Excellon Drill Files for PCB Fabrication
1 resources tagged with "Excellon"
Excellon is the standard drill-file format Chinese PCB fabs expect alongside RS-274X Gerbers, and it tells the CNC drill where every hole goes and at what diameter. The common failure is a mismatch between the Excellon tool table and the Gerber pad sizes, or missing plated/non-plated distinction, which forces the fab to email back for clarification and adds days. We check that drill files, tool sizes, and the board outline agree before release so the panel runs without a query.
An Excellon file pairs a tool list with X/Y coordinates for each hole; if units, leading/trailing zeros, or plated-vs-non-plated flags are ambiguous, the fab guesses or stops. The pitfall is exporting drill data with mismatched format settings, producing wrong hole sizes on the finished board.
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FAQ
Do Chinese PCB fabs prefer Excellon or embedded drill data?
Most fabs accept RS-274X Gerbers plus separate Excellon drill files, and many now also take ODB++ or IPC-2581 which embed drill data. Confirm the fab's preferred package before you export.
What goes wrong with Excellon drill files most often?
Unit and zero-suppression mismatches that change hole sizes, and a missing plated-vs-non-plated separation. Always specify format settings explicitly and verify the tool table matches your pad stack.
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