Although bending is one of the final processes in sheet metal part manufacture, it is relatively inaccurate compared to the other components of sheet metal processing. Critical tolerances at several locations on the sheet metal part impose limitations on bending operations and sequences. The lack of success up to now in embedding accuracy in process planning for sheet metal products has resulted mainly from the fact that tolerance analysis usually requires simulating the manufacturing process. This paper discusses the issue of automatic determination of the bending sequence in sheet metal products subject to critical tolerance constraints. It proposes conditions for identifying cases where the problem of determining the bending order which results in the best accuracy at specific locations is, in fact, a topological problem. Two explicit rules for achieving the best accuracy in such cases are formulated and then demonstrated by using these rules to construct a precedence graph.

1.
Radin
B.
,
Shpitalni
M.
,
Hartman
I.
,
1997
, “
Two Stage Algorithm for Determination of the Bending Sequence in Sheet Metal Products
,”
ASME JOURNAL OF MECHANICAL DESIGN
, Vol.
119
, No.
2
, pp.
259
266
.
2.
Shpitalni
M.
,
Saddan
D.
,
1994
, “
Automatic Determination of Bending Sequence in Sheet Metal Products
,”
Annals of the CIRP
, Vol.
43
, No.
1
, pp.
23
26
.
3.
De Vin
L. J.
,
Streppel
A. H.
,
Kals
H. J. J.
,
1996
, “
The Accuracy Aspect in Set-Up Determination for Sheet Bending
,”
Int. J. Adv. Manufacturing Tech.
, Vol.
11
, pp.
179
185
.
4.
Radin, B., Shpitalni, M., 1997, “Bending Sequence Optimization Subject to Critical Tolerance Constraints in Sheet Metal Products,” The Second World Congress on Intelligent Manufacturing Processes & Systems, Budapest, Hungary, June 10–13, 1997, pp. 236–241.
5.
Juster
N. P.
,
1992
, “
Modeling and Representation of Dimensions and Tolerances: A Survey
,”
CAD
, Vol.
24
, No.
1
, pp.
3
17
.
6.
Kusiak
A.
,
Feng
C.
,
1995
, “
Deterministic Tolerance Synthesis: A Comparative Study
,”
CAD
, Vol.
27
, No.
10
, pp.
759
768
.
7.
Bjorke, O., 1989, Computer-Aided Tolerancing, 2nd ed. ASME press.
8.
Dong, Z., Soom, A., 1991, “Some Application of Artificial Intelligence Techniques to Automatic Tolerance Analysis and Synthesis,” Artificial Intelligence in Design, pp. 101–125.
9.
Huwiler
B.
,
Reissner
J.
,
1993
, “
CAPP Based on Rules and Algorithms in the Manufacturing of Bent Sheet Parts
,”
Manufacturing Sys.
, Vol.
22
, No.
2
, pp.
147
151
.
10.
Inui, M., Kinosada, A., Suzuki, H., Kimura, F., Sata, T., 1987, “Automatic Process Planning for Sheet Metal Part with Bending Simulation,” ASME, WAM, Symposium, on Intelligent and Integrated Manufacturing Analysis and Synthesis, Vol. 25, pp. 245–258.
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