An empirical tool force model for precision machining

摘要

The accuracy of precision machining operations could be improved through tool force feedback. Tool force is ideally suited for use in a control algorithm because it contains information on the instantaneous depth of cut, feed rate and condition of the tool. A tool force model that could form the basis of this new control technique has been developed. By measuring the shear angle frommicrographs of chip cross sections, equations for the forces due to chip formation and the friction between tile chip and the tool have been written. Furthermore, the effects of elastic deformation of the workpiece (spring back) on chip formation and themeasured forces, which can be significant inprecision machining, have been included in the model. Machining experiments were conducted with a 0 deg rake diamond tool and four metals that are commonly diamond turned. For machining with newly lapped as well as v~'orn tools, the calculated forces were in excellent agreement with the measured values for the array of workpiece materials.