Issue link: https://iconnect007.uberflip.com/i/1517668
82 PCB007 MAGAZINE I MARCH 2024 disabled—for someone who is partially para- lyzed or suffers from spastic muscular disorder. is full-body suit stimulates the muscles to help the wearer have better control over their muscles. It's done with electromagnetic pulses getting in touch with the muscles. e flex PCB was used to interconnect these impulse magnets, placed on the legs and arms, to the central controller which is placed on the chest of the suit. You can imagine the problems that could arise with such a flexible suit being bent in extreme and unpredictable ways. When I reviewed the long flex cable, I could imme- diately identify several weak spots in the wire routing of the traces and the placement of the via-holes. ere also needed to be an improve- ment to the stainless-steel reinforcement behind the flex circuit. So, I did the review and wrote an email to our client including pictures and my suggestions for product improvement. Aer just a few design review meetings over Microso Teams, the client was empowered to improve the design and construction of the suit, which also resulted in an improvement in their assembly yield. e flex PCB with the stainless-steel reinforcement was being assem- bled into some silicone, which was experi- encing high failure rates. With these design changes, we managed to decrease their failure rate in the field, almost eliminating the end- user quality claims they had been receiving. at was all due to the placement of the via- holes and the trace wiring design. And by cor- recting the wire design and securing via-holes under the part that was reinforced by the 0.2 mm stainless steel, the connection didn't get damaged when it was bent in unpredictable ways. ere are other minor things when you have a flex piece, like you need to have curved edges instead of sharp angles, or you must add tear- dropping on the via pads to ensure better connection to the traces. Small recommen- dations can lead to big quality improvements. In the case of the exoskeletal muscle stimulat- ing suit, the only thing this process cost was some engineering review time on our side and some reengineering by the designer work- ing in close cooperation with us. We saved them a lot of money, and possibly even their reputation in having fewer end-user quality claims. That all starts to roll down through the lifecy- cle of your product. Of course, the investment there is to make sure that you have a design iteration or two built into the design review process, not iterations in prototype builds. Yes, and it is important to understand the func- tionality of the product and to be involved as