Experimental comparison of non-contact and tactile R-test instruments in dynamic measurement

Abstract

The R-Test measures the three-dimensional displacement of a tool center point with respect to a work table in five-axis machine tool, as linear axes are driven synchronously with a rotary axis. This paper experimentally compares the measuring performance of the R-Test instruments with 1) tactile linear displacement sensors, 2) laser displacement sensors based on the refraction in a glass ball lens (Laser R-Test), and 3) laser interferometers, in dynamic tests described in ISO 10791-6:2014. A tactile displacement sensor pushes its measuring contact to the target surface by a spring, and its stiffness can limit the measurement bandwidth. This paper experimentally investigates this influence in the measurement of dynamic synchronization error of rotary and linear axes particularly near the reversal point in the present tests. This paper also presents a test to measure the bandwidth of a tactile displacement sensor.