A Conceptual Model Combination for the Unification of Design and Tolerancing in Robust Design

In design engineering, the early consideration of tolerance chains contributes to robust design. For this, a link of design and tolerancing domains is essential. This paper presents a combination of the graph-based tolerancing approach and the Contact and Channel approach to link these domains. The combined approach is applied at a coinage machine. Here it provides detailed insights into state-dependent relations of embodiment and functions, which can improve robustness evaluation of the concept. This approach shows a possibility to bridge the gap between design and tolerancing domains

Automated Point-based Tolerance Analysis Model Creation for Sheet Metal Parts

AbstractThis paper focuses on a concept that shows a way to automatically create a point-based tolerance analysis model out of existing development data. Nowadays solutions for an automated tolerance simulation model creation are using a static approach for the model build-up. For this purpose product-/ production- development data are automatically mapped on preexisting models (e.g. skeleton models). If chances during development process occur, the tolerance simulation models have to be reworked. Today only simple changes in the model can be automated (e.g. change of distribution, tolerance range etc.). A complete new tolerance simulation model build-up process for dynamically changing product-/ production- development information is not possible. To give an application example, tolerance simulation models for sheet metal parts in automotive industry are based on different development data. Before the first simulation model is created (to secure the tolerance concepts etc.), all necessary information have already been developed, e.g. in the automotive industry's development process: part geometry, tolerance information, assembly graph, jig and fixture concept, joining location and measurement points. Thus the automated simulation generation should be possible.First step is to describe an interface for a dynamic model creation in tolerance simulation systems. In a second step preprocessing of development data is necessary to map them into tolerance simulation software restrictions. This delivers a solution to fill the gap between the PDM-/ CAD and the CAT-system. The considered approach for automated tolerance simulation model creation provides the opportunity to build-up the tolerance analysis models highly efficient and almost automatically. Tolerance analysis can then be used to rapidly calculate several options. This offers the possibility to increase the product maturity level at a very early stage of the development process

Integrated Tolerance and Fixture Layout Design for Compliant Sheet Metal Assemblies

Part tolerances and fixture layouts are two pivotal factors in the geometrical quality of\ua0a compliant assembly. The independent design and optimization of these factors for compliant\ua0assemblies have been thoroughly studied. However, this paper presents the dependency of these\ua0factors and, consequently, the demand for an integrated design of them. A method is developed\ua0in order to address this issue by utilizing compliant variation simulation tools and evolutionary\ua0optimization algorithms. Thereby, integrated and non-integrated optimization of the tolerances and\ua0fixture layouts are conducted for an industrial sample case. The objective of this optimization is\ua0defined as minimizing the production cost while fulfilling the geometrical requirements. The results\ua0evidence the superiority of the integrated approach to the non-integrated in terms of the production\ua0cost and geometrical quality of the assemblies

Geometrical Variations Management 4.0: towards next Generation Geometry Assurance

Product realization processes are undergoing radical change considering the increasing digitalization of manufacturing fostered by cyber-physical production systems, the internet of things, big data, cloud computing, and the advancing use of digital twins. These trends are subsumed under the term “industry 4.0” describing the vision of a digitally connected manufacturing environment.The contribution gives an overview of future challenges and potentials for next generation geometry assurance and geometrical variations management in the context of industry 4.0. Particularly, the focus is set on potentials and risks of increasingly available manufacturing data and the use of digital twins in geometrical variations management

Simulation of Microstructured Rolling-Sliding Contacts

Abstract: To reduce friction in lubricated tribological contacts, the surfaces of the contacting bodies can be microstructured to improve lubricating conditions. For lower loaded contacts this approach has already reached industrial applications, e.g. the piston-liner contact. For higher loaded contacts the effects are currently in basic research. Elastic deformation in the contact area plays an important role in those cases. This paper presents an approach to compute microstructured elastohydrodynamic contacts using Comsol Multiphysics and compares results with those attained on a test bench

Tolerance Analysis of Rotating Mechanism Based on Skin Model Shapes in Discrete Geometry

AbstractGeometric deviations are inevitably observable on every manufactured workpiece. These deviations affect the function and quality of mechanical products and have therefore to be controlled by geometric tolerances. Computer-aided tolerancing aims at supporting design, manufacturing, and inspection by determining and quantifying these effects of geometric deviations on the product quality and the functional behaviour. However, most established tolerance representation schemes imply abstractions of geometric deviations and are not conform with the standards for geometric dimensioning and tolerancing. These limitations led to the development of a Skin Model inspired framework for the tolerance analysis, which is based on a representation of non-ideal workpieces employing discrete geometry representation schemes, such as point clouds and surface meshes. In this contribution, this Skin Model inspired framework for computer aided tolerancing is extended to systems in motion and applied to the tolerance analysis of rotating mechanism with higher kinematic pairs. For this purpose, the generation of non-ideal part representatives, as well as their processing with algorithms for registration and computational geometry are highlighted. Finally, the results are visualized and interpreted. The procedure as well as the simulation model itself are shown in a case study of a disk cam mechanism