Injection extrution moulding method and advice

Abstract

The method of the present invention is a method of injection-extruding a thin-walled molded product using an injection molding machine. The injection molding machine includes: a pair of movable metal molds and a fixed metal mold forming a forming space; a movable platen mounted on the movable metal mold ; a fixed press plate installed on a fixed metal mold; an injection device for injecting molding materials into the forming space; during the period when the injection device injects molding materials into the forming space, the clamping pressure applied by the moving press plate to the fixed press plate can be controlled clamping device. This method has a no-load inflow step of controlling a mold clamping device receiving the molding material in the injection step so as not to impose substantial inflow resistance on the molding material injected into the molding space by the injection device. In addition, this method also includes a preliminary mold clamping step of controlling the mold clamping device so that a predetermined preliminary mold clamping pressure is applied to the molding material injected into the molding space by the injection device in the injection step.

Description

technical field [0001] The present invention relates to a method and an apparatus for injection molding a thin-walled disc substrate as a thin-walled molded product by using an injection molding machine. Background technique [0002] In the process of forming thin-wall disc substrates such as CD and DVD by using an injection extrusion molding machine, due to the thin thickness of the formed disc, the amount of molten resin used for each disc is very small when forming, and the forming time is only a few minutes. Seconds or so, relatively short. Under such severe conditions, a large amount of digital information is copied from the stamper to the disc. [0003] When manufacturing optically molded products such as thin-walled disk substrates by injection molding, internal strain is likely to occur due to the molecular orientation of the resin during injection and filling of the resin. Accordingly, birefringence and a large bending angle are easily caused. Therefore, in the f...

AI Technical Summary

Problems solved by technology

Therefore, it is difficult to form a substrate that satisfies the full performance of the birefringence and bending angle within the required range while ensuring the replication characteristics.

Specifically, lower birefringence and bend angles can be reduced well when the clamp hold pressure is set relatively low, but cannot meet the required reproduction performance

On the other hand, when the clamping holding pressure is set higher, the reproduction performance is good, but the birefringence and bending angle become larger

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