Design And Optimization Of Specialized Tool For Helical Milling Ti6Al4V Based On Processing Simulation

With the performance of aircraft improving, how to improve the structure strength while relieving the weight of aircrafts becomes a challenge to the aircraft manufacturing. Materials with property of low density, high strength, corrosion resistance andheat resistance like Titanium alloy have been widely used in aircraft structures. However, Titanium alloy has some disadvantage like poor thermal conductivity, small elastic modulus and high chemical activity, which will cause poor heat dissipation effect. Machined face will be chilled because of high cutting temperature, which will lead to increase of tool wear. As for some disadvantages such as high thrust force, tool wear as well as bad machining quality when drilling titanium alloy and composites, which have a negative influence in the intensity and fatigue life, conventional drilling has already not been suitable for aircraft manufacturing.Helical milling is a new hole-making process which uses eccentric processing method. There is enough area for thermal dissipation so that the cutting temperature is much lower than the conventional drilling process. Helical milling can also reduce the cutting force, which has a good effect of machining quality and tool life. In this paper, some problems about specialized tool for helical milling of Titanium alloy are studied through analysis of undeformed chip, finite element simulation and experiments.Firstly, the motion equation and the relation between the control parameters and cutting parameters are established by studying the tool’s movement characteristics while helical milling.In order to find the relationship between tool’s structure and machining performance in helical milling process, a three-dimensional model of undeformed chips by Solidworks was built, Combined with references and experiments. Ideas of design and optimization of specialized tool for helical milling was proposed by analysis of chips and machining quality.A three-dimensional finite element model of helical milling process on Ti6A14V was established and verified to be accuracy by two sets of parameter experiment. Using axial cutting force as the index, a tool parameters orthogonal experiment was carried out. as factors.The impacts of included angle, slant angle and rake angle of V-form front edge on cutting force were deeply analyzed and the optimized tool parameters was established. Also, pilot study has been done on the chip flow characteristic of helical milling process with the FEM, which could be used to optimize the location and direction of cooling holes on specialized tool.Finally, in order to test the tool’s processing properties and life on Ti6A14V, experiment based on helical milling system was carried out. The results show that the tool life was improved to 29 holes compared with 21 holes by tool without optimization.