美国每年在金属切削加工中要花费500～600亿美元。因此,必须通过提高切削速度、延长刀具寿命等手段来降低金属切削加工的成本,这就必须减小刀具与工件之间的摩擦,从而可降低刀刃处的温度、减小变形和磨损。固体膜润滑剂涂层可明显减小刀具的摩擦和磨损,因此可延长刀具的寿命。金属切削过程中主要产生两种能量。这两种能量是在剪切面和刀具面产生的,如图所示。从机械热当量的观点来看,摩擦过程中产生的所有能量都不可逆地转化为热能。如果在金属切削中减小摩擦系数,则在刀具面上的摩擦功和剪切面上的剪切功都减小了。摩擦减小后,可使总能量、切削力和温升都减小,从而可延长刀具的寿命。利用下列几种方法可减小摩擦系数:(1)提高刀具切削刃的光洁度和锐度;(2)采用摩擦功较低的工件材 The United States spends 500-600 billion U.S. dollars each year in metal cutting. Therefore, it is necessary to reduce the cost of metal cutting by increasing the cutting speed and extending the tool life, which reduces the friction between the tool and the workpiece, thereby reducing the temperature at the blade and reducing deformation and wear. Solid film lubricant coating can significantly reduce tool friction and wear, thus extending tool life. The metal cutting process mainly produces two kinds of energy. Both of these energies are generated on the shear plane and the tool face, as shown. From the standpoint of mechanical equivalence, all energy generated during the friction is irreversibly converted into heat. If the coefficient of friction is reduced in metal cutting, both the work of friction and the shear work on the shear face on the tool face are reduced. When the friction is reduced, the total energy, cutting force and temperature can be reduced, which can prolong the life of the tool. Use the following methods to reduce the friction coefficient: (1) improve the tool cutting edge smoothness and sharpness; (2) the use of lower friction work piece