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.
Pre-Hardened P20 Steel
Meaning
Medium carbon alloys are supplied in a heat treated state to allow for immediate machining of mould cavities. Using pre-hardened p20 steel eliminates the need for further heat treatment after the tool is cut, which prevents the risk of warping or cracking. This material typically holds a hardness of 28 to 32 on the Rockwell C scale.
It is a standard choice for large moulds and frames that do not require an extremely high polish.
Machining Efficiency
Cutting tools can shape the metal without the extreme wear associated with harder alloys. Because pre-hardened p20 steel is already at its final hardness, the tool builder can go from the milling machine directly to the assembly bench. This speed reduces the lead time for new production projects.
Hardness Uniformity
Consistent properties throughout the block ensure that the mould will wear evenly over time. Pre-hardened p20 steel provides a stable base for thousands of injection cycles. If the hardness varies, the parting line might develop gaps that lead to flash.
Repair Capability
Welding and re-machining are straightforward because the metal does not require a complex hardening process after the fix. Maintenance teams often prefer pre-hardened p20 steel for tools that will undergo frequent modifications. This flexibility makes it a cost effective option for parts with evolving designs.