Internal Cutouts and Slots


We officially support non-plated slots and cutouts that are at least 100 mil wide (0.1inches / 2.54mm).

These are indicated on the Board Outline layer, and are indicated in a very similar manner. Simply add the edge of the cutout on the board, and the fab will generate the proper tooling paths to cut the cutout as intended.

While not strictly required, it is highly advised to place the text CUT OUT on the dimension layer inside any internal cutouts. This helps explain your intentions to the fab, particularly on boards with complex routing. While not a common occurrence, if the fab is unsure how to interpret your slot they will simply omit it rather than potentially damage other features.

Suggested call out for slots and internal cutouts

The Board Edge text and description should not be included on the board outline layer. That text is included here for reference only.

Include the CUT OUT text on the Board Outline layer.

Fab interpretation

The fab will add in the routing paths as indicated

This is an example of how the fab will route the board.

Not Fully Supported

These features are supported, but will fail in certain circumstances. Caution is advised when using these features.

Routing path slot indications:

Due to our fabrication process, more care must be made to ensure that the fab can reliably interpret them.

Guidelines for path call outs are as follows:

Notches and slots along the board edge

Cutouts that intersect the board edge should be reworked and shown as part of the board edge, as shown in the following picture. While both call outs are likely to produce identical results, the one on the right is more reliable, and easier for the fab to interpret.

If the CUT OUT text is omitted, the design on the left will typically fail, and the resulting board will be missing the notch.

Try to submit a design that the fab can't possibly misinterpret.

Not Supported

We can not guarantee the following features will be fabricated correctly, even if included on the design as described below. They should only be added at the user’s risk. That said: The fab will typically include them as intended if you follow the guidelines below.

Be aware that the use of these features may result in an unusable board, or require modification to parts or the board to complete your project. It’s highly advised to avoid using them on boards with upcoming deadlines, on the off chance that the board isn’t usable.

If at all possible, we suggest replacing any non-supported call outs with a supported feature, typically a large via. See the Replacing Unsupported Features section below for additional details.

Plated slots (larger than 40 mil)

The fab looks for the following indicators when scanning for plated slots. As mentioned above, there is no guarantee that this call out will produce the expected results, and the use of plated slots is discouraged.

The smallest possible slot the fab can produce is 40 mil. This picture shows a slot call out with a high probability of success. If the slot fails, then the result will be a copper pad with a via in it.

Unsupported slot call out: Copper is shown as pink, drill hits are shown as orange, and the board outline is shown as blue.

This will probably work as expected!

Slots smaller than 100 mil

The smallest possible slot the fab can produce is 40 mil. As mentioned, there is no guarantee that this call out will produce the expected results.

If this feature fails, the resulting board will simply have a drill hit it instead of a slot.

Slots smaller than 40 mil

Will not be fabricated as a slot. Will simply be treated as a drill hit, and will be plated if it goes through copper.

Overlapping Drill Hits

Will not be fabricated. Overlapping or intersecting drill hits are automatically removed by the fab, and will not be converted to a slot. Instead, clusters of drill hits will be replaced by a single drill hit. It will be plated if it goes through copper.

Replacing Unsupported Features

Whenever possible in your designs, we advise replacing small or plated slots with a large via. Typically, setting the hole size equal to the slot length is sufficient to fully replace the feature with minimal design impact.

Replace mill callouts with drill hits.