Deformation analysis and error prediction in machining of thin-walled honeycomb-core sandwich structural parts

Due to its low rigidity and poor stiffness, machining deformation in numerical control milling is a big obstacle to achieve accurate shape of thin-walled honeycomb-core sandwich structural parts. In this paper, the factors which affect the machining deformation of these structural parts are analyzed at first. Then, a finite element analysis model is established, which considers the affecting factors of workpiece original stress, fixture constraints and cutting forces, to simulate the magnitude and distribution of the machining deformation. Afterwards, a prediction model is developed by using back propagation neural network to build the relationship between the deformation and machining parameters. Finally, the milling and measurement experiments are performed to validate the proposed prediction model. By comparing the experimental result with the simulation result and the prediction result, it is found that the experimental result was 7.2 and 2.2% less than the simulation result and the prediction result, respectively. Thus, a conclusion is drawn that the machining deformation prediction methodology is feasible.