Product Design for Manufacture and Assembly

Product Design for Manufacture and Assembly......Page 1
Preface to the Second Edition......Page 6
Preface to the First Edition......Page 7
Contents......Page 9
1.1 WHAT IS DESIGN FOR MANUFACTURE AND ASSEMBLY?......Page 16
Contents......Page 0
1.2 HOW DOES DFMA WORK?......Page 23
1.3 REASONS FOR NOT IMPLEMENTING DFMA......Page 31
1.4 WHAT ARE THE ADVANTAGES OF APPLYING DFMA DURING PRODUCT DESIGN?......Page 36
1.5.1 Defense Industry......Page 37
1.5.2 Aerospace......Page 39
1.5.3 Manufacturing Equipment......Page 41
1.5.4 Computers......Page 42
1.5.5 Telecommunications......Page 44
1.5.6 Medical Equipment......Page 45
1.5.7 Transportation......Page 46
1.5.8 Consumer Products......Page 48
1.6 OVERALL IMPACT OF DFMA ON U.S. INDUSTRY......Page 49
1.7 CONCLUSIONS......Page 54
REFERENCES......Page 55
2.1 INTRODUCTION......Page 57
2.2.1 Relationship to Process and Operations Planning......Page 59
2.3 SELECTION OF MANUFACTURING PROCESSES......Page 60
2.4 PROCESS CAPABILITIES......Page 62
2.5.1 Grouping of Materials into Process Compatible Classes......Page 69
2.5.2 Material Selection by Membership Function Modification......Page 70
2.5.3 Material Selection by Dimensionless Ranking......Page 72
2.6 PRIMARY PROCESS/MATERIAL SELECTION......Page 79
2.7.1 Computer-Based Primary Process/Material Selection......Page 85
2.7.2 Expert Processing Sequence Selector......Page 86
2.7.3 Economic Ranking of Processes......Page 90
REFERENCES......Page 97
3.1 INTRODUCTION......Page 99
3.2.1 Design Guidelines for Part Handling......Page 100
3.2.2 Design Guidelines for Insertion and Fastening......Page 101
3.4 ASSEMBLY EFFICIENCY......Page 107
3.6 EFFECT OF PART SYMMETRY ON HANDLING TIME......Page 110
3.7 EFFECT OF PART THICKNESS AND SIZE ON HANDLING TIME......Page 115
3.8 EFFECT OF WEIGHT ON HANDLING TIME......Page 117
3.11 EFFECT OF SYMMETRY FOR PARTS THAT SEVERELY NEST OR TANGLE AND MAY REQUIRE TWEEZERS FOR GRASPING AND MANIPULATION......Page 118
3.12 EFFECT OF CHAMFER DESIGN ON INSERTION OPERATIONS......Page 119
3.13 ESTIMATION OF INSERTION TIME......Page 122
3.14 AVOIDING JAMS DURING ASSEMBLY......Page 123
3.15 REDUCING DISC-ASSEMBLY PROBLEMS......Page 125
3.16 EFFECTS OF OBSTRUCTED ACCESS AND RESTRICTED VISION ON INSERTION OF THREADED FASTENERS OF VARIOUS DESIGNS......Page 126
3.18 EFFECTS OF HOLDING DOWN......Page 129
3.19 MANUAL ASSEMBLY DATABASE AND DESIGN DATA SHEETS......Page 132
3.20 APPLICATION OF THE DFA METHODOLOGY......Page 133
3.20.1 Results of the Analysis......Page 137
3.21 FURTHER DESIGN GUIDELINES......Page 139
3.22 LARGE ASSEMBLIES......Page 142
3.23 TYPES OF MANUAL ASSEMBLY METHODS......Page 144
3.24 EFFECT OF ASSEMBLY LAYOUT ON ACQUISITION TIMES......Page 147
3.25 ASSEMBLY QUALITY......Page 151
3.26 APPLYING LEARNING CURVES TO THE DFA TIMES......Page 155
REFERENCES......Page 157
4.1 INTRODUCTION......Page 160
4.2 WIRE OR CABLE HARNESS ASSEMBLY......Page 162
4.3.1 Solder Connections......Page 165
4.3.2 Low-Pressure Connections......Page 167
4.3.3 High-Pressure Connections......Page 169
4.4 TYPES OF WIRES AND CABLES......Page 172
4.5.1 Preparation......Page 173
4.5.2 Assembly and Installation......Page 180
4.5.3 Securing......Page 185
4.5.4 Attachment......Page 190
4.6 ANALYSIS METHOD......Page 195
4.6.1 Procedure......Page 197
4.6.2 Case Study......Page 198
REFERENCES......Page 203
5.1 INTRODUCTION......Page 204
5.2 DESIGN OF PARTS FOR HIGH-SPEED FEEDING AND ORIENTING......Page 205
5.3 EXAMPLE......Page 209
5.5 HIGH-SPEED AUTOMATIC INSERTION......Page 212
5.6 EXAMPLE......Page 214
5.7 ANALYSIS OF AN ASSEMBLY......Page 215
5.8 GENERAL RULES FOR PRODUCT DESIGN FOR AUTOMATION......Page 216
5.9 DESIGN OF PARTS FOR FEEDING AND ORIENTING......Page 221
5.10.1 Rules for Product Design......Page 223
5.11 PRODUCT DESIGN FOR ROBOT ASSEMBLY......Page 224
5.11.1 Summary of Design Rules for Robot Assembly......Page 228
REFERENCES......Page 230
6.1 INTRODUCTION......Page 231
6.3 TYPES OF PRINTED CIRCUIT BOARDS......Page 232
6.3.4 Device Types......Page 233
6.4 TERMINOLOGY......Page 234
6.5 ASSEMBLY OF PRINTED CIRCUIT BOARDS......Page 235
6.5.1 Assembly Process for Through-Hole Printed Circuit Boards......Page 236
6.5.2 Assembly of Surface-Mounted Devices......Page 246
6.6 ESTIMATION OF PCB ASSEMBLY COSTS......Page 250
6.6.1 Worksheet and Database for PCB Assembly Cost Analysis......Page 251
6.7.1 Measuring Instrument Connector Board......Page 256
6.7.2 Power Supply......Page 260
6.8 PCB MANUFACTURABILITY......Page 261
6.9 DESIGN CONSIDERATIONS......Page 264
6.9.1 Component Geometry and Spacing......Page 265
6.9.3 Component Compatibility......Page 267
6.9.7 Board Size......Page 268
6.9.8 Ground Plane Requirements......Page 270
6.9.9 Solder Resist Requirements......Page 271
6.9.10 Features to Be Avoided......Page 272
6.9.12 Tooling......Page 273
6.9.14 Generally Preferred Features......Page 274
6.10 GLOSSARY OF TERMS......Page 275
REFERENCES......Page 278
7.2 MACHINING USING SINGLE-POINT CUTTING TOOLS......Page 279
7.3 MACHINING USING MULTIPOINT TOOLS......Page 287
7.4 MACHINING USING ABRASIVE WHEELS......Page 296
7.5 STANDARDIZATION......Page 302
7.6 CHOICE OF WORK MATERIAL......Page 303
7.7 SHAPE OF WORK MATERIAL......Page 305
7.8.1 Disc-Shaped Rotational Components (L/D < 0.5)......Page 306
7.8.3 Long, Cylindrical Rotational Components (L/D ^ 3)......Page 309
7.8.4 Nonrotational Components (A/B < 3, A/C ^ 4)......Page 313
7.8.6 Cubic, Nonrotational Components (A/B<3, A/C<4)......Page 315
7.9 ASSEMBLY OF COMPONENTS......Page 319
7.10 ACCURACY AND SURFACE FINISH......Page 320
7.11 SUMMARY OF DESIGN GUIDELINES......Page 323
7.12 COST ESTIMATING FOR MACHINED COMPONENTS......Page 325
7.12.2 Machine Loading and Unloading......Page 327
7.12.3 Other Nonproductive Costs......Page 328
7.12.4 Handling Between Machines......Page 329
7.12.6 Machining Costs......Page 330
7.12.7 Tool Replacement Costs......Page 332
7.12.8 Machining Data......Page 333
7.12.9 Rough Grinding......Page 337
7.12.10 Finish Grinding......Page 339
7.12.11 Allowance for Grinding Wheel Wear......Page 340
7.12.13 Examples......Page 342
7.12.14 Approximate Cost Models for Machined Components......Page 345
REFERENCES......Page 349
8.1 INTRODUCTION......Page 350
8.2 INJECTION MOLDING MATERIALS......Page 351
8.3.1 Injection or Filling Stage......Page 353
8.3.3 Ejection and Resetting Stage......Page 354
8.4.1 Injection Unit......Page 355
8.4.2 Clamp Unit......Page 356
8.5.1 Mold Construction and Operation......Page 357
8.5.2 Mold Types......Page 359
8.6 MOLDING MACHINE SIZE......Page 362
8.7.1 Injection Time......Page 364
8.7.2 Cooling Time......Page 365
8.7.3 Mold Resetting......Page 367
8.8.1 Mold Base Costs......Page 370
8.8.2 Cavity and Core Manufacturing Costs......Page 372
8.9 MOLD COST POINT SYSTEM......Page 378
8.10 ESTIMATION OF THE OPTIMUM NUMBER OF CAVITIES......Page 380
8.11 DESIGN EXAMPLE......Page 383
8.12 INSERT MOLDING......Page 385
8.13 DESIGN GUIDELINES Suppliers of engineering thermoplastics have......Page 386
8.14 ASSEMBLY TECHNIQUES......Page 387
REFERENCES......Page 390
9.1 INTRODUCTION......Page 391
9.2.1 Individual Dies for Profile Shearing......Page 393
9.2.2 Cost of Individual Dies......Page 398
9.2.3 Individual Dies for Piercing Operations......Page 404
9.2.4 Individual Dies for Bending Operations......Page 406
9.2.5 Miscellaneous Features......Page 410
9.3 PRESS SELECTION......Page 413
9.3.1 Cycle Times......Page 417
9.4 TURRET PRESSWORKING......Page 419
9.5 PRESS BRAKE OPERATIONS......Page 423
9.6 DESIGN RULES......Page 426
REFERENCES......Page 432
10.2 DIE CASTING ALLOYS......Page 433
10.3 THE DIE CASTING CYCLE......Page 435
10.4.3 Hot-Chamber Machines......Page 436
10.4.4 Cold-Chamber Machines......Page 438
10.5 DIE CASTING DIES......Page 439
10.6 FINISHING......Page 440
10.7 AUXILIARY EQUIPMENT FOR AUTOMATION......Page 442
10.8 DETERMINATION OF THE OPTIMUM NUMBER OF CAVITIES......Page 443
10.9.1 Required Machine Clamp Force......Page 449
10.9.2 Shot Volume......Page 450
10.9.3 Dimensional Machine Constraints......Page 452
10.10 DIE CASTING CYCLE TIME ESTIMATION......Page 453
10.10.2 Metal Injection......Page 454
10.10.3 Metal Cooling......Page 455
10.10.4 Part Extraction and Die Lubrication......Page 458
10.10.5 Trimming Cycle Time......Page 462
10.11.1 Die Set Costs......Page 463
10.11.2 Cavity and Core Costs......Page 464
10.11.3 Trim Die Costs......Page 465
10.12 ASSEMBLY TECHNIQUES......Page 467
10.13 DESIGN PRINCIPLES......Page 468
REFERENCES......Page 469
11.1 INTRODUCTION......Page 470
11.2.1 Mixing......Page 472
11.3.1 Repressing and Resintering......Page 473
11.3.5 Resin Impregnation......Page 475
11.3.11 Assembly Processes......Page 476
11.4 COMPACTION CHARACTERISTICS OF POWDERS......Page 477
11.4.1 Powder Compaction Mechanics......Page 478
11.4.2 Compression Characteristics of Metal Powders......Page 480
11.4.3 Powder Compression Ratio......Page 483
11.5 TOOLING FOR POWDER COMPACTION......Page 484
11.5.3 Core Rods for Through Holes......Page 486
11.6 PRESSES FOR POWDER COMPACTION......Page 487
11.6.1 Factors in Choosing the Appropriate Press......Page 488
11.7 FORM OF POWDER METAL PARTS......Page 490
11.8 SINTERING EQUIPMENT CHARACTERISTICS......Page 493
11.8.1 Sintering Equipment......Page 494
11.9 MATERIALS FOR POWDER METAL PROCESSING......Page 498
11.10.1 Material Costs......Page 501
11.10.2 Compacting Costs......Page 504
11.10.3 Compaction Tooling Costs......Page 507
11.10.4 Tool Accessory Costs......Page 514
11.10.5 Tool Replacement Costs......Page 515
11.10.7 Sintering Costs......Page 516
11.11.2 Compaction Costs......Page 520
11.12.2 Additional Material Costs......Page 521
11.13 SOME DESIGN GUIDELINES FOR POWDER METAL PARTS......Page 523
REFERENCES......Page 524
12.1 INTRODUCTION......Page 526
12.3 BASIC CHARACTERISTICS AND MOLD PREPARATION......Page 528
12.3.2 The Gating System......Page 529
12.3.3 Mold Risers and Chills......Page 530
12.3.4 Pattern Types......Page 531
12.4 SAND CORES......Page 533
12.5 MELTING AND POURING OF METAL......Page 534
12.6 CLEANING OF CASTINGS......Page 535
12.7.1 Metal Cost......Page 536
12.7.2 Sand Costs......Page 539
12.7.3 Tooling Costs......Page 540
12.7.4 Processing Costs......Page 544
12.8 DESIGN RULES FOR SAND CASTINGS......Page 546
12.9 EXAMPLE CALCULATIONS......Page 551
REFERENCES......Page 555
13.2 PROCESS OVERVIEW......Page 557
13.4 PATTERN INJECTION MACHINES......Page 560
13.6 PATTERN AND CLUSTER ASSEMBLY......Page 562
13.7 THE CERAMIC SHELL-MOLD......Page 563
13.9 PATTERN MELTOUT......Page 564
13.13 PATTERN AND CORE MATERIAL COST......Page 565
13.14 WAX PATTERN INJECTION COST......Page 569
13.16 COOLING TIME......Page 570
13.17 EJECTION AND RESET TIME......Page 572
13.18 PROCESS COST PER PATTERN OR CORE......Page 574
13.20 PATTERN AND CORE MOLD COST......Page 575
13.22 PATTERN AND CLUSTER ASSEMBLY COST......Page 580
13.23 NUMBER OF PARTS PER CLUSTER......Page 582
13.24 PATTERN PIECE COST......Page 583
13.26 SHELL MOLD MATERIAL COST......Page 584
13.27 INVESTING THE PATTERN CLUSTER......Page 585
13.29 BURNOUT, SINTER, AND PREHEAT......Page 586
13.31 COST TO MELT METAL......Page 587
13.32 RAW BASE METAL COST......Page 591
13.35 FINAL MATERIAL COST......Page 592
13.36 BREAKOUT......Page 594
13.38 CUTOFF......Page 595
13.39 DESIGN GUIDELINES......Page 598
REFERENCES......Page 599
14.2 CHARACTERISTICS OF THE FORGING PROCESS......Page 600
14.2.1 Types of Forging Processes......Page 601
14.3 THE ROLE OF FLASH IN FORGING......Page 602
14.3.1 Determination of the Flash Land Geometry......Page 603
14.3.2 Amount of Flash......Page 605
14.3.3 Webs in Forgings......Page 606
14.4 FORGING ALLOWANCES......Page 607
14.5 PREFORMING DURING FORGING......Page 610
14.5.1 Die Layout......Page 614
14.6 FLASH REMOVAL......Page 616
14.7 CLASSIFICATION OF FORCINGS......Page 617
14.7.1 Forging Complexity......Page 619
14.8 FORGING EQUIPMENT......Page 620
14.8.2 Double Acting or Power Hammers......Page 621
14.8.5 Mechanical Presses......Page 622
14.8.8 Choice of Forging Machine Type......Page 623
14.8.9 Comparisons of Forging Equipment......Page 624
14.10 FORGING COSTS......Page 629
14.10.1 Material Costs......Page 630
14.10.2 Equipment Operating Costs......Page 631
14.10.3 Examples of Equipment Selection......Page 634
14.10.4 Forging Processing Costs......Page 635
14.11.1 Initial Die Costs......Page 638
14.11.2 Estimation of Costs for Multi-Impression Forging Dies......Page 639
14.12 DIE LIFE AND TOOL REPLACEMENT COSTS......Page 643
14.13.1 Flash Removal Processing Costs......Page 644
14.13.2 Tooling Costs for Flash Removal......Page 645
14.14.1 Billet Preparation......Page 647
REFERENCES......Page 648
15.2 GENERAL CONSIDERATIONS FOR LINKING CAD AND DFMA ANALYSIS......Page 650
15.2.1 DFMA Analysis......Page 651
15.3 GEOMETRIC REPRESENTATION SCHEMES IN CAD SYSTEMS......Page 652
15.3.1 Wire Frame Models......Page 654
15.3.2 Surface Models......Page 655
15.3.5 Sweep Representations......Page 657
15.3.6 Feature-Based Models......Page 658
15.3.7 Object-Oriented Programming......Page 665
15.3.8 Data Transfer Between and from CAD Systems......Page 666
15.4 DESIGN PROCESS IN A LINKED CAD/DFMA ENVIRONMENT......Page 667
15.4.1 Example Scenario of CAD/DFMA Integrated System Utilization......Page 668
15.5 EXTRACTION OF DFMA DATA FROM CAD SYSTEM DATABASE......Page 670
15.6 EXPERT DESIGN AND COST ESTIMATING PROCEDURES......Page 672
REFERENCES......Page 675