Analytical modeling of the CNC machine axis motion in high-speed milling with local smoothing

Abstract

In high-speed milling (HSM) of free-form surfaces, the tool path is mainly characterized by a set of short discontinuous segments in tangency. These discontinuities bring an intense kinematic parameter fluctuation of the computer numerical control (CNC) machine axes. The smoothing of the programmed tool path and the optimal choice of the manufacturing process parameters ensure a high productivity with the required quality of the machined surfaces. Precise estimation of the machining time allows an accurate evaluation of the machined product cost. Thereby, this is achieved by studying the effect of the tool path smoothing and the CNC controller parameters on the axis kinematics and the following errors. This paper focuses on the geometrical modeling of the local smoothing block adopted by Sinumerik CNC. Further, a kinematic model is proposed to simulate the axis motion in linear interpolation mode with local smoothing. The identification of the interpolator reduction effect on the programmed tolerance leads to the identification of the smoothing model adopted by the CNC unit. Then, the axis kinematic behavior is modeled while taking into account the drive parameter axes defined by the manufacturer of the CNC unit. The experimental results showed a smooth variation of the axis feed rate along the smoothing blocks and a good correlation with the proposed models.

Proposal of a Machining Test to Evaluate Dynamic Synchronization Error of Rotary and Linear Axes With Reversal of Rotation Direction

“…The uniform radial error in circular interpolation can be compensated typically by a feed forward controller [25]. The contour error at corners can be reduced by various corner blending schemes [10][11][12][13][14][15][16][17] without explicitly applying this concept. On the other hand, in order to smooth the tool path in the workpiece coordinate system, the Acc/dec before interpolation has to be implemented, like the researches in [18][19][20][21][22].…”

“…Sencer [10] designed the quintic Bezier blends with six control points to blend the discrete linear segments with curvature continuous transitions. Essid [11] and Rymansaib [12] used the high-order polynomials to describe the velocity profile to generate the tool path. Chen [13], Altintas [14],…”

Reparameterization of Ruled Surfaces: Toward Generating Smooth Jerk-minimized Toolpaths for Multi-axis Flank CNC Milling

“…A tool path is generated such that the maximal angular accelerations of the rotary axes are reduced. By defining smoothing blocks on the toolpath of CNC contour machining, Essid et al [12] perform a local toolpath smoothing. In their kinematic model, they took into account the drive parameter axes defined by the manufacturer of the CNC machine, however, in contrast to our work, the milling path is being modified.…”

Structural Design and Optimization in the Beam of a Five-axis Gantry Machining Center

“…For example, Aruna et al [5] used the CAD/CAM technology for parametric modeling and analysis of the five-axis machining center. Essid et al [6] used the simulation technology to study the kinematic performance of CNC machine tools, thus driving the transformation of mechanical design from static to dynamic design [7]. Decision making regarding design schemes is necessary for the design of machining centers.…”