Machining Fixture Verification for Nonlinear Fixture Systems

This paper presents a fixture configuration verification methodology for nonlinear fixture systems, which is developed on the basis of optimal clamping forces and total restraint. This method can be applied for validating the feasibility of a fixture with point, line and area contacts in two stages: fixturing and machining. The "∞-∞-∞" principle for nonlinear fixture location is proposed. The automatic fixture verification system is modelled as a nonlinear optimisation problem with respect to minimum clamping forces. The method provides a simple and effective means for: (a) verifying whether a particular fixturing configuration is valid with respect to locating stability, deterministic workpiece location, clamping stability and total restraint and (b) determining minimum variable clamping forces over the entire machining time. Two case studies are presented to demonstrate the effectiveness and the capabilities of the methodology.