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46 DESIGN007 MAGAZINE I SEPTEMBER 2023 of the advances we have seen in smartphones and other portable electronic products. Even though most smartphones don't have foldable screens, there are myriad interconnections required between the various features of the modern smartphone: camera, screen, speaker, microphone, GPS, gyroscope, memory stor- age, and yes, the telephone. While original rigid-flex circuit designs sought to minimize the number of connec- tors, the number of low-profile flex connec- tors found in modern cellphones is impressive. Assembly appears to involve a lot of delicate handwork, which doubtless contributes to cost. Watching a few YouTube video teardowns helps me appreciate just how important it is to build in product reliability for these amazing products because rework is clearly not an inex- pensive activity. e adage, "Knowledge is king," is impera- tive when it comes to rigid-flex design. e importance cannot be understated that we must fully understand the intricacies of rigid- flex manufacturing in advance of setting out to design such a product. Many useful articles and publications on rigid-flex circuits exist online, including on manufacturers' websites, all aiming to educate their customers and for the greater benefit. Most rigid-flex manufacturers have instruc- tive websites and self-published books in some cases. I highly encourage you to visit the eBook library at I-Connect007, where you'll find a wide range of topics published by sub- ject matter experts. Tap into this resource and greatly expand your knowledge. One of the best ways to avoid potential pit- falls is to engage with the manufacturer early in the design process. In a previous column, I wrote about the increasing importance of making the manufacturer part of the design team. ere are many "design for" recommen- dations out there: design for environment (or excellence), design for testing, design for reli- ability, and as mentioned, design for manu- facturing. But designing with manufacturing may be the most important design advice of all. Oen, the manufacturer has "seen it all" and, if consulted early in the design process, can greatly increase your chances of first-pass design success. at "seen it all" idea reminds me of a comment from John Wooden, the Hall of Fame basketball coach from UCLA, who said, "It's what you learn aer you know it all that counts." at was an important reminder as this technology has never stood still; it has continued to change and evolve. Because they are so close to the flow, the manufacturer will typically be a great source of guidance. In conclusion, while oen seen as an expen- sive interconnection technology alterna- tive due to the higher degree of engineering required to produce it, rigid-flex circuits in the long run can be a much more cost-effective solution. Reducing the size, weight, and power (SWaP) requirements of products will always be overarching objectives in product develop- ment, and are intrinsic benefits of rigid-flex circuits. However, many buyers don't oen appreciate that it's not just cost in, but cost out the door that must be considered when making purchase decisions. Repackaging and condensing the words and thoughts of some historically great qual- ity gurus of the industry, in general, I now conclude (at least to my own satisfaction) that to succeed in product design, rigid-flex, or any other product, one must first do the right things and then do those things right. Enjoy your rigid-flex design journey, and stay flexible. DESIGN007 Joe Fjelstad is founder and CEO of Verdant Electronics and an international authority and innovator in the field of elec- tronic interconnection and packaging technologies with more than 185 patents issued or pending. To read past columns or contact Fjelstad, click here. Download your free copy of Fjelstad's book Flexible Circuit Technology, 4th Edition, and watch his in-depth workshop series "Flexible Circuit Technology."