Research On Geometric Methods Of Machining And Forming Of Mechanical Parts

At present,there are more and more mechanical parts of complex curved surfaces,and the forming movement towards the surface of the machined parts also tends to be complicated.During machine tool cutting,there is a strict geometric relationship between the tool cutting edge curve/tool surface,the machine tool movement and the workpiece surface.In addition,the machine tool movement is also related to the type of tool.This paper firstly studies the cutting and forming methods of mechanical parts based on geometry and tool classification,including:(1)Using a non-rotating tool,the workpiece surface is formed by the motion scan of the cutting edge curve;(2)Using a rotating tool,the workpiece surface is a curved surface formed by the movement of the tool surface family envelope.On the basis of the above research,the following research work was carried out.(1)In the aspect of forming turning scanning using a single pass in a non-rotating tool to scan the surface of the forming workpiece,the forming turning scanning and its geometric expression are studied,and the research technical route of forming turning scanning forming is proposed.The mathematical modeling and simulation of forming turning is carried out according to the proposed research technology route.Taking the groove of the formed turning ball bearing inner ring as an example,the mathematical modeling of the workpiece design surface and the workpiece surface is carried out,and the radial dimension changes of the workpiece caused by the cutting force and tool wear are analyzed.simulation.(2)In terms of using the three-coordinate NC milling surface of the ball-end mill in the envelope of the dual-parameter surface family in the rotary tool,for the three-coordinate NC milling of the ball-end mill,regardless of the specific topology of the machine tool,it is uniformly stipulated that the machine tool motion is the tool Relative to the motion of the workpiece,a unified machine tool motion relationship is established,and the three-coordinate NC milling of the ball-end mill and the surface error of the workpiece are studied based on the tool motion.There are 21 machine tools geometric errors in the three-coordinate NC machine tool,which will cause the position and attitude deviation from the tool and the workpiece,and then generate errors between the workpiece surface and the design surface.Therefore,based on the geometric relationship to the tool surface,the machine tool movement and the workpiece surface,this paper studies the forming problem of the NC milling workpiece surface with the ball-end mill.Since the rotation of the ball-end mill around the cutter center will not cause the workpiece surface error in the three-coordinate milling of the ball-end mill,this paper decomposes the machine tool motion error into translation based on the ball-end mill center and rotation of the ball-end mill center.The multi-body system theory directly transforms the geometric error of the machine tool for the position deviation from the ball-end mill center of homogeneous coordinating transformation,and studies the workpiece surface forming and workpiece surface error of the ball-end mill three-coordinate milling through the deviation of the surface of the ball-end mill center,and simulated with MATLAB.