Injection molding machine and injection molding machine screw for injecting molten resin in which thermoplastic resin and reinforcing fibers have been mixed and melted

Abstract

The present invention provides an injection molding machine and screw therefor with which, when mixing reinforcing fibers in a molten resin and injection molding same, the reinforcing fibers can be uniformly dispersed in the molten resin. For a screw 7 provided in an injection molding machine 1, a mixing section 17 is provided on the downstream side of a compression section 18. Three helical flights 17a (x, y, z) are provided in the mixing section 17 and three grooves 17b, 17b', which are helically disposed in the opposite or the same direction as the orientation of said flights 17a, 17a', areformed. As a result of said grooves 17b, 17b', it is possible to keep the fiber lengths of the reinforcing fibers long and even if the reinforcing fibers become tangled in the compression section 18,the fibers are defibrated in the mixing section 17, the shearing of long fibers in the molten resin is mitigated, the reinforcing fibers are dispersed uniformly and a good product is obtained.

Description

technical field [0001] The present invention relates to an injection molding machine for injecting molten resin obtained by mixing and melting a thermoplastic resin and reinforcing fibers into a cavity of a mold after mold clamping, and a screw used for the injection molding machine, and particularly relates to a reinforcing fiber capable of using a longer fiber length. An injection molding machine for fibers and a screw used for the injection molding machine. Background technique [0002] In recent years, in order to increase the strength of resin molded products, natural fibers such as bamboo or pulp called fillers, fibers such as glass fibers, and carbon fibers are mixed with resins for injection molding. Specifically, the fiber material is sometimes put into the injection molding machine, and the molten resin is mixed with the fiber to perform injection molding. For longer reinforcing fibers, the long-fiber-reinforced thermoplastic is sometimes called long-fiber-reinforc...

AI Technical Summary

Problems solved by technology

However, when glass fiber or carbon fiber is mixed with a thermoplastic resin and then injection molded, the fiber is easily broken due to the shearing action in the kneading and plasticizing process by the screw, and the fiber length is shortened to a few percent

Furthermore, if the length of the fibers mixed with the resin becomes longer, the fibers kneaded in the molten resin may become entangled in the compression section of the injection molding machine, making it difficult to disperse the fibers.

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