Manufacturing signature in jacobian and torsor models for tolerance analysis of rigid parts (original) (raw)
Related papers
A Geometric Model for Tolerance Analysis with Manufacturing Signature and Operating Conditions
International Journal of Manufacturing, Materials, and Mechanical Engineering, 2019
In this work, a geometric model for tolerance analysis has been carried out. Geometric reasoning has been implemented in the model to simulate the manufacturing process and, then, the assembly sequence. The proposed geometric model has been applied to a case study consisting of two circular profiles due to the turning process, and a hollow rectangular box. The two circular profiles have been assembled inside the box by considering the gravity, and the friction among the parts and the actual points of contact with and without using the manufacturing signature. Matlab® software has been used to implement the geometric model for tolerance analysis. The results have been compared with those obtained by using a literature model with and without considering the manufacturing signature. This work aims to be a first step towards the integration of the design and the manufacturing in a concurrent engineering approach.
Tolerance Analysis of Rotating Mechanism Based on Skin Model Shapes in Discrete Geometry
Procedia CIRP, 2015
Geometric 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.
Skin Model Shapes: A new paradigm shift for geometric variations modelling in mechanical engineering
Computer-Aided Design, 2014
Geometric deviations are inevitably observable on manufactured workpieces and have huge influences on the quality and function of mechanical products. Therefore, many activities in geometric variations management have to be performed to ensure the product function though presence of these deviations. Dimensional and Geometrical Product Specification and Verification (GPS) are standards for the description of workpieces. Their lately revision grounds on GeoSpelling, which is an univocal language for geometric product specification and verification and aims at providing a common understanding of geometric specifications in design, manufacturing, and inspection. The Skin Model concept is a basic concept within GeoSpelling and is an abstract model of the physical interface between a workpiece and its environment.
CAD/tolerancing integration: a new approach for tolerance analysis of non-rigid parts assemblies
The International Journal of Advanced Manufacturing Technology, 2018
The tolerancing integration in CAD model is among the major interests of most mechanical manufacturers. Several researches have been established approaches considering the geometrical and dimensional tolerances on the CAD modelers. However, the hypothesis of rigid parts is adopted in the digital mock-up. Thus, several physical factors are neglected; especially the deformations. In this regard, this paper presents a model for considering both tolerances and deformations in CAD model. The dimensional and geometrical tolerances are taken into account by the determination of assemblies configurations with defects basing on the worst case tolerancing. The finite elements (FE) computations are realized with realistic models. A method for modeling the realistic mating constraints, between rigid and non-rigid parts, is developed. Planar and cylindrical joints are considered. The proposed tolerance analysis method is highlighted throughout two cases study: the first comprises planar joints and the second comprises cylindrical parts in motion. Keywords CAD. GD&T. Realistic mating. Non-rigid component and tolerance analysis 2 State of the art This paper can be positioned under the research works belonging to two themes: (1) Tolerancing of rigid parts; (2) Tolerancing of non-rigid parts. 2.1 Tolerancing of rigid parts Based on models for the representation of a toleranced geometry [4, 5], several studies contributed to the development of * A.
3D Tolerance Analysis with Manufacturing Signature and Operating Conditions
Procedia CIRP, 2016
The present work shows a method to integrate the manufacturing signature and the operating conditions into a model for 3D tolerance analysis of rigid parts. The paper presents an easy way to manage the actual surfaces due to a manufacturing process and the operating conditions, such as gravity and friction, inside the variational model for a 3D tolerance analysis. The used 3D case study is deliberately simple in order to develop a conceptual demonstration. The obtained results have been compared with those due to a geometrical model that reproduces what happens during assembly. It has been considered as reference case.
Towards improvement of geometrical quality for manual assembly parts
2017
Geometrical variation affects all mass-produced products. This variation will lead to deviations from the nominal design of the product both in terms of aesthetical and functional properties. Geometrical variation originates either from the manufacturing of the parts or from the assembly process. In order to minimize the effect of variation robust design principles are often used. In early product development the majority of the properties in the system solutions are fixed and to change these later in the product development will be costly. In order to verify the system solution (locating scheme and tolerances), different simulation techniques are used to predict the behavior of the product. This is done using virtual tools, for example Computer Aided Tolerancing (CAT). In order to gain confidence for such tools it is very important that the simulation results are accurate and that they capture all factors that influence the product. In this thesis the focus has been on geometry as...
Integration of tolerances in the mechanical product process: Assembly with defects modelling
2013
a. Mechanical Engineering Laboratory, National Engineering School of Monastir, Monastir University, Av. Ibn Eljazzar, 5019 Monastir, Tunisia. a, b. LIPPS, ETS, 1100, Notre-Dame Ouest, Montreal, H3C1K3, Quebec, Canada. Borhen.louhichi@etsmtl.ca, abdelmajid.benamara@enim.rnu.tn Abstract: The part and assembly requirements are specified by the tolerances. In the Digital Mock-Up (DMU), the product is designed on nominal configuration and the tolerances are formally allocated to the CAD model. Thus, the impacts of the tolerance stack-up on the advanced phase of the product design (Dynamic computation, F.E Analysis...) are neglected. The DMU improvement requires the tolerance integration in CAD model. A developed model allows obtaining the components with defects according to dimensional and geometrical tolerances specified in the nominal model. In CAD model, the assembly of the components with dimensional and geometrical defects requires the updating of the assembly mating constraints. T...
A Contribution To 3D Modeling Of Manufacturing Tolerance Optimization
2010
The study of the generated defects on manufactured parts shows the difficulty to maintain parts in their positions during the machining process and to estimate them during the pre-process plan. This work presents a contribution to the development of 3D models for the optimization of the manufacturing tolerances. An experimental study allows the measurement of the defects of part positioning for the determination of ε and the choice of an optimal setup of the part. An approach of 3D tolerance based on the small displacements method permits the determination of the manufacturing errors upstream. A developed tool, allows an automatic generation of the tolerance intervals along the three axes.
2016
The present work shows a method to integrate the manufacturing signature and the operating conditions into a model for 3D tolerance analysis of rigid parts. The paper presents an easy way to manage the actual surfaces due to a manufacturing process and the operating conditions, such as gravity and friction, inside the variational model for a 3D tolerance analysis. The used 3D case study is deliberately simple in order to develop a conceptual demonstration. The obtained results have been compared with those due to a geometrical model that reproduces what happens during assembly. It has been considered as reference case. © 2016 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the organizing committee of the 14th CIRP Conference on Computer Aided Tolerancing.