Cad-based Dimensional and Geometrical Tolerancing Implementation by the Use of Virtual Gages: a Case Study

Physical gages permit verification with low uncertainties but remain expensive and inflexible. With the development of 3D CAD modellers and the progress made in coordinate measuring machines, the concept of the virtual gage appeared. The paper focuses on the implementation rather than the inspection of dimensional and geometrical tolerancing in 3D-CAD models of mechanical assemblies by the use of virtual gages. The objective is to provide an easy-to-use CAD-based tool for tolerancing visualisation and functionality analysis during the design phase. An industrial case study of an assembly where total ruunout and tight dimensional tolerances are designated is presented in order to demonstrate the effectiveness of the virtual gages approach. The complete visualization of the dimensional and geometrical tolerances that is achieved by the proposed approach, in conjunction with currently available tolerance analysis and synthesis CAD tools, facilitates and advances the design process significantly.