Design007 Magazine

PCBD-Sept2017

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14 The PCB Design Magazine • September 2017 PREDICTIVE ENGINEERING: HAPPY HOLDEN DISCUSSES TRUE DFM tion can build it? The Japanese did this because they wanted to build all these first-generation products in a building next door in Japan and not ship it offshore like Americans were doing. Contrast that with Apple Inc. Apple de- signs products that are impossible to auto- mate. They're so complex. They're really fanciful, but they have to be built by human hands. You've got 86,000 17-year-old teenage girls in Shenzhen building these Apple prod- ucts. Foxconn put up money to install 1 mil- lion robots to replace these girls. Today only about 400 robots have been installed out of that 1 million, because they found out the products they're building for the Americans can't be automated. I refer to DFM as being designed for manu- facturing the first time. We're not just design- ing it, running software, finding the errors, go- ing back, redesigning it, checking again, going back and re-spinning it, until it works. I'm alone in this defini- tion unless you happen to be knowledgeable about Dewhurst and Boothroyd, which most people in printed circuits aren't. Andy Shaughnessy: I would imagine. Holden: Manufacturers such as General Electric, Westinghouse, or General Motors, understand Dewhurst and Boothroyd, be- cause it's taught at universities. The automotive guys are really big on trying to simplify parts in automobiles to make them more reliable at lower costs and easier to be built up by auto- matic systems. But in electron- ics, it's never caught on. One of the reasons is that Dewhurst and Boothroyd were mechanical engineers. They worked off the kinematics of how many motions it takes to assemble something. How much fixturing, connectors, or screws and bolts it takes to put something together. That's their predicting methodology. The simplest form of automation is the one- axis pneumatic cylinder, or air cylinder. It just goes up and down. If you're going to assemble something on a conveyor belt, with just up and down motions, that's the cheapest automation. Some of the most complex assembly is assem- bling flexible circuits, which I managed for Fox- conn. It's one of the reasons they kept showering me with money to automate out these 8,000 girls I had in Shenzhen who would do the final non-conformal part assembly of flex circuits, because they would work for six months on Apple products. When Apple stopped ordering after Christmas, the girls would sit around for the next four months and knit, because there were no orders. We couldn't fire them or lay them off because they were too highly skilled. Figure 1: Predictive engineering contains more than just "density modeling." It provides caution on "failure-prone components" and "suitability for test," as well as optimizing electrical performance and minimizing signal integrity problems.

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