Commercially-available reconfigurable fixtures, used for holding compliant sheet metal, composite and plastic parts during secondary machining operations, are extremely expensive and overly-complicated devices. A computer-controlled, reconfigurable fixturing device (RFD) concept for compliant parts, based on a matrix of individually-stoppable pins lowered by a single rigid platen, has been developed as a simple and low-cost design alternative to commercially-available devices. Two different approaches to stopping and clamping individual pins have been investigated: a combination electromagnet assist and gas springs compressed with a toggle mechanism, and a pneumatic clamp. Simple mechanical models have been developed for predicting the stopping and clamping performance of both designs including pin positioning accuracy, vertical load-carrying capacity of a pin, and deflection of a pin subjected to lateral loads. An RFD prototype, consisting of a single pin actuated by a servoed platen, has been designed, built and tested. It has demonstrated the feasibility of this new RFD design. [S1087-1357(00)02204-8]

Issue Section:
Technical Papers
Keywords:
machining, manufacturing processes, deformation, design for manufacture
Topics:
Clamps (Tools), Deflection, Design, Electromagnets, Fixturing, Machining, Pins (Engineering), Springs, Stress, Computers, Manufacturing, Sheet metal
1.
Lowell, W. F., 1982, “Geo-metrics II: Dimensioning and Tolerancing,” ANSI/ASME Standard, Y13.5M, pp. 35–52.
2.
Youcef-Toumi
,
K.
,
Liu
,
W. S.
, and
Asada
,
H.
,
1988
, “
Computer-Aided Analysis of Reconfigurable Fixtures and Sheet Metal Parts for Robotic Drilling
,”
Rob. Comput.-Integr. Manufact.
,
4
, No.
3/4
, pp.
387
–
393
.
3.
Rearick
,
M.
,
Hu
,
S. J.
, and
Wu
,
S. M.
,
1993
, “
Optimal Fixture Design for Deformable Sheet Metal Workpieces
,”
Trans. NAMRI/SME
,
21
, pp.
407
–
412
.
4.
Cai
,
W.
,
Hu
,
S. J.
, and
Yuan
,
J. X.
,
1996
, “
Deformable Sheet Metal Fixturing: Principles, Algorithms, and Simulations
,”
J. Manuf. Sci. Eng.
,
118
, pp.
318
–
324
.
5.
Trappey
,
J. C.
, and
Liu
,
C. R.
,
1990
, “
A Literature Survey of Fixture-Design Automation
,”
Int. J. Adv. Manuf. Technol.
, No.
5
, pp.
240
–
255
.
6.
Williams, C. J., and Skinner, T., 1923, “Spring-Forming Device,” U.S. Patent No. 1465152, Issued Aug. 14, 1923.
7.
Walters, T., 1943, “Press,” U.S. Patent No. 2334520, Issued Nov. 16, 1943.
8.
Frosch, R. A., Zebus, P. P., Packer, P. N., and Haynie, C. C., “Variable Contour Securing System,” U.S. Patent No. 4088312, Issued May 9, 1978.
9.
Godding, R. G., “Holder of Irregularly Shaped Articles,” U.S. Patent No. 4200272, Issued April 29, 1980.
10.
Pinson, G. T., 1980, “Apparatus for Forming Sheet Metal,” U.S. Patent No. 4212188, Issued July 15, 1980.
11.
Douglas, W. A. and Ozer, T., “Universal Holding Fixture,” U.S. Patent No. 4684113, Issued Aug. 4, 1987.
12.
Laskowski, J. S., and Pintz, A., 1998, “Computerized System for Lost Foam Casting Process using Rapid Tooling Set-up,” U.S. Patent No. 5796620, Issued Aug. 18, 1998.
13.
Felix, A., 1999, “Characterization and Modeling of a Magnetic Workholding Device,” M.S. thesis, Woodruff School of Engineering, Georgia Institute of Technology, Atlanta, GA.
14.
Yeaple, F., 1990, Fluid Power Design Handbook, 2nd Ed., Marcel Dekker, New York.
15.
Green, R. E., ed., 1996, Machinery’s Handbook, 25th ed., Industrial Press, New York, 1996.
Copyright © 2000
 by ASME
You do not currently have access to this content.