ComputerAided_Design_Engineering_amp_Manufactur.pdf

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FIGURE 5.23 Achievable lower limits of accuracies and surface finishes based on routing for internal cylindrical surfaces. finished part, and (3) dividing the total material to be removed into a number of pockets which can be associated with various machining operations. In GIFTS, backward planning is adopted since it makes planning easier. This is also closely related to the thinking strategy of the process planner. At the end of the operation selection procedure, PPIR is filled with pocket and operation details only. PPIR is partial since other details (machine, tool, parameters, etc.) need to be determined in subsequent modules. For the purpose of process planning the pockets are divided into three categories: 1. Basic primary pockets: These are the basic types of pockets, rectangular in nature, which can be machined using the most basic of the lathe operations such as turning, facing and boring. These can be further subdivided into roughing and finishing pockets to take care of the technological specifications given. 2. Complex primary pockets: These can be done in the conventional machine tools by using special processes or form tools such as fillet and chamfer. If a CNC turning center is chosen, then the basic and complex primary pockets would be combined. 3. Secondary pockets: These require special operations or tools. Examples are grooves, threads, and knurls. The pocket identification procedure recursively modifies the final part by identifying the pockets until the part reaches the blank shape. As these pockets are identified, the machining operation (e.g., rough turning, threading, etc.) is also attributed to the pocket description. Pocket identification is explained below with the help of an example. The example part containing some representative external features is shown in Figure 5.24. The steps involved in the pocket identification for this part are illustrated in Figure 5.25.
FIGURE 5.24 An example rotational part. 1. Secondary pockets: Grooves, threads, and knurls are considered in this stage. There are no roughing or finishing operations associated with these secondary features; hence, one-to-one mapping between these features and the operations can be established. All these features are stored as pockets in the pocket file (Figure 5.25a) and are simultaneously updated to their parent features. For example, a groove is converted to a turn feature. Similarly, the thread is unthreaded and the knurl is unknurled. This step results in an intermediate part (Figure 5.25b) without these secondary features. The material to be removed from the intermediate part (to reach the final part) forms a single pocket in NC machining, which can be subdivided into finishing and roughing profiles. For conventional machining, the pocket identification has to be further carried out as follows. 2. Complex primary pockets: It is assumed that machining the chamfers and fillets and rounding off the corners will be carried out as distinct operations on conventional machines using form tools. At this stage, these pockets are stored in the pocket file (Figure 5.25c) and an intermediate component is regenerated (Figure 5.25d). 3. Finishing pockets: The finishing operations are not primarily used as material removal operations but are intended to achieve the technological attributes of the surface. Nevertheless, the small amount of the material being removed in a finishing operation is also represented as a pocket to facilitate uniform handling by the system. The stepped component, obtained in the previous step, is then analyzed to offset the elements (usually turn and taper) that require finish machining. Sometimes, the adjoining elements need to be offset along with the turn and taper elements because of the accessibility constraints. These finish pockets (offset volumes) are then appended to the same pocket file (Figure 5.25e). At this stage, what remains is the intermediate part (Figure 5.25f) which needs to be inverse rough-machined. 4. Roughing pockets: At this stage, the stepped component contains a series of face, turn and taper features without any technological attributes present. The pocket identification for rough machining is carried out as follows: • Face pockets: In this step, the pockets to be removed by a facing operation on either end of the part are marked (Figure 5.25g) leading to the part shown in Figure 5.25h. • Taper pockets: Since taper turning is a distinct operation, these are identified as pockets (Figure 5.25i). This step results in an intermediate part shown in Figure 5.25j. • Turn pockets: At this stage, the intermediate part contains only face and turn elements. The pattern The patterns these elements make are used to identify the pockets to be machined in the rough-turning operation. Three patterns of interest are shown in Figure 5.26. Identifying such
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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
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FIGURE 1.7 through the control expe
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2. machining facility (e.g., gang m
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from the FBDS. The user also specif
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Depending on the type of feature to
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TABLE 1.6 Tolerance synthesis is de
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FIGURE 1.12 Display of the NC tool
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component geometric entities and va
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FIGURE 1.14 The system architecture
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TABLE 1.10 User Input for the Toler
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TABLE 1.11 Tolerance Specifications
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7. Z. Young and I. R. Groose. A rul
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FIGURE 2.1 Tool paths generated for
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FIGURE 2.2 sented by instances of f
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TABLE 2.1 A CAD-Generated Hole Conf
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FIGURE 2.6 mounted on the rotary ta
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FIGURE 2.8 fixture for the machinin
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FIGURE 2.10 or best-fit, or the cur
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FIGURE 2.11 Linear approximation of
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FIGURE 2.13 Circular approximation
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FIGURE 2.14(b) Circular approximati
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FIGURE 2.16 Types of biarcs. FIGURE
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FIGURE 2.18 Approximation of scanne
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FIGURE 2.20 A touch trigger probe c
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TABLE 2.4 Substitute Elements in CM
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FIGURE 2.21 CMM planning requiremen
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Product Model Representation for Co
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© 2001 by CRC Press LLC TABLE 2.5
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TABLE 2.7 Partial Listing of Dimens
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24. Makinouchi, S., Okamoto, M., an
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Bijan Shirinzadeh Monash University
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FIGURE 3.1 Trends in flexible manuf
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FIGURE 3.3 and constrain different
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Other Fixturing Techniques There ar
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FIGURE 3.6 contact point. The geome
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FIGURE 3.8 The vertical support fix
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and moments about the contact point
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een identified, the normals are use
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one of choosing the variables: such
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Fixture Module Location An importan
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FIGURE 3.15 Illustration of functio
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FIGURE 3.18 Minimum separation test
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direction) the face, respectively.
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FIGURE 3.21 Software structure for
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3.8 Conclusion A reconfigurable fix
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Heui Jae Pahk Seoul National Univer
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FIGURE 4.1(b) Conceptual framework
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4.3 Measurement Points Sampling and
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Surface S2 Measurement Path FIGURE
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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
Page 123 and 124: FIGURE 4.7(c) Trailing edge. (c) th
Page 125 and 126: FIGURE 4.8(a) Profile tolerance of
Page 127 and 128: The calculated minimum form error i
Page 129 and 130: FIGURE 4.11(a) A typical mold havin
Page 131 and 132: FIGURE 4.11(d) Inspection results f
Page 133 and 134: FIGURE 4.12(c) Maximum deviation (p
Page 135 and 136: 5.1 Introduction Developments in th
Page 137 and 138: process plan for a part (Figure 5.3
Page 139 and 140: FIGURE 5.5 leading to the developme
Page 141 and 142: the previously stored process plan
Page 143 and 144: FIGURE 5.7 Techniques of defining a
Page 145 and 146: Feature Recognition and Extraction
Page 147 and 148: in relation to another feature (e.g
Page 149 and 150: FIGURE 5.9 Framework for building a
Page 151 and 152: FIGURE 5.10 Process plan content.
Page 153 and 154: FIGURE 5.12 Schematic sketch of the
Page 155 and 156: Several techniques of defining a fe
Page 157 and 158: TABLE 5.1 Data Structure for Repres
Page 159 and 160: FIGURE 5.16 Classification of the t
Page 161 and 162: system to ensure that the part bein
Page 163 and 164: FIGURE 5.19 Graphical model of the
Page 165 and 166: TABLE 5.4 Data Structure for Repres
Page 167 and 168: FIGURE 5.20 Mapping between machini
Page 169: algorithms. (Some details of the pr
Page 173 and 174: FIGURE 5.26 Down_face-turn-up_face
Page 175 and 176: FIGURE 5.27 Procedure for machine t
Page 177 and 178: FIGURE 5.28 Determining the number
Page 179 and 180: DL is needed to be set only if the
Page 181 and 182: FIGURE 5.31 Operation sequencing co
Page 183 and 184: Cutting Tool Selection Selection of
Page 185 and 186: 1. A tool is searched for in the da
Page 187 and 188: FIGURE 5.32 Inputs to optimization
Page 189 and 190: When these values are substituted,
Page 191 and 192: Usually, maximum and minimum speed
Page 193 and 194: FIGURE 5.33 Solution methodology.
Page 195 and 196: TABLE 5.6 Process Plan Internal Rep
Page 197 and 198: In a strict theoretical perspective
Page 199 and 200: 18. Domazet, D. S. and Lu, S. C. Y,
Page 201 and 202: 63. Prasad, A. V. S. R. K., Rao, P.
Page 203 and 204: CAD systems. The sample consists of
Page 205 and 206: learn to master the new system. An
Page 207 and 208: Although researchers appear to agre
Page 209 and 210: Link and Zmud28 found that organic
Page 211 and 212: Informal Training Informal CAD trai
Page 213 and 214: informal training programs, felt th
Page 215 and 216: 6. C. A. Beatty, Tall Tales and Rea
Page 217 and 218: A.Y.C. Nee National University of S
Page 219 and 220: 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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