A Bi-criterion Flexible Registration Method for Fixtureless Inspection of Compliant Parts

Manufactured mechanical parts such as sheet metal and thin-wall featured parts, often have significant geometrical differences compared to their nominal CAD models as they have a considerably different shape in a free state condition due to gravity and/or residual stress. Thus, expensive conformation fixtures are traditionally used during inspection operations. Naming such parts flexible (non-rigid or compliant), in this paper, a new method for avoiding fixtures is introduced. Validation was conducted on a virtual industrial case study typically produced with waterjet cutting. Obtained satisfactory results reflect the effectiveness and utility of this approach in precision detection of manufacturing defects.