Stay Flexible!

Estimated reading time: 4 minutes

Now, isn’t that the mantra we all hear today? For me, it’s Tai Chi to maintain physical flexibility. But of course, that is not what we’re here for. We’re talking flexible circuits including all the variations of same, which is why we called this issue “The Wide World of Flex.” Because the world of flex is broad—and it’s rapidly getting wider.

We just came from a dynamic IPC APEX EXPO in San Diego. Spirits and optimism were high all around. We had fun with some new video equipment in our booth; IPC celebrated its 60th anniversary; the show floor was busy and so were the conference rooms; there was a really good PCB Executive Forum; I met a bunch of new people and a few that I have been wanting to talk with over the past year.

So, as mentioned, our topic this month is flex circuitry and it is more than apropos as the flex market is going nowhere but up. As more designers learn about the versatility of flexible circuits, not just the well-known bending and flexing, but building into unusual shapes and sizes. So we have a varied lineup of articles and columns covering many different flex types.

I asked All Flex’s Dave Becker to write a lead article about the different types of flexible circuits and he did just that. We gave it the title of our topic: The Wide World of Flex. Who knew there was more to this topic than just flex and rigid-flex?

Anyone who has worked with flex circuits knows that one of the most difficult problems is handling them during fabrication and assembly. Tara Dunn of Omni PCB supplies us with many tips to help improve in this area.

Next, John Talbot of Tramonto Circuits gives us a fine article on flexible heaters, an interesting market for flex manufacturers. He explains common uses of these heaters and then gets into detail on design criteria.

ESI’s Patrick Reichel continues the ESI series on laser processing with a discussion on process development. Discussing tradeoff choices, he advocates taking the time to test, document and adjust laser processes for specific materials and constructions to build a process library that reflects your company’s business goals.

It is unusual to have two articles by the same author or company in one issue, but this next column was just too perfect to pass up. So, we have a second piece by Becker, this one on dimensional stability in flex circuits, certainly one of the most challenging aspects of flex manufacture, especially as feature sizes and tolerances continue to shrink.

Did I mention that PCB designers are learning more about designing flex? What could be more perfect than a new e-book on just that subject, which brings me to our next article. In a short interview with the authors we learn about The Printed Circuit Designer’s Guide to...Flex and Rigid-Flex Fundamentals, which published March 1. The interview includes a link for downloading your own free copy.

As one would expect, nothing in electronics ever holds still. New processes, new equipment, and new materials are constantly being developed to address new products with new performance requirements. One of those new technologies is stretchable electronics. Andy Behr of Panasonic Electronic Materials gives us a great overview of the technology and also introduces a novel stretchable thermoset material that is being developed by his company.

Switching gears, we have both a column and article on final surface finishes. First, Mike Carano, of RBP Chemical Technology, discusses corrosion resistance of two final finishes, ENIG and immersion silver, and a new development that shows promise in preserving solderability and minimizing corrosion.

Following this is a MACFEST article by Tom Jones of Heriot Watt University (UK), whose research project was carried out at Merlin Circuit Technology. The project involved using ionic liquid technology in place of other, more dangerous chemistries in the ENIPIG plating process. Several tests were performed on the final finish including solder reflow and wetting.

Bringing up the rear this month is IPC’s John Mitchell with an inspiring column on advocacy. After explaining IPC’s Global Policy Framework in some detail, he tells us what we all need to do to get involved.

You’ve heard it here before, but I’ll mention it again: One of the most important events is IPC’s IMPACT Washington, DC, this year to be held at the beginning of May (see our Events page at the back of this magazine).

There has never been a better time to get your congressperson’s ear and make our collective voice heard (numbers do count in Washington, especially those of small business owners). And, as we keep hearing, “If you’re not at the table, you’re on the menu.” I’m sure you know what that means!

So, that’s it for March. Spring is showing a few weeks early here in Pennsylvania—Punxsutawney Phil got it wrong this year. (Of course, much can happen weather-wise in the next two months.) Next month our topic is high-speed materials, certainly a critical part of the PCB puzzle as the race for more speed continues.

A special callout to Gary Ferrari, FTG Circuits, my very good friend and colleague, who received the Dieter W. Bergman IPC Fellowship Medal at this year’s IPC APEX EXPO conference in San Diego. Congratulations Gary!

Patricia Goldman is a 30+ year veteran of the PCB industry, with experience in a variety of areas, including R&D of imaging technologies, wet process engineering, and sales and marketing of PWB chemistry. Active with IPC since 1981, Goldman has chaired numerous committees and served as TAEC chairman, and is also the co-author of numerous technical papers. To contact Goldman, click here.