THE GEOMETRIC ERROR MEASUREMENT AND COMPENSATION FOR A FIVE-AXIS MACHINING CENTER'S TILTING ROTARY TABLE

The geometric error measurement and compensation for a five-axis machining center's tilting rotary table is a difficult problem in the machine tool industry. Aiming at this problem, and based on a thorough study of the geometric error of a vertical five-axis machining center's tilting rotary table, a method has been suggested in this paper to measure the geometric error of the tilting rotary table using the ball bar performing a three-axis circular interpolation. Eight center bias values in the X and Y directions were obtained by the use of four specific three-axis circular interpolation tests. According to the geometric relations of these four specific forms of circular tests, a geometric error separation model of the tilting rotary table was established. The process of circle test of A-axis and C-axis for vertical five-axis machining center is given in detail. The contrast tests, before and after compensation, were carried out in a vertical five-axis machining center. The experimental results showed that the positional errors and angular errors after compensation were much smaller than those before compensation. The positional error decreased from the maximum value of - 0.089 mm before compensation to the maximum value of - 0.004 mm, and the angle error decreased from the maximum value of - 0.012 degrees before compensation to the maximum value of 0.002 degrees. This method has provided an important reference for the geometric error measurement and compensation for a vertical five-axis machining center's tilting rotary table.