Investigation on the spindle thermal displacement and its compensation of precision cutter grinders Yung-Cheng Wang a,⇑ , Ming-che Kao a , Chung-Ping Chang b a Institute of Mechanical Engineering, National Yunlin University of Science and Technology, No. 123, Uni. Road, Section 3, 640 Douliu, Yunlin, Taiwan b Department of Mechanical Engineering, National Central University, Taiwan article info Article history: Received 24 July 2010 Received in revised form 7 March 2011 Accepted 16 March 2011 Available online 30 March 2011 Keywords: Cutter grinder Spindle thermal displacement Laser displacement sensor Compensation mechanism abstract The axial performance of cutter grinders will have direct effects on the precision of ground cutters. Therefore, error elimination will be beneficial for the precision improvement of cutter grinders. One of the main axial error sources is the spindle thermal displacement. General cutter grinders are not equipped with the cooling systems, because of their rel- ative lower rotating frequencies (<8000 rpm), small working range and slower thermal gra- dient. On condition without cooling, there will be obvious thermal errors at the beginning hours of operations or the restarting of machines. That will cause materials waste and lower working efficiency. In this investigation, an efficient measurement system and the compensation mechanism have been established for the minimization of thermal displacements. About 80% of the thermal displacement can be reduced and the thermal displacement error becomes less than 5 lm. With this solution, the precision of cutter grinders can be improved. Ó 2011 Elsevier Ltd. All rights reserved. 1. Introduction Precision cutter grinders (Fig. 1) can be widely applied in either traditional mechanical industries or high-tech industries. The so-called maternal genetic effect available in products would mean that the precision of products de- pends mainly on the machine tools, of which the errors can be classified as: geometrical errors, temperature rise errors and dynamic errors, etc. According to relevant studies, 40–70% of errors of machine tools result from the thermal displacement [1,2], where the main source of heat lies in the friction between spindle and transmission belt, and that between spindle and ball bearings. So far, some companies have developed the sensors laid inside the spindles by which to compensate the errors of thermal displacement [3]. Yet machines equipped with such spindles would increase working cost for small and middle sized cutter grinder manufacturers, while there will be certain limits on the varieties and adoption of spin- dles, and on the promotion of performances of used machines. In this study, we have integrated an optical displace- ment sensor system, a temperature sensor system, and a signal acquisition and analysis system to construct an independent module measurement system of spindle, by means of which it can be easy to find out the mathematical correlation between temperature and thermal displace- ment for the spindle of cutter grinders. That can be used to test the quality of spindles and also provides the basis for compensation of thermal displacement during practical manufacturing process. 2. Construction of measurement system Temperature sensors and a displacement sensor were installed in the measurement system (Figs. 2 and 3). From the spindle test system, temperature and displacement sig- nals have been gained. After processes of signal converters 0263-2241/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.measurement.2011.03.018 ⇑ Corresponding author. Tel.: +886 5 5342601x4122; fax: +886 5 5312062. E-mail address: wangyc@yuntech.edu.tw (Y.-C. Wang). Measurement 44 (2011) 1183–1187 Contents lists available at ScienceDirect Measurement journal homepage: www.elsevier.com/locate/measurement