基于边缘碎裂效应的切割-推挤式加工的机理分析

Mechanism Analysis of Cutting and Extruding Processing Technology Based on Edge-chipping Effect

基于边缘碎裂效应的切割-推挤式加工技术可以采用低于被加工材料硬度的工具实现工程陶瓷等脆性材料的加工。通过高速摄像观察、微观形貌观察等方法研究,材料破碎去除是源于预制裂纹在外加三维拉应力场和自由边缘表面的作用下迅速扩展。通过实时检测车刀表面温度变化,表明新技术加工过程能以较小的能量消耗实现材料去除。通过对比背侧预制缺陷和双侧预制缺陷的挤压破碎特性,揭示了凸缘受挤压的侧表面存在的缺陷对轴向推挤力有减小的重要作用。此外,还通过能量角度揭示了材料去除的破碎规律和机理。

Cutting and extruding processing technology for ceramics based on edge-chipping effect can be realized by using tools whose hardness is lower than that of processed materials. Through high-speed camera observation,micro morphology observation and other methods,it was discovered that material removal was derived from the rapid expansion of the prefabricated crack under the action of the applied threedimensional tensile stress field. The temperature real-time change in the face of tool was detected,and it indicated that the new technology can achieve material removal with less energy consumption. By contrasting the fracture characteristics between the dorsal prefabricated defects and the bilateral prefabricated defects,it revealed that the prefabricated defect of the extruded side has an important role to reduce the axial pushing force. In addition,it also revealed the chipping rules and the mechanism of material removal.