Papers by Author: L.J. Ma

Abstract: Though the high-speed cutting experimentation of high alloy antifriction cast iron, the materials performance and request on tools in cutting were analyzed. Though single-factor experimentation, the factors of affecting on cutting efficiency were discussed, such as tools materals, cutting speed, feed speed and cutting depth. The results show that the durability of PCBN tools is higher, but the durability of ceramics and tungsten-cobalt carbide tipped tools is low. The influence curve of cutting speed to machining efficiency is a part of parabola. And the influence curve of cutting depth to machining efficiency can be divided two parts of materials removal and tools wear. In the ensuring of technical requirements of work-piece machining. The high cutting efficiency can be obtained, when cutting speed vc=75~100m/min, feed speed f≤8mm and cutting depth ap =0.1~0.3mm.

Abstract: The machinable fluorophlogopite was drilled with tungsten-cobalt carbide and high-speed steel drill bits, respectively. The wear widths of major flank were measured, and the wear characteristic of twist was analyzed during drilling fluorophlogopite ceramics.Drilling experiments were carried to consider influence factors of drill bit wear, such as tool materials, cooling condition, spindle speed and tool angles. Tool materials and cooling conditions are the major factors to affect wear of drill bits. High-speed steel drill bits are not suitable for drilling fluorophlogopite ceramics. Cooling condition affects wear remarkably. With the rising of spindle speed, the wear widths of major flank grows. But apex angle has little affects on the tool wear rate. Research results indicate that low tool wear can be obtain through optimizing tool material and machining parameters in drilling fluorophlogopite ceramics.

Abstract: Machinable ZrO2/CePO4 composite was fabricated. ZrO2/CePO4 and mild steel materials were machined with tungsten-cobalt carbide twist drills. The material removal characteristic was analyzed by consideration of tool wear in different stock removals. Wear of twist drills was observed with SEM. Wear widths on major flank were measured with microscope. The experimental results show when ZrO2/CePO4 was drilled, wear widths on flank were much bigger comparing to mild steel drilling processes. The wear of twist drills occurred on major flank, minor flank and on chisel edge. Wear on minor flank is a unique characteristic in drilling of ZrO2/CePO4 ceramics. There exist obvious scratch remarks on tool wear. The tool wear results from abrasive wear, adhesive wear and oxidation wear.