Meaning
Compression damage on the matching faces of a mould tool results from excessive clamping force or the presence of trapped material. Usually, parting line crushing occurs when the steel exceeds its compressive yield strength, creating gaps that lead to flash. The damage often happens at the corners of the cavity or near the vents.
Mechanical Deformation
Permanent compression of the metal prevents the two halves of the tool from sealing perfectly during the injection phase. The damage caused by parting line crushing requires expensive grinding and welding to restore the original shut-off surface.
Clamping Pressure
Calculation of the required clamp force must account for the projected area of the part to avoid unnecessary stress on the parting line. Excessive pressure concentrates at the points of contact and can flatten the delicate edges of the tool over time. Operators must monitor the tonnage used on the press to ensure it does not exceed the structural limits of the mould base.
Maintenance Cost
Repairing crushed steel surfaces involves pulling the tool from production and sending it to a specialised tool room. This downtime increases the overall cost of ownership and disrupts the supply chain for the moulded parts. Preventing this defect through regular cleaning and pressure checks is more economical than reactive repairs.
