Research Progress on the Manufacturing of Screw-Shaped Parts in Screw Compressors

Abstract

Screw compressors are highly researched and developed prospects in industry because of their long service life, high transmission efficiency, low footprint and low vibration. As the key core part of the screw compressor, the screw is a typical, long-shaft, complex profile part. Its processing method, manufacturing accuracy and quality have an extremely important impact on the performance of the whole screw compressor. In this work, the research progress on the manufacturing of screw-shaped parts in screw compressors is summarised from the aspects of the cutting process, solid plastic forming, casting and additive manufacturing. The merits and demerits of these manufacturing processes are provided and discussed, which is conducive to the development of the high-efficiency, precise and high-performance forming process of screw-shaped parts. Additionally, a novel forming process is proposed to solve the problems of serious material waste and low production efficiency for the screw-shaped parts. In the proposed process, the semi-solid spherical grain is firstly prepared by radial forging and the isothermal treatment of long-shaft raw materials. The large strain energy can be stored in the bar by the radial forging of long-shaft raw materials, which is used to induce the generation of semi-solid spherical grains with the assistance of the isothermal procedure. After that, the screw is fabricated by the high-efficiency semi-solid closed extrusion process.