Mechanistic Modeling of Process Damping in Peripheral Milling

Abstract

This paper extends analytical modeling of the milling process to include process damping effects. Two cutting mechanisms (shearing and plowing mechanisms) and two process damping effects (directional and magnitude effects) are included. The directional effect is related to vibration energy dissipation due to directional variation of cutter/workpiece relative motion. The magnitude effect is associated with change in force magnitude due to variation of rake angle and clearance angle. Process damping is summarized as containing these separate components; direction-shearing, direction-plowing, magnitude-shearing and magnitude-plowing. The total force model including the process damping effect is obtained through convolution integration of the local forces. The analytical nature of this model makes it possible to determine unknown process damping coefficients from measured vibration signal during milling. The effects of cutting conditions (cutting speed, feed, axial and radial depths of cut) on process damping are systematically examined. It is shown that total process damping increases with increasing feed, axial and radial depths of cut, but decreases with increasing cutting velocity. Predictions based on the analytical model are verified by experiment. Results show that plowing mechanism contributes more to the total damping effect than the shearing mechanism, and magnitude-plowing effect has by far the greatest influence on total damping.

Investigation of machining stability in micro milling considering the parameter uncertainty

“…[1][2][3][4] Due to the fragile nature of the miniature tools, even a minute vibration in micro end milling can lead to part failures. When cutting conditions are not appropriate, tools are easily fractured, which wastes time and money.…”

The influence of feed rate on process damping in milling: modelling and experiments

“…Some of these models have focused on the forces arising due to physical interference between the tool and workpiece, whilst other work has investigated the consequence of a changing relief and rake angle on the dynamic cutting forces [27]. Perhaps the most comprehensive work involving the former method is that described in the PhD thesis of Ranganath (see Ranganath et al [24]).…”

“…More recently Huang and Wang [27] proposed a semi-analytical model that considered the dynamically changing angles of the ploughing and shearing forces during cutting. A matrix of empirical coefficients was used to characterize the process-damping forces, which were assumed to be functions of the direction of relative motion between tool and workpiece.…”

Analysis and Prediction of Micromilling Stability with Variable Tool Geometry

“…Micro-end milling can overcome the limitations of semiconductor based processing techniques by utilizing miniature tools to make complex 3D parts from different engineering materials with no need for expensive masks [1][2][3][4]. Due to the fragile nature of the miniature tools, even minute vibration in micro-end milling can lead to part failures.…”