Design Secrets for Mass Production

We see further when standing on the shoulders of giants.
We learn faster by learning from the experience of predecessors.

This book is the English version of the third edition of 龜毛機構設計：講究與將就, with some contents revised and an additional chapter of readers'' Q&A added. Graduating from the Department of Mechanical Engineering at the National Taiwan University of Science and Technology in 1984, I have more than 25 years of experience in product development and design, DFM/DFA, and ODM/OBM, while having the practical experience in the production process from trial assembly, testing, improvement, simulation to troubleshooting. I had engaged in successful mass production of products, including automotive sheet metal parts, hand tool hardware, telephones, test devices, palm­sized radios, PDAs, and smart phones.

In my design career, I had observed that when inexperienced beginners were trying to look for a mechanical design book with practical design examples, they often ended up finding none. Experienced designers, however, had no willingness nor time for such a complicated and trivial work of writing. Fortunately, having engaged in mechanical design for more than 25 years and achieved mastery of relevant skills, I can now concentrate on preparing this book as a retiree. Therefore, after 39 months of efforts, the world''s first unique mechanical design book has finally been completed.

This book is especially suitable for design engineers (mechanical design, product structure design, and industrial design) in the fields of computers, communications, consumer electronics, stationery, toys, sports equipment, and peripheral accessories. As this book features clear textual description, supplemented with pictures, you will get it as you read it.

By reading this book thoroughly:
1. You can rectify incorrect concepts as early as possible; after all, if you do it right in the first place, you will always get it right.
2. You will significantly reduce the number of times of modification, the time for repeated design modifications, as well as production and tooling modification costs.
3. You, as an inexperienced designer, can enhance your own skills without solely relying on experienced ones'' guidance.
4. You, as an experienced designer, will be enlightened at the right time to integrate your own design experience without wasting time on repetitive trials and errors.
5. You, as a design supervisor, can adopt this book as a reference for the development of internal education and training as well as design guidelines to increase design efficiency in your department.
6. You, as a project manager, can anticipate design defects and remind designers to respond in time to improve the overall product development efficiency.

From the perspective of mechanical designers, this book delves into various issues of ªdesign.Ý For other technical discussions on molds, injection molding, secondary processing, and surface treatment, you may need to collect relevant information by yourself. With the figure on the left page and textual description on the right page, you may find it easy to read the book and explore the content in depth. Therefore, this book is well­suited for design technicians as well as engineering and technical supervisors. Hopefully, in addition to absorbing my experience, you will draw inferences from this book when reading it and eventually excel in this field. As what the butterfly on the front cover of this book symbolizes, I hope that you, after reading this book, will break out of your own cocoons and undergo the metamorphosis to outstanding design talents so as to excel in this field.

Oct 2020, Taipei

We see further when standing on the shoulders of giants.
We learn faster by learning from the experience of predecessors.

This book is the English version of the third edition of 龜毛機構設計：講究與將就, with some contents revised and an additional chapter of readers'' Q&A added. Graduating from the Department of Mechanical Engineering at the National Taiwan University of Science and Technology in 1984, I have more than 25 years of experience in product development and design, DFM/DFA, and ODM...

1. Problematic Designs at a Glance 1
A. Design Defects 2
B. Manufacturing Considerations 14
C. Management Issues 15
2. Low-­Cost Designs 17
A. Design Strategies 18
B. Manufacturing Choices 28
C. Management Considerations 43
3. Stable and Smooth Operation 49
A. Exploration of Principles 50
B. Examples 54
4. Delicate Appearance 63
A. Industrial Design Problems and Improvements 64
B. Control of Appearance Gaps and Steps 73
C. Delicate Appearance and Operation 93
5. Use of Elasticity and Prepressing Setting 105
A. Principles and Classifications 106
B. Examples 123
C. Prepressing Setting 128
6. Datum and Positioning 141
A. Essentials and Plane Positioning 142
B. Height Positioning 155
C. Common Positioning Problems 161
7. Gap Values and Explanations 185
A. Principles and Empirical Value of Reserved Gaps 186
B. Improvement Measures 206
8. Impacts of Deviation enlargement 225
A. Definitions 226
B. Enlargement of Lever 228
C. Enlargement of Rotation 233
D. Enlargement of Skewness 235
9. Myths of Hook Design 245
A. Definitions 246
B. Principles 251
C. Design Thinking 260
D. Troubleshooting 279
10. Screw Application 289
11. Methods of Increasing Strength 305
A. Basic Reinforcing Methods 306
B. Reinforcement in Loading Direction 324
C. Strengthening of Adhesion of Tape 339
D. Impact Protection 348
12. Important 2D Assembly Sectional Views 355
A. Purpose and Methods 356
B. Guidelines 358
C. 2D Drawing Improvements 363
13. Simulation 369
A. Overview 370
B. Drawing-­based Simulation 372
C. Mock-­up-­based Simulation 380
D. Case Study 383
14. Designs that are Hard to Control 387
A. Effective Designs 388
B. Assembly Reliability 398
C. Blind Spots in Design 402
D. Test Improvement 410
15. Differences between Mock­-Ups and Tooling Parts 413
A. Changes of Thinking 414
B. Manufacturing Issues and Know-­How of Tooling Parts 423
16. Rounds, Chamfers, and Sharp Corners 445
A. Machined Natural Fillets and Sharp Corners 446
B. Rounds 450
C. Chamfers 456
17. 6σ Design and Tolerance Analysis 459
A. Introduction 460
B. Meaning and Attitude 463
C. Design Methods and Examples 465
D. Pitfalls and Challenges 495
18. Process Capability Improvement of Factories 501
A. Design Requirements 502
B. Process Improvement of Suppliers 505
19. Parting Line 509
A. Examination of Principles 510
B. Better Choices 514
20. Technology Management 529
A. Supervisor Functions 530
B. Talent and Organization Management 541
C. Shortening of Research and Development Time 550
D. Enhancement of Design Effects 557
21. Interaction with Readers Q&A and Case Study 570
References 589

1. Problematic Designs at a Glance 1
A. Design Defects 2
B. Manufacturing Considerations 14
C. Management Issues 15
2. Low-­Cost Designs 17
A. Design Strategies 18
B. Manufacturing Choices 28
C. Management Considerations 43
3. Stable and Smooth Operation 49
A. Exploration of Principles 50
B. Examples 54
4. Delicate Appearance 63
A. Industrial Design Problems and Improvements 64
B. Control of Appearance Gaps and Steps 73
C. Delicate Appearance and Operation 93
5. Use of Elasticity and Prepres...