High-Speed Dual-Spectrum Imaging for the Measurement of Metal Cutting Temperatures
Eric P. Whitenton
Models are important tools for optimizing the metal cutting process, allowing industry to make parts at less cost. Measurements of the process using thermal and visible imaging can be used to improve and verify the accuracy of these models. There are many potential error sources. It is important to understand how they affect measurement uncertainty. Some are familiar to anyone performing thermography measurements, such as uncertainties in the basic camera calibration. However, metal cutting presents unique measurement challenges due to factors such as the high magnification required, high surface speeds, micro-blackbody effects, and changing emissivity as the metal is cut. MADMACS, the MAnufacturing Deformation MACro videography System, developed by MEL (Manufacturing Engineering Laboratory) at NIST (National Institute of Standards and Technology), consists of a high-speed visible light camera, a medium speed thermal camera, and a common primary lens so the two cameras are imaging the same scene. A data acquisition system records timing information for the cameras, as well as other signals such as cutting forces. Researchers may review the images and signals synchronized to each other. This report focuses on thermal spectrum measurements, though visible spectrum measurements are also shown. The report is not intended to be an exhaustive list of all possible uncertainty sources, but shows many qualitative examples of the sources that can occur. Some examples illustrate basic concepts, while others are complex. Images of a number of cutting experiments with different cutting conditions and materials are shown. For brevity, the specifics of the cutting experiments are not given, as this report has a measurement focus. The two primary goals of this report are to discuss the issues involved when performing thermal imaging of the metal cutting process and also describe MADMACS to assist those who wish to either use MADMACS or build a similar system.
uncertainty, metal cutting, dual-spectrum, high-speed imaging, infrared thermography
High-Speed Dual-Spectrum Imaging for the Measurement of Metal Cutting Temperatures, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.IR.7650
(Accessed December 2, 2023)