Generating geometric dimensioning and tolerancing (GD&T) specifications for mechanical assemblies is a complex and tedious task, an expertise that few mechanical engineers possess. The task is often done by trial and error. While there are commercial systems to facilitate tolerance analysis, there is little support for tolerance synthesis. This paper presents a systematic approach toward collecting part and assembly characteristics in support of automating GD&T schema development and tolerance allocation for mechanical assemblies represented as neutral B-Rep. First, assembly characteristics are determined, then a tentative schema is determined and tolerances allocated. This is followed by adaptive iterations of analyses and refinement to achieve desired goals. This paper will present the preprocessing steps for assembly analysis needed for tolerance schema generation and allocation. Assembly analysis consists of four main tasks: assembly feature recognition (AFR), pattern detection, directions of control, and loop detection. This paper starts with identifying mating features in an assembly using the computer-aided design (CAD) file. Once the features are identified, patterns are determined among those features. Next, different directions of control for each part are identified and lastly, using all this information, all the possible loops existing in an assembly are searched.

References

References
1.
ISO 1101,
2012
,
Geometrical Product Specifications (GPS)—Geometrical Tolerancing—Tolerances of Form, Orientation, Location, and Run-Out
,
ISO
, Switzerland.
2.
ASME,
1994
,
Dimensioning and Tolerancing, ASME Y14.5M-1994
,
American Society of Mechanical Engineers
,
New York
.
4.
Whitney
,
D. E.
,
2004
,
Mechanical Assemblies—Their Design, Manufacture, and Role in Product Development
,
Oxford University
, New York, pp.
35
36
.
5.
Chase
,
K.
,
Gao
,
J.
,
Magleby
,
S.
, and
Sorenson
,
C.
,
1996
, “
Including Geometric Feature Variations in Tolerance Analysis of Mechanical Assemblies
,”
IIE Trans.
,
28
(
10
), pp.
795
808
.
6.
Sambhoos
,
K.
,
Koc
,
B.
, and
Nagi
,
R.
,
2009
, “
Extracting Assembly Mating Graphs for Assembly Variant Design
,”
ASME J. Comput. Inf. Sci. Eng.
,
9
(
3
), p.
034501
.10.1115/1.3184607
7.
Wu
,
Y.
,
Shah
,
J.
, and
Davidson
,
J.
,
2003
, “
Computer Modeling of Geometric Variations in Mechanical Parts and Assemblies
,”
ASME J. Comput. Inf. Sci. Eng.
,
3
(
1
), pp.
54
63
.10.1115/1.1572177
8.
Shen
,
Z.
,
2003
, “
Software Review-Tolerance Analysis With EDS/VisVSA
,”
ASME J. Comput. Inf. Sci. Eng.
,
3
(
1
), pp.
95
99
.10.1115/1.1573236
9.
Chiesi
,
F.
, and
Governi
,
L.
,
2003
, “
Software Review-Tolerance Analysis With eTol-Mate
,”
ASME Trans.
10.
Shen
,
Z.
,
Ameta
,
G.
,
Shah
,
J. J.
, and
Davidson
,
J. K.
,
2005
, “
A Comparative Study of Tolerance Analysis Methods
,”
ASME J. Comput. Inf. Sci. Eng.
,
5
(
3
), pp.
247
256
.10.1115/1.1979509
11.
Shah
,
J.
,
Anderson
,
D.
,
Kim
,
Y.-S.
, and
Joshi
,
S.
,
2001
, “
A Discourse on Geometric Feature Recognition From CAD Models
,”
ASME J. Comput. Inf. Sci. Eng.
,
1
(
1
), pp.
41
51
.10.1115/1.1345522
12.
Shah
,
J.
, and
Rogers
,
M. T.
,
1993
, “
Assembly Modeling as an Extension of Feature-Based Design
,”
Res. Eng. Des.
,
5
(
3
), pp.
218
237
.10.1007/BF01608364
13.
Kramer
,
G.
,
1991
,
Solving Geometric Constraint Problems
, MIT Press, Cambridge, MA.
14.
Noort
,
A.
,
Hoek
,
G. F. M.
, and
Bronsvoort
,
W. F.
,
2002
, “
Integrating Part and Assembly Modeling
,”
Comput.Aided Des.
,
34
(
12
), pp.
899
912
.10.1016/S0010-4485(01)00145-2
15.
De Fazio
,
T. L.
,
1990
, “
A Prototype of Feature-Based Design for Assembly
,”
B.
Ravani
, ed.,
Advances in Design Automation 1990
, ASME,
Chicago, IL
, pp.
9
16
.
16.
Bordegoni
,
M.
, and
Cugini
,
U.
, 1997, “
Feature-based Assembly Design: Concepts and Design Environment
,” Paper No. DETC97/CIE-4266.
17.
Jacobs
,
T. M.
, 1998, “
An Automated Framework for Managing Design Complexity Draft
,” Ph.D. thesis, University of Utah, Salt Lake City, UT.
18.
Rachuri
,
S.
,
Han
,
Y.
,
Foufou
,
S.
,
Feng
,
S. C.
,
Roy
,
U.
,
Wang
,
F.
,
Sriram
,
R. D.
, and
Lyons
,
K. W.
,
2006
, “
A Model for Capturing Product Assembly Information
,”
ASME J. Comput. Inf. Sci. Eng.
,
6
(1), pp.
11
21
.10.1115/1.2164451
19.
Anantha
,
R.
,
Kramer
,
G.
, and
Crawford
,
R.
,
1996
, “
Assembly Modeling by Geometric Constraint Satisfaction
,”
Comput.Aided Des.
,
28
(
9
), pp.
707
722
.10.1016/0010-4485(96)00001-2
20.
Murshed
,
M.
,
Dixon
,
A.
, and
Shah
,
J.
,
2009
, “
Neutral Definition and Recognition of Assembly Features for Legacy Systems Reverse Engineering
,”
ASME
Paper No. DETC2009-86739.10.1115/DETC2009-86739
21.
Murshed
,
M.
,
Dixon
,
A.
, and
Shah
,
J.
,
2010
, “
Assembly Feature Tutor and Recognition Algorithms Based on Mating Face Pairs
,”
Comput.Aided Des. Appl.
,
7
(
3
), p.
319
.
22.
Lai
,
D.
, and
Yuen
,
M.
,
2011
, “
Vector Based Datum Transformation Scheme for Computer Aided Measurement
,”
Comput.Aided Des. Appl.
,
9
(
3
), pp.
289
305
.10.3722/cadaps.2012.289-305
23.
Arimillotta
,
A.
,
2013
, “
A Method for Computer Aided Specification of Geometric Tolerances
,”
Comput.Aided Des.
,
45
(
12
), pp.
1604
1616
.10.1016/j.cad.2013.08.007
24.
Anselmetti
,
B.
,
2006
, “
Generation of Functional Tolerancing Based on Positioning Features
,”
Comput. Aided Des.
,
38
(
8
), pp.
902
919
.10.1016/j.cad.2006.05.005
25.
Shen
,
Z.
,
Shah
,
J.
, and
Davidson
,
J.
,
2008
, “
Analysis Neutral Data Structure for GD&T
,”
J. Intell. Manuf.
,
19
(
4
), pp.
455
472
.10.1007/s10845-008-0096-2
26.
Shah
,
J.
,
Ameta
,
G.
,
Shen
,
Z.
, and
Davidson
,
J.
,
2007
, “
Navigating the Tolerance Analysis Maze
,”
Comput. Aided Des. Appl.
,
4
(
5
), pp.
705
718
.10.1080/16864360.2007.10738504
27.
Chen
,
K. Z.
,
Feng
,
X. A.
, and
Shen
,
Q. S.
,
2002
, “
Intelligent Location-Dimensioning of Cylindrical Surfaces in Mechanical Parts
,”
Comput. Aided Des.
,
34
(
3
), pp.
185
194
.10.1016/S0010-4485(01)00076-8
28.
Ramaswamy
,
S.
,
Shah
,
J.
, and
Davidson
,
J.
,
2001
, “
Computer Aided GD&T Advisor Based on Y14.5 Conformance and Good Practice
,”
ASME Proceedings of the Design Engineering Technical Conferences
, Pittsburgh, PA,
ASME
Paper No. DETC01/DFM-21172.
29.
Park
,
S.
, and
Lee
,
K.
,
1998
, “
Verification of Assemblability Between Toleranced Parts
,”
Comput. Aided Des.
,
30
(
2
), pp.
95
104
.10.1016/S0010-4485(97)00008-0
30.
Lu
,
C.
,
Fuh
,
J. Y. H.
, and
Wong
,
Y. S.
,
2006
, “
Evaluation of Product Assemblability in Different Assembly Sequences Using the Tolerancing Approach
,”
Int. J. Prod. Res.
,
44
(
23
), pp.
5037
5063
.10.1080/00207540600579656
31.
Gao
,
W.
,
Shao
,
X.
, and
Liu
,
H.
,
2014
, “
Virtual Assembly Planning and Assembly-Oriented Quantitative Evaluation of Product Assemblability
,”
Int. J. Adv. Manuf. Technol.
,
71
(
1–4
), pp.
483
496
.10.1007/s00170-013-5514-8
32.
Ohashi
,
T.
,
Iwata
,
M.
,
Arimoto
,
S.
, and
Miyakawa
,
S.
,
2002
, “
Extended Assemblability Evaluation Method (AEM). Extended Quantitative Assembly Producibility Evaluation for Assembled Parts and Products
,”
JSME Int. J. Ser. C.
,
45
(
2
), pp.
567
574
.10.1299/jsmec.45.567
33.
Shen
,
Z.
,
Shah
,
J. J.
, and
Davidson
,
J. K.
,
2005
, “Simulation-Based Tolerance and Assemblability Analyses of Assemblies with Multiple Pin/Hole Floating Mating Conditions,”
ASME
Paper No. DETC2005-8539810.1115/DETC2005-85398.
34.
Jaishankar
,
L. N.
,
Davidson
,
J. K.
, and
Shah
,
J. J.
,
2012
, “
Representing Stresses That Arise in Parallel Assemblies That Contain Imperfect Geometry Allowed by Tolerances
,”
ASME
Paper No. DETC2012-70208.10.1115/DETC2012-70208
35.
Joshi
,
N.
,
2005
, “
Data Exchange of User Defined Features Using Neutral Representation Language (NRep)
,” MS thesis, Arizona State, Phoenix, AZ.
36.
Mohan
,
P.
,
Haghighi
,
P.
,
Shah
,
J. J.
, and
Davidson
,
J. K.
,
2014
, “
Automatic Detection of Directions of Control in Mechanical Parts
,”
Proceedings of ASME 2014 International Manufacturing Science and Engineering Conference
, Detroit, MI, June 9–13,
ASME
Paper No. MSEC2014-4143.
37.
Haghighi
,
P.
,
Mohan
,
P.
,
Shah
,
J. J.
, and
Davidson
,
J. K.
,
2014
, “
Automatic Detection and Extraction of Tolerance Stacks in Mechanical Assemblies
,”
Proceedings of ASME 2014 DETC
, Buffalo, NY, Aug. 17–20,
ASME
Paper No. DETC2014-35315.
You do not currently have access to this content.