we see virtually all new component packages and learn about what makes them tick very quickly. We use both stencils and paste jet printers, depending on which works best for the most challenging component on a given board. We’ve gotten pretty good at picking a proper reflow profile as well as customizing the paste cutouts, both of which help tremendously in keeping paste problems down.
Warner: What level of concern do counterfeit parts have on your business and what type of risk mitigation activities do you use?
Benson: We carefully vet our suppliers and don’t touch the grey market. We have had very few instances of counterfeit parts over the years. It almost never happens due to the efforts of our diligent purchasing and supply chain departments. Where supply chain is concerned, we only deal with people we can trust. Going with non-reputable suppliers just isn’t worth the risk.
Warner: You are the author of a small periodical called Circuit Talk. What motivated you to publish this and what kind of response have you gotten from readers?
Benson: Electronics design has changed so much over the past few decades. Support staff in engineering departments has been drastically cut. Older engineers that used to act as mentors have retired or are too busy to do so. The typical design engineer now has to do so much more than creating a schematic.
Because Screaming Circuits sees so many different components and techniques, we have a unique opportunity to learn from that and help educate the engineering world. Every day we see the results of designers, through no fault of their own, not having been properly trained on layout, library management or documentation. We can help alleviate those problems. I’ve made it my mission to pass on as much of this knowledge as possible. Teaching designers what we have learned makes their lives easier, and ours in turn, as well.
Warner: What is your favorite and least favorite part of the EMS business and why?
Benson: My least favorite part? The thought of leaving it (which I have no plans to do). There was a time when I thought manufacturing would be boring. Maybe it was once, but it’s certainly not here. That’s what I really love about it. We have customers that put wirelessly connected motion detectors in sea turtle nests to help the little hatchlings get to the ocean safely. We’ve built boards that helped detect gravity waves — predicted by Einstein in 1915 and finally detected in 2015. We have boards in space, deep underwater, and just about everywhere in between. Things that will be out in the world next year are here in our shop now. At Screaming Circuits, we’re in touch with such an amazing future; I really can’t imagine doing anything else.
Warner: Me neither! Thanks very much for your time and insight, Duane.
Benson: My pleasure, Judy.