Issue link: https://iconnect007.uberflip.com/i/1398328
26 SMT007 MAGAZINE I AUGUST 2021 proto. What are some of the problems giving designers headaches when they switch from prototype to high volume? Dack: Yes, the first thing I can think of—and it happened over and over at a previous EMS supplier I worked for—had to do with commu- nication of the design specification for copper. Copper is a major component on the board and if we don't specify it, or we specify it unclearly, it causes big problems for manufacturability down the line. e supplier has to meet a spec- ification. If the specification is not clear, the CAM department is going to have to give you a phone call. is has to do with something as simple as specifying copper as base copper in the stackup vs. finished copper in the stackup. We like to design to finished specification. We like to make our current-carrying calcu- lations and our impedance calculations based on what the finished copper will be; however, that's subjective to the supplier where we have it manufactured. For instance, if we have a board manufactured at a high-end prototype shop onshore, and we ask for a full ounce of copper in the via holes, we can expect a full ounce of copper. And that can relate to current-carrying capacity. How- ever, if we don't specify that properly, and we just make an assumption, "Everybody supplies a full ounce of copper or a thousandths thick- ness of copper," and we make that assumption without a specification, then there is a poten- tial problem when that board goes offshore. ere's an understanding with offshore suppli- ers that they manufacture strictly to specifica- tion. And the fab might take something like an IPC-6012 Class 2 spec and go right to the part where it shows minimum/maximum of plating thicknesses and orient their processes from a timing standpoint and a cost standpoint, right to the minimum. I think it goes down to 80% of what we think we're going to get. I'm bad at standing math. It'd be 80% of a mil. at's a big one. Matties: How is digital twin, the automated or the AI factory 4.0, affecting this? Because with a digital twin, you have to have all these things answered and a recipe built in computer before you even send it to a fabricator or an EMS. Is that going to be more the case in the near future? Vaughan: I don't have a lot of experience in that area, but as the new technology comes online, we're seeing it all connected, whether it be CFX or some other platform, but we all see the IoT and digital twin conversation gaining trac- tion. It's on its way. Johnson: John, you were talking about a so- ware environment that could help facilitate communication, the transfer of the informa- tion up and down the supply chain. en, a few minutes later, we talked about how fabs and the EMS suppliers tend to hold some of their capabilities to their vest, considering it intel- lectual property. If, in a soware environment, we're creat- ing a place for that communication for the designer, the designer is going to need some soware modeling—simulation, if you will— of what will happen further down the manu- facturing chain. e designer should be able to see DFM rules that are detailed, characterizing what the fab can actually achieve on the board. ey'll need to see manufacturing capabilities and so forth, for part selection, if they're mak- ing those decisions. at's the rub: the so- ware is going to require the participants in the