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.

FlashPCB Library usage

We require that components from the FlashPCB Library be used as is without any manipulation. If you would like to edit the components from the FlashPCB library you will have to save them under a different library name in order to use them in your designs.

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 Layer	KiCad Layer	Details
39	F.CrtYd	Top Keepout Layer: This is the component's top courtyard.
40	B.CrtYd	Bottom Keepout Layer: This is the component's bottom courtyard.
117	NA	Edge Layer: This specifies the edge of the element which must remain on the board. If not present we fallback to layer 39.
119	NA	Overhang 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.

Type	Minimum size
Drill	0.2 mm (8 mil)
End mill	0.35 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.

Layer	Minimum width
Copper layers	0.127 mm (5 mil)
Silkscreen	0.0762 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.

Layer	Minimum width
Copper layers	0.127 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.

Type	Minimum radius
Inner corner radius	0.5 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.

Layer	Trimmed by
Copper layers	Board dimensions
Drill layers	Board dimensions
Soldermask	Board dimensions
Solder stencil	Board dimensions, drills
Silkscreen	Board dimensions, drills, soldermask

Next steps

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