Detecting milling deformation in 7075 aluminum alloy thin-walled plates using finite difference method

With the development of modern airspace technology, entire thin-walled structures have been widely and increasingly used. Given the complicated milling process and poor rigidity of thin-walled plates, deformation and surface errors are apparent in workpieces. Finite difference method (FDM) has been applied to some engineering fields for establishing mathematical models because of its simplicity and efficiency. However, FDM has not yet been introduced and employed in the aerospace field, especially in the prediction of deformations in thin-walled plates. A novel mathematical method is developed in this study to detect deformations in thin-walled plates given the actual milling situation. This method is based on FDM. Then, the deformation can be estimated under three different boundary conditions using a program written with program codes. Given the stiffness of fixtures, a deformation experiment was conducted under preload forces to compare FDM with finite element method (FEM). In this experiment, FDM is similar to FEM. Moreover, the deformation parameters are validated by comparative results. Most of the errors are within 10 %. The reason for these errors is determined to improve the reliability of the calculation. Thus, this research introduces an effective method for obtaining solutions to the deformation of thin-walled plates in the milling process. This work also expands the application of FDM in the engineering field.