01 What happens
- CNC drills PTH and NPTH; laser drills microvias on HDI. Slots are routed or punched.
- Drill size in CAM is often a bit larger than finished hole after plate.
- Entry/exit material and hit count keep the bit from wandering on small vias.
PCB / Drilling
Bare board · 04
Drilling
Holes for vias, PTH and mounting. Aspect ratio and min hole decide whether the quote is real.
02 On an ESP32 board
- ESP32 modules usually want vias that a cheap fab can plate: finished 0.2–0.3 mm is safer than heroic 0.1 mm.
- Mounting holes and connector NPTH must be called NPTH or they get plated shut.
- Via-in-pad under a QFN or module needs fill and cap, not an open barrel under paste.
03 What usually fails
- Broken bits, nail-heading, or holes off pad (breakout).
- Aspect ratio too high for the fab’s plate line — voids in the barrel.
- NPTH plated because the layer was wrong.
04 What we check
- We check min hole, annular ring and whether via-in-pad is specified as filled.
- We do not send a first ESP32 board out with HDI tricks unless the module footprint forces it.
← Previous step: Lay-up and laminationNext step: PTH and copper plate →
中文
PCB工艺 / 钻孔
光板 · 04
钻孔
过孔、金属化孔、安装孔。孔径比和最小孔决定报价是不是真能做。
01 这一步做什么
- 数控钻 PTH/NPTH；HDI 用激光微孔。槽孔铣或冲。
- CAM 钻孔通常比成品孔略大，后面还要电镀。
- 盖板和钻嘴寿命影响小孔是否偏。
02 落到 ESP32 板上
- ESP32 模组过孔尽量让普通厂镀得上：成品 0.2–0.3 mm 比硬上 0.1 mm 稳。
- 安装孔和连接器 NPTH 必须标明 NPTH，否则会被镀死。
- QFN 或模组盘中孔要填孔盖镀，不能在锡膏下面留空桶。
03 常见失败
- 断钻、钉头、孔破环。
- 厚径比超出电镀能力，孔壁空洞。
- NPTH 画错层，被镀上铜。
04 我们查什么
- 查最小孔、环宽，盘中孔有没有写填孔。
- 第一块 ESP32 板不玩 HDI，除非模组封装逼着你做。