General Requirements It is important to provide track-to-edge clearance on all layers for multiple reasons: 1) To avoid partial or complete removal of tracks. Apart from the obvious problem associated from such an occurrence, partial removal will result in exposed copper on the edge of the board causing : possible shorting, if in contact with metal case or guide. possible shorting of inner layer ground and power plane from resulting burrs. oxidised copper over time especially in corrosive or humid environments. 2) To enable complete encapsulation of the tracks with solder mask which also improves the adhesion of the mask on the edge of the board.

Edge Clearance Requirements
Our minimum track-to-edge clearance requirement is 0.3mm (0.012"). This requirement equally applies to tracks & planes on outer & inner layers. If possible a larger clearance is preferable especially on inner layer planes.

Even with 0.3mm clearance, track edge exposure is still possible, if all of the allowable variables are on maximum and in opposite directions. These variables include machining under nominal by 0.2mm and pattern location movement of 0.1mm.

Scored Jobs A larger clearance is required for Scored (V-grooved) jobs, to allow for the angle of the blade. On 1.6mm thick boards, using a 30 blade, an extra 0.15mm is needed. In cases other than 1.6mm thickness, use the following formula to calculate the clearance required on top of the 0.30mm specified above: additional clearance = Tan (15 o ) X depth of cut

Please Contact our Customer Support Department, if any further clarification is required.