Copper and the Board Edge
There are three options under our Advanced options heading which may be confusing:
- Copper up to board edge
- PTH on the board edge
- Round-edge plating.
Here’s how to sort them out.
Copper up to Board Edge
To avoid damage to the copper during the profiling operation we normally ask for a minimum distance between the copper features and the edge of the PCB. This distance is:
- 0.25 mm on outer layers with breakrouting
- 0.40 mm on inner layers with breakrouting
- 0.45 mm on all layers with V-cut scoring.
These figures are needed to accommodate industry-standard manufacturing and machining tolerances. For V-cut scoring it is also necessary to accommodate the V of the cutter.
Sometimes it is necessary to run a copper plane up to the board edge. In this case select “Copper to board edge”. There is no extra charge for this but it alerts our engineers to set up a different cutter speed.
“Copper to board edge” should normally only be used for planes and large copper areas where any slight damage to the copper will not impact on the performance of the PCB.
Tracks must not be placed within the minimum distance of the board edge where they could be damaged. Our engineers will raise an exception whenever they find tracks within the exclusion zone.
If we find pads within the minimum distance of the board edge, we will clip them back to restore the minimum copper-free space unless:
- the pads are part of an edge connector (usually with a bevelled edge)
- the pads are marked as “up to the board edge” in a separate mechanical layer
- the clipping is more than 25% of the pad surface in which case we will send an exception to the customer.
Copper to board edge cannot be combined with V-cut scoring.
We will always cut inner layer planes back by 0.40 mm to avoid any risk of shorting.