Laser Guidance for Repairing Gas Turbine Parts

As a result of normal operating conditions, jet engine parts tend to distort. During repair, many of these parts require some form of selective cutting. Due to the differences between each individual part, automation such as CNC machining becomes complex. The need to map each individual part prior to machining has prohibited repair facilities from introducing sophisticated automation. This paper presents for the first time a novel method that addresses many problems related to selective material removal in jet engine repairs. Similar to a terrain-following cruise missile, a laser-guided cutter is used to follow a selected datum surface. For example, in the case of Honeycomb Airseals, the thin laser beam penetrates the honeycomb cell structure to follow the base metal. The method minimizes parent metal removal and under-minimum-wall condition. As a result, life potential of parts is extended, and repair costs are reduced. The ability to track a moving part and modify the cutting path automatically produces one more significant advantage: Accurate setup of a part on a machine is no longer critical. The method has applications in the repair of airseals, frames and cases, and airfoils.