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JUNE 2021 I DESIGN007 MAGAZINE 23 engineers are becoming the most sought-aer technologists in the industry. We have new ways to manufacture fine lines to fit the components and keep up with the speed of the circuits. Flex designs are being embedded into clothing and fabrics. Medical breakthroughs are happening with laser technology and artificial 3D printed devices becoming commonplace. Space is finally being explored once again. Maybe we'll actually venture out to other plan- ets, both within our solar system and beyond. Hopefully, this will happen before I hit 100 years old. But I hope to be designing boards until then. Star Date 2028 "ere is a way out of every box, a solution to every puzzle; it's just a matter of finding it." —Captain Jean-Luc Picard DESIGN007 Cherie Litson is an instructor at Everett Community College in Lynnwood, Washington. Redesigning a printed circuit board is a chore that no one likes. Respins of printed circuit boards cost money, delay the sched- ule, and just aren't enjoyable for anyone. Yet, many companies are not taking advantage of avail- able tools that can reduce—and i n m a n y cases elim- inate—PCB respins. Instead, issues that make the PCB d i f f i c u l t o r i m p o s s i b l e t o manufacture are found late in the process, even by the fabricator or assembler. The later in the process, the greater the cost to fix—and it's not linear. There are many causes that commonly result in a board that is either impossible to fabricate or assemble, or would produce such a small yield that the cost would be out of range. When- ever this happens, the board must be redesigned to correct the problem before manufac- turing can commence. Often issues are not caught early because of lack of insight to the fabrication/assembly process, and inability to detect the problems visually. A design may appear to meet specs for trace width, but a particular manu- facturer may not be able to maintain a minimal-width trace due to undercutting. This is something that would not normally be in a PCB designer's realm of knowledge. The key to avoiding respins is to employ design for manufacturing (DFM) tech- niques, not just before releas- ing to manufacturing, but all throughout the product design and creation process. Here are five ways that DFM can help you reduce or even eliminate PCB respins by employing Sie- mens PCB DFM solutions. Every PCB design begins with a stackup. The top and bot- tom must be aligned as well as any signal and planes in a multi- layer board. Stackup issues are one of the top reasons that res- pins are required. With higher and higher edge rates, material selection becomes more criti- cal. The traditional methods of using a spreadsheet to define the stackup has run out of gas for today's speeds. To read this entire article, click here. Hate PCB Respins? Five Ways to Reduce or Eliminate Respins Patrick McGoff

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