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MARCH 2026 I I-CONNECT007 MAGAZINE 81 positive planes on a desktop machine with a 386 processor and plenty of memory. Upon successful pouring, the challenge of using this new capability wasn't over. I had to output artwork files (massive for the time), which had to be sent over this new "internet thing." They would be received by the supplier, and I could then begin the time-consuming pho- toplotting process. Suppliers: "Ugh, positive data!" This new data workflow tied up photo- plotting for hours. So, what did we learn? First, the desire to design in WYSIWYG is not wrong; it is nat- ural. What made it a bad choice years ago is that processing and data transfer speeds were in the Stone Age. Today, modern layout tools offer many options for creating solid planes, split planes, iso- lated power "puddles," and just about any solid-pour require- ment imaginable. These options now pour and verify instanta- neously. That fact, coupled with advances in inter- net communication speeds, has virtually eliminated the challenge and, therefore, the main resistance to using the plane-pouring methodology. The Challenge to Practice DFM Whether you prefer positive or negative, we've come a long way in CAD design and PCB plane creation, yet after a decade working alongside PCB fabricators and EMS providers, I still see the same disconnects as when designers laid out power planes. From the fabrication side, the top issue is ignor- ing process limits tied to copper thickness. Design- ers often apply the same tiny thermal spokes used for 1-ounce copper to 3-ounce layers. Thicker cop- per demands greater clearances and wider spokes for reliable imaging and etching, regardless of the intended current capacity. TA RG E T C O N D I T I O N " Just because a board can be fabricated doesn't mean it can be assembled. My final advice: Avoid pouring poor pours." Next is the copper balance. Today's tools make it easy to pour planes into irregular shapes across adjacent layers, but inconsistent copper distribu- tion can introduce lamination stress, thickness variation, and warpage. What looks creative in CAD can be- come problematic in press. From the EMS perspective, the biggest complaint is insuf- ficient thermal relief. With au- tomated plane pours and easy solid connections, it's tempting to maximize copper for perceived perfor- mance. The result can be a through-hole lead tied directly into multiple heavy copper planes; it's a perfect heat sink. Now, assembly must heat the lead, pad, barrel, and several 3-ounce inner layers at once. That's a reliability risk waiting to happen. Electrical performance mat- ters, but if the joint can't be soldered reliably, the design fails in assembly. Thermal relief isn't a cosmetic CAD option; it's a manufacturing enabler. The goal isn't maximum copper, it's balanced copper. Designs must consid- er fabrication limits, lamination stability, and solder- ability from the start. Just because a board can be fabricated doesn't mean it can be assembled. My final advice: Avoid pouring poor pours. I-CONNECT007 Kelly Dack, CIT CID+, specializes in DFx-driven PCB design and applica- tions engineering at Pioneer Circuits, Inc. To read past columns, click here.