| Due to its superior performance,SiCp/Al composite are widely used in aerospace,chip manufacturing,electronic packaging,optical components and other fields.Its essence is a typical difficult-to-process material,which is greatly limited in processing.Ultrasonic Vibration Assisted Cutting(UVAC)has the advantages of high processing efficiency and good processing quality compared with conventional cutting.The principle is that the ultrasonic generator sends out the signal,and the amplitude lever makes the tool along the special track produce regular vibration.Although previous researches on UVAC have been carried out for many years,there are few researches on the cutting temperature of SiCp/Al composites assisted by two-dimensional ultrasonic vibration.The cutting temperature affects the wear and service life of the tool during machining,as well as the surface quality and performance after machining.Therefore,this paper studies the cutting temperature of SiCp/Al composites for two-dimensional ultrasonic vibration-assisted cutting from the numerical theoretical model,finite element simulation analysis and ultrasonic vibrationassisted turning experiment,and the main research content is as follows:(1)Establish a cutting temperature field prediction model for UVAC cutting SiCp/Al composites.Considering the real-time variation of cutting depth,tool front angle and shear angle characteristics of UVAC,a theoretical model of instantaneous cutting thickness and transient shear angle is established.The relationship between cutting speed,shear speed and chip flow velocity in the UVAC process is revealed,as well as the magnitude of shear force and rake face friction.On this basis,considering the influence of ultrasonic vibration on material softening,an improved Jonson-Cook model is introduced.Finally,the influence of heat generated in the rake face heat source area and the shear heat source area on the temperature rise is calculated,and the temperature field model is established.(2)The finite element simulation analysis software is used to establish a finite element model of two-dimensional ultrasonic vibration-assisted cutting irregular multi-particle SiCp/Al composite,and the interface model between Al matrix and SiC particles is considered,and the tool can perform periodic two-dimensional elliptical motion in the plane by giving the tool amplitude.On this basis,the cutting temperature in the cutting process is analyzed,and the cutting depth,cutting speed,tool amplitude(X-direction amplitude,Ydirection amplitude)and tool vibration frequency are simulated and analyzed by the singlefactor control variable method,and the relationship between different parameters and cutting temperature is obtained,which provides a theoretical basis for subsequent experimental research.Finally,the surface quality of workpiece in the cutting process is analyzed,and the damage form of SiC particles in the cutting process is studied.(3)The experiment of processing SiCp/Al composites by UVAC was carried out.The experiment of turning SiCp/Al composites with 25% volume fraction was carried out,and the cutting temperature data was measured and recorded by infrared thermal imaging device.Single-factor experiments were carried out on cutting speed,cutting depth and feed,and the change of cutting temperature under different parameters was compared,and the change law of temperature was obtained,and finally the obtained experimental data and theoretical values were compared to verify the effectiveness of the theoretical model.At the same time,the cutting temperature of conventional cutting and UVAC is compared,and then the surface quality of the workpiece is observed under different conditions when cutting under different conditions by scanning electron microscopy. |
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