Geometrical product specifications - model for product life cycle

As technology increases and performance requirements continually tighten, the cost and required precision of assemblies increase as well. There exists a strong need for increased attention to tolerance design to enable high-precision assemblies to be manufactured at lower cost. For automotive and aircraft industries, the tolerancing process has become an important issue in product and process design. There is an important question that would need to be looked into: "How to define a coherent expression of Geometrical Product Specification during the tolerancing process along life cycle?". There is a necessity for developing a complete answer representing standard tolerance practices. This paper proposes a model to allow a complete and coherent tolerancing process. The description of GeoSpelling, the model proposed to ISO for rebuilding standards in the fields of tolerancing and metrology, allows a unified description of geometrical specification. This model takes into account, not only the specification on isolated parts, but also on assemblies with the integration of the quantifier concept. (C) 2008 Elsevier Ltd. All rights reserved.