Surface Integrity And Cutting Parameters Optimization In Machining Of New Titanium Alloys

Titanium alloy is one of the most widely used materials in aerospace, but the unique material property of titanium alloy make it difficult to machine. The improvement of cutting quality and maching efficiency of titanium alloy is an urgent problem. This paper investigated the machined surface integrity and cutting parameters optimization of developed TC21 and TC4 titanium alloy. The main work in this paper includes the following aspects.1. Factors such as cutting data, geometry angle of cutting tool and tool wear which may affect the surface roughness of the new type titanium were investigated by turing experiments. The influence of cutting data on surface metallographic structure and work hardening are also studied. The results show that it is easy to obtain lower surface roughness in the turning of the new type titanium when selecting appropriate tool geometry angle and the tool wear criterion.The feed has the greatest influence on the surface roughness, while the cutting speed and the cutting depth have no significant effect on the roughness. The work hardening and hardened layer depth of turing titanlium alloy is quite low.2. The influence of cutting data and tool wear on surface roughness of the new type titanium was analysed by milling experiments. Principle for milling parameters were also given. Surface topography of high speed milling titalium alloy was analyzed. Moreover, the influence of process parameters on working hardening and the influences of cutting data and tool wear on surface residual stress were studied.The results show that surface roughness, residual compressive stress and work hardening of the new type titalium alloy were quite low when using high speed milling.3. On account of high speed milling of titanium alloy, a mathematical model for cutting data optimization was built with the target function of maxmium productivity and minimum surface roughness. Liminting factors such as milling machine, cutting tools and processing technology were selected as constraint condition. Computing formula of cutting force, residual stress and surface roughness for high speed milling was fitting based on experimental data. Parameters for high speed milling on TC4 B-1 titanium alloy were optimized using genetic algorithrm. Expermental results show that the measured machined surface roughness, the feeding component force and the width component force are consistent with theoretical results when using optiminzed milling parameters. Cutting effciency can also be improved.