Miniature Uncooled and Unchopped Fiber Optic Infrared Thermometer for Application to Cutting Tool Temperature Measurement.

Andrew Heeley,Matthew Hobbs,Hatim Laalej,Jon Willmott

doi:10.3390/s18103188

Andrew Heeley, Matthew Hobbs + Show 2 more

Open Access

https://doi.org/10.3390/s18103188

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Abstract

A new infrared thermometer, sensitive to wavelengths between 3 μm and 3.5 μm, has been developed. It is based on an Indium Arsenide Antimony (InAsSb) photodiode, a transimpedance amplifier, and a sapphire fiber optic cable. The thermometer used an uncooled photodiode sensor and received infrared radiation that did not undergo any form of optical chopping, thereby, minimizing the physical size of the device and affording its attachment to a milling machine tool holder. The thermometer is intended for applications requiring that the electronics are located remotely from high-temperature conditions incurred during machining but also affording the potential for use in other harsh conditions. Other example applications include: processes involving chemical reactions and abrasion or fluids that would otherwise present problems for invasive contact sensors to achieve reliable and accurate measurements. The prototype thermometer was capable of measuring temperatures between 200 °C and 1000 °C with sapphire fiber optic cable coupling to high temperature conditions. Future versions of the device will afford temperature measurements on a milling machine cutting tool and could substitute for the standard method of embedding thermocouple wires into the cutting tool inserts. Similarly, other objects within harsh conditions could be measured using these techniques and accelerate developments of the thermometer to suit particular applications.

Highlights

Temperature measurement is fundamental to understanding the performance of many manufacturing processes and products
The photosensitivity of this photodiode was lower than other candidate photodiodes; its availability in a compact transistor outline (TO) type, TO-46 package favored its usage in our example application
We have demonstrated what we believe to be the first photovoltaic MWIR fiber optic thermometer that has no cooling of the infrared detector or optical chopping

Summary

Introduction

Temperature measurement is fundamental to understanding the performance of many manufacturing processes and products. Materials machining is one of the most commonly used manufacturing techniques [1], and the efficiency of the process and quality of the final product are both affected by the temperatures achieved. A thorough understanding of the relationships between temperature, process parameters, and product relies upon acquiring accurate, or at least, representative temperature measurements during manufacture [1,2,3,4]. The need to improve machining process efficiency and product quality affords motivation for research into improved methods of temperature measurement during machining. Thermocouples have been the standard thermometer used for many industrial measurements, including temperature measurement during material machining. The principal drivers for using thermocouples have been the low capital and installation costs incurred and the wide range

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