Theoretical And Experimental Studies On The Ultra-Precision Face-milling Of Engineering Ceramics

As one of the feasible methods of ultra-precision machining of the hard/brittle materials, ultra-precision milling is widely used in national defense, aviation, computer, automobile and other new and high technology fields. To inosculating the requirement of the development of ultra-precision machining, the thesis deals with the ultra-precision machining technology by means of differential geometry, metal cutting theory and cutting dynamics, machine tool testing and computer simulation technology, etc. Emphases are placed on the milling force, milled surface topography. The creative fruits may be summarized as follows:1. In the aspect of modeling of mill force: Based on the analysis of characteristics of micro-milling, a dynamic model of milling force is established. Starting with cutting theory, the model considers the effect of volume forces on ultra-precision milling process, and stresses on the simulation of ultra-precision face-milling.2. On the milled surface generation theory: Founding the movement locus of insert cutting edge; Modeling surface topography;, analyzing its influencing factors by simulated results.3. In the aspect of experiment research: for engineering ceramics such as ZrO2^Si3N4)experiments are carried out by a diamond face mill cutter. Cutting force and machined surface roughness are measured, they indicate:(1) Based on the experiments of scratching and ultra-precision face-milling, it is considered that micro-milling depth is the most important influence factor to realize brittle/plastic transition. At the same time, material mechanical properties is also crucial.(2) The measured cutting forces are basically agreement with the simulation results. In the ultra-precision milling, the cutting forces are very low. When the cutting depth is less than 10 fjm , the milling forces are no more than 1 N , and the axial force is none but 0.1-0.5 N .(3) The measured Ra shows that on the machined surface, the roughness is different on every point. It is higher on the symmetrical line than on the two sides, and relevant to the ratio of workpiece width to cutter diameter.The work in the thesis will lay a solid foundation for investigating the ultra-precision machining theory, designing machining equipment and cutting tool, establishing process technique and predicting machined surface roughness of ultra-precision face-milling.