Chatter in interrupted turning with geometrical defects: an industrial case study

Abstract

In this paper, machine tool chatter arising in an interrupted turning process is investigated in a strong industrial context with a complex flexible part. A detailed analysis of the real cutting process is performed with special respect to the geometrical defects of the part in order to highlight the source of machine tool vibrations. The analysis is completed by simple models to estimate the forced vibrations in interrupted turning, the gyroscopic effect, and the mode coupling using a new simplified formulation. Then, a new dynamical model with interrupted cutting and geometrical inaccuracies-runout and orientation of eccentricity-is presented. Stability analysis of this model is performed by the semidiscretization method, an improved technique for analyzing delay-differential equations. The use of all these models on a given machining configuration allows comparing several vibration mechanisms. Thus, behavior's specificities are highlighted, especially the influence of eccentricity runout on stability. A sensitivity analysis shows the effect of the value and the orientation of the geometrical defects for low speed conditions. Then this result are extrapolated to high-speed conditions to look for possible new stable cutting conditions and shows a period doubling flip instability, never described before in turning operations. The main focus of this paper is developing and exploring a stability model for interrupted cutting in turning with geometrical defects. The complexity of the industrial context led to methodically compare different chatter and vibration mechanisms; this approach can be generalized to other industrial contexts.

Quenching chatter instability in turning process with a vibro-impact nonlinear energy sink

“…This mechanism, called the regenerative effect, has been first explained by Tobias and Fishwick [3] and is mainly responsible for chatter instability. Since these works, many researchers have improved the knowledge by the well known stability lobe representation and its application to special cases [4][5][6][7][8][9][10]. A detailed nonlinear analysis of chatter instability on turning processes has been carried out in [11] using the method of multiple scales.…”

Investigation of the Machining Stability of a Milling Machine with Hybrid Guideway Systems

“…The optimization of the machine tool design has been studied by incorporating the FE models for full machine analyses with the consideration of machining stability in process [19,20]. Studies of Mousseigne et al, [21,22] found the variation of the tool point dynamic response with the change of milling, which further caused great influences on the stability lobe curves. Their study also suggested that a precise estimation of the natural frequencies is of importance for lessening the uncertainty of the stability lobe curves.…”

Effect of Nominal Chip Thickness on Stability of Interrupted Turning

“…A novel dynamic cutting force model is proposed by Li et al [13], in which the cutting mechanism and the cutting force contribution on both the peripheral and the front cutting edges are taken into consideration simultaneously. An interrupted turning cutting force model was proposed and a detailed analysis of the stability was performed by Seguy et al [14]. In the above studies [1][2][3][4][5][6][7][8][9][10][11][12][13][14], the cutting force models are linear, without considering nonlinearities in terms of chip thickness.…”

“…An interrupted turning cutting force model was proposed and a detailed analysis of the stability was performed by Seguy et al [14]. In the above studies [1][2][3][4][5][6][7][8][9][10][11][12][13][14], the cutting force models are linear, without considering nonlinearities in terms of chip thickness. Given this, powerlaw function for cutting force was used to analyse chatter by Hanna and Tobias [15] and Stépán et al [16] and Yang et al [17].…”

“…It is worth noting that, in the above studies [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], dynamic cutting forces are only the function of dynamic chip thickness, and cutting force versus unit of dynamic chip thickness must be unique. However as shown in Figure 1, cutting forces versus the same dynamic chip thickness (Δℎ 1 = Δℎ 2 ) are unequal at different nominal chip thickness (Δ 1 ̸ = Δ 2 ), due to the fact that the nominal chip thickness is neglected.…”