Officially Supported

Drill slots are officially supported. Most design tools can generate a drill slot by use of a built-in command on the footprint or board layout editor. These slots are represented on your Drill file, rather than an outline.

Note that limitations apply to the use of drill slots. Certain applications of drill slots generate board feautures that are unsupported, and may not be fabricated as expected. See below for some use cases.

Additionally, drill slots do not necessarily follow the same DRC rules as standard drill hits. Since most tools do not have Slot specific DRC checks, you’ll need to validate these manually.

Design Tools with drill slots

These tools are known to create drill slots that are supported by our system.

  • KiCad
  • Altium Designer
  • Altium CircuitMaker
  • DesignSpark
  • Diptrace
  • ORCAD/Cadence

Most tools create drill slots, but we can’t list them all. You can use the tips below to identify if a tool generates supported slots. You can also always ask us at support.

Design Tools without drill slots

Some tools cannot generate drill slots natively. Slots from these tools can be indicated on the board outline, but those slots cannot be guaranteed.

The only commonly used tools that cannot generate drill slots are:

  • Autodesk Eagle
  • Fritzing

Eagle users can use our Eagle Slots support page for detailed instructions. When done correctly, it is possible to get fully supported slots from Eagle.

For all other tools, see our Legacy Slots support page for general instructions.

Supported Drill Slot Features

When using native slot callouts, we support the following

  • Plated Slots
  • Non-Plated Slots
  • Slot widths 20mil (0.508mm) or wider.

Plated slots have the same annular ring requirement as plated drills. Annular ring specs are listed on the Services page for your board options.

For now, supported slots must meet the following criteria

  • Defined fully within your board area
  • Must not cut through another slot or drill hit
  • Non-plated slots must not cut through copper
  • Plated slots must have a valid annular ring, as well as have copper beneath the entire slot.

Unsupported / Untested Drill Slot Features

Some use cases remain where we have not seen extensive testing. These slots cannot yet be guaranteed, and may be not fabbed at all, fabbed inconsistently, have high failure rates, or have restrictions that result in unsatisfactory fabrication. As these slots are further tested, we’ll adjust documentation to clarify what to expect.

These include, but are not limited to, the following:

  • Intersecting slots (eg, a + pattern)
  • Multiple slots forming an open path (eg, a zigzag or slots forming one larged curved slot)
  • Multiple slots forming an closed path (eg, a milling path for a cutout)
  • Large or long cutouts using small-diameter bits
  • Long slots parallel to board edges (can cause structural issues for shipping/depaneling)
  • Slots crossing the board edge (eg, castellations or plated edges)
  • Slots crossing through copper boundaries
  • Using slots to define panelized board configurations

If you have feedback on the success or a failure of a board with these feautures, please contact us so we can consider how these feautures are handled.

If your design uses slots in a way that you suspect may not work right, feel free to contact us at [email protected] and inquire.

Identifying Supported Slots

Verifying slots on

Most notably, when uploading your board you will see the slots rendered as expected. They will be rendered on the following preview images:

  • Drill File
  • Board Top
  • Board Bottom

If the slot is not rendered on the Drill File preview, then it may not have been generated using the design tool’s slot method. Double check the callout or contact [email protected] if you have concerns.

To help with identification, we will emit a note indicating that we’ve detected slots in your design.

Verifying slots with a text editor

Since drill files are simply text, you can read them quite easily. Simply open your drill file, and look for one of the common slot types. These will match one of the following ways of indicating slots in valid NC Drill files.

G85 slots

Used by most tools with native slots.

G00/M15/G01/M16 slot paths

This method is common among the professional-grade tools, notably Altium and ORCAD.


Legacy Slot Callouts

Slots generated on the Board Outline using the older documentation have not changed, and will work exactly as they have previously. The support status of these feautures is as follows:

  • Non-Plated slots with a width of 0.1” defined on the Board Outline were previously supported, and remain supported.
  • All other slots defined on the Board Outline remain unsupported, with no guarantees of success. However, they should work, just like the have in the past.

If your tool cannot create drill slots, you can find the legacy documentation for these slots here: Eagle Cutouts And Slots

Board Cutouts

Cutouts represented on the Board Outline are noted on the Board Outline page.