Accuracy decay mechanism of ball screw in CNC machine tools for mixed sliding-rolling motion under non-constant operating conditions

Abstract

The ball screw (BS) has become an indispensable key functional component in many fields, such as CNC machine tools, precision transmission system and special service requirements. Its accuracy reliability is a key performance in many application fields. There is a phenomenon of mixed slip-roll motion during the BS operation, however, both non-constant working conditions and mixed sliding-rolling motion mode affect the its accuracy decay. In this paper, the modeling method of accuracy decay for mixed sliding-rolling motion behavior is established under non-constant operating conditions. The accuracy reliability of the BS is analyzed under single non-constant operation condition or multiple non-constant operating conditions, and the accuracy decay is predicted though modeling method proposed. In addition, the experimental analysis of the BS accuracy degradation is carried out under three different amplitudes of AL (non-constant axial load), FR (non-constant feed rate) and AL+FR combination conditions. The average value of the accuracy loss relative error between theoretical model and experimental test results is smaller than that under pure sliding motion. It shows that the accuracy decay analysis model established is beneficial to predict the BS accuracy reliability.

Deformation error compensation by stiffness model of mechanical joint on a flexible track drilling robot for aircraft assembly

“…The cantilever model of the lead screw fixed at each end by gravity has a small bending deflection due to its own weight, and is not placed horizontally with respect to the ground. On the other hand, for horizontally placed lead screws, the lead error due to self-weight bending is generally 4 to 10 percent [22] of the maximum amount of bending in the intermediate position of the support, and the effect on the overall error is weaker [23]. Therefore, axial errors due to self-weight bending are neglected in the modeling.…”

Load Distribution Analysis and Contact Stiffness Prediction of the Dual-Drive Ball Screw Pair Considering Guide Rail Geometric Error and Slide Position

“…The ball screw pair has gained significant popularity in the precision equipment primarily due to its notable benefits, such as excellent transmission efficiency, substantial stiffness, and robust bearing capacity [1][2][3][4]. The contact load distribution and contact stiffness of a ball screw pair are critical factors influencing transmission performance [5][6][7]. The axial load on each ball screw pair in the dual drive system of fixed gantry machine tools with cross-rail movement is subjected to variation due to geometric error of the column guide rail and the position of the slide.…”