A Method for Measuring the Temperature Distribution Along the Cutting Edges of a Drill

Abstract

A drill-foil thermocouple system is developed for measuring the temperature distribution along the cutting edges of a drill. The system is simple to implement, and it does not suffer the problems experienced by previously developed methods. Experiments show that the method is accurate, produces repeatable measurements, and is sensitive to the drilling conditions, including the speed, feed, and drill geometry.

The location of the maximum temperature on the cutting edges of a drill

“…In summary, the current model predicts a temperature profile in the drill point that is consistent with experimental data, in which the maximum temperature occurs on the chisel edge [13,14]. In contrast, simulations that are based on the method presented in previous studies, in which the heat flowing into the tool is simply assumed to be a fraction of the heat generated by friction on the rake face of the tool, predict that the temperature on the chisel edge is significantly lower than on the primary cutting edges.…”

“…(18), and if the restriction were removed so that R 2 could take on any value, then the resulting equation would be nearly identical to Eq. (14). In other words, the only significant difference between the analysis of the heat flux developed in the current study and that developed by Agapiou and DeVries [3] is that the current study avoids the intermediate term, R 2 .…”

“…The heat flux loads applied to the drill are calculated using Eq. (14). This study analyzes the case in which a high-speed steel drill of diameter 9.92 mm produces a hole in a workpiece of aluminum 319 to a depth of 25 mm using a speed of 998 rpm and feed of 124 microns per revolution.…”

“…4. The solid line in the figure represents the temperature distribution along the cutting edges measured using a drill-foil thermocouple [14], which measures the electromotive force generated between the cutting tool and an insulated foil embedded in the workpiece. By calibrating the measured voltage with the temperature at the interface of the dissimilar metals, the temperature profile along the entire cutting edge is determined as the drill point passes through the foil.…”

“…Mills and Mottishaw [13] measured the drill temperature profile by examining microstructural changes in the drill material, and they found that the highest temperatures occurred near the axis of the drill. Experimental studies by the authors of the current study using drill-foil thermocouples [14,15] have also revealed that the maximum drill temperature can occur on the chisel edge.…”