A model of milled surface generation for time domain simulation of high-speed cutting

Abstract

Modelling the machined surface during time domain simulation is a complex and time consuming problem. However, calculation time can be reduced using specific models dedicated to milling operations. This research presents 2.5-dimensional geometrical modelling of the milled surface generation used in a time domain simulation of end milling operations. It is dedicated to the study of flexible workpiece-flexible tool system and high-speed cutting conditions. This modelling provides an accurate representation of the machined surface and is independent of the time discretization imposed by the dynamic of the cutting process. The material removal process is achieved by considering the effective paths of tool teeth relative to the workpiece, including vibrating motions of both tool and workpiece. At each time step the tooth motion is interpolated with a quadratic form model allowing low interpolation error even for long incremental tooth displacements. Simulation is compared with experimental results; the surface defects due to vibrating behaviour are shown, and a good correlation is obtained.

Simulation of low rigidity part machining applied to thin-walled structures

“…The basis of the dynamic milling model is given in [23,29]. This model was developed to generate precisely the real chip thickness for a flexible workpiece.…”

“…Montgomery and Altintas [22] provided a time domain milling model in which the surface profile, during simulation, is generated by linear interpolation. This approach was improved by quadratic interpolation [23] in order to reduce error. It is important to note that these works consider a flexible element, which can be the tool, the part or both of them, having a rigid body motion [24].…”

Robotic Machining Simulation using a Simplified Multibody Model

“…However, the estimated value seemed quite high (D ref =4960 [N.m.s/rad]) and lead to purely real poles characterised by a damping coefficient of 100 %. In order to find more realistic values, the damping coefficient was rescaled as a function of the squared root of the ratio involving K ref (provided in [14]) and the stiffness to associate, as indicated by equation (9). Table 2 finally provides the stiffness and damping values used for the simplified robot model.…”

“…Indeed, it is of great importance when chatter phenomenon occurs as it is a regenerative process appearing when the tool removes material from a previously machined surface [13]. In DyStaMill, the update of the workpiece is inspired from the "eraser of matter" model proposed by G. Peigné [14]. The part is divided into superimposed slices and each 2D contour is approximated by a succession of straight segments.…”

Machine Tool Chatter and Surface Quality in Milling Processes

“…Closed form stability conditions can not be given for the general milling case. Usually, numerical simulations [4][5][6][7][8] and different analytical techniques [9][10][11][12][13][14][15][16][17][18][19][20][21] are used to derive stability charts.…”