A FLASH THERMOGRAPHY TECHNIQUE FOR IN SITU INSPECTION FOR THE LASER POWDER BED FUSION PROCESS

摘要

A sub-surface defect detection technique is investigated for in situ inspection of the laser powder bed fusion process using a flash thermography technique. Several thermal image analysis methods are investigated, and a technique based on fitting the logarithm-scale temperature curve to a linear function is found effective in detecting near-surface defects in a metal defect artifact. The measurement on an additively manufactured defect sample also shows this technique holds some promises for sub-surface defect detection for the laser powder bed fusion process.