OSH Park Docs
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: http://wiki.altium.com/display/ADOH/NC+Drill+Output+Options
The drill format options we use are as follows:
We prefer a 2:4 format when using Inches, or a 3:3 when using Millimeters. Some versions of Altium do not have these options, so you should use 3:4 in Inches, or 4:4 in Metric, and verify that the drill hits align correctly on the previews.
Keep Leading And Trailing Zeroes
Generate Seperate NC Drill files,
Use Drilled Slot Command, and
Generate Board Edge Route Paths. This will force Altium to produce a single drill file with both plated and non-plated holes. Providing multiple drill files can cause serious fabrication errors, and should be avoided. Note, that drilled slots and plated slots are not supported. If your board contains slots, please see our Internal Cutouts and Slots guide to ensure that we can fabricate your board correctly.
Coordinate Positions”, you’ll typically check
Reference to Absolute Origin. However, since this option needs to align with a similar CAM setting for the gerber files, consider changing it to
Reference to Relative Originif your gerbers appear incorrect in our previews.
Optimize Change Location Commandsdoesn’t matter, as we will recalculate drill movement.
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 firstname.lastname@example.org for assistance.
2 layer Drill Specs
- Minimum 10 mil drills with 5 mil annular rings.
- Maximum plated hole size is 265 mils. Unplated holes do not have a maximum size.
4 Layer Drill Specs
|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|
|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.