Dimensional variation is one of the most critical issues in the design of assembled products. This is especially true for the assembly of compliant parts since clamping and joining during assembly may introduce additional variation due to part deformation and springback. This paper discusses the effect of geometric covariance in the calculation of assembly variation of compliant parts. A new method is proposed for predicting compliant assembly variation using the component geometric covariance. It combines the use of principal component analysis (PCA) and finite element analysis in estimating the effect of part/component variation on assembly variation. PCA is used to extract deformation patterns from production data, decomposing the component covariance into the individual contributions of these deformation patterns. Finite element analysis is used to determine the effect of each deformation pattern over the assembly variation. The proposed methodology can significantly reduce the computational effort required in variation analysis of compliant assemblies. A case study is presented to illustrate the methodology.

Issue Section:
Technical Papers
Keywords:
assembling, joining processes, principal component analysis, finite element analysis, deformation
Topics:
Deformation, Manufacturing, Principal component analysis
1.
Lee
,
W. J.
, and
Woo
,
T. C.
,
1990
, “
Tolerances: Their Analysis and Synthesis
,”
ASME J. Ind.
,
112
, pp.
113
–
121
.
2.
Chase, K. W., and Parkinson, 1991, “A Survey of Research in the Application of Tolerance Analysis to the Design of Mechanical Assemblies,” Research in Engineering Design, No. 3, pp. 23–37.
3.
Mantripragada
,
R.
, and
Whitney
,
D. E.
,
1999
, “
Modeling and Controlling Variation Propagation in Mechanical Assemblies Using State Transition Models
,”
IEEE Trans. Rob. Autom.
,
115
(
1
), pp.
124
–
140
.
4.
Ding, Y., Ceglarek, D., and Shi, J., 2000, “Modeling and Diagnosis of Multi-Stage Manufacturing Process: Part I—State Space Model,” Japan-USA Symposium of Flexible Automation, Ann Arbor, Michigan.
5.
Liu
,
S. C.
, and
Hu
,
S. J.
,
1997
, “
Variation Simulation for Deformable Sheet Metal Assemblies Using Finite Element Methods
,”
ASME J. Manuf. Sci. Eng.
,
119
, pp.
368
–
374
.
6.
Camelio
,
J.
,
Hu
,
S. J.
, and
Ceglarek
,
D.
,
2003
, “
Modeling Variation Propagation of Multi-Station Assembly Systems With Compliant Parts
,” ASME J. Mech. Des. 125(4).
7.
Merkley, K., 1998, “Tolerance Analysis of Compliant Assemblies,” PhD Thesis, Brigham Young University.
8.
Johnson, R., and Wichern, D., 1998, Applied Multivariate Statistical Analysis, Prentice Hall, 4th Edition.
9.
Jackson
,
J. E.
,
1980
, “
Principal Component and Factor Analysis: Part I—Principal Components
,”
J. Quality Technol.
,
12
(
4
), pp.
201
–
213
.
10.
Hu
,
S. J.
, and
Wu
,
S. M.
,
1992
, “
Identifying Sources of Variation in Automobile Body Assembly Using Principal Component Analysis
,”
Transactions of NAMRI/SME XX
,
pp.
311
–
316
.
Copyright © 2004
 by ASME
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