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 two unknown dynamic cutting factors 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.

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

“…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.…”

“…To summarize, there have been a number of attempts to model the forces that occur during milling at low spindle speeds, based upon the original conceptual theory proposed over 50 years ago. 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]).…”

An improved semi-analytical approach for modeling of process damping in orthogonal cutting considering cutting edge radius

“…To understand the process damping, pioneers have already done some excellent works trying to explain how process damping generates and affects the machining stability. 7–14 Moreover, process damping models for specific issues, such as 2-degree-of-freedom (DOF) regenerative chatter, 15 different tool geometries, 16 influence of feed rate on process damping, 17 micro-milling operations, 18 mode coupling, 19 and thin-wall milling, 20 were also discussed. To identify the coefficients related to process damping, several methods were established, including fast tool servo device, 21 energy dissipation principle, 22 inverse stability analysis method, 23,24 operational modal analysis method, 25,26 turning process excitation method, 27 and the generalized method with static milling forces.…”

Radial depth of cut stability lobe diagrams with process damping effects

“…Many prior process damping studies have identified it as energy dissipation due to interference between the cutting tool clearance face and machined surface during relative vibrations between the two [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. Because process damping enables increased material removal rates at low cutting speeds, it is an important consideration when modeling machining operations for hard-to-machine materials.…”