Stream-of-Variation Modeling I: A Generic 3D Variation Model for Rigid Body Assembly in Single Station Assembly Processes

Abstract

A stream-of variation analysis (SOVA) model for 3D rigid body assemblies in single station is developed. Both product and process information such as part and fixture locating errors are integrated in the model. The model represents a linear relationship of the variations between Key Product Characteristics (KPCs) and Key Control Characteristics (KCCs). The generic modeling procedure and framework are provided, which involves: (1) an assembly graph (AG) to represent the kinematical constraints among parts and fixtures; (2) a unified method to transform all constraints (mating interface and fixture locators etc.) into a 3-2-1 locating scheme; and (3) a 3D rigid model for variation flow in a single station. The generality of the model is achieved by formulating all these constraints with a unified generalized fixture model. Thus, the new model accommodates various types of assemblies. This model provides a building block for complex multi station assembly model, in which the inter-station interactions are taken into account. The model has been verified by using Monte Carlo (MC) simulation and a standardized industrial software. It provides the basis for variation control through tolerance design analysis, synthesis and diagnosis in manufacturing systems.

Design verification and validation in product lifecycle

“…Stream-of-Variation Analysis (SOVA) is a mathematical model to describe the relation between final product quality and process parameters of complex multistage assembly [145,146]. SOVA can predict potential downstream assembly problems, based on evaluations of the design using a large array of process variables.…”

Closed-Loop Analysis in Semantic Tolerance Modeling

“…The singlestation methods were also extended to multi-station approaches (Shiu et al [27], Camelio et al [28]) where variations are propagated in stages with tooling variations incorporated. Recently, Huang et al [29,30] developed a stream-of-variation method to estimate dimensional variations in rigid-body assemblies for single-station and multi-station systems considering fixtures based on kinematic constraints.…”

Assembly process optimization for reducing the dimensional error of antenna assembly with abundant rivets

“…On one hand, the dimensional issues in the automotive body assemblies are comprehensively studied from the mechanical tolerance analyses to a series of fruits relating to the stream-of-variation analysis (SOVA) (Chase and Greenwood 1988;Ceglarek et al 2004;Cai 2008;Huang et al 2007;Huang and Kong 2008;Wang and Ceglarek 2009), and to the dimensional analyses for self-pierce riveted sheets (Cai et al 2005;Masters et al 2011). Among these researches, many insightful attempts target to more complex dimensional propagations, e.g.…”

“…Among these researches, many insightful attempts target to more complex dimensional propagations, e.g. the three-dimensional (3D) rigid SOVA model (Huang et al 2007), the variation propagation model that considers the joining and releasing schemes especially for the preliminary design (Wang and Ceglarek 2009), the dimensional analysis taking the experimentally tested rivet distortions (Cai et al 2005), and the global finite element (FE) simulation projecting the riveted distortion yielded from the local FE analysis (Masters et al 2011). On the other hand, the mechanical strength and fatigue problems are mainly focused on for the aircraft structure safety that usually takes the local rivet joint as the crucial part Manes et al 2011;Aman et al 2013).…”