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74 DESIGN007 MAGAZINE I AUGUST 2020 nents. We have to consider that we may go to a 180°C material, which is a noticeable cost difference in volume. It might only be 20–30 cents more per board, but if you multiply that by one or two million, it can kill a project. We want to expose the customer to expectations early on; the best way to do that is to commu- nicate early on in the design cycle. Johnson: What needs to be communicated to the designers as they're doing their designs? Dack: In the design and manufacturing world, I'd like to see more communication and col- laboration between the customer, design, and manufacturing. To do that, it goes back to organizations like IPC and the PCEA to foster that. For example, the PCEA is presently col- laborating with the SMTA as they both want to incorporate more designer information to their people up front. Johnson: That helps create more opportunity to have those conversations, but what happens right now? Do you have these conversations with your customers about design rules only after the quote has been received and priced out? Dack: About 95% of the communication occurs after the design review if it even hap- pens at all. Manufacturers are accustomed to not complaining during DFM reviews, as anything they point out might be considered a capability weakness. Personally, I think it is because they don't want to lose the quote; they want to submit a low price so that they will win the business. Once the quote is won, weeks or months have gone by, and the order starts, that's when the EQs come out, such as, "We can't etch this line using this thickness of copper foil because it's a poor design," or, "We can't plate the specified amount of copper in these holes. Will you accept a lot less?" Those are heavy-hitters. If we could establish a better audit up front and a more communicative audit of awareness between the customer and manufacturer, we'd waste less time. The problem still exists: Who is supplier management going to buy from? Supplier management is not technical; they're going to buy from the lowest complainer. That's just a fact of life. On the assembly side, it's similar. EMS pro- viders would prefer not to complain up front, win the quote, and then talk the customers through the issues, but 95% of the issues are not addressed at the time of build or contract. Hopefully, they'll work through it, and things can be manipulated or adjusted by time of build, but it's typically on the supplier to work through the problems; again, that's just the way it is. Johnson: What are some things you can't unsee from a designer's perspective? Dack: You can't unsee this stuff, such as 0201 components that are tombstoned or glass epoxy boards that are warped to high heaven. It's horrible and ugly and is a result of poor design, poor manufacturing capability, or both via poor communication. For example, when an unbalanced double- sided PCB assembly goes through its first-pass component placement, the stencil screening process, and on to the reflow oven, it goes in totally flat but comes out warped like a potato chip. Now, it must be flipped over for the sec- ond pass stenciling, which may or may not work well. But when it gets to the stage for automated placement of components for the second side, the warpage sets up a resonance on the board. I've seen components placed onto the surface of a PCB that was so warped, the springy con- dition caused a vibration to set up on the PCB; as the placement heads came into contact with the bouncing PCB surface at the end of the placement process, this caused the com- ponents placed at the beginning of the run to bounce off the board like popcorn! It was another crazy anomaly that I'll never unsee. Johnson: Kelly, thanks for taking the time to speak with me. Dack: You are very welcome, Nolan. DESIGN007

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