Abstract: As high hardness and small finish machining allowance of automobile panel dies, sliding-friction phenomenon between tool and workpiece often occurs in dies finishing machining, especially in convex surface machining, which is due to unreasonable machining allowance, resulting in multiple region cannot be machined, seriously affecting assembly precision of automobile panel dies and increasing artificial grinding time. Aiming at the sliding-friction phenomenon between tool and workpiece in convex surface finishing machining, a test method is provided for determining the minimum cutting thickness of workpiece material, and the minimum cutting thickness values of hardened steel Cr12MoV under different cutting speeds are obtained. Based on the research above and through theoretical analysis, the limit cutting depth prediction model for automobile dies finishing machining of convex surface is established considering cutter deflection, and the accuracy of the model is verified by experiment. The model provides a minimum value for the selection of dies finishing machining allowance, in order to ensure the normal cutting and also for improving the quality and assembly precision of dies allowance should be selected greater than the limit cutting depth predictive value, which ultimately provides theoretical basis and technical guidance for parameters selecting in high quality automobile panel dies machining.

Key words: cutter deflection, cutting edge, dies finish machining, hardened steel, limit cutting depth