Research On The Deformation Of Blades-Whirling Process

Blades,as the core components for modern devices to extract energy like turbines,in order to maximize the performance of these devices,are developing with the higher requirements,such as large torsion angle,thin wall and higher precision,in modern industry.Blades with these characteristics make the blade-cutting process need to be realized by Four-axis and above four-axis CNC machines.It has been proved that common blade-cutting methods,including point-to-point milling,side milling and turning milling,have some disadvantages like low efficiencyWhirling,as one of the high-speed and effective machining methods,has been widely used in the screw-machining.In recent years,the whirling machines equipped with disk milling cutters has shown the possibility of producing many other parts This paper proposes a machining method that uses the three-axis linked whirling machines equipped with disk milling to cut the blade,following the complicated tool path.This is an economical,efficient,innovative method,which can meet the quality requirements.However,due to the free-formed surface of the blade,it is easy to deform during the blade-whirling process because of many factors.The detailed work of this paper is as follows:First,the detailed process of the blades-whirling with disc cutter was analyzed from the macro and micro perspectives.The helical milling trajectory of the tool was established.Then we regarded the disc cutter and inserts as a equivalent torus tool formed by the rotation of the cutting edge.By introducing the plane-whirling model,the three-dimensional geometry of the chip in the process was given,and the influence of the blade curvature on the change of chip volume was analyzed,thereby modifying the chip model generated in blades-whirling process.According to the geometric characteristics of the blade and the workpiece,three mathematical models,the instantaneous cutting thickness h,the maximum instantaneous contact height hcut and the instantaneous cutting area S during the blades-whirling process was established.By dividing the process of chip formation into four stages,the instantaneous dynamic milling force could be expressed as a piecewise function about the cutting angle β.Finally,cutting experiments of the H59 brass was finished to prove the correctness and effectiveness of the established force model,and the influence of cutting parameters on cutting force was analyzed.Then,the complex blades-whirling process was simplified to an approximate 3D straight-line cutting model for simplification.Using ABAQUS finite element simulation software,a 3D thermal coupling cutting simulation model was established to simulate and analyze the cutting force,cutting heat,stress,etc,generated during the cutting process.Finally,the comparation of the simulated cutting force and the measured force verified the feasibility of the simulation model and the accuracy and reliability of the simulation resultsFinally,using the ABAQUS software,we established the elastic deformation model in the blades-whirling process.By loading and unloading the instantaneous cutting force on the reference points set at different positions on the blade surface,the values and trend of elastic deformation at different positions during the blades-whirling were simulated.We drawn the trend of deformation at different reference points as the map of deformation change.According to the map of deformation change on seven sections,the corresponding maximum displacement curve was drawn to fit the three-dimensional elastic deformation prediction surface in Matlab software.Finally,the elastic deformation law of this specific blade is summarized.