Design Optimization: Specifications for Adding Process Edges and Positioning Holes

In production, the process edge of PCB panels can sometimes break if it' s designed without enough mechanical strength. Most of these cases are related to the width of the process edge and the size and position of tooling holes. From a cost perspective, the narrower the process edge, the better. However, for SMT assembly, the process edges cannot be too narrow: if the process edge is not wide enough, components close to the edge of the board might collide with the guide rails in the production line, leading to misplaced and missing components and requiring rework.

First, let's analyze several common situations where an inappropriate design of process edges and tooling holes leads to the breaking of the process edge (please also consider the position of the fiducial marks) :

For boards that use JLCPCB's SMT assembly service, we recommend 5 mm process edges, 2 mm tooling holes, and 1 mm fiducials placed 3.85 mm from the panel edge: