| Titanium alloy is very popular with outstanding properties in the field of aerospace. However, the difficulty of machining titanium alloy has been the focus in the field of processing. In order to reduce the weight of aircrafts, improve the strength of the structure and meet the new requirements of the maneuverability, load capacity and service life, the thin web structures are widely used in the aerospace monolithic components. The large cutting vibration is easy to generate because of big cutting force, the weak rigidity, not only debase the machining precision and quality, but also greatly reduce the tool wear, increase the cost of production, reduce production efficiency, it is urgent to need a strategy to weaken the cutting vibration of web. After the researching the mechanism of vibration, designing the special cutter for web is considered as the most feasible research method now.First of all, this paper conducts the thorough research of the cutting mechanism of titanium alloy. The influence of process parameters on the cutting performance of titanium alloy, from the cutting force and vibration, based on the orthogonal tests. Through the range analysis and variance analysis, the trend of the cutting performance of titanium alloy, the significance and contribution of process parameters for cutting performance of titanium alloy are obtained. Then the deep rules of process parameters for the cutting performance of titanium alloy are revealed. The influence of rake angle, angle and helix angle on the cutting performance of titanium alloy is obtained, through the contrast test of two tools which have different structure.The wear forms of the solid carbide cutting tool for titanium alloy are obtained and the wear mechanism is analyzed, through the tool life test with the help of SEM and EDS analysis method. The internal mechanism of tool wear and cutting force is revealed, by the modified cutting force model. This paper conducts the change rules of the processing system vibration with the tool tear, based on the two degree of freedom model and frequency spectrum analysis of milling vibration system, obtains the inherent relationship of the tool wear and cutting vibration.The parameters optimization combination of rake, relief and edge radius for the end cutting edges is proposed, through the finite element simulation analysis based orthogonal design for parameters of the tool structure. With the application of the theory of oblique cutting, a reasonable cutting edge inclination is added to the end cutting edges. A Z direction cutting force model is established, using MATLAB to calculate this cutting force and conduct the Fourier transform. Then, a optimization for the variable pitch is presented, taking the minimum standard deviation of the frequency spectrum of the cutting force as the goal function.A contrast cutting test of web about a self-design cutter which is used to suppress vibration of the titanium alloy web and a imported tool is carried out, considering z direction cutting force, cutting vibration and surface roughness as the evaluation indexes, verifies the effectiveness of the self-design cutter for reducing the cutting vibration of web. |
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