# Research Progress on the Manufacturing of Screw-Shaped Parts in Screw Compressors
## 5 Conclusions  
1. The manufacturing technology of screw-shaped parts mainly includes a cutting process (including milling and grinding), solid plastic forming, casting and additive manufacturing. Among of these processes, the main manufacturing method adopted by many enterprises is the cutting process due to the advantages of overall manufacturing and short process flow, and whirlwind milling is one of the most widely used cutting processes. Moreover, grinding has gradually become the main method for the fine machining or integral machining of complex screw profile parts because the element made in whirlwind milling is only a workpiece that further requires roughing and finishing. 2. Compared with the traditional cutting process with the disadvantages of serious material waste, complex process passage and high equipment cost, solid plastic forming has almost no material loss, and can also significantly improve the production \begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Manufacturing Processes** & **Near-Net Formation** & **Production Efficiency** & **Dimensional and Shape Accuracy** & **Service Life of Die and Tool** & **Mechanical Properties** & **Further Improved Mechanical Properties by Heat Treatment** \\ \hline \multirow{4}{*}{Cutting process} & \multirow{4}{*}{Milling} & \multirow{2}{*}{No} & \multirow{2}{*}{Low} & ISO ITS level, and requires subsequent manufacturing steps including grinding and polishing. & Short & High & No \\ \cline{3-8}  & & & & & & \\ \cline{2-8}  & & & & & & & \\ \cline{2-8}  & & & & & & & \\ \cline{2-8}  & & & & & & & \\ \cline{2-8}  & & & & & & & \\ \cline{2-8}  & & & & & & & \\ \cline{2-8}  & & & & & & & \\ \hline \multirow{4}{*}{Solid plastic forming process} & \multirow{4}{*}{MBRFF method} & \multirow{2}{*}{Yes} & \multirow{2}{*}{High} & \multirow{4}{*}{ISO IT14-18 levels, and requires subsequent manufacturing steps including cutting, grinding and polishing.} & Short & High & Yes \\ \cline{2-8}  & & & & & & Short & High & Yes \\ \cline{2-8}  & & & & & Short & High & Yes \\ \cline{2-8}  & & & & Short & High & Yes \\ \cline{2-8}  & & & & Short & High & Yes \\ \hline \multirow{4}{*}{Casting process} & \multirow{4}{*}{Gravity casting} & \multirow{2}{*}{Yes} & \multirow{2}{*}{Low} & ISO IT12-15 levels, and require subsequent manufacturing steps such as machining, grinding and polishing. & Long & data & No \\ \cline{2-8}  & & & & & & & \\ \cline{2-8}  & & & & & & Short & data & No \\ \cline{2-8}  & & & & & & Short & data & No \\ \cline{2-8}  & & & & & & Short & data & No \\ \cline{2-8}  & & & & & & & Short & data & No \\ \cline{2-8}  & & & & & & & Short & data & No \\ \cline{2-8}  & & & & & & & Short & data & No \\ \hline \multirow{4}{*}{Casting process} & \multirow{4}{*}{High-pressure casting} & \multirow{2}{*}{Yes} & \multirow{2}{*}{High} & \multirow{4}{*}{ISO IT8-12 level, and require subsequent manufacturing steps including grinding and polishing.} & Short & data & No \\ \cline{2-8}  & & & & & & & Short & data & No \\ \cline{2-8}  & & & & & & & Short & data & No \\ \cline{2-8}  & & & & & & Short & data & No \\ \hline \multirow{4}{*}{Casting process} & \multirow{4}{*}{3D-printinging process} & \multirow{4}{*}{Yes} & \multirow{2}{*}{Low} & ISO IT8 level, and require subsequent manufacturing steps including grinding and polishing. & Long & Low & No \\ \cline{2-8}  & & & & & & & \\ \cline{2-8}  & & & & & & & \\ \cline{2-8}  & & & & & & & \\ \hline \multirow{4}{*}{Our process} & \multirow{4}{*}{SSCEF process} & \multirow{4}{*}{Yes} & \multirow{2}{*}{High} & \multirow{4}{*}{polishing.} & Long & Very high & Yes \\ \cline{2-8}  & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Similarities and differences between our novelty SSCEF process and the common screw manufacturing processes. efficiency. The solid plastic forming process mainly includes the WCR process, MRRFF process, FEF process, RCEF process, IDFF process, etc.