ACCURACY OF MACHINE TOOLS IDEPENIDING ON THE POSITIONING MEASUREMENT SYSTEM AND THERMAL STATE

P. H. Andersson, S. J. Tervinen

Abstract

Temperature behaviour of machine tools is one of the main reasons for process dispersion of the modem accurate production. This paper presents a comparison of the effect of thermal expansion and positioning measuring System on the production accuracy of machine tools. In the project the positioning accuracy of pulse encoders and linear positioning measurement systems (two types) in different thermal conditions was compared and analysed. Both measuring systems were used interchangeably on each machine tool at the same time.<BR />The test environment includes a modern sheet metal turret punch press and two horizontal machine centres, one in laboratory and one in industrial environment. The initial state of the machinery was examined in a throughout inspection using both conventional measuring equipment and a modern quick test method (doubie ball bar). All workpiece and test piece measurements were performed using a co-ordinate measuring machine in an accredited calibration laboratory.

Keywords

thermal expansion, machine tool accuracy, positioning accuracy

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IMEKO-WC-2000-TC14-P353.pdf

DOI

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IMEKO TC

TC14 - Measurement of Geometrical Quantities

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