A kind of hollow pipe body forming method

Abstract

The invention relates to a method for forming a hollow pipe body. Before the mold is closed, the upper core-pulling slider in the upper cavity is at the back dead point position, and the lower core-pulling slider in the lower cavity is also at the rear dead point position; After the mold is closed, the upper core-pulling slider and the lower core-pulling slider advance to the front dead center position at the same time according to the set time; internal high-pressure blowing is performed from the lower part of the pre-blown blank; the upper core-pulling slider and the lower core-pulling slider The core slider retreats to the rear dead center at the same time; the upper mold moves up and takes out the product. This technical solution divides the original integral cavity into a cavity with a core-pulling slider that can advance and retreat independently, and then delays the advancing time of the core-pulling slider so that the part can first contact the material of the cavity. The contact time between the billet and the cavity is delayed, so that the billet at this place can be stretched better, so as to alleviate the excessive stretching phenomenon in the area of ​​insufficient wall thickness.

Description

technical field [0001] The invention belongs to the technical field of blow molding preparation of hollow pipe bodies, in particular to a method for forming hollow pipe bodies. Background technique [0002] At present, the molding methods of plastic hollow tubes are mainly extrusion molding and blow molding. Extrusion molding has great advantages in forming linear hollow tubes. The wall thickness of the tubes is uniform and the length is not limited. The cross-section of the pipe is unique during the molding process, and it is impossible to achieve alternate changes in thick and thin cross-sections on a pipe, and it is also impossible to produce curved hollow pipes, and the design freedom of hollow pipes is low; while blowing In addition to forming curved hollow tubes, plastic molding can also achieve alternate changes in thick and thin cross-sections on the same tube, so it is widely used. [0003] However, in recent years, with the continuous promotion of its application ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a hollow tube forming method to solve the problem in the prior art that when the hollow tube is partially or entirely flat, the wall thickness near this area is too thin and does not meet the requirements

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