织构刀-屑界面滑移区微通道特性数值研究

刀-屑界面滑移区的接触及微通道分布特性直接影响切削液的渗入和刀-屑界面摩擦,对金属切削过程有着重要的影响,针对滑移区接触及微通道分布特性测量难、切削液在刀-屑界面渗入不易量化等问题,建立微织构粗糙刀-屑界面滑移区的接触数值模型,分析滑移区的接触、微通道分布特性以及微织构作用机制。研究表明:滑移区存在3种不同的宏观接触特性,分别为近黏结特性、微通道特性和近分离特性;在近黏结特性区内,刀-屑界面不存在微通道,微织构主要功能为减少刀-屑界面接触面积;在微通道特性区内,刀-屑界面存在大量微通道,微织构主要功能为连接微通道;在近分离特性区内,刀-屑界面微通道消失,微织构主要功能为存储切削液。刀-屑界面应力分布系数对各特性区长度有影响,应力分布系数减小,近黏结区和微通道区长度增大,而近分离区长度相应减小。

Numerical Investigation of Micro-channel Characteristics in Slipping Zone of Textured Tool-Chip Interface

The slipping zone characteristics occurring in the tool chip interface play an important role in controlling the cutting fluid infiltration and tool chip tribological characteristics and the quality of workpiece.The numerical model of the slipping zone in tool chip interface was established for the reason of difficult to quantify the cutting fluid infiltration in the tool chip interface and measure the sliding contact characteristics and micro channel distribution.The sliding contact characteristics and micro channel distribution and the mechanism of micro texture in the tool surface were analyzed.The results show that there are three different types of macroscopic contact characteristics in slipping zone of the tool chip interface,which are nearly bonding characteristic,micro channel distribution characteristic and nearly separation characteristic.The mechanism of micro texture in the tool rake face is to reduce the contact area because of no micro channels in the nearly bonding zone,to connect the micro channel because of the large quantity micro channels in the micro channels distribution zone,and to store the cutting fluid because of the disappearance of micro channels in the nearly separation characteristic zone.The stress distribution coefficient of the tool chip has an obvious effect on the length of each characteristic region.With the drcreasing of stress distribution coefficient,the contact length is increased in the nearly bonding zone and micro channels distribution zone,and is decreased in the nearly separation characteristic zone.