IPC International Community magazine an association member publication
Issue link: https://iconnect007.uberflip.com/i/1546209
24 I-CONNECT007 MAGAZINE I AUGUST 2026 FLEX007 | F L E X C O N N ECT I O N S worked in various PCB manufacturing environ- ments, including production, prototype, and R&D, each setting provided distinct technical and process-related insights, and reinforcing the importance of anticipating downstream challenges and planning several steps ahead to ensure successful execution. Thousands of PCB designs have crossed my desk over the years. Most have been practical manufac- turing designs with requirements aligned to avail- able process capability. Others, however, included specifications and layout decisions that were diffi- cult to justify from a manufacturing standpoint. Here are a few examples that illustrate the "just because you can doesn't mean you should" idea. From Tape to CAD When I started, PCB artwork was created with tape on enlarged layouts. Every change took time and effort, so designers naturally thought carefully be- fore making one. You didn't make a design more complicated unless there was a good reason. Today's software allows us to make changes almost instantly, which is an incredible advantage. But that same convenience also makes it easy to add complexity without stopping to ask whether it's necessary. But just because your software lets you route one more trace through a congested area doesn't mean that's the best engineering solution. Sometimes moving a component or changing the stackup creates a board that's easier to manufacture, easier to inspect, and ultimately more reliable. Tolerances One example I've seen many times is dimensional tolerances. Designers can specify incredibly tight positional tolerances for connector holes, pads, and other critical features. I've seen flex designs where every bend area carried unnecessarily tight fabrication requirements. Sometimes that's exactly what's needed. But just because you can specify a tighter toler- ance doesn't mean the product requires it. Every tighter tolerance limits your manufacturing options. It may increase cost, extend lead times, and reduce the number of suppliers capable of building the board, all without improving how the product actu- ally performs. That same principle applies to highly dense routing combined with fabrication requirements that only a limited number of suppliers can meet. While modern layout software makes extremely challenging designs possible, those decisions must still be evaluated against program cost targets, schedule constraints, and practical manu- facturability. IPC Class 3 I see the same thinking when IPC Class 3 gets spec- ified. It's easy to assume that asking for the highest level of workmanship automatically produces the best board. But just because you can specify Class 3 doesn't mean your application benefits from it. Class 1 applies to products for which the primary require- ment is the basic function of the completed assembly. Class 2 applies to products that require continued performance and extended service life, where uninterrupted operation is desired but not mission-critical. If the product truly requires a Class 3 high perfor- mance/harsh environment, then it's absolutely the right decision. But if the product is really a Class 2 application, you've added inspection, documenta- tion, testing, and cost without adding value to the customer. Class 3 generally carries the highest fabri- cation and verification cost, and it can extend lead time depending on the qualification and inspection requirements imposed. This becomes especially important in flex and rigid-flex designs, where manufacturing complexity is already higher than in conventional rigid boards. Each IPC class establishes distinct acceptance criteria, including annular ring dimensions, copper plating thickness, and allowable feature-level anom- alies such as nicks, pits, and other discontinuities. Working With Flex Flexible circuits allow us to do some remarkable things today. We can create incredibly dense rigid- flex designs with multiple bend areas, exotic materi- als, and complex constructions. But just because a design can be built doesn't necessarily mean it should be built that way. Some- times a slightly larger bend radius, a simpler layer