Accessibility analysis in efficient inspection of closed blisk on 3-axis CMM with 2-axis probe head

Accessibility analysis plays a vital role in the inspection planning with Coordinate Measuring Machine (CMM), while the complex structure of closed blisk makes the accessibility difficult to determine. Traditional accessibility analysis has to make a trade-off between efficiency emphasizing by the 2D projection method and accuracy underlining by the 3D intersection method. This paper further develops the accessibility analysis by taking both of the two crucial aspects into account to achieve efficient calculation, avoiding intersection detection or over-simplification aroused in previous methods. We first analyze the geometric features that contribute to the complexity of the accessibility problem. A new model is then proposed to build a relationship between the accessibility and the geometric structure. Based on this model, a 2D-projection-3D-reconstruction method is presented to find accessible regions. Finally, the proposed method is validated on a closed blisk model and compared with a referenced method. The result proves the efficiency and correctness of the method in this paper.