The Effects of Integration Time and Size-of-Source on the Temperature Measurement of Segmented Chip Formation Using Infrared Thermography
ASME 2009 International Manufacturing Science and Engineering Conference, Volume 2
This paper illustrates the errors due to integration time and size-of-source effects when measuring the temperature of segmented chip formation using infrared (IR) thermography. Segmented chip formation involves narrow periodic shear bands that experience rapid heating and move at high velocities and accelerations. As a result, the values of the measured temperatures depend strongly on the temporal and spatial measurement window used. In this study, an ideal infrared camera is simulated to
... stand the effects of integration time and size-of-source on the measurement. This analysis does not consider the temporal and spatial transfer functions of the camera system, thus simplifying the analysis to be applicable to all IR thermography users. Incorporating appropriate transfer functions would make the analysis specific to a given camera system. Finite element analysis (FEA) simulation results provide a reference cutting process which is manipulated to mimic motion blur and size-of-source effects. For this purpose, the FEA results adequately represent the cutting process with rapid heating and high chip velocities. For the studied cases, size-of-source has relatively little impact on the measurement results when compared to the effects of integration time. Results show integration times from 1 μs to 90 μs significantly affect the measurement results. The 1 This paper is an official contribution of the National Institute of Standards and Technology and is not subject to copyright in the United States. Commercial equipment and materials are identified in order to adequately specify certain procedures. In no case does such identification imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment are necessarily the best available for the purpose. maximum temperature measured by the simulated IR camera decreases from an FEA maximum of 735 °C to 668 °C at 90 μs integration time. Integration time significantly affects temperature measurement in the periodic shear band but does not significantly affect the simulated measurement error of the chip temperature near the tool rake face.