Research On The Process Mechanism Of Difficult-to-machine Materials With Vibration Assisted Diamond Cutting

In recent years,with the wide application of high-performance functional components,the requirements for the quality of processed surfaces have become higher and higher.Single crystal silicon is a hard and brittle material.To obtain a smooth surface,it is necessary to control the cutting depth to cut in the plastic zone.Traditional diamond turning has a small plastic cutting depth and low processing efficiency.As a kind of high-temperature alloy,nickel-based alloy has low thermal conductivity and high strength,which makes it prone to tool wear during turning.Ultrasonic vibration turning is to impose a certain highfrequency small vibration on the tool tip to realize the periodic contact and separation between the tool and the workpiece.It has significant advantages in ultra-precision cutting of difficult-to-machine materials.In this paper,two different types of typical difficult-tomachine materials of single crystal silicon and nickel-based single crystal superalloy are studied by ultrasonic vibration cutting.First,analyze the kinematics principle of one-dimensional ultrasonic vibration turning.A single crystal silicon simulation model is established based on finite element software.Through the finite element simulation,the chip formation mechanism and the change of cutting force under ultrasonic vibration turning and ordinary turning are analyzed,and the reasons for the change of the shear angle under ultrasonic vibration turning are analyzed.The law of the influence of vibration frequency,ultrasonic amplitude and cutting speed on the shear angle is further analyzed.Then,the ultrasonic vibration oblique cutting experiment on single crystal silicon was carried out to study the influence of different amplitudes on the cut depth of the single crystal silicon plastic brittleness transition,and the morphology,Raman change and cutting force of the single crystal silicon grooves with different amplitudes were analyzed.The effects of vibration frequency and cutting speed on the depth of cut of single crystal silicon from plastic brittleness were studied,and the mechanism of single crystal silicon removal under ultrasonic vibration cutting was analyzed.On this basis,a single crystal silicon ultrasonic vibration end face cutting experiment was carried out to explore the feasibility of end face cutting.Finally,the surface integrity of nickel-based single crystal superalloys under two cutting methods,ordinary turning and ultrasonic vibration turning,is analyzed,and the differences in surface morphology,chip morphology,tool wear,mechanical properties and other aspects of the two different cutting methods are analyzed,revealing The surface integrity mechanism of vibration-assisted turning of nickel-based single crystal superalloy.Aiming at the influence of processing parameters on surface quality,the effects of amplitude,cutting speed,feed rate and cutting depth on the surface quality of nickel-based single crystal high temperature vibration assisted turning are studied through experiments,and the optimal processing parameters are summarized.