Cutting of Rock by Wire-Sawing in Vacuum (2nd Report)

—Temperature Rise during Machining—

Abstract

This paper deals with the measurement and simulation of the saw wire temperature during machining a rock sample in vacuum. It is expected for wire-sawing to keep cutting performance by successive supply of cutting edges. The performance of wire-sawing in vacuum has been investigated for lunar and planetary explorations. To clarify the deterioration due to the nickel adhesion on the rock, the temperature rise was investigated. In the experiment, the saw wire was reciprocated with slider-clank mechanism to machine a rock sample. A workpiece holder was mounted on a lever though an octagonal load cell with strain gauges to measure the principal force and thrust simultaneously. The saw wire temperature was measured by its electric resistance during machining. In vacuum, the saw wire temperature rose about 30°C at a wire speed of 0.16 m/s. The generated heat during machining was conducted to the rock sample as well as the saw wire. The temperature rise of a saw wire during machining in vacuum was analyzed by a three-dimensional finite difference model. In the simulation, the saw wire temperature rose about 55°C at the same wire speed as the experiment. The trend of the simulated temperature rise coincided with the measured one. The generated heat during machining affected little on the nickel adhesion and the performance of wire-sawing in vacuum.