Castellated Holes Done Right: Mechanical and Electrical Trade-offs
For modules that solder onto motherboards — when castellation is the right answer, and when it bites you.
Layer-Up Engineering·4/27/2026Castellated edges turn your PCB into a surface-mount module. They're elegant — until your reflow profile gets uneven.
When castellation wins
If you're building a Wi-Fi module, an ESP32-based daughterboard, or any "PCB on a PCB", castellation is the right move. It's mechanically simple and visually inspectable.
When it bites you
Half-plated holes have asymmetric thermal mass. If your customer's reflow oven runs cold, you get cold joints on the castellated edges first. The fix: insist your customer uses a longer soak — or move to land-grid arrays.