The Parametic Modeling And Structural Optimization Of Cemented Caribide Tools For Machining Titanium Alloys

Titanium alloys has become an important material in aerospace industry,biomedical and other fields due to its high specific strength,toughness,good corrosion resistance,high heat resistance and good biocompatibility.However,due to the small deformation coefficient,poor thermal conductivity,high chemical activity and small elastic modulus of titanium alloy,the machinability of titanium alloys is deteriorated.Therefore,research on the tool for machining titanium alloys has become an important issue.The base materials,coating materials,coating techniques and tool structure design skills have important effect on tool's performance.By analyzing its research status,this thesis will carry out research and optimization work on cemented carbide tools from the aspect of tool structure design.The mathematical analytical model of the four-blade flat-end milling cutter was established by analyzing its geometric parameters,providing a theoretical basis for parametric modeling of tools.In order to improve the design efficiency,the parametric modeling of tools was studied by UG secondary development method.Structural design work for various types of carbide tools which are used machining titanium alloys are done.A three-dimensional simulation model for cutting Ti-6Al-4V with four-blade flatend milling cutter was established using finite element software.The geometric parameters of the tool are optimized by analyzing the cutting force,cutting temperature,stress distribution on the tool and the chip shape during the cutting process.The structure of the tool has been improved to strengthen its chip removal performance.The orthogonal optimization of the tool's geometry parameters has been carried out,the results show that the improved four-blade flat end mill has the best performance when the helix angle,rake angle and clearance angle are 45°,10° and 13° respectively,and the geometric parameters of the two-blade and six-blade flat-end milling cutters are also optimized.The dynamic performance was analyzed and the designed tool was proved to have good dynamic performance and a small tool overhang was recommended.Simulation of Ti-6Al-4V cutting with different cutting parameters was carried out by self-designed two-blade,four-blade and six-blade flat-end milling cutters respectively.By comparing and analyzing the temperature and cutting force in the simulation results,it is found that the self-designed four-blade flat-end milling cutter has the best cutting performance,while the two-blade flat-end milling cutter is the second,and the six-blade flat-end milling cutter is the worst.A preliminary process experiment was carried out using the prepared four-blade flat-end milling cutter.The groove's quality was best when the depth of cut,spindle speed and feed rate were 1.0 mm,2000 r/min and 120 mm/min respectively.The cutting performance comparison experiments were carried out using two-blade,four-blade,six-blade flat-end milling cutters and commercial four-blade flat-end milling cutters respectively.The cutting performance of the tool is judged by analyzing the burr length of the groove,the surface quality of the groove bottom,and the degree of wear.The results show that the designed two-blade and four-blade cutting tools are superior to the commercial four-blade flatend milling cutter and the self-designed six-blade flat-end milling cutter,which is consistent with the results in simulation.It verified the correctness of the simulation model and the cutting performance of the designed tools.