FlashPCB logo

Designing Your Board

Our design rule checks

When designing your board it's important to be aware of the design rule checks that we will run against your board during our checkout process. Following is a non-exhaustive list of our design rule checks.

Layer count

We currently accept 2, 4, 6, and 8 layer boards.

Board size

Your board must fit within a 10-inch by 10-inch box.

Autodesk Eagle specific checks

We recommend that you load our design rules into Eagle. This will help make sure you stay within the bounds of our manufacturing specs while you design your board. You can download our rules here and load them into Eagle by opening the DRC window from the Tools dropdown in Eagle then loading the file you downloaded. This blog post explains how to interact with design rule checks in Eagle.

Part placement

Our library encodes information that is used by our design rule checks to validate part placement. This information is contained within the following layers:

Eagle LayerKiCad LayerDetails
39F.CrtYdTop Keepout Layer: This is the component's top courtyard.
40B.CrtYdBottom Keepout Layer: This is the component's bottom courtyard.
117NAEdge Layer: This specifies the edge of the element which must remain on the board. If not present we fallback to layer 39.
119NAOverhang Layer: This specifies parts of the element which must overhang the board.

Board border is continuous

We check that your board has a continuous border. If you have two boards in the same file, we require that you separate them into separate files and upload them separately.

Drill placement

We check that the center of every drill is at least 0.254 mm (10 mil) from any other drill or the board's edge.

Minimum drill and end mill size

We check that all the drilled holes in the board are larder than our minimum drill size. We check that all the slots or non-circular holes in the board are larger than our minimum end mill size.

TypeMinimum size
Drill0.2 mm (8 mil)
End mill0.35 mm (14 mil)

Minimum trace widths

We check that all the features in the copper and silkscreen layers are larger than our minimum widths. If there are features in a copper layer smaller than the minimum width this check will produce an error. If there are features smaller than the minimum width in a silkscreen layer they will be removed from the board.

LayerMinimum width
Copper layers0.127 mm (5 mil)
Silkscreen0.0762 mm (3 mil)

Minimum trace spacing

We check that all the copper traces are spaced from each other by at least our minimum widths. If there is spacing between traces in a copper layer smaller than the minimum spacing this check will produce an error.

LayerMinimum width
Copper layers0.127 mm (5 mil)

Minimum inner radius

We check that all the inner corner radii on the outer perimeter of the board are large enough for our routing end mill. We will attempt to add a radius to an inner corner if necessary. If we are unable to add a radius an error will be produced.

TypeMinimum radius
Inner corner radius0.5 mm (20 mil)

Layer trimming

We trim board layers based on our manufacturing capabilities. This process will remove features that extend beyond the outer dimensions of the board. For The silkscreen layers, silkscreen is also removed from areas without soldermask.

LayerTrimmed by
Copper layersBoard dimensions
Drill layersBoard dimensions
SoldermaskBoard dimensions
Solder stencilBoard dimensions, drills
SilkscreenBoard dimensions, drills, soldermask

Next steps

Continue to the next section to finish getting your board made with FlashPCB.