Parting Line Steel Preload Calculation for Multi Cavity Injection Moulds
Calculate multi cavity parting line preload by balancing machine clamp force against internal hydraulic separation force to maintain positive shut-off land sealing stress.
Crush Pad Design
Meaning
Sacrificial metal platforms are integrated into a mould to protect the delicate shutoff surfaces from excessive clamping force. Implementing a crush pad design ensures that the machine tonnage is absorbed by specific areas rather than the cavity edges. These pads are usually made from a softer steel or are designed to be easily replaced if they become deformed.
They provide a safety margin for the tool during high volume production runs.
Deflection Management
Controlling how the mould plates compress under load prevents the flash that occurs when a tool opens slightly. A proper crush pad design places the support points as close to the cavities as possible without interfering with the cooling lines. This placement keeps the parting line tight and maintains part quality.
Surface Protection
Shutoff areas where the two halves of the mould meet are prone to damage from debris or misalignment. Because the crush pad design stands slightly proud of the rest of the parting line, it takes the initial hit as the mould closes. This feature keeps the expensive cavity inserts from making hard contact and losing their sharp edges.
Loading Variance
Measuring the height of these pads during maintenance checks shows the amount of wear the tool has experienced. When a crush pad design shows signs of flattening, it indicates that the press tonnage is too high or the material is too soft. Replacing these pads restores the original alignment of the mould.