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How to add edge rails/fiducials for PCB assembly order

How to add edge rails/fiducials for PCB assembly order

Edge rails and fiducials are required for JLCPCB Standard PCB Assembly.

Edge rails are added for increasing component–to-board-edge clearances. Fiducials are small pads that are placed on a PCB to aid Pick & Place machines during component placement. They are also frequently added to the edge rails. To achieve better assembly results, we recommend that you follow the below guidelines to add Edge rails/fiducials to your PCB design.

Edge rails

Edge rails that are added for increasing component–to-board-edge clearances are to be at least 5mm.

(A kind reminder: We will deliver the assembled boards with edge rails by default. If you would like us to remove the edge rails, please inform us when placing the order and there will be some post-production fee caused.)


1. The fiducial marker is made by placing a non-drilled copper layer in a circular shape. The fiducial marker must be free from solder mask.

2. The optimum size of a fiducial marker should be 1 mm. The diameter of the solder mask opening should be double the diameter of the bare copper for the fiducial.

3. 3-4 fiducial markers are placed on the edge of the boards for the best accuracy.

4. The fiducial marker must maintain a distance of 3.35mm to the edge of the board, including the clearance area of the fiducial marker.

Last updated on July 25, 2023

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