R-Test Analysis Software for Error Calibration of Five-Axis Machine Tools --Application to a Five-Axis Machine Tool with Two Rotary Axes on the Tool Side --
Soichi Ibaraki, Yu Nagai, Hisashi Otsubo, Yasutaka Sakai, Shigeki Morimoto, and Yosuke Miyazaki
Abstract
The R-test measures the three-dimensional displacement
of a precision sphere, attached to amachine spindle,
by using three displacement sensors fixed to the
machine’s table. Its application to error calibration
for five-axis machine tools has long been studied. This
paper presents software for analyzing the measured
R-test trajectories for error diagnosis and numerical
compensation for rotary axis location errors and error
motions. The developed software first graphically
presents the measured R-test trajectories to help a
user intuitively understand error motions of the rotary
axes. It also numerically parameterizes the rotary
axis geometric error parameters, and then generates a
compensation table that can be implemented in some
latest-generation commercial CNC systems. An actual
demonstration of its application to a five-axis machine
tool with a universal head (two rotary axes on the spindle
side) is presented.
Keywords:
Metrology, R-test, five-axis machine tools, calibration, location error, error motion, geometric error.
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