Research On Ultrasonic Vibration Assisted Milling Process For Hybrid Manufacturing Of Additive And Subtractive Materials

The hybrid manufacturing process of additive and subtractive materials has the advantages of additive manufacturing that are easy to manufacture complex parts,short manufacturing cycle and high material utilization,as well as the advantages of subtractive manufacturing that are high processing accuracy and good surface quality,which can realize rapid and efficient manufacturing of high performance and complex parts.This technology has broad development prospects in the field of aerospace.In this paper,titanium alloy parts are used as research objects,ultrasonic vibration assisted milling is introduced during additive manufacturing process and after additive manufacturing is completed.The main research work completed is as follows:The trajectory equation of the cutting edge of ultrasonic vibration assisted milling is established,and its motion characteristics are analyzed.The separation and combination time of the cutting edge and the workpiece are solved.The influence of the spindle speed,ultrasonic amplitude and ultrasonic frequency on the separation characteristics is explored.The finite element model of ultrasonic assisted milling after additive manufacturing and the milling mechanical model considering the initial residual temperature during additive manufacturing process are completed,and the effect of additive residual temperature on the milling force is studied.The milling force and milling temperature after additive manufacturing were measured through experiments,the accuracy of the finite element model is verified,and the change rule is discussed.The index prediction model of ultrasonic assisted milling force and milling temperature is established.Because of the low stiffness of titanium alloy aerospace parts,a dynamic model of ultrasonic vibration assisted milling for the flexible workpiece is established.Based on the completely discretized algorithm,the stability is predicted to obtain the stability leaflet diagram,and then the effect of the ultrasonic vibration parameters,cutting parameters,cutter parameters and additive residual temperature on the stability of ultrasonic vibration assisted milling is studied.The prediction model of ultrasonic vibration assisted milling surface quality based on BP neural network is established to realize the prediction of surface roughness.An optimization model is established to optimize the process parameters of ultrasonic vibration assisted milling after the additive manufacturing is completed,and the optimization results are obtained under the goals of the best surface quality and the highest processing efficiency.