Issue link: https://iconnect007.uberflip.com/i/1547450
56 SMT007 MAGAZINE I NOVEMBER 2026 F E AT U R E A RT I C L E Designing PCBs for Heat Staking: The Hole, the Head, and the Copper Around Them BY A L E X S P U RG EO N , U. S . H E ATSTA K E An engineer once sent us a board that had passed every electrical test his team could throw at it: in-circuit test, functional test, and a week of burn-in. Six months into the field, units started coming back with cracked ceramic capacitors and one intermittently open BGA. The schematic and solder were fine. The failure analysis traced it to the assembly step that nobody had questioned: The board was being ultrasonically staked into its housing, and every unit had taken a dose of 20 kHz vibration inches from its most fragile compo- nents. High-frequency vibration has its place in assembling plastic components, but next to a ceramic capacitor, it may as well be a paint mixer. The fix was to move the joint to heat staking— heat and steady pressure on the stud, no vibra- tion—and the returns stopped. Heat staking is one of the most common ways a PCB ends up mounted in a plastic enclosure, and it is routinely the last thing we think about. The mechanical engineer picks the process after the board is released; the manufacturing engineer inherits whatever geom- etry shipped; and the circuit designer—the one person who could have made the joint reliable for free—usually hears about it for the first time at a failure analysis meeting.