Modeling and analysis of the instantaneous undeformed chip thickness in multi-axis torus milling in the aspect of tool wear

Abstract

Tool wear is one of the main challenges for prediction and optimisation in machining. This becomes even more important in the multi-axis milling of Ni-based difficult-to-cut materials, once because of kinematics of the process, two because of properties of the material, and three because of unknown physical couplings. Tool wear is constituted in the area of the instantaneous undeformed chip. From the point of view of tool wear, in multi-axis machining with an inclined tool axis, it becomes important to know how the thickness of the undeformed chip is distributed over the cutting edge as a function of tool rotation angle. As this distribution has not yet been investigated, a three-dimensional model of the undeformed chip was developed in a function of the instantaneous contact angle between the torus cutter and the machined surface. Simulation studies based on this model were carried out together with the distribution of the maximum chip thickness in the basic plane of the cutter blade. In the following, experimental studies were carried out to verify this distribution and its comparability with the formation of the torus milling cutter wear forms for the declared threshold wear values given. From the results obtained, it was found that as the value of the tool axis inclination angle increases, the life of the torus milling cutter lengthens over the range of this inclination studied. This is due, among other things, to the demonstrated in this work to a reduction in the value of the tool's working angle while dispersing the value of the maximum chip thickness in the base plane of the cutting edge. The developed 3D model of the instantaneous undeformed chip can form the basis of tool wear prediction techniques and systems, and further investigations, particularly for the notching wear type of the multi-axis torus milling process. The precision of the developed model in terms of predicting tool wear area based on the maximum chip thickness distribution is 97 %. The error in predicting the maximum chip thickness does not exceed 15 %.