Inspection method for geometrical tolerance using virtual gauges

In this paper we propose an inspection method for geometrical tolerances using virtual gauges for measurement with coordinate measuring machine (CMM). For evaluation of the geometrical tolerance virtual measuring gauge as computerized replacement for the real gauge is introduced. The evaluation model for calculation of the virtual gauge uses geometrical constraint for representation of implicit relationships between feature and datums. The implementation evaluation method is small displacement screw method with optimization procedure min-max. Application examples and an extension of small displacement screw method to handle the constraint is provided. We resolve the difficulties for geometrical tolerance inspection, by providing an explicit representation of relationships between features and datums that can be used in an inspection system. Proposed computerized tolerance inspection closely resembles the real gauge measurements and is in concordance with ISO tolerance system.