| The scroll compressor mainly relies on the meshing action of the moving and rotating scroll to compress the gas.Therefore,the research of the scroll compressor mainly focuses on the research of the core component scroll.With the improvement of the meshing performance requirements of the moving and rotating scroll,the research of the scroll has been developed from a single type line to a combined type line.The variable-section scroll formed by the combined line can increase the wall thickness of the scroll,reduce the compression time of the gas,and achieve a high compression ratio.Therefore,processing a variable-section scroll that satisfies the machining accuracy is advantageous for improving the working performance of the scroll compressor.Milling variable wall thickness wraps is a difficult point in the manufacture of variable-section scrolls.Milling wraps are a very complex dynamic nonlinear process,not only with physical phenomena such as milling forces,milling heat and tool wear,but also vortexes.Milling of thin-walled teeth usually varies to varying degrees.Aiming at this situation,this paper establishes a finite element model for 3D milling of thin-walled teeth with variable-section scrolls.The milling simulation model predicts the real-time milling of variable wall thickness spiral teeth.The details are as follows:(1)Establish a mathematical model of the variable-section scroll teeth.In this paper,based on the theory of vortex-type line meshing,the combined vortex line is used as the busbar,and the inner and outer wall profiles of the vortex are constructed by the normal equidistant line method.The three-dimensional geometric model of the variable-section scroll is established by Pro/E software.(2)A three-dimensional milling finite element model of variable-section scroll teeth was established.In this paper,based on the actual milling wrap,the DEFORM-3D milling module is used to define the material properties of the wrap and the milling cutter,the contact between the design milling cutter and the wrap,the milling cutter and the vortex.The rotator meshes the mesh,sets the milling boundary conditions,checks the data,and establishes a three-dimensional milling finite element model of the variable-section vortex thin-walled teeth.(3)Optimize milling parameters.By proposing the factors affecting the surface quality of the vortex thin-walled teeth,the changes of milling heat and milling force under different milling parameters are predicted,and the fluctuations and average values of the milling force curves under different milling parameters in the same time domain are analyzed.The milling speed is 471m/min,the optimum milling depth is 0.25 mm,and the optimum feed rate is 0.05mm/r.(4)Milling experiments of variable-section scroll teeth.Milling the wraps with different milling parameters on the CNC milling machine,collecting the optimized milling parameters and the unoptimized milling parameters,the milling force changes under milling,verifying the correctness of the optimized milling parameters,and calculating the average milling in the simulation.In the force and experiment,the maximum relative error of the average milling force in the Fx direction is 18.89%,and the maximum relative error in the Fy direction is 11.82%.The reliability of the milling force in the simulation was verified.In this paper,the milling finite element model of vortex thin-walled teeth is used to predict the machining condition of vortex thin-walled teeth.The milling parameters are optimized from the macroscopic aspects of milling force data changes,and the reliability and optimization of finite element simulation are verified by experiments.The correctness of the post-milling parameters provides a theoretical reference for the high-precision milling of the wrap. |
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