Designing Capable and Reliable Products

Designing Capable and Reliable Products offers an introduction to the importance of capability, quality and reliability in product development. It introduces the concept of capable design, focusing on producing designs that meet quality standards and also looks at linking component manufacture and its process capability with failure rates. It provides an introduction to reliable design, incorporating the probabilistic concept of reliability into the product design. This quantitative and highly practical volume provides practical methods for analysing mechanical designs with respect to their capability and reliability. Practising engineers who have to hit definite standards for design will find this book invaluable, as it outlines methods which use physically significant data to quanitify engineering risks at the design stage. By obtaining more realistic measures of design performance, failure costs can be reduced. Taking product design as its central theme, this book is a very useful tool for postgraduate students as well as professional engineers. Preface......Page 9 Notation......Page 13 Abbreviations......Page 15 1.1 Statement of the problem......Page 17 1.2 The costs of quality......Page 24 1.3 How and why products fail......Page 33 1.4 Risk as a basis for design......Page 38 1.5 Designing for quality......Page 41 1.6 Designing for reliability......Page 46 1.7 Summary......Page 50 2.1 Manufacturing capability......Page 53 2.2 Component Manufacturing Variability Risks Analysis......Page 59 2.3 Assembly capability......Page 74 2.4 Component Assembly Variablility Risks Analysis......Page 79 2.5 The effects of non-conformance......Page 83 2.6 Objectives, application and guidance for an analysis......Page 90 2.7 Case studies......Page 104 2.8 Summary......Page 122 3.1 Introduction......Page 125 3.2 Background......Page 126 3.3 Tolerance stack models......Page 129 3.4 A methodology for assembly stack analysis......Page 130 3.5 Application issues......Page 136 3.6 Cash study - revisiting the solenoid design......Page 138 3.7 Summary......Page 147 4.1 Deterministic versus probabilistic design......Page 148 4.2 Statistical methods for probabilistic design......Page 153 4.3 Variables in probabilistic design......Page 168 4.4 Stress-strength interface (SSI) analysis......Page 192 4.5 Elements of stress analysis and failure theory......Page 207 4.6 Setting reliability targets......Page 212 4.7 Application issues......Page 217 4.8 Case studies......Page 219 4.9 Summary......Page 265 5.1 Introduction......Page 268 5.2 Product development models......Page 272 5.3 Tools and techniques in product development......Page 278 5.4 Supporting issues in effective product development......Page 284 5.5 Summary......Page 291 Statistical representation of data......Page 293 Representing data using histograms......Page 294 Properties of the Normal distribution......Page 296 The Standard Normal distribution......Page 298 Process capability concepts......Page 304 Process capability index......Page 305 A Failure Mode and Effects Analysis (FMEA)......Page 311 B Quality Function Deployment (QFD)......Page 317 C Design for Assembly/Design for Manufacture (DFA/DFM)......Page 320 D Design of Experiments (DOE)......Page 324 Index to maps......Page 329 Sheet A Casting processes......Page 333 Sheet B Casting processes (continued)......Page 334 Sheet C Casting processes (continued)......Page 335 Sheet D Hot forging processes......Page 336 Sheet E Cold forming processes......Page 337 Sheet F Cold drawing and rolling processes......Page 338 Sheet G Extrusion processes......Page 339 Sheet H Sheet metalworking processes......Page 340 Sheet I Sheet metalworking processes (continued)......Page 341 Sheet K Machining processes......Page 342 Sheet L machining processes (continued)......Page 343 Sheet M Powder metallurgy processes......Page 344 Sheet N Plastic moulding processes......Page 345 Sheet P Elastomer and composite moulding processes......Page 346 Sheet Q Non-traditional machining processes......Page 347 Sheet R Non-traditional maching processes (continued)......Page 348 Appendix 5 Sample case studies used in validation......Page 349 A Miscellaneous operations......Page 360 B Later mechanical deformation......Page 361 C Adhesive bonding......Page 362 D Brazing and soldering......Page 363 E Resistance welding......Page 364 F Fusion welding......Page 365 A Variability risks results table......Page 366 B Conformability matrix......Page 367 Appendix 8 Assembly problems with two tolerances......Page 368 A Probability Density Functions (PDF)......Page 371 B Equivalent mean and standard deviation......Page 372 C Cumulative Distribution Functions (CDF)......Page 373 A Cumulative ranking equations......Page 376 C Distribution parameters from linear regression constants A0 and A1......Page 377 A Partial derivative method......Page 379 B Finite difference method......Page 381 C Monte Carlo simulation......Page 384 D Sensitivity analysis......Page 387 Appendix 12 Simpson's Rule for numerical integration......Page 389 Example 1......Page 390 Example 2......Page 392 Area under a Function......Page 394 References......Page 397 Bibliography......Page 410 Index......Page 411 One of the basic expectations of the customer is conformance to specification, that is, the customer expects output characteristics to be on target with minimum variation (Abraham and Whitney, 1993; Garvin, 1988). Practical methods for analysing mechanical designs with respect to their capability and reliability are combined in this volume. The book is written with postgraduate students and professional engineers in mind