Work Coordinate Setup in the Ultra‐precision Machine Tool Using Electrical Breakdown

Author(s): Sangjin Maeng and Sangkee Min


Publication: International Journal of Precision Engineering and Manufacturing

Acknowledgment: FANUC

Citation: International Journal of Precision Engineering and Manufacturing, Published online March 9, 2023

Work coordinate setup in an ultra-precision machine tool is one of the important tasks to fabricate a structure at the desired position with high accuracy. Setting up the work coordinate is very challenging because it requires high precision, direct measurement, and non-contact preferred. This paper proposes a new method to measure the relative distance between tool-work materials using the electrical breakdown where current flows through electrical insulator when an applied voltage is higher than the breakdown voltage. The applied voltage is linearly proportional to the relative distance in nanoscale. Experiment with Al6061, SS316, AISI1018 steel, and OFHC Cu work materials, and WC and CBN tools showed a successful and easy application of this method in work coordinate setup with 70 nm uncertainty at low applied voltage. Surface damages by the electrical breakdown of Al6061, SS316, AISI1018 steel, and OFHC Cu were not found at less than or equal to 1, 2, and 3 V, respectively. An automated detection test was conducted and found approaching speed of 0.1 mm/min without surface damage. Standard uncertainty analysis validated the confidence of the proposed method.