The Deformation And Compensation Concerning On Thin-walled Workpiece Induced By Force And Heat

Thin-walled workpiece with high precision is widely used in various of high-tech industries, such as aerospace industry and ship industry. Its typical applications include engine blades, propeller, engine casing and so on. With the quick development of exploration into deep space and deep sea, as well as mechanical technique in recent years, the thin-walled workpiece with high precision and complex structure receives more and more application. Also, the requirement of its precision becomes higher.But the workpiece can easily give out deformation with its low stiffness,induced by cutting force and cutting thermal. When its size is smaller, the phenomenon becomes heavier. This not only greatly limits its further application, but also push up the cost. Therefore, doing research on milling force and thermal, also the induced dimensional error, is important to the manufacturing technology with significance realistic and economic value.Considering both shearing and ploughing mechanism, a milling force is proposed on the basic of milling mechanism. Firstly, the infinitesimal milling force model along the axial direction is set up, then integrated along the cutter, thus getting milling force of one cutter edge. As the frequency of contacting between cutter and workpiece, the total milling force presents periodic characteristics. As Fourier series’ effectiveness in dealing with frequency signal, the milling force is transformed into Fourier series forms. In order to improve the realistic value of proposed milling force model, the entrance angle, exit angle and cutting thickness, which have important influence on the force model, are deduced under various of trajectory respectively, such as circle and arbitrary lines, expanding theapplication of the model.Then the temperature predicted model which is suitable for milling is established, bu modifying the heat model which is suitable for cutting,according to the periodic characteristics of milling. This model, combined with the milling force model, lays the basis of the prediction the workpiece’s deformation induced by force and temperature.Side milling experiments are designed to verify the two established models. The milling force coefficients are regressed with the measured milling force, thus establishing the mathematical milling force. Then the milling force and milling temperature under various of parameters, which are calculated with Matlab, are compared to the measured ones. The well agreement of the results validate the milling force model and milling heat model well.Then the calculated milling force and thermal transmitted into the workpiece are applied to the thin-walled part in ANSYS to predict its deformation and provide reference for the cutter trajectory modification.The time-consuming operation with GUI in ANSYS gives limitation to the practical application of the compensation method, So this paper introduces an quick calculation method with APDL language, which can accomplish model building, meshing, calculating and result outputting automatically.This method can reduce calculating time largely on the same precision level and improve the practical application of the compensation method.Finally, the side milling experiments concerning thin-walled workpiece are carried out. The deformation of the woripiece under certain milling parameters are predicted by APDL. Also, the deformation of the cutter is considered which is viewed as a cantilever, then the cutter trajectory is modified to improve milling precision. Through comparison of the surface error between the two workpiece, one with compensation and the other not, the availability and effectiveness of the compensation strategy is verified, and also the milling force model and milling thermal model.