切削刀具倒棱刃口挤压力的理论计算

Theoretical Calculation of Extruding Force at the Edge of Cutting Tool Having Negative Primary Land

根据试验观察．揭出了刀具刃口带负倒棱时的切削模型。在此模型中，刀具刃口 存在一个“金属死区”。以新模型为基础．采用能量法，对高温、高应变率下刀具刃 口的挤压力进行了理论计算。所做工作的特点是：１）在材料变形分析中计入了挤压 层金属绕过刀具刃口时的过剩变形；２）进行有关材料变形与物理特性的计算时，考 虑了温度与应变率的影响。利用新研制的压电式切削测力仪进行验证试验，其结果表 明，理论计算值与实测数据较好一致。

According to experimental observation, a cutting model for the tool having negative primary land is put forward. In this model, there exists a 'dead metal region' nearby the edge of the cutting tool. Based on the new model, the extruding force at the edge of the cutting tool at high temperature and high strain rate is theoretically calculated by energy method. The characteristics of the work completed are as follows: 1 ) The excess deformation of the extruded metal passing through the edge of the cutting tool is counted in the analysis about deformation of the machined material; 2 ) The influence of temperature and strain rate is considered when carrying out the calculation about the defor-mation and physical characteristics of the machined material. The results of verifying tests which are completed by means of a newly developed piezoelectric dynamometer show that the theoretical calculation is well in accordance with practice.