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Proceedings Paper

Detection of defects in laser powder deposition (LPD) components by pulsed laser transient thermography
Author(s): S. P. Santospirito; Kamil Słyk; Bin Luo; Rafał Łopatka; Oliver Gilmour; John Rudlin
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Paper Abstract

Detection of defects in Laser Powder Deposition (LPD) produced components has been achieved by laser thermography. An automatic in-process NDT defect detection software system has been developed for the analysis of laser thermography to automatically detect, reliably measure and then sentence defects in individual beads of LPD components. A deposition path profile definition has been introduced so all laser powder deposition beads can be modeled, and the inspection system has been developed to automatically generate an optimized inspection plan in which sampling images follow the deposition track, and automatically control and communicate with robot-arms, the source laser and cameras to implement image acquisition. Algorithms were developed so that the defect sizes can be correctly evaluated and these have been confirmed using test samples. Individual inspection images can also be stitched together for a single bead, a layer of beads or multiple layers of beads so that defects can be mapped through the additive process. A mathematical model was built up to analyze and evaluate the movement of heat throughout the inspection bead. Inspection processes were developed and positional and temporal gradient algorithms have been used to measure the flaw sizes. Defect analysis is then performed to determine if the defect(s) can be further classified (crack, lack of fusion, porosity) and the sentencing engine then compares the most significant defect or group of defects against the acceptance criteria – independent of human decisions. Testing on manufactured defects from the EC funded INTRAPID project has successful detected and correctly sentenced all samples.

Paper Details

Date Published: 22 May 2013
PDF: 11 pages
Proc. SPIE 8705, Thermosense: Thermal Infrared Applications XXXV, 87050X (22 May 2013); doi: 10.1117/12.2016139
Show Author Affiliations
S. P. Santospirito, Kingston Computer Consultancy Ltd. (United Kingdom)
Kamil Słyk, Kingston Computer Consultancy Ltd. (United Kingdom)
Bin Luo, Kingston Computer Consultancy Ltd. (United Kingdom)
Rafał Łopatka, Polkom Badania (Poland)
Warsaw Univ. of Technology (Poland)
Oliver Gilmour, TWI Ltd. (United Kingdom)
John Rudlin, TWI Ltd. (United Kingdom)


Published in SPIE Proceedings Vol. 8705:
Thermosense: Thermal Infrared Applications XXXV
Gregory R. Stockton; Fred P. Colbert, Editor(s)

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