Mold Venting is very important on plastic injection molds. Inadequate mold venting will cause burns and inadequate part filling. Too deep vents may cause flash on the part in the area of the vent. Below is a list of common vent depths for various plastics. This is just a “jumping off” point as the requirements vary by the specific manufacturer of each plastic.
Plastic Type Vent Depth in inches
ABS 0.002”
Acetal 0.0007”
Acrylic 0.002”
Acetate 0.001″
Butyrate 0.001”
Nylon 6/6 0.0005”
Polycarbonate 0.002”
Polypropylene 0.001”
Polyethylene 0.001”
PPO 0.002”
PPS 0.0005”
Polysulfone 0.001”
Polystyrene 0.001”
Rigid PVC 0.002”
Flex PVC 0.0015”
This would be the depth of the vent at the edge of the plastic part