MACHINE VISION INSPECTION OF COMBUSTOR HOLES

A major component in the gas turbine engine is the combustion chamber liner. These components are toroidal in shape and typically contain several hundred and in many cases thousands of small holes. At present, the quality of these holes is insured by manually inspecting each one with go/nogo pin gages. Inspecting holes in this fashion indicates only minimum hole diameter and assumes that the holes are round. This is a labor intensive process, subject to error, and ineffective in the inspection of holes which may be out-of-round. This paper deals with the development of an alternative method of inspecting combustor holes through the use of machine vision. Work to date has shown that more valuable information can be gathered faster through machine vision inspection than through pin gaging. It has also been found that due to the speed at which measurements can be made, this method of inspection is well suited for in-process inspection and adaptive control of the hole making process. The most difficult aspect of this method of inspection is related to quantifying and controlling the source of inspection errors.