DESIGN AND MACHINING OF COPPER SPECIMENS WITH MICRO HOLES FOR ACCURATE HEAT TRANSFER MEASUREMENTS

Abstract

This article presents a technique that has been developed specifically for drilling 0.5334-mm-diameter, 19-mm-deep holes in copper for use in temperature measurement. The holes accept thermocouples, which are used for the measurement of the temperature gradient and the wall temperature of the specimen. Errors due to the intrusion of the probe, ami the finite size and mass of the probe, are reduced as the diameter of the probes is reduced. A machining procedure for drilling deep micro holes in copper cannot be found in conventional texts; this article advocates holes that are deeper than those traditionally recommended. This article is written for both machinists and experimentalists. Both heat transfer and machining criteria are considered. The necessary equipment and their specifications are discussed. Special attention is given to specifying drilling speeds, feed rates, and lubricants. Step-by-step drilling instructions are given. An analysis is performed to reveal the important parameters for reducing the errors associated with the uncertainty in the location, the relative position of the thermocouples, and the individual temperature measurements.

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Notes on contributors

M. A. Kedzierski

Address correspondence to M. A. Kedzierski, National Institute of Standards and Technology, Building and Fire Research Laboratory, Gaithersburg, MD 20899.