Research Papers

Controlling Geometrical Variation Caused by Assembly Fixtures

[+] Author and Article Information
Kristina Wärmefjord

Department of Product and
Production Development,
Chalmers University of Technology,
Göteborg SE-412 96, Sweden
e-mail: kristina.warmefjord@chalmers.se

Johan S. Carlson

Fraunhofer-Chalmers Research Centre,
Chalmers Science Park,
Göteborg SE-412 88, Sweden
e-mail: johan.carlson@fcc.chalmers.se

Rikard Söderberg

Department of Product and
Production Development,
Chalmers University of Technology,
Göteborg SE-412 96, Sweden
e-mail: rikard.soderberg@chalmers.se

Contributed by the Design Engineering Division of ASME for publication in the JOURNAL OF COMPUTING AND INFORMATION SCIENCE IN ENGINEERING. Manuscript received July 1, 2015; final manuscript received January 26, 2016; published online February 17, 2016. Assoc. Editor: Vijay Srinivasan.

J. Comput. Inf. Sci. Eng 16(1), 011007 (Feb 17, 2016) (8 pages) Paper No: JCISE-15-1214; doi: 10.1115/1.4032625 History: Received July 01, 2015; Revised January 26, 2016

In the auto body assembly process, fixtures position parts during assembly and inspection. Variation in the positioning process propagates to the final assembly. To control the assembly fixtures, repeatability studies are used. Those studies are, however, usually done with long intervals and the fixtures might be afflicted with variation between studies. There are also other sources of variation in the final assembly, such as variation in parts due to previous manufacturing steps. To separate variation caused by fixtures and the variation caused by previous manufacturing processes, a multivariate fixture failure subspace control chart is proposed.

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Söderberg, R. , Lindkvist, L. , and Carlson, J. , 2006, “ Virtual Geometry Assurance for Effective Product Realization,” 1st Nordic Conference on Product Lifecycle Management (NordPLM’06), Jan. 25–26.
Söderberg, R. , and Lindkvist, L. , 1999, “ Computer Aided Assembly Robustness Evaluation,” J. Eng. Des., 10(2), pp. 165–181. [CrossRef]
Wärmefjord, K. , Carlson, J. S. , and Söderberg, R. , 2009, “ A Measure of the Information Loss for Inspection Point Reduction,” ASME J. Manuf. Sci. Eng., 131(5), p. 051017. [CrossRef]
Kunzmann, H. , Pfeifer, T. , Schmitt, R. , Schwenke, H. , and Weckenmann, A. , 2005, “ Productive Metrology-Adding Value to Manufacture,” Ann. CIRP, 54(2), pp. 691–713. [CrossRef]
Montgomery, D. , 2005, Introduction to Statistical Quality Control, Wiley, New York.
Shewart, W. A. , 1931, Economic Control of Quality of Manufactured Product, Van Nostrand, New York.
Gou, Y. , and Dooley, K. , 1992, “ Identification of Change Structure in Statistical Process Control,” Int. J. Prod. Res., 30(7), pp. 1655–1669. [CrossRef]
Carlson, J. S. , and Söderberg, R. , 2003, “ Assembly Root Cause Analysis: A Way to Reduce Dimensional Variation in Assembled Products,” Int. J. Flexible Manuf. Syst., 15(2), pp. 113–150. [CrossRef]
Camelio, J. A. , Hu, S. J. , and Ceglarek, D. , 2003, “ Modeling Variation Propagation of Multi-Station Assembly Systems With Compliant Parts,” ASME J. Mech. Des., 125(4), pp. 673–681. [CrossRef]
Yu, K. , Jin, S. , and Lai, X. , 2009, “ Fixture Variation Diagnosis of Compliant Assembly Using Sensitivity Matrix,” J. Shanghai Jiaotong Univ., 14(6), pp. 707–712. [CrossRef]
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(3), pp. 368–374. [CrossRef]
Kong, Z. , Ceglarek, D. , and Huang, W. , 2008, “ Multiple Fault Diagnosis Method in Multistation Assembly Processes Using Orthogonal Diagonalization Analysis,” ASME J. Manuf. Sci. Eng., 130(1), p. 011014.
Liu, Y. G. , and Hu, S. J. , 2005, “ Assembly Fixture Fault Diagnosis Using Designated Component Analysis,” ASME J. Manuf. Sci. Eng., 127(2), pp. 358–368. [CrossRef]
Camelio, J. A. , and Heichelbech, B. , 2006, “ Comparison of Diagnosis Methodologies on Sheet Metal Assembly,” Trans. NAMRI/SME, 34, pp. 135–142.
Liu, J. , 2010, “ Variation Reduction for Multistage Manufacturing Processes: A Comparison Survey of Statistical-Process-Control vs Stream-of-Variation Methodologies,” Qual. Reliab. Eng. Int., 26(7), pp. 645–661. [CrossRef]
Wärmefjord, K. , Söderberg, R. , and Carlson, J. , 2010, “ Including Assembly Fixture Repeatability in Rigid and Non-Rigid Variation Simulation,” ASME Paper No. IMECE2010-37218.
Söderberg, R. , Lindkvist, L. , and Carlson, J. S. , 2006, “ Managing Physical Dependencies Through Location System Design,” J. Eng. Des., 17(4), pp. 325–346. [CrossRef]
Wang, M. Y. , and Pelinescu, D. M. , 2001, “ Optimizing Fixture Layout in a Point Set Domain,” IEEE Trans. Rob. Autom., 17(3), pp. 312–323. [CrossRef]
Wärmefjord, K. , Söderberg, R. , and Lindkvist, L. , 2014, “ Decoupled Fixturing Strategies for Minimized Geometrical Variation During Cutting of Stamped Parts,” J. Eng. Manufact., pp. 1401–1408.
Carlson, J. S. , Soüderberg, R. , and Lindkvist, L. , 2003, “ Geometrical Inspection Point Reduction Based on Combined Cluster and Sensitivity Analysis,” ASME Paper No. IMECE2003-42308.
Wärmefjord, K. , Carlson, J. S. , and Söderberg, R. , 2007, “ Geometrical Inspection Point Reduction for Rigid and Non-Rigid Parts Using Cluster Analysis—An Industrial Verification,” 10th CIRP Conference on Computer Aided Tolerancing, Specification and Verification for Assemblies, Erlangen, Germany, Mar. 21–23.
Wärmefjord, K. , Carlson, J. S. , and Söderberg, R. , 2010, “ An Investigation of the Effect of Sample Size on Geometrical Inspection Point Reduction Using Cluster Analysis,” CIRP J. Manuf. Sci. Technol., 3(3), pp. 227–235. [CrossRef]
Wetherill, G. B. , and Brown, D. W. , 1991, Statistical Process Control, Chapman & Hall, London.
Jackson, J. E. , 1991, A User's Guide to Principal Components, Wiley, New York.
Hotelling, H. H. , 1947, “ Multivariate Quality Control Illustrated by the Air Testing of Sample Bombsights,” Techniques of Statistical Analysis, McGraw-Hill, New York, pp. 111–184.
Alt, F. B. , 1982, “ Multivariate Quality Control: State of the Art,” Transactions of the 1982 ASCC Quality Congress, pp. 886–893.
Johnson, R. A. , and Wichern, D. W. , 1998, Applied Multivariate Statistical Analysis, Prentice-Hall, Upper Saddle River, NJ.
RD&T Technology, 2015, “ RD&T Webpage,” http://rdnt.se/


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Fig. 1

The product realization loop

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Fig. 2

A 3-2-1 locating scheme

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Fig. 3

Top: The side panel assembly consists of the door panel and the outer side panel. Middle: The assembly is positioned in xz-direction using the locators labeled B1 and B2. Bottom: The assembly is measured in four inspection points.

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Fig. 4

Top: The original data from inspection point 2 in x-direction, side panel assembly. Bottom: The same data but with the trends eliminated.

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Fig. 5

Tfixture2 - and SPEfixture -chart to control the variation in the fixture failure subspace, side panel assembly

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Fig. 6

The bumper and floor are assembled. Finally, 14 points on the bumper are measured.

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Fig. 7

Inspection data for 36 assemblies in 14 inspection points

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Fig. 8

Tfixture2- and SPEfixture -chart to control the variation in the fixture failure subspace, bumper assembly



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