Milling force prediction of inclined rib with low rigidity in milling process of hollow thin-walled structural parts

In order to improve the prediction accuracy of low rigidity inclined rib milling force model in the milling process of hollow thin-walled structural parts, the static deformation of low rigidity inclined rib was solved by means of numerical analysis and finite element simulation method; moreover, the deformation mixed prediction model was established by combining general regression neural network with fruit fly optimization algorithm and cross validation algorithm to efficiently predict the dynamic deformation of low rigidity inclined rib under different parameters. Thereafter, based on this model, the dynamic feed per tooth solving model was established to predict the dynamic milling force, and it was verified by experiments. The results show that under the processing conditions of 6000 r/min, 0.14 mm/z, and 4 mm cutting width, the theoretical values of the maximum milling forces in X, Y, Z directions at the right diagonal rib position are 361 N, 788 N, and 229 N, respectively, and the experimental values are 398 N, 802 N, and 218 N, respectively. Under the processing conditions of 7000 r/min, 0.14 mm/z, and 3.5 mm cutting width, the theoretical values of the maximum milling forces in X, Y, Z directions at the right diagonal rib position are 361 N, 788 N, and 229 N, respectively, and the experimental values are 398 N, 802 N, and 218 N, respectively. The increase of cutting width leads to the increase of Y-direction force, besides, the increase of feed speed will lead to the increase of X-direction forces and Z-direction forces. The range of X-direction prediction error rate is 8.45–16.15%, Y-direction prediction error rate is 1.50–4.85%, Z-direction prediction error rate is 10.5–15.65%, and the milling force prediction error is kept below 16%.