PCB / CAM and DFM incoming

Bare board · 01

CAM and DFM incoming

The fab reads Gerber, drill and stack-up before copper is touched. Most boards that fail in SMT already failed here.

01 What happens

  • CAM imports Gerber/ODB++, Excellon drill, stack-up, netlist and the fabrication drawing.
  • Engineers check min trace/space, annular ring, hole-to-copper, soldermask dams, slot size and panel utilisation.
  • They may move copper, grow pads or change drill sizes so the job can run on their line. You should know what they changed.

02 On an ESP32 board

  • ESP32 modules need keep-out under the antenna; a CAM operator who floods copper there kills range.
  • Impedance notes (USB, RF, DDR if any) must be on the stack-up, not only in a chat message.
  • A 2-layer ESP32 sensor board is simpler than a 4-layer S3 panel board — say the layer count in the drawing, not only in the filename.

03 What usually fails

  • Missing NPTH, wrong units (inch vs mm), or outline on the wrong layer.
  • Pads smaller than the stencil can print; QFN thermal pads with no paste-split.
  • Silkscreen over pads, or via-in-pad with no fill specified.

04 What we check

  • We review the same list before you order: footprint vs datasheet, antenna keep-out, paste on QFN, and whether the fab can actually make the min space.
  • If CAM must change copper, we want that marked. Silent CAM edits are how RF boards come back dead.

Next step: Inner layer image and etch →

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PCB工艺 / CAM 与 DFM 来料

光板 · 01

CAM 与 DFM 来料

工厂在动铜之前先读 Gerber、钻孔和叠层。很多 SMT 才爆的问题，这里已经埋下了。

01 这一步做什么

  • CAM 导入 Gerber/ODB++、钻孔、叠层、网络表和工艺图。
  • 检查最小线宽线距、环宽、孔到铜、阻焊桥、槽孔和拼板利用率。
  • 他们可能挪铜、涨焊盘、改孔径。你要知道改了什么。

02 落到 ESP32 板上

  • ESP32 模组天线下方要净空；CAM 把铜铺进去，射频就废了。
  • 阻抗要求（USB、射频）必须写在叠层上，不能只在聊天里说。
  • 两层传感器板和四层 S3 板不是同一档，层数要写在工艺图里。

03 常见失败

  • 漏 NPTH、单位英寸/毫米搞反、外形画错层。
  • 焊盘比钢网开孔还小；QFN 散热垫没有分锡。
  • 丝印压焊盘，或盘中孔没有填孔说明。

04 我们查什么

  • 下单前按同一份清单看：封装对不对数据手册、天线净空、QFN 锡膏、工厂线宽做不做得出。
  • CAM 若改铜，要留痕迹。静悄悄改射频板，回来就是死板。

下一步: 内层图形与蚀刻 →