Vacuum-exhausting-type screw barrel

Abstract

The invention relates to a vacuum-exhausting-type screw barrel. A heating layer is arranged on the outer wall of the barrel, a feeding screw is arranged in the barrel, a hopper mounting hole and a vent hole are formed in the barrel, the vent hole is connected with a vacuum pump, the feeding screw is divided into a metering feeding plastifying section, a forcedly-pressurizing plastifying section, a feeding pressure-reduction plastifying section and a forcedly-feeding plastifying section, the vent hole is arranged in the feeding pressure-reduction plastifying section, three grooves are formed in the inner wall of the barrel, the lengths of three grooves are consistent to a distance from the hopper mounting hole to the rear end part of the barrel, and an electric heating coil is arranged above the vent hole and at the lower end of the vacuum pump. Compared with the prior art, the vacuum-exhausting-type screw barrel is provided with the three grooves, the lengths of the three grooves are consistent to the distance from the hopper mounting hole to the rear end part of the barrel, and the electric heating coil is arranged above the vent hole and at the lower end of the vacuum pump. The vacuum-exhausting-type screw barrel is used for an exhaust-type injection molding machine.

Description

technical field [0001] The invention relates to a screw barrel, in particular to a vacuum venting screw barrel for a venting injection molding machine. Background technique [0002] Vented injection molding machine for plastic injection molding refers to the volatile gas or water vapor in the raw material generated during the extrusion process, which can be discharged from the barrel before the molten material is injected. An injection machine that can remove gas before being injected is called a vented injection molding machine. If these gases in the melt are not discharged, they will be mixed in the injection molded parts, which will affect the strength and appearance quality of the products. With an injection molding machine that can discharge gas during the production process, the qualified rate of injection molded products can be improved, the drying process of this raw material before injection molding can be reduced, and the production cycle of injection molded produ...

AI Technical Summary

Problems solved by technology

[0004] There are structural defects in the existing vented screw barrel: when the injection molding machine stops working, the molten plastic at the vent will solidify and block the vent, which will directly affect the next work; in addition to the rotational movement of the injection screw, it must also Axial movement, almost no gap between the injection screw and the inner wall of the barrel, directly affects the function of feeding, drainage and exhaust pressure

Therefore, the existing exhaust type injection molding machine has a high failure rate and is difficult to popularize and apply

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