Optical 3D measurement of cooling holes in gas turbine and aircraft engines

Learn more about

The quality control of cooling holes is an important topic for increasing the efficiency and ensuring the safety in high-performance systems. Even if heat-resistant materials are used (Inconel steels), the surface must be cooled because the surrounding gases are in the range of the melting point. This is done with compressed air from the inside of the blade. The position, orientation and shape of the holes thus play a major role in the safety of the turbine. These turbine blades are used in aircraft turbines and gas turbines.

Currently, the geometry is measured using computer tomography or fiber probes. The proposed method (vertical focus probing) offers advantages in terms of measurement time, resolution, non-contact measurement and the possibility to measure deep into the hole. We demonstrate the strength of vertical focus probing for cooling hole measurement by several results of highly accurate 3D measurements of differently shaped holes as well as their geometric inspection.