At the conclusion of our webinar, PCB Design: Top Factors Related to Data Routing and Layout, several questions were submitted to our presenter, Angie Brown, Product Manager of Printed Circuit Boards at Epec. We have compiled these questions into a readable format on our blog.
Q&A From Our Live Webinar
Quick Links:
- What pushes cost and communication away from the standard quote and order?
- You mentioned impedance controls several times. Could you explain a bit more why maintaining consistent impedance is so important for PCB performance?
- Does Epec provide layout services?
- How do you determine design rules for setting up your routing and layout?
- At what point in the PCB design process should our team ideally reach out to your manufacturing experts to ensure we avoid any last-minute design issues?
- What are some common mistakes or oversights that you frequently see in PCB designs submitted by customers, and how can we avoid them?
Watch the Recording Below:
Question: What pushes cost and communication away from the standard quote and order?
Answer: When controlled impedance, high voltage/current, non-standard components, or flex layout and routing are involved, it is best to review and then collaborate on a call to be sure we fully understand the project.
Question: You mentioned impedance controls several times. Could you explain a bit more why maintaining consistent impedance is so important for PCB performance?
Answer: Impedance is impacted by copper weight, trace length, trace width, and the dielectric from where the impedance layer is. As we look at the impedance values in our PCBs and we develop the layout and the routing of it, we know where to place them. We know their length, and we also know how to test them. Running the test values at design routing and layout gives us the room to make changes. It also gives us the room to look at stack-ups. What we can currently do with common stock. To make changes to those trace widths so they'll be compatible with what you need. Testing comes into play in manufacturing. So, all in-circuit testing for impedance is done on-site at production.
Question: Does Epec provide layout services?
Answer: We do the layout and the routing with our supply chain (our design group that we have across the United States). We have some outsourced suppliers as well. We work very closely with our domestic team of designers to do the routing and the layout because most of our customers are here as well. And being on the same continent, not necessarily the same time zone, is advantageous for communication.
Question: How do you determine design rules for setting up your routing and layout?
Answer: We determine the setting or rules by the bill of materials (BOM), schematic, and by following the standard. IPC-6021, primarily driven by voltage and current requirements.
Question: At what point in the PCB design process should our team ideally reach out to your manufacturing experts to ensure we avoid any last-minute design issues?
Answer: PCB designers and our PCB engineering team work closely together. The design is completed at our design group and passed to engineering, where they do a full design for manufacturing (DFM). They go back and forth with the design team if needed and make any changes or suggested corrections. And then we'll receive back the data set again from routing and layout, and we'll do another complete DFM on it. You don't receive the design package completed until we have reviewed it fully in engineering and where confident that it can be processed with ease through manufacturing.
Question: What are some common mistakes or oversights that you frequently see in PCB designs submitted by customers, and how can we avoid them?
Answer: That's a loaded question. But some of the things that we see are bundled space and trace. So, you have a three-mil circuit, three-mil spacing, and you bundle them together, so now, you have a set of 15 traces that are up against each other that are only 3-mils wide, 3-mils spacing. Adding just a half a mil of space between those 3 mil traces makes manufacturing so much easier. Pad-to-hole ratios, not considering annular ring, not supplying any kind of netlist testing or netlist data to us so we can test out your data to be sure it's correct, missing drawings, and missing drill programs; just not enough information sometimes coming in the door.
