Requirements for Datum Systems in Computer Aided Tolerancing and the Verification Process

The recent attempt in Geometrical Product Specification to change from dimensional to geometrical tolerancing leads to a stronger focus on datum systems. Two aspects on the requirements for these and their effects on each other will therefore be discussed in this paper. A new approach to develop a functional datum system in the early stages of the methodical design process that is derived from the functional interaction of the indeterminate workpiece geometry within the outlined assembly group will be explained. It will also show current research results to overcome the gaps in ISO 5459 about extraction and association requirements for the verification process.