Abstract
The structure and the cavity surface hardened steel mold of automobile cover is very complex. In the stamping process, the local structure bears higher extrusion stress than the type surface, which often causes local wear and even cracking. The process of multi hardness splicing joint is applied to ensure the service life of the die according to the features of each part of the mold. The impact load caused by the repeatedly cut-in which always leads to the instability of cutting force in the whole process. The machining quality of the mold surface is reduced. Aiming at the machining process of the ball-end milling cutter in the mold splicing area, the impact at the moment of contact between the cutter and the workpiece is analyzed. The instantaneous chip thickness model that considers impact factors and the state model that calibrates the cutting state by coefficients is established. Finally, the prediction model of the milling force of the splicing area is obtained. The model is verified based on the machining cutting force measurement experiment in the case of die hardened steel Cr12MoV with single hardness and multi-hardness splicing. The average prediction error of experiments and simulation results is within 10%, which proves the accuracy of the model. The results show that the model has certain guiding significance for the actual processing of the splicing area of automobile mold cover parts.
Acknowledgements
This project is supported by National Natural Science Foundation of China (Grant No. 51905137). This project is supported by Natural Science Foundation of Heilongjiang Province, China(Grant No.LH2019E063).