The Effects of Dynamic Milling Force and Spatial Errors of Machine Tool on Workpiece Dimensional Errors

• Main Authors: Chi-ming Peng, 彭啟明
• Other Authors: Jiunn-jyh Wang
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/27639272531593386137

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 97 === Except the spatial errors of machine tool, the force-induced tool displacement is also an important factor related to the workpiece dimensional error in milling process. As the demands for the functions of micro-machine system are increasing, the accuracy of micro-machine tool and workpiece must be upgrade to a higher level simultaneously. Furthermore, in order to accurately predict the workpiece dimensional errors and measured the machine tool spatial error by means of the workpiece dimensional errors, considering and handling the spatial errors of machine tool and process errors in the same time are important and necessary task. The workpiece dimension error model comprising of the spatial errors of machine tool and process errors in milling process is presented in this thesis. The spatial errors of machine tool are analyzed by vector method with Laser Doppler Displacement Measurement (LDDM). The important factors of process errors considered in this model include the dynamic milling force, tool stiffness, workpiece stiffness and tool runout. The surface generation window is proposed on the basis of chip width density function of convolution modeling method to relate the generation of workpiece surface to the dynamic milling force. This model not only predicts workpiece dimensional accuracy, but also serves as a new tool to calculate spatial errors of machine tool. Moreover, the effects of all the parametric variance of this model are investigated. It is shown that the dimensional error is most affected by the variance of the dynamic milling force. Finally, the parallelism of the machined surface is shown to be accurately predicted by combining the workpiece dimensional error model and variance analysis.