A board passes design review. The paste prints, and a 0.4 mm QFP bridges on three pins. The QFN center pad traps flux gas and voids at 35 percent. None of this shows up in the schematic. It starts at the steel sheet that lays down the solder. SMT stencil design is the discipline that sets how much paste lands on every pad. It also decides first-pass yield before the oven heats up. This article gives the rules we work to on every new job. Short answer up front: size the foil to the finest pitch, hold the area ratio at 0.66 and the aspect ratio at 1.5, shrink apertures […]

A carton of bare boards lands on a customer’s receiving dock in July. Still, the box looks fine. Inside, one panel has a cracked corner. The pads on a second panel have dulled past their solderability window. And the bag that should have shielded the assembly turns out to be pink poly with no metal layer. However, nobody dropped anything and nothing went to the wrong place. The team simply never wrote a packaging spec. PCB packaging for shipping is the discipline that decides whether boards arrive solderable, flat, and intact. Short answer up front: four threats set the specification: moisture, electrostatic discharge (ESD), mechanical shock, and contamination. Bare boards […]

A procurement lead forwarded a quote that looked 30% below the field. Two weeks later the invoice arrived with a stencil charge, an expedite fee, and a component overage they had never seen. An accurate PCBA quote starts long before the price — it starts with the files you send. Send four things upfront and the number holds: complete manufacturing data (Gerber or IPC-2581), a bill of materials with real manufacturer part numbers, a pick-and-place/centroid file, and your test plus IPC-class requirements. We have reviewed thousands of RFQs, and the lesson repeats: complete packages quote in hours, incomplete ones drift by 20% or more before the first board ships. Short […]