A Generalized Machining Process Damping Model for Orthogonal Cutting

Abstract

Chatter vibrations in machining degrade the surface quality, cause premature tool and machine failures, and reduce the productivity. The dynamic interference between the cutting tool and the wavy part surface damps the machining process in the presence of vibrations. Machining process damping improves the chatter stability especially for difficult-to-cut materials and is even more pronounced via optimized cutting edge geometries. However, there is not any analytical model that can consider arbitrary edge profiles in modeling the process damping. This study introduces a new generalized analytical model to predict the process damping forces for any two-dimensional cutting edge geometries by taking the vibration parameters, work material properties, cutting conditions, and cutting edge geometry into account. That is achieved by discretizing the tool–workpiece contact using a series of springs with a nonlinear Winkler foundation and by employing a material constitutive model to describe the behavior of the deformed springs beyond elasticity. The process damping force is calculated from the contact pressure between the edge and the work material and linearized with an equivalent viscous damper dissipating the same energy. The proposed model has been verified experimentally and numerically for different tool geometries. It is demonstrated that the model can eliminate the time-intensive experimental and numerical identification of process damping coefficients and can digitalize the design phase of cutting tools by rapidly evaluating their machining dynamics performance in place of physical tests.