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.
Prussian Blue Inspection
Meaning
Manual testing procedures utilize a pigment paste to check the fit between two mating metal surfaces. Performing a prussian blue inspection shows exactly where a mould is touching and where gaps exist at the shutoff. A thin layer of the blue dye is applied to one half of the tool before it is closed and opened again.
This method is the standard way to verify that a mould will not flash during production.
Contact Analysis
Transfer of the pigment from one surface to another indicates a tight seal. A successful prussian blue inspection reveals a consistent pattern across the entire parting line. Areas that remain clean indicate a gap that must be fixed by shimming or welding the steel.
Shutoff Validation
Moving slides and lifters must fit perfectly into their pockets to prevent plastic from leaking. Using prussian blue inspection on these moving parts identifies points of interference that could cause the tool to gall or seize. This check is performed every time a tool is reassembled after maintenance.
Surface Indication
The thickness of the paste determines the sensitivity of the test. A heavy application of prussian blue inspection can hide small gaps, so a very thin film is required for accurate results. Skilled toolmakers rely on the intensity of the color to judge the pressure between the steel components.