Determining the Minimum Cutting Thickness (MCT) of Hardened Steel Based on Ball End Milling Method

doi:10.3901/JME.2017.01.180

Abstract

Abstract: The machining allowance is small in finish-machining of automobile panel dies (APD). The small finish-machining allowance is of the same order of magnitude as the cutting edge radius. In order to realize the high quality machining of APD, the influence of cutting edge radius should be paid attention to. Because of the existence of cutting edge radius, there is the minimum cutting thickness (MCT) in plastic material machining. When the actual cutting thickness is smaller than the minimum permitted cutting thickness of the die material, as a result, the tool will slide on workpieces. Therefore, the machining accuracy and the surface quality of the APD are hard to be guaranteed. A new method based on ball end milling is provided to determine the MCT, and the practicability of the method is verified as well. The common hardened AISI D2 steel is used to determine the MCTs under different hardness by using the method. The influence of cutting speed on the MCT of hardened AISI D2 steel is studied as well. The study results show that the temperature effect caused by cutting speed has greater influence than the strain rates effect in the hardened AISI D2 steel chips forming process. In this state, as the cutting speed increases, the MCT increases as well.

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

LIU Xianli, MA Jing, YUE Caixu, WAN Quan. Determining the Minimum Cutting Thickness (MCT) of Hardened Steel Based on Ball End Milling Method[J]. Journal of Mechanical Engineering, 2017, 53(1): 180-189.

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