Overview
The main impact of the following proposal of the three participants Hexagon Metrology GmbH, Hexagon Technology Center GmbH, and Fraunhofer Institute for Industrial Mathematics ITWM was an integrated approach to the measurement of geometric and automatical identification and characterisation of surface defects of a BLISK (bladed disk). An automatic visual inspection of the BLISKs created a significant contribution to better and safer processes at lower cost.
The key innovations of AMI4BLISK was a unique and new approach for automated BILISK measurement and inspection; an innovative and new image processing algorithms and visual inspection sensor setup and a new sensor for defect characterisation and measurement.
In a first step the geometrical measurement with a coordinate-measuring-machine (CMM) provided the information of the shape and surface of the BLISK in combination with the CAD model that provides basic information of the geometry.
In a second step all possible defects needed to be found with the use of an intelligent image-processing-system. The location and type of the questionable defects were then be qualified and stored automatically.
In a third step the defects were classified. With the known position of the defects, a program to measure all the defects with another CMM was generated automatically. These measurements gave a quantitative description of the possible defects. In some cases where a defect may be questionable the inspection by a person of skill was still necessary.
Funding
Results
Executive Summary:
In the framework of the present Project, Hexagon Metrology GmbH generated a sellable system for automated BLISK measurement. This measurement system based on a coordinate measuring machine includes:
- the geometrical measurement of the complete blisk surface by using the tactile sensor;
- the roughness determination of strategic surface areas on the blisk; and
- the measurement of special geometries such as radii and edges by using the optical sensor developed and tested during the presented project.
The automated visual inspection system needed further development to be marketable and ready for serial production. These activities were scheduled and traced at Hexagon Metrology GmbH. The outcome of it was a system that delivered more reliable results than recently delivered by human inspectors. Therefore, the system finally enabled manufacturers to produce more reliable engines that finally contribute to more security in the equipped airplanes. Moreover, it also contributed to a longer lifetime of the engines and therefore a more efficient use of natural resources. Finally, the new engine generation also showed significantly lower noise emissions.