Research On Formation Mechanism And Characteristics Of Edge Defect When Drilling SiCp/Al Composites

SiCp/Al composite has been widely used due to its excellent physical, mechanicalproperties and good development prospect. In the21st century, with the application inthe high-tech fields of SiCp/Al composite, the machined edge quality already becamethe most significant factor which influences its usability, reliability and working life.Until now, there is little research on the edge defects of drilling of SiCp/Al composite.According to the drilling process of SiCp/Al composite, the formation mechanism,morphology and features classification of edge defects of drilling SiCp/Al compositewith PCD bit and electroplated diamond bit were researched in this thesis, and theinfluence of drilling parameters on edge defects was studied. The main research work isas follows:The formation process and characteristics of drilling edge defects were researched,and proposed the corresponding relationship between the entrance edge defectsformation and drilling force variation. The entrance edge defects were classified intofour forms, i.e. macro fracture, particle shedding, particle fracture/breaking and plasticbulge according to the defect morphology, and the formation mechanism of these fourforms were analyzed. The exit edge defects were classified into three forms, i.e. widerange of punch, matrix ductile fracture and particle shedding according to themorphology of exit defects, and the formation mechanism of these three types of edgedefects was analyzed.The influence of drilling process parameters on drilling force and edge defects wasresearched. Based on Grey Relational Analysis and grey system theory modelingsoftware (GTMS3.0), the influences of drilling parameters on drilling force and edgedefects when drilling high volume fraction, large particle size SiCp/Al composite withPCD bit were analysized,.proposed the scope of parameters selected when drilling tominimize the edge defects.The classification of edge defects when drilling SiCp/Al composite with PCD bit was given by using cluster analysis method and SPSS software. According to theresearch on the morphology of edge defects, proposed three types of edge defects. Thecharacteristic of each type of edge defects was researched and the topography map wasestablished.