Injection molding tool for forming undercut moldings has retractable slide connected to retacting guide so that slide moves along the axes of demolding guide and retraction guide

摘要

The tool has a fixed die plate(16) and movable stripper plate(18), tool plates(20,58) and slide(42). A demolding guide(48) on the slide extends along a cut-out(54) in the tool plates. A connection between the slide and a retraction guide(60) ensures that during tool opening along the main tool axis the retraction guide contacts the slide(42) or stripper plate(18). The slide is therefore forced to move out of the molding undercut(44) in the axial directions(68,70) of the retraction guide and demolding guide. The tool preferably has a three plate construction. A cut-out(66) in the slide(42) holds the retraction guide(60) which is connected to the stripper plate(18). The base of the retraction guide is rectangular and has sliding pads for contact with the slide. A continuous cut-out(59) through the stripper plate allows insertion of the retraction guide from outside. At least one surface of the demolding guide(48) contacting the tool plates during tool opening has sliding pads. A system for locking the stripper plate prevents movement of the latter relative to the die plate during tool opening along the main tool opening axis(26) but, on conclusion of tool opening, can be released by a control mechanism to allow further common movement of stripper plate, slide and tool plates along the tool opening axis. A tool plate insert(58) design holds the slide against the stripper plate and die plate when the tool is closed so that moldings have identical shape. An independent claim is included for a method for producing an injection molding(40) with an undercut(44) which involves: a) closing the claimed tool; b) injecting melt into the tool to form a molding; c) cooling the me d) opening the tool by moving tool plates away from the stripper plate along a tool opening axis and simultaneously causing the slide to move out of the undercut.