Workpiece temperature measurement in machining

Abstract

Temperature plays a vital role in the machining industry today. With increasing cutting speeds being used in machining operations, the thermal aspects of cutting have become more important. The temperature not only directly influences the rate of tool wear but also will affect the thermal expansion and final surface finish of a workpiece material. The surface temperatures of newly machined workpieces are investigated in this paper. An experimental study was performed using both thermocouples and infrared thermography to monitor the newly machined surface temperatures of an aluminium alloy tube for various cutting conditions. Cutting temperatures have been measured for a range of cutting speeds and feed rates at a constant depth of cut. The effects of tool wear were also investigated. The results showed that machined surface temperatures decrease with corresponding increases in feed rates. Cutting forces were measured by a dynamometer and were shown to decrease with increasing cutting speed, but they increased with greater tool flank wear land. The progression of tool wear is also accompanied by a consistent increase in workpiece temperature. An infrared thermal imaging camera was used to monitor the cutting process and these results were correlated with thermocouple readings.