Issue link: https://iconnect007.uberflip.com/i/773715
10 The PCB Design Magazine • January 2017 Andy Shaughnessy is managing editor of The PCB Design Magazine. He has been covering PCB design for 17 years. He can be reached by clicking here. turing costs are determined during the design stage. A lot of PCB designers tell me they haven't visited a fabricator in years, and some have nev- er been inside a manufacturing facility. Does the same hold true for designers of sheet metal and tooling? The push for DFM in the PCB world was in full swing by the 1990s. Designers swore they would never "throw the PCB design over the wall" again, so great was their devotion to solid DFM practices. DFM classes at industry confer- ences began filling up as designers tried to learn all they could about fabrication processes. De- signers began communicating with their fabri- cators from the beginning of the design process. By all accounts, the situation has greatly improved. Thanks, in part, to DFM techniques, many designs are now "right the first time." But fabricators are still receiving bad or incomplete data, especially from new customers. And some designs are still expensively over-constrained, leading to the dreaded phone calls to the de- signer at 4:45 pm on a Friday. This month, we focus on DFM, starting with our feature story by PCB designer and CID in- structor Kelly Dack. He explains how today's ad- vanced EDA tools have to be tightly controlled to achieve good DFM practices, even for issues as simple as copper-to-edge spacing, and why designers should check with IPC-2221 in such instances. In an interview, Gary Ferrari of FTG Corp. discusses the art and science of DFM tech- niques, and some of the most prevalent, yet eas- ily avoidable design process and data errors that fabricators encounter. We've also provided an index of the Top 10 recent DFM articles pub- lished by I-Connect007 over the past few years. Some of these useful articles have garnered thousands of views. We also have an interview with Altium's Rainer Asfalg, who explains what it means to be a designer, and why great EDA tools use automation to help designers deal with manufacturing data. We also have an article by Lance Olive of Better Boards Inc., a design bureau based in Cary, North Carolina. Lance discusses the many challenges related to selling EDA services in the 21 st century, and how design service providers can best differentiate themselves. And colum- nist Barry Olney details the proper placement of decoupling capacitors that are necessary to complement the power distribution network. I hope you all had plenty of rest over the hol- iday, because it looks like it's going to be a busy 2017. We'll be bringing you coverage of Design- Con, IPC APEX EXPO, and the CPCA Show in Shanghai, China. If you can't make it to these trade shows, don't worry; we've got you covered. Have a happy new year! PCBDESIGN TRUE DFM: WE'RE NOT THERE YET Spin-based transistors could replace conven- tional transistors in the future. Spin transistors require significantly less energy, but industrial conversion has so far failed due to the lack of a suitable material. A young scientist, Zeila Za- nolli, has found a novel combination of graphite and barium manganese oxide, which meets the contradictory requirements. The hybrid material allows both precise spin alignment and good spin transport, as demonstrated by simulations on supercomputers at the Jülich Supercomputing Center (JSC). Transistors are probably the most important basic building blocks of modern memory sticks and processors. The switching processes in a spin- based transistor, on the other hand, are based on changes in the electron spin, like all applications in the field of spintronics. However, the implementation of spin transis - tors is made more difficult by contrasting material requirements. Traditional semiconductors, such as those currently used in chip manufacturing, offer a strong spin-orbit coupling: the electron spin can be aligned well with an external field. New Hybrid Material for Spin Transistors of the Future