Research On Prediction And Compensation Method Of Grinding Deformation Of Ultrasonic Knife

Ultrasonic cutting process of Honeycomb has been widely used in the field of aerospace manufacturing due to its green advantages.As the core component of this special processing technology,the dual characteristic requirements of traditional knife tools and ultrasonic longitudinal vibration mode for ultrasonic knife need to be taken into account.The blade shape of the tool mainly presents geometric characteristics such as multi-edged surfaces,thin slices,and long cantilevers,which will lead to low bending stiffness.Thus,deformation error which is easily produced during edge grinding will reduce the edge surface forming accuracy and affect the ultrasonic cutting performance of this tools.Taking the ultrasonic knife as the object,this paper studies the grinding deformation prediction and active control method of grinding deformation.It can also provide a theoretical reference for the prediction of grinding force and deformation of other similar thin and slender tools.The main work of the paper is as follows:1.A grinding force model with variable edge width is constructed.According to the characteristic that the grinding width of the conical edge of the knife is dynamically varied along the feed direction,an equivalent mapping method of the grinding contact area is introduced.Based on the grinding mechanism of single abrasive particle and the average volume method,the expressions of debris formation force,friction force generated by debris outflow and abrasive sliding friction force are derived.Then,the variable edge width grinding force model is constructed,and the accuracy of the model is verified by grinding experiments,which is benefit to the subsequent programming calculation and analysis of dagger grinding force and deformation during the actual grinding.2.The active prediction method of grinding deformation is studied.Based on the characteristic of thin slices,long cantilevers and weak rigidity,and also on the coupling mechanism between grinding force and deformation,a deformation prediction method integrating ANSYS and MATLAB is proposed.The parametric model of ultrasonic knife is constructed by APDL language,and the establishment of geometric characteristics and material attribute definition of knife are programmed.As the main control program,MATLAB uses an iterative algorithm to repeatedly call APDL for coupling calculation of deformation,which makes deformation calculating program automatically to improve the calculation efficiency and prediction accuracy.3.The active compensation module for knife grinding error is developed.Based on the principle of mirror image compensation,the overall scheme of deformation error coupling compensation is proposed.The "secant method" is used to replace the traditional "fixed point iteration method" to calculate the grinding deformation of discrete points,which improves the calculation efficiency;The cubic spline curve is used to reconstruct the compensation contour to ensure the smooth connection of the discrete points,and the compensation curve is transformed into a straight line segment by the variable step length linear interpolation method,which improves the applicability of the compensation program.Finally,the parametric programming interface of ultrasonic knife is developed based on MATLAB,which integrates the functions of grinding deformation calculation,active compensation and compensation program generation.The easily-operated compensation program can be generated automatically,which improves the calculation efficiency and prediction accuracy.