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.
Support Pillars
Meaning
Structural metal columns placed within the ejector housing of an injection mould provide essential reinforcement for the support plate. Support pillars prevent the plates from bending or bowing under the immense pressure of the injection and clamping forces. This stability is a requirement for maintaining the dimensional accuracy of the parts and the longevity of the tool.
Deflection Prevention
Rigidity of the tool assembly is maintained by bridging the gap between the back plate and the support plate. Support pillars are typically made from hardened steel and are ground to a precise height to ensure even contact. Without these components, the support plate would flex, causing the cavities to move and creating flash on the parts.
Clamping Force
Distribution of the load across the entire tool prevents localized stress concentrations. Support pillars allow the mould to withstand the hundreds of tons of pressure applied by the press without deforming the internal components. The number and placement of these pillars are calculated based on the projected area of the parts and the expected injection pressure.
Mould Geometry
Design of the ejector system must account for the space required by these structural elements. Support pillars must be positioned so they do not interfere with the movement of the ejector pins or the return pins. In large tools, these pillars are massive and may even be bolted to the plates to provide maximum stability.
Regular inspection is necessary to ensure that the pillars have not compressed or shifted over time, which would lead to a loss of support.