Modeling of Moving Table with Linear Roller Guides Subjected to Geometric Errors In Guide Rails
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International Journal of Precision Engineering and Manufacturing https://doi.org/10.1007/s12541-020-00394-w
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Modeling of Moving Table with Linear Roller Guides Subjected to Geometric Errors In Guide Rails Van‑Canh Tong1 · Sun‑Woong Kwon2 · Seong‑Wook Hong3 Received: 4 December 2019 / Revised: 16 July 2020 / Accepted: 22 July 2020 © Korean Society for Precision Engineering 2020
Abstract This paper presents a model of a linear roller guide that considers geometric errors in rails. A five degree-of-freedom model of a table supported by linear roller guides with guide rail errors was built to determine table-motion errors during its motion along erroneous rails. The model was verified by comparing the simulated displacements of a linear guide estimated by the proposed model and those by an existing transfer-function method. Two types of geometric errors were considered for the guide rail: general form and waviness errors. The influence of external load, initial preload, and a few important parameters of the rail—such as wavelength and amplitude—on the displacement of the carriage and table were investigated extensively. The simulation results demonstrated the ability of the model to obtain complicated motion errors for moving tables with a number of supporting linear guides subjected to guide errors. Keywords Linear roller guide · Carriage · Linear table · Rail waviness error · Geometric error
1 Introduction A linear guide unit consists of a guide rail and a carriage moving along the guide rail under rolling contact with balls or rollers. Linear guides are commonly employed in modern machine tools to support the movement of cutting tools or workpieces. Because the linear guide is directly responsible for the machine’s axis movements, its precise motion plays a vital role in the precision of the whole machine [1,2]. However, unpredictable deviation in linear-guide dimensions from their ideal geometries is a common problem that causes deterioration of precision motion. Among them, straightness and angular errors are known to be two most common factors; these are often caused by the manufacturing process [3–5]. In addition, carelessness during the assembling * Seong‑Wook Hong [email protected] 1
Department of Ultra‑Precision Machines and Systems, Korea Institute of Machinery and Materials, 156 Gajeongbuk‑ro Yuseong‑gu, Daejeon 34103, Republic of Korea
2
Photomechanic Inc., 100, Inha‑ro, Michuhol‑gu, Incheon 22212, Republic of Korea
3
Department of Mechanical System Engineering, Kumoh National Institute of Technology, 61 Daehak‑ro, Gumi, Gyeongbuk 39177, Republic of Korea
process can cause errors in linear-guide systems, for example, parallel misalignment in the rails and unequal height level of the rails. Moreover, during installation and use of the linear guide, various factors can produce relevant geometric imperfections such as unequal elastic deformation due to bolt fastening, unflattening of the mounting surface, and thermal distortion of the rail. Studies on geometric errors and th
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