Algorithm Of Tool Axis Vector Optimization For Five-axis CNC Machining Of High Precision Surface

When processing high-precision curved surfaces,five-axis CNC technology has outstanding advantages.It not only has extremely high processing accuracy and processing efficiency,but also has the advantages of higher degrees of freedom,etc.It has a wide range of applications in the processing and production of high-precision parts such as military products,aviation blades,and measuring tools.It has also become a powerful assistant to the country's industrial development and manufacturing prosperity in the aerospace field,automotive field,ship manufacturing,and mold production.The optimization of the tool axis vector in five-axis CNC machining is the core link that affects the processing quality and efficiency,so the optimization method of the tool axis vector become a key issue that needs to be solved at present.This article first summarizes the five-axis CNC machining and tool axis vector planning algorithms;the modeling method and differential geometry characteristics of NURBS complex surfaces are analyzed;the processing line spacing and processing step length under different surface types are deduced.The design of the curved tool path are completed.An algorithm for adjusting the tool axis vector based on the cutting force of the tool is proposed.From the perspective of reducing the tool deviation,the tool axis vector is optimized.Finally,on the basis of simulation experiments,the feasibility and actual value of this algorithm are revealed: the tool axis vector controlled by the cutting deflection can effectively improve the machining accuracy,machining efficiency and surface quality of the workpiece.The specific work and innovation are shown as follows:(1)The instantaneous static flexibility calculation model of the tool contact is deduced,and the tool axis vector control model and algorithm based on the tool deflection are established.The tool deflection is determined by the cutting force and the tool static flexibility.In order to reduce the deformation of the tool during processing and improve the processing quality,the static flexibility of the tool is optimized,and the instantaneous static flexibility of the tool contact is proposed.The tool axis vector optimization model i s established to suppress the surface error caused by the tool deflection to obtain higher machining accuracy.(2)In the process of applying five-axis numerical control technology,non-linear error will reduce the quality of the processed surface,which is optimized by interpolation algorithm.The first task is to explore the reason for the formation of non-linear error and the correlation between non-linear error and curvature of the curved surface.Secondly,the non-linear error are modeled and solved,the maximum error value of the nonlinear error and the position where the maximum error occurs are obtained.A calculation method to reduce this error is proposed: the interpolation tool contact point position is obtained through the tool contact point position of the tool trajectory line,and adopts the intermediate tool axis vector as the interpolation tool axis vector.(3)Through software simulation experiments,the effectiveness of the proposed method is verified.First,use NX 10.0 to model the surface,and plan the path of the rough machining,semi-finishing,and finishing stages.Secondly,use the tool axis vector optimization method to adjust the initial tool axis vector for finishing stages.Finally,it is concluded that the proposed method can improve the processing quality of curved surfaces under the premise of taking into account the efficiency.