Optimization measurement for the ballscrew raceway profile based on optical measuring system

Abstract

Given that the ballscrew raceway profile directly affects the service characteristics and precision retention of ball screws, this paper proposes an optimized continuous measuring method for the ballscrew raceway profile, without the need to adjust the sensor for the measurement of each raceway. Based on a comparison with existing measuring methods and principles, an optical measuring system is constructed, in which installation errors in the LED sensor and the linear calibration system, together with the straightness of the mobile platform, are obtained and analyzed. More importantly, in this work, we propose a transformation algorithm for the helix angle as well as an arc-selecting principle. Compared to the measurment results and time consumption of the profilometer, the maximum error for the measured radius and contact angle of the system proposed in this paper is 1.5 μm and 35′, and the measuring efficiency is increased by 15.8%, 58.6%, and 67.5% for 1, 5, and 20 continuous raceways, respectively, indicating effective performance in terms of accuracy, repeatability, and efficiency. Moreover, the system is also capable of measuring the pitch diameter and lead error of the ballscrew, which is significant in regard to classifying the accuracy of the ballscrew raceway profile, and improving machining precision.

A Novel Non-Contact Measurement Method of Ball Screw Thread Profile Detection Based on Machine Vision

“…At present, many relevant scholars at home and abroad have conducted research on this subject and have already formed a relatively complete thread detection system, as in [3]- [8], which can be described as follows: First, the original image of the thread profile by CCD or other optical camera is captured, then the features of thread profile based on image processing techniques such as filtering, boundary extraction and curve fitting are extracted, and finally the parameters are measured from the acquired features such as the thread profile, which are considered as the result of detection. Min and Zhao respectively designed a non-contact thread parameter measurement system based on machine vision to support efficient and accurate measurement of the thread contact angle, as in [9], [10]; Rao et al summarized the image processing technology and computer vision algorithms currently used for external thread detection, as in [11]; Senthilnathan used a diffuse reflection light source to obtain a thread profile projection, and proposed a profile processing algorithm to estimate the thread parameters, as in [12]; Chen et al integrated the photoelastic effect and an image processing algorithm to measure the contact angle of the ball screw, as in [13]; Li et al proposed a Res Unet-based thread edge recognition method that eliminates the need for thread area calibration and identifies the thread edge in a complex environment, as in [14]; Chen took the possible thread shape distortion during CCD shooting into account, and gave a corresponding compensation algorithm for the image distortion on the optical angle, as in [15]. However, the above solutions are only applied to the detection of ordinary threads with a linear profile, while the Journal homepage: https://content.sciendo.com thread profile of the ball screw is a curve, which is more difficult to detect.…”

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

“…And the model proposed was compared with the Wei model [7] from the perspective of prediction accuracy. Wang [17] et al studied the raceway profile for the BS, indicating that measuring basis is an influence factor of the raceway error on positioning precision. Zhao and Lin [18] et al studied the accuracy degradation behavior of double-nut ball screws due to raceway wear based on fractal theory [16].…”

Numerical analysis and experimental research on the accuracy decay of a ball screw with geometric errors under non-constant operating conditions

“…Considering the actual contact area between the ball and the raceway, based on the fractal theory, Liu and Ma et al 25 studied the mechanism of the BS accuracy degradation and compared the prediction accuracy to the Wei model results. 16 Wang et al 26 studied the raceway profile for the BS and demonstrated that measuring basis was one of the key influence factors of the raceway error on positioning precision. Zhao and Lin 27 studied the accuracy degradation behavior and accuracy prediction of the double-nut BS, due to raceway wear, based on fractal theory.…”