Issue link: https://iconnect007.uberflip.com/i/1093246
36 DESIGN007 MAGAZINE I MARCH 2019 it was a long time ago, or a lot of them have never been. Teta: What's interesting is there are many differ- ent ways to build a board and get the same final product. Some board shops will do certain things differently, which doesn't affect the end use but can make it either cheaper or faster to build. It all comes back to understanding the board shop's capabilities regarding certain aspect ratio holes, HDI builds, or buried and blind vias as well as how quickly they can do things. You also need to know what final finishes they have, especially with some of the high-speed and RF applications where you can't necessarily use just any finish because that's going to affect your end board. It's super important to under - stand their in-house capabilities too. Via fill is something that not everybody can do. Again, Isola is one of our top suppliers, and we offer many of their materials that are glass- reinforced, which can help a lot due to the nature of the resin and how they're using it; then, they can use typical lamination cycles. A lot of the other materials, even some of the DuPont flex materials, need a higher tempera- ture press. Knowing what facilities have that capability is important before you go and design something in. Something might be per- fect for your application, but if you can only get it built by one or two fabricators, that's not always helpful either. Shaughnessy: And then we hear horror stories of people designing a board for 3/3 spaces and traces, for example, that they didn't know was going to be built offshore. A designer might build and design a board, but then the shop in Asia can't do it, and the designer has to redo it. Teta: I know this has been said a million times, but working closely with the board manufac- turer is critical. You need to know what their capabilities are and what they can do versus just designing a board and sending it to them. They might have to make modifications, which delays the whole process. Make sure that you can manufacture it easily. Anything can be done, but it might take much more time and have a lower yield, which is never good. We work hand-in-hand with suppliers, designers, fabricators, and OEMs to ensure a viable path- way. We're all in this together. Shaughnessy: Is there anything else you want to mention? Teta: I'm very lucky. I entered the industry at a very good time, and there are going to be a lot of opportunities coming up. Shaughnessy: Definitely. It was great talking to you. Thank you. Teta: Thank you. I appreciate it. DESIGN007 Trisha Andrew, materials chemist at the University of Mas- sachusetts Amherst, and Linden Allison, her Ph.D. student, have developed a fabric that can harvest body heat to pow- er small wearable microelectronics such as activity trackers. Writing in Advanced Materials Technologies, Andrew and Alli- son explain that in theory, body heat can produce power by tak- ing advantage of the difference between body temperature and ambient cooler air—a thermo- electric effect. Materials with high electrical conductivity and low thermal conductivity can move electrical charge from a warm region toward a cooler one in this way. The researchers took advantage of the naturally low- heat transport properties of wool and cotton to create ther- moelectric garments that can maintain a temperature gra- dient across an electronic device known as a thermopile, which converts heat to electrical energy even over long pe- riods of continuous wear. This is a practical consideration to ensure that the conductive material is going to be elec- trically, mechanically, and thermally stable over time. (Source: University of Massachusetts Amherst) Materials Chemists Tap Body Heat to Power Smart Garments