The small hole helical mill-grinding process and application in high volume fraction SiCp/Al MMCs

Abstract

With the volume fraction of SiC increasing, the machinability and electrical machining performance of SiCp/Al metal matrix composites (SiCp/Al MMCs) decreases gradually. Therefore, it is difficult to machine small holes in high volume fraction SiCp/Al MMCs. Based on the material properties and grinding mechanism, the small hole helical mill-grinding process in high volume fraction SiCp/Al MMCs with super abrasive wheel is presented. Furthermore, the wheel kinematic characteristic is analyzed during hole helical mill-grinding. The essential reason for reducing the hole exit defects is presented, which is changing the main feeding direction from axial to tangential. Meanwhile, the experiments of small hole helical mill-grinding in 65% volume fraction SiCp/Al MMCs are carried out. The experimental results show this process has the superiority in decreasing axial force, avoiding hole exit defects, and improving the small hole machinability. Under the premise of no obvious defects in the orifice and the inner surface roughness no more than Ra0.4 μm, the wheel grits and parameters in rough and finish machining are optimized to increase the hole machining efficiency and wheel life. At last, the experimental results fully illustrate that the small hole helical mill-grinding in high volume fraction SiCp/Al MMCs with high efficiency and quality has great superiority and application value.