Reaserch Of Non-Contact Measurement By Circular Testing For Geometric Error Of NC Machine Tools

Geometric error is the key factor which impacts the precision of NC machine tools. The motion precision of NC machine tools can be improved obviously by compensating geometric error. As the result, the more advanced machining precision can be gained. So it is quite important to measure geometric error fleetly and accurately. Now, Laser Interferometer and the Ball Bar are two common instruments for testing geometric error of NC machine tools. It can obtain a high precision to measure single geometric error using Laser Interferometer, but the process is quite complex and take a lot of time. The manipulate of ball bar is sample and measuring is rapid, but the test range is narrow and precision is low.This paper presents a new non-contact method which is based on circle testing to measure the geometric error of NC machine tools .This method is fit for test FXYZ NC machine tools and it has the advantage of testing precision and high efficiency. When NC machine move around a circle on XOY Plate, the integrated error can be gained using two Laser Interferometers and photoelectricity aiming device which is constitute with semiconductor laser and two quadrants silicon photocell. Then except angle error, five geometric errors can be derived with the model of separating single error and least-squares procedure.In this paper, the method of non-contact measurement by circular contouring for geometric error of NC machine tools has been deeply discussed. Then the testing system has been designed and the model of separating single error has been derived. Furthermore, the experiment of measuring the geometric errors of MCV-510 NC machine center using the method of non-contact measurement by circular contouring and QC10 ball bar have been done. Compared with the result of two methods, the method of non-contact measurement by circular contouring for geometric error of NC machine tools is proved feasible.