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How do I produce drill files for my PCB design?

by DesignSpark

This tutorial requires:

DesignSpark PCB V11.0.0

Suggested Settings

The settings required for most manufacturers are as follows and are setup in the Manufacturing Output.

Select the "Drill Data - Through Hole" (highlights in blue) and then the "Settings" tab".

Ensure both the "Plated Holes" and "Unplated Holes" are checked.

Make sure the options under "Boards" are un-checked as shown.

Output Manufacturing Plots

In the Plots list the "Drill Ident Drawing" is NOT required and to avoid confusion should not be sent to the manufacturer.

Now click the "Options" button and then the "NC Drill..." button.

Here you should select "Format 1" and "Remove Duplicate Drill Holes"

Make sure the "Separate Files for Plated and Unplated Holes" is not checked.

Setup NC Drill

The area highlighted in orange may need configuring to match the manufacturers requirements, but those shown should meet what the majority will require.

You are now ready to produce your Gerber plots, just check all those required and "Run" the plot generation.

Note when checking your files ensure your Gerber viewer is set to match the drill file settings you used.

A little bit of background and history

The Excellon drill file format is designed for Excellon drilling machines, however, it has evolved into the industry standard for PCB manufacturers, but this has led to some confusion and assumptions.

The main questions asked relate to why are there options for three drill files and what do I require?

  • Drill Data - [Through Hole] (Unplated).drl
  • Drill Data - [Through Hole].drl
  • Drill Ident Drawing - [Through Hole].gbr

For those using an Excellon drilling machine, the first is a drill file that is drilled with holes of the specified size.

The second file is for drilling the holes that will be through hole plated, these are drilled 'over size' such that when plated they reduce to the expected hole size.

The final file type (which is a Gerber file) is used for visual inspection and checking hence contains shapes and symbols to identify specific hole sizes.

For modern PCB manufacture the un-plated and plated drilling is combined in one file.  The manufacturer will translate these into their own CNC format and whether a hole is plated or not is identified by the presence of copper around the hole. If copper is present their default manufacture is to plate the holes, hence these will also be drilled oversize. If this is not required for specific holes the manufacturer will need to have a separate instruction from you.

For those interested in even more details please see the Excellon File Format FAQ.

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