Papers by Author: Jiu Hua Xu

Abstract: Temperature theoretical model of Ti-6Al-4Valloy during electrical discharge machining (EDM) process is established in this paper. Based on finite element thermal analysis, the temperature field of EDM Ti-6Al-4V on a single discharge is simulated with the aid of ANSYS software. The results show that there is a high temperature distribution around the spark point while the thermal-affected zone is quite small. Additionally, the profiles of discharge crater geometry have been predicted and the relation between crater shape and parameters under different current and pulse duration are also explored.

Abstract: Single-grain grinding test plays an important part in studying the high speed grinding mechanism of materials. In this paper, a new method and experiment system for high speed grinding test with single CBN grain are presented. In order to study the high speed grinding mechanism of TC4 alloy, the chips and grooves were obtained under different wheel speed and corresponding maximum undeformed chip thickness. Results showed that the effects of wheel speed and chip thickness on chip formation become obvious. The chips were characterized by crack and segment band feature like the cutting segmented chips of titanium alloy Ti6Al4V.

Abstract: Chip formation and surface generation were investigated when ultra-precision turning of SiCp/2009Al and SiCp/ZL101A composites using Single Crystal Diamond (SCD) and Polycrystalline Diamond (PCD) tools. The results showed that the machined surfaces took on many defects of pits, voids, microcracks, grooves, protuberance, matrix tearing etc. It was noticed that most of these defects had an intimate relationship with the removal process of SiC particle. The surface finish was much better when the SiC particles were removed by cut through or in-situ pressed into mechanisms. Material swelling and side flow, tool-workpiece relative vibration, feed rate and tool nose radius, removal mode of SiC particles were these main mechanisms of surface generation. Generally, a saw-toothed chip was formed when ultra-precision turning this kind of material and the mechanisms of this type of chip were dynamic microcrack behavior and strain concentration, which induced by the non-uniform deformation of the workpiece material.

Abstract: Given the stringent operating conditions to which super alloys are subjected to in aerospace, nuclear power and gas turbine industries, their efficient machining and generation of machined surfaces with high integrity assumes a lot of importance. Therefore, this paper presents an experimental investigation on the surface roughness and cutting force of Inconel 718 machined with several different kinds of cutting tools. Both single-factor and orthogonal experiments were carried out with cemented carbide, cermet and CBN tools. The effects of cutting tools and cutting parameters on the surface roughness and cutting force are investigated and the optimal cutting conditions are recommended.