The detection of blocked surface cooling holes in hollow jet engine turbine blades and vanes during either manufacture or overhaul can be crucial to the integrity and longevity of the parts when in service. A fully automated infrared inspection system is being established under a tri-service's Manufacturing Technology (ManTech) contract administered by the Air Force to inspect these surface cooling holes for blockages. The method consists of viewing the surface holes of the blade with a scanning infrared radiometer when heated air is flushed through the blade. As the airfoil heats up, the resultant infrared images are written directly into computer memory where image analysis is performed. The computer then makes a determination of whether or not the holes are open from the inner plenum to the exterior surface and ultimately makes an accept/reject decision based on previously programmed criteria. A semiautomatic version has already been implemented and is more cost effective and more reliable than the previous manual inspection methods.

Date Published: 28 March 1986
PDF: 6 pages
Proc. SPIE 0581, Thermosense VIII: Thermal Infrared Sensing for Diagnostics and Control, (28 March 1986); doi: 10.1117/12.950879

Published in SPIE Proceedings Vol. 0581:
Thermosense VIII: Thermal Infrared Sensing for Diagnostics and Control
Herbert Kaplan, Editor(s)