A Comprehensive Tolerancing System for 3D Mechanical Assemblies

2010 ◽  
Vol 139-141 ◽  
pp. 1289-1293 ◽  
Author(s):  
Dong Ya Yang ◽  
Jun Gong
Keyword(s):  
Design Principle ◽  
Tolerance Analysis ◽  
Automatic Generation ◽  
Geometric Feature ◽  
Design Practice ◽  
Simulation Environment ◽  
Assembly Tolerance ◽  
Detail Design ◽  
Comprehensive Method ◽  
Mechanical Assemblies

A comprehensive tolerancing system is presented with its design principle, system architecture and key functions. The following functional modules, automatic generation of dimension chain, equivalent variational mechanism (EVM) modeling and visualized 3D tolerance analysis, are described in detail. Design intent is expressed by assembly tolerance specifications, which may be added to the model and used in computing predicted quality levels. A comprehensive method, based on equivalent replacement, has been developed for modeling variations in 3D mechanical assemblies. The models are constructed of common engineering elements: dimension chain, kinematic joints, assembly datums, dimensional and geometric feature tolerances, and assembly tolerance limits. The method is consistent with engineering design practice and is well suited for integration with commercial CAD systems. To make the tolerancing system robust and efficient, new functionalities are added to well-known CAD software and simulation environment. Tested by many samples, this system shows good robustness and practicability.

Visualized Equivalent Variational Modeling in Tolerance Analysis of 3D Mechanical Assemblies

2011 ◽  
Vol 201-203 ◽  
pp. 229-233
Author(s):  
Dong Ya Yang ◽  
Jun Gong
Keyword(s):  
Kinematic Model ◽  
Tolerance Analysis ◽  
Geometric Feature ◽  
Velocity Analysis ◽  
Assembly Tolerance ◽  
Variational Modeling ◽  
Mechanical Assemblies ◽  
Dimensional Variation ◽  
Kinematic Joint

This paper introduces a new, visualized approach for including all the geometric feature variations in the tolerance analysis of mechanical assemblies. It focuses on how to characterize geometric feature variations in vector-loop-based assembly tolerance models. The characterization will be used to help combine the effects of all variations within an assembly in order to perform tolerance analysis of mechanical assemblies by employing commercial 3D kinematic software (e.g. ADAMS). Equivalent variational modeling, based on TAKS method, has been developed for modeling variations in 3D mechanical assemblies. Create a library of Equivalent Variational Joints (EVJs) to allow inclusion all kinds of variations in analysis, and allow the kinematic model to include both geometric and dimensional variation in a velocity analysis. EVJ, for use in tolerance analysis, was developed for commonly used 3D kinematic joint types, and was implemented with examples to explain their use to form Equivalent Variational Mechanisms (EVMs).

scholarly journals Reliability-based tolerance redesign of mechanical assemblies using Jacobian-Torsor model

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110132
Author(s):  
Bingxiang Wang ◽  
Xianzhen Huang ◽  
Miaoxin Chang
Keyword(s):  
Optimization Model ◽  
Economic Effect ◽  
Tolerance Analysis ◽  
Lambert W Function ◽  
Mechanical Assembly ◽  
Assembly Tolerance ◽  
Tolerance Optimization ◽  
Geometric Tolerances ◽  
Mechanical Assemblies ◽  
Proposed Model

The purpose of this paper is to present a new method to redesign dimensional and geometric tolerances of mechanical assemblies at a lower cost and with higher reliability. A parametric Jacobian-Torsor model is proposed to conduct tolerance analysis of mechanical assembly. A reliability-based tolerance optimization model is established. Differing from previous studies of fixed process parameters, this research determines the optimal process variances of tolerances, which provide basis for the subsequent assembly tolerance redesign. By using the Lambert W function and the Lagrange multiplier method, the analytical solution of the parametric tolerance optimization model is obtained. A numerical example is presented to demonstrate the effectiveness of the model, while the results indicate that the total cost is reduced by 10.93% and assembly reliability improves by 2.12%. This study presents an efficient reliability-based tolerance optimization model. The proposed model of tolerance redesign can be used for mechanical assembly with a better economic effect and higher reliability.

Fuzzy Tolerance Analysis of 3-D Mechanical Assemblies

1997 ◽  
Author(s):  
K. Srikanth ◽  
F. W. Liou ◽  
S. N. Balakrishnan
Keyword(s):  
Fuzzy Logic ◽  
Manufacturing Process ◽  
Three Dimensional ◽  
Tolerance Analysis ◽  
Tolerance Design ◽  
Cost Information ◽  
Assembly Tolerance ◽  
Mechanical Assemblies ◽  
Representation Scheme ◽  
Tolerance Assignment

Abstract Tolerance design is interdisciplinary in nature and is characterized by a highly uncertain environment. In recent years, fuzzy logic has appeared as a credible alternative for tolerance design. In this paper a fuzzy based tolerance representation scheme is presented to model three dimensional (3-D) tolerances. With this representation, relative assembly tolerance constraints can be expressed. A fuzzy tolerance generation and assignment process for assembly is discussed. Fuzzy tolerance equations are generated for 3-D assembly considerations. Manufacturing process information, along with uncertain cost information modeled in fuzzy terms, is added to the system to arrive at a cost-optimal tolerance assignment.

Including Geometric Feature Variations in Tolerance Analysis of Mechanical Assemblies

1996 ◽  
Vol 28 (10) ◽  
pp. 795-807 ◽  
Author(s):  
Kenneth W. Chase ◽  
Jinsong Gao ◽  
Spencer P. Magleby ◽  
Carl D. Sorensen
Keyword(s):  
Tolerance Analysis ◽  
Geometric Feature ◽  
Mechanical Assemblies

Tolerance analysis and design of nesting forces for exactly constrained mechanical assemblies

2004 ◽  
Vol 15 (3) ◽  
pp. 182-191 ◽  
Author(s):  
Eric Pearce ◽  
Alan Parkinson ◽  
Kenneth Chase
Keyword(s):  
Tolerance Analysis ◽  
Analysis And Design ◽  
Mechanical Assemblies

Computer Aided Tolerance Analysis of Parts and Assemblies

1989 ◽  
Author(s):  
R. T. Scott ◽  
G. A. Gabriele
Keyword(s):  
Real World ◽  
Probability Distributions ◽  
Three Dimensional ◽  
Tolerance Analysis ◽  
The Real ◽  
Assembly Tolerance ◽  
Computer Aided ◽  
Probability Information ◽  
Exact Constraint

Abstract An exact constraint scheme based on the physical contacting constraints of real part mating features is used to represent the process of assembling the parts. To provide useful probability information about how assembly dimensions are distributed when the parts are assembled as intended, the real world constraints that would prevent interference are ignored. This work addresses some limitations in the area of three dimensional assembly tolerance analysis. As a result of this work, the following were demonstrated: 1. Assembly of parts whose assembly mating features are subjected to variation; 2. Assemble parts using a real world set of exact constraints; 3. Provide probability distributions of assembly dimensions.

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