Using Semantic Geometric Dimensioning and Tolerancing (GD&T) Information from STEP AP242 Neutral Exchange Files for Robotic Applications

Abstract

This article proposes the use of Geometric Dimensioning and Tolerancing (GD &T) information from STEP AP242 for robotic manufacturing applications. This information can be directly added to the relevant features of the 3D model as per Model Based Definition methodology during the design phase of the product life cycle. STEP AP242 neutral exchange files enable the availability of product definition at the downstream operations, thus completing the Digital Thread as part of Industry 4.0 practices. This article discusses two methods; using custom Unicode strings and the standard entities; for including GD &T using the STEP AP242 Edition 2 neutral file exchange format. A method to form a single Unicode string to add all the GD &T information to the STEP files is described in this paper. The GD &T information in the Unicode string is fully semantic and can easily be parsed to extract the relevant PMI for tolerance analysis. A novel process of extracting and interpreting the relevant PMI for robotic manufacturing applications is described in detail. This article discusses various applications of this information for robotic manufacturing through two use-cases using the second edition of the STEP AP242 standard.