A prediction model of the surface topography due to the unbalance of the spindle system in ultra-precision fly-cutting machining

Dongju Chen,Ri Pan,Chenhui An,Jinwei Fan,Xianxian Cui

doi:10.1177/1687814017747145

Dongju Chen, Ri Pan + Show 3 more

Open Access

https://doi.org/10.1177/1687814017747145

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Abstract

In ultra-precision fly-cutting machining, the aerostatic spindle is the key component, which has significant influence on the machined surface quality. The unbalanced spindle directly affects the machining accuracy. In this article, a prediction model of machining surface topography is proposed which involves the effect of the gas film performance of spindle in microscale. With the Weierstrass function, unstable transient response of the aerostatic spindle system is derived by the motion model of the spindle, which response signal represents the surface profile in the ultra-precision machining. Meanwhile, the experiment is performed with different rotation speed of the spindle. And the effect of the unbalanced aerostatic spindle on the surface generation is discussed in time and frequency domain. The conclusion shows that the similar cyclical surface ripple of the workpiece is independent of the spindle speed, and the rotation speed of the spindle and unbalanced spindle directly affects the machining surface topography. This study is quite meaningful for deeply understanding the influence rule of spindle unbalanced error from the viewpoint of machined surface and vibration frequency.

Highlights

The morphology features of the machined surface are critical factors that affect the quality of manufactured products which is one of the most important considerations for any manufacturer
The unstable transient response of the aerostatic spindle system is relative to the surface topography, and this excitation is shown in equation (3) in section ‘‘Dynamic unbalance of the spindle system.’’ The transient response of the translational displacement in radial (X ) and axial (Z) directions is simulated as shown in Figure 5, where the displacements in both X- and Z-directions fluctuate with time
It is found that f = 718 Hz occurs in Figures 9(d) and 10(d), which corresponds to the high-fluctuation amplitude and affects the machining surface topography greatly

Summary

Introduction

The morphology features of the machined surface are critical factors that affect the quality of manufactured products which is one of the most important considerations for any manufacturer. The corresponding frequency of the surface topography is about f = 2p 3 L 3 6.67 r/s/84.5 mm = 156.15 Hz, the rotation speed of the aerostatic spindle is 400 r/min (i.e. 6.67 r/s), and the distance between the center of the spindle axis and the cutting tool is L = 315 mm.

Results

Conclusion