Reconstruction of Microscopic Thermal Fields from Oversampled Infrared Images in Laser-Based Powder Bed Fusion

This article elucidates the need to consider the inherent spatial transfer function (blur), of any thermographic instrument used to measure thermal fields. Infrared thermographic data were acquired from a modified, commercial, laser-based powder bed fusion printer. A validated methodology was used to correct for spatial transfer function errors in the measured thermal fields. The methodology was found to make a difference of 40% to the measured signal levels and a 174 degrees C difference to the calculated effective temperature. The spatial gradients in the processed thermal fields were found to increase significantly. These corrections make a significant difference to the accuracy of validation data for process and microstructure modeling. We demonstrate the need for consideration of image blur when quantifying the thermal fields in laser-based powder bed fusion in this work.

Automated summary

This article emphasizes the importance of considering the inherent spatial transfer function of a thermographic instrument when measuring thermal fields. A validated methodology was used to correct spatial transfer function errors, resulting in significant changes to signal levels and effective temperature, which in turn affected the accuracy of validation data for process and microstructure modeling. These corrections demonstrate the necessity of considering image blur when quantifying thermal fields in laser-based powder bed fusion.