Mapping of GD&T information and PMI between 3D product models in the STEP and STL format

Abstract Increasing specialization of design, manufacturing, assembly, and inspection have fostered the need for sophisticated product documentation practices to allow the clear and unambiguous communication of product information between design and all downstream activities. This need has led to the development of various standards for the exchange of product geometry and related information and particularly to the emergence of STEP as a standard for the exchange of product model data. Though STEP is widely used as an exchange format in design and related domains, other standards and file formats are frequently used for transferring product geometry information from design to downstream activities today, such as the STL (Standard Tesselation Language) format, which uses a discrete geometry representation scheme for describing part geometry by an unstructured triangulated surface. However, there exists a gap between STEP, which offers great benefits regarding the documentation of nominal product geometry and product manufacturing information, and the STL format, which offers a discrete geometry representation by triangles. With the aim to close this gap, this paper presents a novel method that allows an automatic mapping of PMI (Product and Manufacturing Information) and GD&T (Geometric Dimensioning and Tolerancing) information assigned on the CAD model from STEP files on discrete geometries. The method comprises the interpretation of ISO STEP AP 242 files as well as a novel feature recognition approach. The combined data model, that represents the geometry in tessellated format and includes the GD&T information assigned on the triangulated features, may then serve as an interface model between design, simulation, manufacturing, and inspection and thus contributes to the consistency of product documentation throughout the digital thread in the product life-cycle. The applicability of the method is highlighted using a case study of a car brake system of industrial complexity. In addition, its benefits are underlined by the exemplary application of the method in the context of injection molding simulation and tolerance analysis.

[1]  Vijay Srinivasan.  Standardizing the specification, verification, and exchange of product geometry: Research, status and trends , 2008, Comput. Aided Des..

[2]  Sandro Wartzack,et al.  Skin Model Shapes: A new paradigm shift for geometric variations modelling in mechanical engineering , 2014, Comput. Aided Des..

[3]  Sebastian Handschuh,et al.  JT Format (ISO 14306) and AP 242 (ISO 10303): The Step to the Next Generation Collaborative Product Creation , 2013, NEW PROLAMAT.

[4]  S. S. Pande,et al.  Automatic recognition of features from freeform surface CAD models , 2008, Comput. Aided Des..

[5]  Manuel Contero,et al.  3D Model Annotation as a Tool for Improving Design Intent Communication: A Case Study on its Impact in the Engineering Change Process , 2012 .

[6]  Allison Barnard Feeney,et al.  Toward a Lifecycle Information Framework and Technology in Manufacturing , 2017, J. Comput. Inf. Sci. Eng..

[7]  Manuel Contero,et al.  Extended 3D annotations as a new mechanism to explicitly communicate geometric design intent and increase CAD model reusability , 2014, Comput. Aided Des..

[8]  Sandro Wartzack,et al.  Evaluation of geometric tolerances and generation of variational part representatives for tolerance analysis , 2015 .

[9]  Allison Barnard Feeney,et al.  Recent advances in sharing standardized STEP composite structure design and manufacturing information , 2013, Comput. Aided Des..

[10]  Sandro Wartzack,et al.  Shaping the digital twin for design and production engineering , 2017 .

[11]  Joshua Lubell,et al.  Conformance checking of PMI representation in CAD model STEP data exchange files , 2015, Comput. Aided Des..

[12]  Paul K. Wright,et al.  Volumetric feature recognition for machining components with freeform surfaces , 2004, Comput. Aided Des..

[13]  Sandro Wartzack,et al.  A discrete geometry approach for tolerance analysis of mechanism , 2014 .

[14]  Enrico Vezzetti,et al.  Model-based definition design in the product lifecycle management scenario , 2011 .

[15]  Alan Arokiam,et al.  Closed Loop PMI Driven Dimensional Quality Lifecycle Management Approach for Smart Manufacturing System , 2016 .

[16]  Sandro Wartzack,et al.  Approaches for the assembly simulation of skin model shapes , 2015, Comput. Aided Des..

[17]  Kai Hormann,et al.  The point in polygon problem for arbitrary polygons , 2001, Comput. Geom..

[18]  Utpal Roy,et al.  Interpreting the semantics of GD&T specifications of a product for tolerance analysis , 2014, Comput. Aided Des..

[19]  Allison Barnard Feeney,et al.  A Portrait of an ISO STEP Tolerancing Standard as an Enabler of Smart Manufacturing Systems , 2014, J. Comput. Inf. Sci. Eng..

[20]  Sandro Wartzack,et al.  Novel approaches for the assembly simulation of rigid Skin Model Shapes in tolerance analysis , 2018, Comput. Aided Des..

[21]  Riza Sulaiman,et al.  A Review and Comparison of IGES and STEP , 2010 .

[22]  Thomas Hedberg,et al.  Interoperability: linking design and tolerancing with metrology , 2016, Procedia CIRP.

[23]  Kristin L. Wood,et al.  Functional tolerancing: A design for manufacturing methodology , 1996 .

[24]  Sandro Wartzack,et al.  An Approach to the Sensitivity Analysis in Variation Simulations considering Form Deviations , 2018 .

[25]  Indira Thouvenin,et al.  Supporting design with 3D-annotations in a collaborative virtual environment , 2009 .

[26]  Thomas R. Langerak,et al.  Local parameterization of freeform shapes using freeform feature recognition , 2010, Comput. Aided Des..

[27]  Sebti Foufou,et al.  OntoSTEP: Enriching product model data using ontologies , 2012, Comput. Aided Des..

[28]  Paul Witherell,et al.  Towards Annotations and Product Definitions for Additive Manufacturing , 2016 .

[29]  Sandro Wartzack,et al.  Challenges of Geometrical Variations Modelling in Virtual Product Realization , 2017 .

[30]  Louis Rivest,et al.  Will Model-based Definition replace engineering drawings throughout the product lifecycle? A global perspective from aerospace industry , 2010, Comput. Ind..