Issue link: https://iconnect007.uberflip.com/i/1525004
14 DESIGN007 MAGAZINE I AUGUST 2024 reliability. It takes more time, skill, and expe- rience to keep a tighter design using through- hole vias, and it's not always possible depend- ing on the pitch of parts, or other electrical requirements, but when it is, that can be worth it in saved manufacturing cost. is brings up another cost adder that designers and customers may not think about, which is the tradeoff of one-time/upfront costs in design vs. repeated costs in manufacturing. ere is oen a push to get a design to fabri- cation as quickly as possible. However, if the designer just had a bit more time, maybe the design could've been done without microvias or via-in-pad, or maybe they could've done it in fewer layers. Designers should try to push back on unrealistic customer schedules and expectations and help explain the benefits of taking the time to do it "right." Remembering that PCB design is fairly late in the product design lifecycle, designers are usually pres- sured to make up time and are given unrealis- tic schedules. is leads to mistakes or short- cuts that can result in scrapped boards, which means respins, and that means a lot of lost money and time. Take time to learn about how the fabrica- tion process works. It is a common mistake for newer designers to create via structures that are impossible to fabricate or stackups that are overly complex and add unnecessary lamina- tion cycles. Sometimes customers drive these complex stackups; designers should push back and help the customer understand the fabrica- tion process and how additional lamination cycles drive up cost. Customers can also be the ones driving use of tight aspect ratio holes or tight placement of parts. Help them under- stand the risks. Similarly, take time to learn about how the assembly process works. I've already talked about several assembly issues related to panel- ization, but something as simple as component placement can drive up costs. Don't place very tall parts next to very short parts. Don't place through-hole parts very close to SMT parts. Space out your parts as much as you can, so rework is a possibility. Make sure to turn those courtyards on while you work on placement. Also, remember to add fiducials, both on the board and on tight pitch, larger BGA, QFN, and other leadless packages. IPC standards exist for a reason. Know them. ey aren't just suggestions. Whenever possi- ble, follow them for both PCBs and PCBAs. If you are knowingly violating a standard, try to The footprint was incorrect for this part. You can see the part upside down in the middle and in two locations it was to be placed right underneath the part body. Since this was a pick and place part, the issue wasn't found until X-ray inspection after assembly reflow, so the parts had to be manually removed from each board and the boards cleaned up. As this was a multi-lam build and expensive, we wanted to salvage the boards. This mistake ate up time for everyone. It was a prototype run that was fixed on a later rerun. (Right) What we chose to live with after replacement part.