Papers by Author: Ying Fei Ge

Abstract: High-speed milling tests were performed on vol. (5%-8%) TiC_p/TC4 composite in the speed range of 50-250 m/min using PCD tools to nvestigate the cutting temperature and the cutting forces. The results showed that radial depth of cut and cutting speed were the two significant influences that affected the cutting forces based on the Taguchi prediction. Increasing radial depth of cut and feed rate will increase the cutting force while increasing cutting speed will decrease the cutting force. Cutting force increased less than 5% when the reinforcement volume fraction in the composites increased from 0% to 8%. Radial depth of cut was the only significant influence factor on the cutting temperature. Cutting temperature increased with the increasing radial depth of cut, feed rate or cutting speed. The cutting temperature for the titanium composites was 40-90 °C higher than that for the TC4 matrix. However, the cutting temperature decreased by 4% when the reinforcement's volume fraction increased from 5% to 8%.

Abstract: Titanium matrix composites (TMCs) possess many outstanding properties and have increasing and potential application in aerospace, automobile and other industries. However, TMCs are typical difficult-to-machining material due to the rapid tool wear rate and excessive machining induced defects. In this paper, tool wear, cutting forces, cutting temperature and surface roughness were investigated when milling TMCs with Polycrystalline Diamond (PCD) and carbide tools. The results showed that the values of surface roughness obtained by carbide tools were higher than that of PCD tools under the same cutting conditions. The value of cutting temperature for PCD tool was about 75% of the carbide tools, and the main cutting force value of PCD tool was about 85% of the carbide tool. Abrasive and adhesive wear were the main wear mechanisms of PCD and carbide tools. In all, PCD tools had a better cutting performance than carbide tools during finishing milling titanium matrix composites.

Abstract: High-speed turning tests were performed on vol.10%(TiC_p+TiB_w)/TC4 composite (TMC) in the speed range of 60-120m/min using PCD and carbide tools to investigate the tool life, tool wear, cutting temperatures and cutting forces. The results showed that the carbide tool was not suit for the machining of TMC. Tool life of PCD was confined to 12 min for all the cutting conditions. Flank wear increased obviously with the increasing cutting speed especially when the cutting speed surpassed 80m/min. PCD tool mainly took place chipping, peeling, abrasive wear and adhesive wear at the rake face and flank. The cutting temperatures of carbide were about 1.5-2.0 times higher than that of the PCD. Under the same cutting condition, cutting temperature of TMC was nearly 100°C higher than that of the TC4 matrix. The cutting forces were confined to 130N and 150N for the PCD and carbide tool respectively. For the carbide the cutting forces slightly decreased when the cutting speed increased from 60m/min to 120m/min. When using the worn tool, the cutting forces significantly decreased with the increasing cutting speed especially for the peripheral force component.

Abstract: Particle reinforced metal matrix composites (PMMC) possess many outstanding properties and are increasingly applied in automobile, aerospace, electronics and medical industries. However, PMMC is a typical difficult-to-machining material due to the rapid tool wear rate and excessive machining induced defects. Although large amount of investigations have been done on the conventional machining of PMMC, merely several researchers have dedicated themselves to the study of milling, especially high speed milling of this material. Within the milling studies, most researchers have selected the carbide coated or uncoated solid carbide tools whose tool life was not satisfactory for engineering application. The literatures review indicates that most researchers limited their study to sintering or casting SiCp/Al composites at the low or moderate cutting speed. Material produced by the in-situ reaction method or titanium matrix composites was seldom selected as the research object. The research content was limited to the effect of cutting parameters on the machined surface quality or cutting forces. It is suggested that high-speed milling with PCD tool should be conducted in order to improve the machined surface quality and material removal rate and decrease the machining cost. Tool life modeling, surface roughness prediction, cutting parameters optimization and high-speed milling data base and the expert system should be greatly noticed by the researchers.

Abstract: High-speed milling tests were performed on SiC_p/2009Al composites in the speed range of 600-1200m/min using PCD tools to investigate the cutting temperatures and the influence factors. The results showed that the cutting temperature could reach 580°C under the given cutting conditions. Graphitization took place on the PCD tools under the high cutting temperature coupled with the effects of abrasive wear of SiC particles and catalysis of copper in the 2009 aluminum matrix. Cutting parameters, tool materials, workpiece materials and tool wear condition had significant effect on the high speed milling temperature while tool geometries had the minor effect. Among these influence factors, cutting speed was the most significant factor. Reinforcement volume fraction was the less significant factor and followed by radial depth of cut, feed rate and tool materials.

Abstract: High speed milling tests were performed on the SiCp/2009Al composites to investigate the cutting forces by using PCD tools in the speed range of 600-1200m/min. The results showed that the peak value of the cutting force Fy (in the tool radial direction) was in the range of 700-1450N under the present cutting condition. The maximum amplitude of cutting force vibration in the tool radial direction can reach 700N. Cutting forces increased with increasing feed rate or radial depth of cut and decreased with increasing cutting speed. Negative rake angle and relatively large tool nose radius were recommended as far as cutting forces was concerned. Materials with higher volume fraction or smaller reinforcement particle size had the bigger cutting forces. T6 heat treatment can increase the cutting forces significantly but the using of coolant can decrease the cutting forces evidently.

Abstract: Tool life and tool wear, cutting forces and cutting temperature, surface finish, chip formation and surface generation were investigated when milling SiC_p/2009Al composites at the cutting speed of 1200m/min using PCD tools. The results showed that PCD tool life was 150min when the 0.1mm tool wear criterion was chosen. PCD tool mainly suffered from tool grain breaking-off, chipping, abrasive wear, micro cracks and adhesive wear due to he very high-frequency impact and scrape of SiC particles. The peak value of the cutting force Fy (the radial direction) was over 1300N and the cutting vibration was very severe. The cutting temperature was 523.7°C. Pits, voids, matrix tearing and scratch were the main defects on the machined surface. The deformation layer thickness was about 20-35μm. The chip for the vol.20%SiC_p/2009Al composite took the form of flow type and the mechanisms of the chip formation were the combination of dynamic behavior of voids/micro-cracks and adiabatic shear. For the vol.35%SiC_p/2009Al composite, the chip was non-continuous and had the tendency of saw-toothed type. Material swelling and side flow, tool-workpiece relative vibration, feed rate and tool nose radius, removal mode of SiC particles were the main mechanisms of surface generation.