BOOTHYORD DEWHURST AND HITACHI AEM DESIGN FOR ASSEMBLY: A COMPARATIVE STUDY MUHAMAD FARKHANIF BIN JAMALUDDIN

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1 i BOOTHYORD DEWHURST AND HITACHI AEM DESIGN FOR ASSEMBLY: A COMPARATIVE STUDY MUHAMAD FARKHANIF BIN JAMALUDDIN Report submitted in fulfillment of the requirements for the award of the degree of Bachelor of Mechanical Engineering with Manufacturing Engineering FACULTY OF MECHANICAL ENGINEERING UNIVERSITI MALAYSIA PAHANG DECEMBER 2010

2 ii UNIVERSITI MALAYSIA PAHANG FACULTY OF MECHANICAL ENGINEERING We certify that the project entitled Boothyord Dewhurst and Hitachi AEM Design for Assembly: A Comparative Study is written by Muhamad Farkhanif Bin Jamaluddin. We have examined the final copy of this project and in our opinion; it is fully adequate in terms of scope and quality for the award of the degree of Bachelor of Engineering. We herewith recommend that it be accepted in partial fulfilments of the requirements for the degree of Bachelor of Mechanical Engineering with Manufacturing Engineering. Dr. Akhtar Razul Razali Examiner. Signature

3 iii SUPERVISOR S DECLARATION I hereby declare that I have read this project report and in my opinion this project report is sufficient terms of scope and quality for the award of the degree of Bachelor of Mechanical Engineering with Manufacturing Engineering. Signature : Name of Supervisor : MR. MAHENDRAN A/L SAMYKANO Position : LECTURER Date : 06 DECEMBER 2010

4 iv STUDENT S DECLARATION I Muhamad Farkhanif Bin Jamaluddin declare that this report entitled Boothyord Dewhurst and Hitachi AEM Design for Assembly: A Comparative Study is the result of my own research except as cited in the references. The report has not been accepted for any degree and is not concurrently submitted in candidature of any other degree. Signature : Name : MUHAMAD FARKHANIF BIN JAMALUDDIN ID Number : ME08012 Date : 06 DECEMBER 2010

5 vi ACKNOWLEDGEMENTS First of all, I have to readily acknowledge and thank to Allah, The Omnipotent and Omniscient who created everything and in giving me the ability to start and complete this project. This project was conducted under the supervision of Mr. Mahendran A/L Samykano in University Malaysia Pahang (UMP). I am very grateful to him for his patience and his constructive comments that enriched this research project. His time and efforts have been a great contribution during the preparation of this thesis that cannot be forgotten forever. I would also like to thank Mr. Hadi bin Abdul Salaam as my academic advisor. This study would not be complete without the support from him. Thank you for all the help and advice given. I also gratefully acknowledge the assistance of everybody who helped in the execution of this project in UMP. I also thank to all Mechanical students for their friendship and help when thinking through problems and for sharing their knowledge of DFMA. Finally, I would like to thanks to my family for their continuous support and confidence in my efforts.

6 vii ABSTRACT Children's tricycles are typically used by children between the ages of two until four before they usually switch to a bicycle. This product is a good design to be commercialized. However, before releasing to the market, the product has to be cheap and good quality. Therefore, to achieve this goal, design for manufacture and assembly methodologies are used to evaluate the design of the product. Specifically, DFMA, which is Boothroyd-Dewhurst and Hitachi AEM, are used to evaluate the product. The strategy of evaluating the existing design is first to choose the available product in the market in order to solve a problem. The products choose were then disassembled into several families or sub-assemblies. This is for understanding how the parts functioning during normal operating mode. After that, each parts been critics and study if there is a chance for redesign. Finally, referring to result from current product based on Boothroyd-Dewhurst and Hitachi AEM method, the new parts designs are generated. Than the results for both analyses for improvement design are compared.

7 viii ABSTRAK Basikal roda tiga biasanya digunakan oleh kanak kanak berusia dua hingga empat tahun sebelum mereka beralih kepada basikal. Produk tersebut adalah sangat berpotensi untuk dipasarkan. Walau bagaimanapun, produk itu haruslah berkualiti dan murah sebelum ianya dijual di pasaran. Oleh yang demikian, untuk mencapai matlamat tersebut, kaedah Design for Manufacture and Assembly (DFMA) digunakan untuk menilai reka bentuk produk. Dua kaedah yang berbeza digunakan untuk menilai reka bentuk produk iaitu kaedah DFMA yang berdasarkan teknik Boothroyd-Dewhurst dan teknik Hitachi AEM. Strategi dalam menilai potensi rekabentuk sedia ada bermula dengan pemilihan produk yang sesuai dan berpotensi untuk dibangunkan. Kemudian, produk yang dipilih akan di leraikan mengikut kategori yang tertentu bagi memudahkan proses pemahaman cara produk berfungsi. Selepas itu, setiap komponen akan dikaji dan dikritik mengenai cara pemasangan dan pengendaliannya untuk memastikan komponen yang boleh diasingkan atau dicamtum. Akhirnya, merujuk keputusan dari produk semasa berdasarkan teknik Boothroyd-Dewhurst dan teknik Hitachi AEM, reka bentuk komponen baru dibuat. Kemudian keputusan kedua dua analisis untuk rekabentuk yang telah diperbaiki dibandingkan.

8 ix TABLE OF CONTENTS EXAMINER DECLARATION SUPERVISOR DECLARATION STUDENT DECLARATION DEDICATION ACKNOWLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF FIGURE LIST OF TABLE LIST OF SYMBOLS LIST OF ABBREVIATIONS Page ii iii iv v vi vii viii ix xii xiii xvi xvii CHAPTER 1 INTRODUCTION 1.1 Introduction Problem Background Problem Statement Objective of Studies Scope of Studies 3 CHAPTER 2 LITERATURE REVIEW 2.1 Introduction Design For Assembly DFA Guidelines Various Method of DFA Boothroyd-Dewhurst DFA Method Hitachi Assemblability Evaluation Method Lucas Hull DFA Method

9 x 2.5 Comparing Various Method of DFA Summary 23 CHAPTER 3 METHODOLOGY 3.1 Introduction 3.2 Design of The Study 3.3 Process Flow Chart Framework of the study Gathering the Information of parts/product Current Design Review CHAPTER 4 RESULT AND DISCUSSION 4.1 Introduction 4.2 Product Description 4.3 Specification of Children Tricycle Part Critique Figures and Dimension of The Part Product Tree For Current Design Product Assembly Operation For Current Design Application of Hitachi AEM on Current Product Application of Boothroyd Dewhurst on Current Produc Suggestion of Improvement on Current Tricycle 4.11 Product Tree for Improvement Design 4.12 Product Assembly Operation For Improvement Design 4.13 Application of Hitachi AEM on Improvement Product 4.14 Application of Boothroyd Dewhurst on Improvement 4.15 Comparison Curent Design And Improvement Design 4.16 Comparison Hitachi AEM and Boothroyd Dewhurst 4.17 Summary

10 xi CHAPTER 5 CONCLUSION & RECOMENDATION 5.1 Introduction 5.2 Conclution 5.3 Future Recommendation REFERENCES 116 APPENDICES A1 Gantt Chart FYP A2 Gantt Chart FYP B1 Middle current assembly DFA software 121 B2 B3 B4 C1 C2 C3 C4 D1 D2 D3 Front current assembly DFA software Rear current assembly DFA software Front wheel current assembly DFA software Middle improvement assembly DFA software Front improvement assembly DFA software Rear improvement assembly DFA software Front wheel improvement assembly DFA software Hitachi AEM penalty scores Boothyord Dewhurst manual handling Boothyord Dewhurst manual insertion

11 xii LIST OF FIGURE Figure No. Page Figure 2.1 Boothroyd Dewhurst DFA analysis. 7 Figure 2.2 The operation model of an assembly station 11 Figure 2.3 Basic Element Example 15 Figure 2.4 Lucas hull DFA analysis. 17 Figure 3.1 Flowchart of the project methodology 26 Figure 4.1 Children tricycle current product 33 Figure 4.2 Children Tricycle Product Tree 54 Figure 4.3 Middle Assembly operaton sequence for current design 55 Figure 4.4 Front Assembly operaton sequence for current design 56 Figure 4.5 Front Wheel Assembly operation sequence for current 57 design Figure 4.6 Rear Assembly operation sequence for current design 58 Figure 4.7 Main Assembly operation sequence for current design 59 Figure 4.8 Children tricycle product tree for improvement design 82 Figure 4.9 Middle Assembly operaton sequence for improvement design 83 Figure 4.10 Front Assembly operaton sequence for improvement design 84 Figure 4.11 Front Wheel Assembly operation sequence for improvement 85 Figure 4.12 Rear Assembly operation sequence for improvement design 86 Figure 4.13 Main Assembly operation sequence for improvement design 87 Figure 4.14 Figure 4.15 Figure 4.16 Figure 4.17 Figure 4.18 Comparison basket design Comparison chassis design Comparison Seat design, Comparison front cover design Comparison rear rim design

12 xiii Figure 4.19 Figure 4.20 Comparison product in 1 hour Comparison total efficiency

13 xiv LIST OF TABLE Table No. Page Table 2.1 DFA worksheet analysis 8 Table 2.2 the relationship between AEM score, assemblability, and 12 assembly cost Table 2.3 Production information and evaluation information processing. 12 Table 4.1 Children Tricycle Specification. 32 Table 4.2 Part Critique and Material 33 Table 4.3 Chassis (base). 35 Table 4.4 Cap Fork. 35 Table 4.5 Tricycle Dashboard 36 Table 4.6 Front Cover. 36 Table 4.7 Pin. 37 Table 4.8 Pin Clip. 37 Table 4.9 Front Wheel. 38 Table 4.10 Paddle Shaft. 38 Table 4.11 Table 4.12 Table 4.13 Table 4.14 Table 4.15 Table 4.16 Table 4.17 Table 4.18 Table 4.19 Table 4.20 Table 4.21 Table 4.22 Wheel Holder. Pin Holder. Hand Grip. Side Mirror. Horn Wheel Clip. Big Washer. Medium Washer Front Rim. Rear Rim. Bracket. Paddle

14 xv Table 4.23 Table 4.24 Table 4.25 Table 4.26 Table 4.27 Table 4.28 Table 4.29 Table 4.30 Table 4.31 Table 4.32 Table 4.33 Table 4.34 Table 4.35 Table 4.36 Table 4.37 Table 4.38 Table 4.39 Table 4.40 Table 4.41 Table 4.42 Table 4.43 Table 4.44 Table 4.45 Table 4.46 Table 4.47 Table 4.48 Table 4.49 Table 4.50 Table 4.51 Table 4.52 Table 4.53 Table 4.54 Table 4.55 Seat Seat Cover. Bolt Seat Screw U Tube. Screw Cover Seat. Screw Front Cover Screw Dashboard. Screw Bracket. Screw Basket. Big Nut. Medium Nut Bush. Rear Wheel. Basket Lifter U Tube Fork Truss. Current Middle Assembly Hitachi Worksheet A Current Middle Assembly Hitachi Worksheet B Current Front Assembly Hitachi Worksheet A Current Front Assembly Hitachi Worksheet B Current Rear Assembly Hitachi Worksheet A Current Rear Assembly Hitachi Worksheet B Current Front Wheel Assembly Hitachi Worksheet A Current Front Wheel Assembly Hitachi Worksheet B Current Main Assembly Hitachi Worksheet Current Middle Assembly Boothroyd Dewhurst Worksheet Current Middle Assembly Software DFA Current Front Assembly Boothroyd Dewhurst Worksheet Current Front Assembly Software DFA Current Rear Assembly Boothroyd Dewhurst Worksheet Current Rear Assembly Software DFA Current Front Wheel Assembly Boothroyd Dewhurst Worksheet

15 xvi Table 4.56 Table 4.57 Table 4.58 Table 4.59 Table 4.60 Table 4.61 Table 4.62 Table 4.63 Table 4.64 Table 4.65 Table 4.66 Table 4.67 Table 4.68 Table 4.69 Table 4.70 Table 4.71 Table 4.72 Table 4.73 Table 4.74 Table 4.75 Table 4.76 Table 4.77 Table 4.78 Table 4.79 Current Front Wheel Assembly Software DFA 77 Current Main Assembly Boothroyd Dewhurst Worksheet 78 Current Main Assembly Software DFM 79 Suggestion Improvement 80 Improvement Middle Assembly Hitachi Worksheet A 88 Improvement Middle Assembly Hitachi Worksheet B 89 Improvement Front Assembly Hitachi Worksheet A 90 Improvement Front Assembly Hitachi Worksheet B 91 Improvement Rear Assembly Hitachi Worksheet A 92 Improvement Rear Assembly Hitachi Worksheet B 93 Improvement Front Wheel Assembly Hitachi Worksheet A 94 Improvement Front Wheel Assembly Hitachi Worksheet B 95 Improvement Main Assembly Hitachi Worksheet 96 Improvement Middle Assembly Boothroyd Dewhurst Worksheet 98 Improvement Middle Assembly Software DFA 99 Improvement Front Assembly Boothroyd Dewhurst Worksheet 100 Improvement Front Assembly Software DFA 101 Improvement Rear Assembly Boothroyd Dewhurst Worksheet 102 Improvement Rear Assembly Software DFA 103 Improvement Front Wheel Assembly Boothroyd Dewhurst 104 Worksheet Improvement Front Wheel Assembly Software DFA 105 Improvement Main Assembly Boothroyd Dewhurst Worksheet 106 Improvement Main Assembly Software DFM 107 Totals comparison between current and improvement design. 111

16 xvii LIST OF SYMBOLS E d E ma Nmin T a T h T ma T i Functional efficiency Design efficiency Theoretical minimum number of parts Basic assembly time = 3 second Handling time Estimated time to complete the assembly of the product Insertion time

17 xviii LIST OF ABBREVIATIONS AEM CAD CAE CE CFE DFA DFM DFMA NPD Assemblability Evaluation Method Computer-aided design Computer-aided engineering Concurrent Engineering Candidate for Elimination Design for Assembly Design for Manufacture Design for Manufacture and Assembly New Product Development

18 CHAPTER 1 INTRODUCTION 1.1 INTRODUCTION New Product Development (NPD) is a complex and creative process, which is inherently difficult to manage and improve. Having a great design is one thing, bringing that design effectively to market is another. The ability to deliver innovative products to the market on time, at the right cost and quality is a good indicator of a company s NPD capability. The significance of NPD in the business value chain must not be Underestimated, gone are the days where companies can simply compete on quality and cost. Developing successful product requires the ability to predict, early in the product development process, the life cycle impact of design decisions. Any misjudges can leads to poor product designs that may cause unforeseen problems and excessive costs. Cost to redesign at this late stage can be prohibitive. Sometimes companies must simply accept higher manufacturing costs and reduced product effectiveness resulting from early design errors. In this chapter, an overview of the background, objectives and scope of this project are reviewed. Basically, the objective of this study is to redesign a new selected product for a better design and lower production cost. Here, the DFA Method was applied to analyze the original product (children tricycle). Lastly, in this chapter, the overall thesis outlines are reviewed and discussed in general.

19 2 1.2 PROJECT BACKGROUND Design for assembly (DFA) is a way to improve assembly ease and reduce assembly time. It can also reduce product costs by reducing the number of parts, optimizing manufacturing processes, simplifying parts handling and improving product assembly. Furthermore, the implementation of DFA can encourages the design of products to be produced at minimum cost with maximum quality and reliability. Many leading companies such as Ford, Kodak, General Motors, IBM, NCR, Xerox and more have save millions of money when using DFA analysis in their designs. Three of the better-known quantitative evaluation techniques has been used in industry are Boothroyd-Dewhurst (USA), Lucas (UK) and Hitachi (Japan). However, this project only focuses on design for assembly using Boothroyd Dewhurst method and Hitachi Assembleability Evaluation Method (AEM) 1.3 PROBLEM STATEMENTS Each new product is a good design to be commercialized. However, before releasing to the market, the product has to be cheap and good quality. Therefore, to achieve this goal, design for manufacture and assembly methodologies are used to evaluate the design of the product. Specifically, DFA, which is Boothroyd- Dewhurst Method and Hitachi method are used to evaluate the product in this project. The results for both analyses are compared to look for any variation in term of parts to be eliminated and combined. 1.4 OBJECTIVE OF STUDIES The aim of this project are to: 1) To design and improve existing design by using DFA method 2) Comparing 2 method DFA and choice the best evaluation method

20 3 1.5 SCOPE OF STUDIES In order to achieve the objectives the following scope of studies are performed: 1) Information contents gathering a. Find out part function for each component. b. Dimensioning the current design using manual measured. c. Modeling the CAD drawing of current design by using Solid works software. 2) Product select a. original design analysis b. new design analysis 3) Evaluate the product(children tricycle) based on Hitachi Assembleability Method and Boothroyd Dewhurst.

21 4 CHAPTER 2 LITERATURE REVIEW 2.1 INTRODUCTION This chapter provides a review of the concept of product design and methods of product developments. This chapter also relates how product design affects the cost, cycle time, and overall product quality. Besides that, this chapter also includes the information about advantages and disadvantages of DFA method, various methods of DFA and basic design concept and guidelines. 2.2 DESIGN FOR ASSEMBLY The manufacturing process of assembly is generally thought of as consisting of two distinct operation: handling followed by insertion. Both handling and insertion can be done either manually or automatically (C. Poli, 2004) In this project, type of assembly that must be considered is manual assembly. Design for assembly (DFA) may be defined as a process for improving product design for easy and low-cost assembly, focusing on functionality and on assimilability concurrently. Design for assembly (DFA) analyzes product designs to improve assembly ease and reduce assembly time. Often this is accomplished through a reduction in part count. The implementation of DFA techniques has played an important role in reducing costs of manufacturing over the last two decades. It is apparent that for both manual and automated assembly, the effective methods to reduce assembly costs were those applied during design; manufacturing and production changes have less impact on product cost.

22 5 The majority of commercial DFA methodologies developed in the last 15 years are applicable only during the embodiment design phase. The ability to apply DFA analysis at the conceptual design stage has been neglected. As a result, the DFA methods then force another iteration on the design, thus consuming time, material, and financial resources (R. B. Stone 2004) 2.3 DFA GUIDELINES Different book described DFA Guidelines in different ways. Some authors list many guidelines and described it with detail while other authors categories it with few list before divided the main principle to another few principle. But surely the main objectives for all guidelines remain same, to reduce the cost of assembly. The principles of DFA are: 1) Reduce the part count. The objective of this guidelines is to minimize the total number of parts. There is two ways how this objectives can be achieved: first, design for minimum number of part and second, minimize number of fasteners and their components. (C. Poli, 2004) 2) Design for minimum number of part. Focussing on the main parts, when number of part is decreasing, the cost the assembly and whole product can decreasing. There is 3 factor that should be considered. First, reduce the number of part. Second, remove non essential component with its function still achieved and third, combine several part into one components and manufactures as integral multifunctional component. (C. Poli, 2004) 3) Minimize number of fasteners and their components. Screw and washers can increase the cost and time to assembly. Other alternatives fasteners can be used to replace the screw and washers, such as snap fits press fits and molded hinges, straps or hook. It seems obvious with this technique (reduce part count), the assembly costs would be less. Butt the question remains whether the overall manufacturing costs have been reduced. (Knut Holt 2002) 4) Standardize on component, materials and fasteners. Generally, small similar shaped component can be difficult to differentiate. Feeders can become jammed because wrong part have been fed in by operators. This also can save the storage, inventory and ordering cost and time. (C. Poli, 2004)

23 6 2.4 VARIOUS METHOD OF DFA There are various methods that were using in Design for Assembly in industry nowadays such as: 1) The DFA method exploited by Boothroyd Dewhurst Inc, USA. 2) The Hitachi Assemblability Evaluation Method (AEM) by Hitachi Ltd, Japan. 3) The Lucas Design for Assembly Methodology by Lucas-Hull, UK Boothroyd-Dewhurst DFA Method Design for assembly (DFA) that formulated by Boothroyd and Dewhurst are one of the most widely DFA methodologies which is used on productivity improvement through product design in term of assembly ease and reduce assembly time. Boothroyd and Dewhurst DFA methodology has been recognized as a very useful tool in increasing competitiveness by reducing the part number of components, simplifying the product design structure and improving product design reliability. The procedure for analyzing product for manual assembly Boothroyd and Dewhurst method is summarized as following below (Stoll W.H, 1999). 1) Obtain the best information about the product or assembly. Useful items include engineering drawing, exploded three-dimensional views, an existing version of the product, or prototype. 2) Take the assembly apart. Assign an identification number to each item as it is removed. Initially, treat subassemblies as parts and then analyze them as assemblies later. 3) Reassemble the product starting with the part having the highest identification number. As each part is added to the assembly, analyze its ease of handling and insertion and use the three questions to decide if it is a candidate for elimination or combination with other parts 4) Redesign the assembly using the insights gained from the analysis. Analyze the new design by repeating step 1 through 4 and gage improvements by comparing design efficiencies between current and modified design. Iterate until satisfied.

24 7 The Boothroyd and Dewhurst DFA analysis is basically completed in 6 steps. The flow chart of Boothroyd and Dewhurst DFA analysis is shows in Figure 2.1 (Boothroyd, et. al, 2002) Design for manual Assembly analysis Theoretical minimum number Manual handling analysis Manual Insection analysis Total operation time Total assembly time Design Efficiency Figure 2.1: Boothroyd Dewhurst DFA analysis. Source : Muhammad Faizal Bin Alias,2007.