Fluid-assisted injection moulding process - has variable throttle in fluid injection nozzle to change vol. flow of fluid into cavity and enhance product surface

摘要

In a fluid-assisted thermoplastic injection moulding process the wall thickness of components can be altered by injection fluid through a nozzle (1) in the tool wall. The nozzle may be integral with or separate from the injection nozzle for the thermoplastic. Volumetric fluid flow is varied by changing the throttle cross-section of the injection nozzle. A device for altering flow is incorporated in the outlet (4,5) from the nozzle. USE/ADVANTAGE - For varying wall thickness of thermoplastic mouldings during moulding. Reduces time from the end of thermoplastic injection to the build up of pressure in the tool cavity and therefore enhances outer surface finish.