Altium Designer: Drill File CAM Configuration

Our service cannot process Altium’s Drill Drawing (DD1) or Drill Guide (GG1) files. We need the drill file to be in NC Drills format file. Altium typically generates these with a .TXT extension.

Altium has published a guide on producing those files here:

The drill format options we use are as follows:

In some cases, including the binary .DRL file will cause us to reject the board even if you have a .TXT file in NC Drill format. Deleting the .DRL file will resolve that issue.


The following image shows a properly aligned drill file, and should resemble your previews when uploading your board. If anything looks strange, consult our Drill Troubleshooting Guide for some tips or email for assistance.

Correctly Aligned Drills

2 layer Drill Specs

4 Layer Drill Specs

Spec Size
Minimum annular ring 4 mil
Minimum hole size 10mil
Maximum plated hole size 260 mil
Maximum non-plated hole size None
Via plating thickness 1mil
Blind Vias No
Buried Vias No


Fabrication Tolerances

Drill Tolerances

Spec Maximum Typical
Drill size variance Max +/- 2.5 mil +/-1.5 mil typical
Hole positional variance Max 2.5 mil <1 mil typical
Stop Mask alignment Max 3 mil <1 mil typical

The hole diameter after plating will be within +/-2.5 mil of the drill size specified on the drill file, although it’s typically within 1.5 mil of the size specified. For tight-fitting components, it’s important to note this spec, and make sure that the component will still fit if the hole size shrinks. If the hole grows, it typically does not present a problem since it simply reduces the annular ring slightly.