Circuits Assembly Online Magazine - Features

Features Articles

Mike Buetow Still inspired by the session on the “The Future of PCB Engineers” from PCB West last fall, I spent my early December poring over courses at universities across the US, looking for signs of printed circuit board instruction. I’m happy to say it was a fruitful exercise.

Mike Buetow Speaking, as we were last month, about roadmaps, their role, who uses them and how, I call your attention to the retrospective that begins on page 27 of this month’s issue. It’s a reflection of the early days of the IPC Roadmap, which was published some 25 years ago.

As with our other year-end retrospectives on the introduction of RoHS and its effective ban on leaded solder and the launch of the IPC Designers Council, we wanted to capture the recollections of those who were on the front lines of the project. (A sad omission: Dieter Bergman, the project’s biggest champion and perhaps the one person most responsible for the first couple iterations, passed away in 2014. I still miss you, Big Guy.)

In 1993, of course, the electronics supply chain was a very different animal. Outsourcing wasn’t new, but it hadn’t taken hold in all corners, especially assembly. AT&T, IBM, H-P, Texas Instruments and Digital Equipment were among the leaders in vertical manufacturing. Many technologies accepted as routine today (SMT and HDI among them) were still finding their way – or hadn’t even made it off the drawing board.

Peter Bigelow Your most valuable asset may be the ability to access critical information in real-time.

“What’s your company’s most valuable asset?”

It’s a question asked by customers and investors for years, perhaps decades. Yet, regardless of who is asking, or why, it always sounds like a trick question. I wonder, however, whether it is the question, or the ever-changing answer, that really is the trick!

The typical response is “our employees” or “our facility” or maybe “our customers.” All credible and understandable responses. But value, like technology, is a fickle metric.

At a recent industry event, I was looking for equipment and materials that might be valuable additions to my company’s capabilities and assets. Various mini technical presentations were on the show floor. Each lasted only a few minutes and covered everything from esoteric theory to what seemed to me at least micro-minutia on a very specific topic. Caught in foot traffic at the intersection of several booths, I paused just long enough to catch one session that was, indeed, more than thought-provoking. That presentation was on a topic I had previously little interest in, let alone understanding of: data.

Sue Mucha Calculating costs to move physical gear is much simpler than predicting inefficiencies of new locales.

As I write this, a trade deal with China that will eliminate the tariffs appears to be in development, but China is continuing to talk tough. The tariffs are causing significant pain to manufacturers in both the US and China, so I suspect some type of deal will happen eventually. In the meantime, the tariffs motivated many companies to look hard at the geographies involved in their outsourcing strategy. Some OEMs have moved or are in the process of moving some of their business, and a much larger number are thinking about it. I think it is important to carefully weigh the pros and cons.

The potential benefits of moving include:

Unit price decreases related to moving to a lower-cost labor market.
Elimination of tariff liability on all or part of the product.
Cost reductions related to moving projects to better-fit regions.

Clive Ashmore In the first of two parts, our columnist looks at the printability of Type 5 and 6 pastes.

In understanding the dynamics of reliably assembling metric 0201 components, an analysis of all key process steps – printing, placement and reflow – is required. While effective printing is central to the success of steps down the line, the reality is that with dimensions this small, the integrity of all elements is critical. With this as the backdrop and informed by previous analysis of metric 0201 printing, our company engaged in comprehensive evaluation of metric 0201 assembly, beginning with printing and the most viable materials for the job. This column will present findings on the stencil printing investigation, and, in a departure from the normal “printing” focus, the next column will reveal the placement and reflow study results.

To begin, we wanted to gain an appreciation regarding the effectiveness of certain solder paste materials. In full disclosure, this was not an exhaustive evaluation of multiple solder paste suppliers’ materials. Rather, our team selected two suppliers and three materials with which we have had past success. This is an important point, as not all materials are created equal and, in evaluating Type 5 and Type 6 solder pastes, it is imperative manufacturers test them under specific manufacturing conditions with specific tool sets, as all variables play a role in performance.

David Bernard Voiding under edge terminations is often overlooked, to the detriment of yields.

My last column focused on voiding under QFNs. Primarily, this concentrated on voiding under the central termination. As I discussed, the potential for voiding in this area is high, owing to the limited available escape pathways to remove outgassing volatiles created during reflow from under the center of these planar objects. This can result in the often-typical voiding issues that are usually clearly seen in their x-ray images. Therefore, this can then be the natural and easy focus for an operator to concentrate on as the location of the likely fault or failure, even if the “substantial” level of voiding may be acceptable from a supplier and customer point-of-view. With voiding (when present) usually being so obvious, yet probably at an acceptable level, once the central termination has been considered and passed by the operator, then the edge terminations may not then be fully considered, or possibly even ignored completely, as the potential source of problems. Therefore, I would like to present some images of good and bad QFN edge terminations to highlight some of the features that may be seen in the x-ray images to indicate the problem could be at the edge and not in the center.