Injection-moulding device with needle valve nozzle and guide bush

Abstract

Injection molding device (1) with: distribution plate (3) in which at least one flow channel (4) for flowable material is formed; at least one needle closing nozzle by which the nozzle is closing , the flowable material can be fed to the separable mold insert under the guidance of the flow channel; at least one closing needle (20), the closing needle (20) at least partially moves longitudinally through the flow channel and can be in an open and closed position by means of a drive member; and a guide sleeve (30) which allows the closure needle (20) to pass and seals the closure needle (20). The guide sleeve has a region which surrounds the closing needle with little movement play and which is located at least partially in the flow channel. This region thus has a contact surface for the flowable material, which is at least partially located within the flow channel. The flowable material flows around the region and all sides of the interface (44).

Description

technical field [0001] The invention relates to an injection molding machine with a needle shut-off nozzle according to the general concept of claim 1 . Background technique [0002] The needle shut-off nozzle is inserted into the injection molding machine in order to supply the flowable mass at a predeterminable temperature and under high pressure into the separable mold insert. Needle closing nozzles usually have a pneumatically or hydraulically driven closing needle which periodically opens and closes the casting opening in the mold insert. This enables the most precise material dosing possible, especially in fast shot sequences. However, it is also possible to inject the flowable mass in sections, for example in cascade casting. [0003] Each closing needle is installed axially displaceably in the tool-side area of ​​the injection molding device and preferably centrally through the flow channel for the substance to be processed in the nozzle-side area (see for example ...

AI Technical Summary

Problems solved by technology

[0005] Despite such an optimized configuration of the sealing system, due to the relatively high pressure in the tool and due to the lifting movement of the needle, it cannot be avoided that the material to be processed seeps through the guide sleeve or the sealing sleeve

The result is material loss

In addition, material residues contaminate not only the closing needle but also the tool, which not only impairs the sealing effect, but may hinder the opening and closing movement of the closing needle over a long period of time

Expensive cleaning or maintenance work is unavoidable

Images