Feasibility Study on Noncontact Monitoring of Temperature Distributions of Rotating Tool

Abstract

In the fields of materials science and engineering, measuring temperature has become one of the most fundamental and important issues. In particular, there are growing demands for monitoring temperature gradient and its transient variation of materials being processed at higher temperatures because the temperature state during processing crucially influences the quality of final products. Such temperature monitoring is also required for rotating machining processes such as tuning, milling and friction stir welding (FSW). In this work, a new noncontact method for monitoring temperature distribution of a heated rotating cylindrical object is presented. A laser-ultrasonic technique is employed in the method. Surface temperature measurements for the cylindrical object using the laser-ultrasonic technique and heat conduction analyses are combined together for making quantitative evaluation of temperature distribution in the radial direction of the cylindrical object. To demonstrate the feasibility of this method, an experiment with a steel cylinder of 100 mm in diameter rotating at 300 min-1 and heated up to 100 °C on the surface is carried out. A pulsed laser generator and a laser Doppler vibrometer are used for generating and detecting surface acoustic waves (SAWs) on the steel cylinder, respectively. Measured SAWs are used for determining both surface and internal temperatures of the cylinder. As a result, the estimated temperature distributions during heating almost agree with those measured by an infrared radiation camera.