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The basic building block for the inspection model in a CAIPS-CMM is the measurement associated with a geometrical surface element on a part. The measured element can then be evaluated for downstream operations such as evaluation of GD&T and construction of other geometrical elements, and for establishing part coordinate systems. For convenience, it is appropriate to call this building block for the CAIPS-CMM an inspection feature (IF). An inspection feature can be defined as a frame of information necessary for planning measurement of a geometrical element on a part with the objective of evaluating all GD&T associated with it. The inspection feature defined above essentially consists of the following classes of information: • Measurement element: This is the basic surface entity on the part model where measurement points have to be taken for evaluation of GD&T or for construction of other elements. The surface entity is intended to conform to the basic geometrical elements supported by DMIS. The list of elements is shown in Table 2.2. The data structure for such an element will include information such as geometric element type, element identity, reference to the construction feature, number of points to sample, where to sample, and CMM operation parameters such as the start point, end point, speed, approach, and retract distance. • Evaluated element: This is computed from the sample points of a measurement element based on mathematical function. The function to be used is dependent on the GD&T or construction elements to be evaluated. • GD&T specifications: This is a list of GD&T specifications associated with a measurement element. The data structure for the GD&T specification is outlined in Tables 2.2 and 2.3. It should be noted that there may be more than one GD&T specification for a particular measurement element. For example, a cylindrical surface of a hole may be evaluated as a cylinder or a circle depending on the GD&T specifications. Moreover, the measurement element could have been used as a reference for other elements. • Setup and part coordinate system (PCS): The selection of the setup to carry out the measurement. This will include the orientation of the part as well as the selection of a suitable PCS. The data structure will include the identifier for the setup, identifier for the PCS, evaluated elements, and parameters for establishing the PCS. • Probe selection: The probe to be used for the measurement element will depend on considerations such as accessibility and tolerance requirements. The data structure for the probe selection will include information such as the identifier for the probe selection, parameters for the probe orientation, and the physical configurations of the probe. It is clear that it may not be possible to assign all information based on the product model itself. Information such as the assignment setup, PCS, and probe system for each inspection feature has to undergo further reasoning processes in the CAIP-CMM system as shown by the flow chart of Figure 2.22. Figure 2.23 shows a prismatic model created using ProEngineer, which is a CAD system that uses feature and parametric technology for product model creation. The basic module supports the design-by-features concept for machining operations with features like hole, cut, slot, etc. and supporting features like datum and PCS. The feature-based model for ProEngineer is evaluated in BREP for solid representation. A listing of some relevant information for the model created is shown in Table 2.5. GD&T can also be specified for the model; this information can be tied to the feature or the geometry. Figures 2.24 and 2.25 show some of the geometric and dimensional tolerances specified for the model, while Tables 2.6 and 2.7 show partial listings of the GD&T information. A module has been written in ProDevelop to extract information from the CAD model to organize it into inspection features for computer aided measurement. Since inspection is directed by GD&T specifications, the CAD data extraction module first searches through the data base for all GD&T specifications and then obtains a listing of geometrical elements required for evaluation. This geometrical element may be direct © 2001 by CRC Press LLC
© 2001 by CRC Press LLC TABLE 2.5 Partial Listing of Construction Features Used for CAD Model Feature ID Feature Type Axis ID Surface IDs 1 FT_FIRST_FEAT Nul [2] [7] [12] [14] [16] [18] 20 FT_DATUM Nul [21] 22 FT_DATUM Nul [23] 24 FT_DATUM Nul [24] 26 FT_CSYS Nul [2] [18] [12] 28 FT_CUT Nul [36] [41] [43] [45] 67 FT_HOLE 84 [79] [81] 95 FT_HOLE 108 [100] [103] [105] 117 FT_SLOT Nul [125] [130] [132] [134] [136] 174 FT_HOLE 189 [181] [184] [186] 194 FT_CUT Nul [200] [203] 242 FT_HOLE 257 [249] [252] [254] 262 FT_CUT Nul [268] [271] TABLE 2.6 Partial Listing of Geometric Tolerances for CAD Model Mat’l GTOL Feature Datum GTOL ID GTOL Type Value Cond. Reference ID Reference 0 LOC/POS 0.1 MMC AXIS [84] 67 [20] [22] [24] 1 LOC/CONC 0.2 MMC AXIS [108] 95 A_1 [67] 2 FORM/FLAT 0.1 RFS SRF [7] 1 NUL 4 FORM/STRGHT 0.4 RFS AXIS [84] 67 NUL 5 FORM/CIR 0.01 RFS SRF [105] 95 NUL 6 FORM/CYL 0.02 RFS SRF [186] 174 NUL 7 ORIENT/ANG 0.1 RFS SRF [203] 194 [20] 9 ORIENT/PERP 0.1 RFS AXIS [189] 174 [22] 10 ORIENT/PAR 0.01 RFS SRF [7] 1 [20] FIGURE 2.23 Representative construction features from a CAD model.
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COMPUTER-AIDED DESIGN, ENGINEERING,
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Library of Congress Cataloging-in-P
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Editor Cornelius T. Leondes, B.S.,
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Chapter 1 Chapter 2 Chapter 3 Chapt
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the implementation of the IPD syste
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In our IPD system implementations,
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2. Specification of analysis-specif
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FIGURE 1.2 base or the design insta
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FIGURE 1.4 System architecture of t
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of a beam is considered for FEA. Th
Page 21 and 22: FIGURE 1.7 through the control expe
Page 23 and 24: 2. machining facility (e.g., gang m
Page 25 and 26: from the FBDS. The user also specif
Page 27 and 28: Depending on the type of feature to
Page 29 and 30: TABLE 1.6 Tolerance synthesis is de
Page 31 and 32: FIGURE 1.12 Display of the NC tool
Page 33 and 34: component geometric entities and va
Page 35 and 36: FIGURE 1.14 The system architecture
Page 37 and 38: TABLE 1.10 User Input for the Toler
Page 39 and 40: TABLE 1.11 Tolerance Specifications
Page 41 and 42: 7. Z. Young and I. R. Groose. A rul
Page 43 and 44: FIGURE 2.1 Tool paths generated for
Page 45 and 46: FIGURE 2.2 sented by instances of f
Page 47 and 48: TABLE 2.1 A CAD-Generated Hole Conf
Page 49 and 50: FIGURE 2.6 mounted on the rotary ta
Page 51 and 52: FIGURE 2.8 fixture for the machinin
Page 53 and 54: FIGURE 2.10 or best-fit, or the cur
Page 55 and 56: FIGURE 2.11 Linear approximation of
Page 57 and 58: FIGURE 2.13 Circular approximation
Page 59 and 60: FIGURE 2.14(b) Circular approximati
Page 61 and 62: FIGURE 2.16 Types of biarcs. FIGURE
Page 63 and 64: FIGURE 2.18 Approximation of scanne
Page 65 and 66: FIGURE 2.20 A touch trigger probe c
Page 67 and 68: TABLE 2.4 Substitute Elements in CM
Page 69 and 70: FIGURE 2.21 CMM planning requiremen
Page 71: Product Model Representation for Co
Page 75 and 76: TABLE 2.7 Partial Listing of Dimens
Page 77 and 78: 24. Makinouchi, S., Okamoto, M., an
Page 79 and 80: Bijan Shirinzadeh Monash University
Page 81 and 82: FIGURE 3.1 Trends in flexible manuf
Page 83 and 84: FIGURE 3.3 and constrain different
Page 85 and 86: Other Fixturing Techniques There ar
Page 87 and 88: FIGURE 3.6 contact point. The geome
Page 89 and 90: FIGURE 3.8 The vertical support fix
Page 91 and 92: and moments about the contact point
Page 93 and 94: een identified, the normals are use
Page 95 and 96: one of choosing the variables: such
Page 97 and 98: Fixture Module Location An importan
Page 99 and 100: FIGURE 3.15 Illustration of functio
Page 101 and 102: FIGURE 3.18 Minimum separation test
Page 103 and 104: direction) the face, respectively.
Page 105 and 106: FIGURE 3.21 Software structure for
Page 107 and 108: 3.8 Conclusion A reconfigurable fix
Page 109 and 110: Heui Jae Pahk Seoul National Univer
Page 111 and 112: FIGURE 4.1(b) Conceptual framework
Page 113 and 114: 4.3 Measurement Points Sampling and
Page 115 and 116: Surface S2 Measurement Path FIGURE
Page 117 and 118: FIGURE 4.4 Rough phase alignment ba
Page 119 and 120: deviation between the nominal CAD d
Page 121 and 122: FIGURE 4.6(a) Sum of squares distan
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FIGURE 4.7(c) Trailing edge. (c) th
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FIGURE 4.8(a) Profile tolerance of
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The calculated minimum form error i
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FIGURE 4.11(a) A typical mold havin
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FIGURE 4.11(d) Inspection results f
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FIGURE 4.12(c) Maximum deviation (p
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5.1 Introduction Developments in th
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process plan for a part (Figure 5.3
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FIGURE 5.5 leading to the developme
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the previously stored process plan
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FIGURE 5.7 Techniques of defining a
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Feature Recognition and Extraction
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in relation to another feature (e.g
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FIGURE 5.9 Framework for building a
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FIGURE 5.10 Process plan content.
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FIGURE 5.12 Schematic sketch of the
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Several techniques of defining a fe
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TABLE 5.1 Data Structure for Repres
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FIGURE 5.16 Classification of the t
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system to ensure that the part bein
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FIGURE 5.19 Graphical model of the
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TABLE 5.4 Data Structure for Repres
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FIGURE 5.20 Mapping between machini
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algorithms. (Some details of the pr
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FIGURE 5.24 An example rotational p
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FIGURE 5.26 Down_face-turn-up_face
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FIGURE 5.27 Procedure for machine t
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FIGURE 5.28 Determining the number
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DL is needed to be set only if the
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FIGURE 5.31 Operation sequencing co
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Cutting Tool Selection Selection of
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1. A tool is searched for in the da
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FIGURE 5.32 Inputs to optimization
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When these values are substituted,
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Usually, maximum and minimum speed
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FIGURE 5.33 Solution methodology.
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TABLE 5.6 Process Plan Internal Rep
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In a strict theoretical perspective
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18. Domazet, D. S. and Lu, S. C. Y,
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63. Prasad, A. V. S. R. K., Rao, P.
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CAD systems. The sample consists of
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learn to master the new system. An
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Although researchers appear to agre
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Link and Zmud28 found that organic
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Informal Training Informal CAD trai
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informal training programs, felt th
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6. C. A. Beatty, Tall Tales and Rea
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A.Y.C. Nee National University of S
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FIGURE 7.1 Planning, design, and ma
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A metal stamping can have the follo
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FIGURE 7.3 Strips used to notch out
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A Skeletal Approach for the Recogni
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These findings can be used to devel
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Semi-Direct Piloting In cases where
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a larger value, the die operations
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FIGURE 7.9 Symbolic relationship be
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FIGURE 7.11 The shape of the envelo
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TABLE 7.1 Schema for the Generation
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strong reasons to support a move to
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FIGURE 7.16 3-D CAD model of a part
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References Cheok, B.T. et al. (1994
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include the once forbidden generati
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A temporal matrix (T-Matrix) is pro
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FIGURE 8.1 A basic process. (From R
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FIGURE 8.4(a) Generate a new IG usi
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Note if the pair of nodes are both
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TABLE 8.1 Summary of the Rules Cond
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The correctness of these rules is e
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needs to show that after each full
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ule is violated, a warning should b
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Π1 Π3 Π4 FIGURE 8.8(a) After add
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
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A ik � ‘U’ and is in a cycle
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FIGURE 8.12(a) Add [p2 t7 p7 t8 p4]
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FIGURE 8.12(c) Add a token to p8 vi
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FIGURE 8.12(e) Add [p8 t9 p14 t10 p
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FIGURE 8.13 An example of rule TT.0
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FIGURE 8.14 A GPN model of a machin
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FIGURE 8.15(b) The first exclusive
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FIGURE 8.15(d) The last exclusive T
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FIGURE 8.15(f) After entering the a
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FIGURE 8.15(h) Completion of Compon
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FIGURE 8.15(j) Two PP-generations:
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FIGURE 8.15(l) The last exclusive T
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t1 t5 p1 p5 t6 (a) t2 t3 t4 2 2 p2
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FIGURE 8.17 An example of partial f
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Theorem 10: If pi → pk in a synth
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Note that control transitions are o
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t j than the lower at , it indicate
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• Programming logic and VLSI arra
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7. Chao, D. Y. and D. T. Wang, Appl
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53. Villaroel, J. L., J. Martinez,
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q u : the numerator of the least ra
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geometric modeling, engineering ana
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In dimension driven or parametric d
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FIGURE 9.3 configuration of bodies
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FIGURE 9.6 FIGURE 9.7 Geometric Int
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FIGURE 9.8 Intersection of degrees
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will introduce a way to propagate p
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Completeness of Dimensions Complete
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FIGURE 9.12 3-D constraints. © 200
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The distance constraint from pt �
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therefore: Now merge the lists and
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Quantity analysis methods have the
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y a revolute joint. By selecting al
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