Research On High Efficiency And Precision Machining Of Titanium Circular-Arc Rabbet

As key component of advanced aviation turbofan engine, the machining accuracy of titanium alloy wide-chord hollow fan blade has a great effect on the enhancement of bypass ratio and thrust-weight ratio of engine. Circular-arc rabbet is an important form of the connection between fan blade and blade disc. The machining accuracy and surface quality of the rabbet has a significant impact on the performance of fan blade and the entire turbofan engine. However, the problem of instable machining quality, low productivity, high obsolescence rate and serious tool wear exist in production. Therefore, with the focus on profile precision, grinding burn and machining vibration, experiments of profile grinding and profile milling have been conducted. The major research works are included as follows:1. In the experiment of profile grinding, wheel topography and dressing efficiency were analyzed to determine the dressing method. Grinding force, force ratio and grinding ratio were investigated to evaluate the cycle of grinding and dressing in order to control the accuracy. The effects of cooling condition, process parameter on specific grinding energy and grinding temperature were studied to propose the method of improving grinding burn. Finally, the surface integrity was analyzed to verify the optimization of the parameter.2. In the experiment of profile milling, the effects of tool material and cutting parameters on cutting force were studied. Combined with the frequency spectrum analysis, milling process parameters were optimized. Tool wear characteristic was observed during the experiment, together with the study of tool life, the parameters of rough machining and finishing of rabbet were established. At last, surface integrity was analyzed to verify the feasibility of profile milling.3. According to the characteristic of titanium circular-arc rabbet, the fixture and test specimens were designed and fabricated. Based on previous study and machining allowance, machining of titanium circular-arc rabbet was experimented. The profile accuracy and surface integrity were analyzed to verify that the application of profile grinding and profile milling could ensure high efficiency and precision machining of titanium circular-arc rabbet.