Assessing The Thermal Distortion Caused BySpindle Rotation Of A Machining Centre Using TheDraft Standard ISO / DIS 230-3

This paper presents the results of an investigative study using the draft international standard ISO 230-3 as the basis to test the behaviour of a machine tool structure subjected to thermal effects produced by spindle rotation. For these tests a special two sphere mandrel was fitted into the spindle of a vertical machining centre, while a fixture capable of holding five displacement transducers is clamped to the machine worktable. Five capacitance non-contact probes were located into the fixture, providing for three orthogonal displacements and two tilt measurements. Tests were performed using both of the prescribed methods laid down in the draft standard, namely constant spindle speed and -variable spindle speed. Temperatures, displacements and tilts were recorded for the duration of each test. From the investigation recommendations are made for amendments to the standard that need to be considered for inclusion in the final version of the draft standard.