UNIVERSITI TEKNIKAL MALAYSIA MELAKA

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1 UNIVERSITI TEKNIKAL MALAYSIA MELAKA DESIGN ANALYSIS OF A BABY STROLLER BY USING DESIGN FOR MANUFACTURING AND ASSEMBLY METHOD (BOOTHROYD DEWHURST) This report submitted in accordance with requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor's Degree in Manufacturing Engineering Technology (Product Design) (Hons.) by AZIE NOOR MARLIA BINTI RUSLAN B FACULTY OF ENGINEERING TECHNOLOGY 2015

2 UNIVERSITI TEKNIKAL MALAYSIA MELAKA BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA TAJUK: Design Analysis of a Baby Stroller by Using Design for Manufacturing and Assembly Method (Boothroyd Dewhurst) SESI PENGAJIAN: 2014/15 Semester 2 Saya AZIE NOOR MARLIA BINTI RUSLAN Mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut: 1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan pertukaran antara institusi pengajian tinggi. 4. **Sila tandakan ( ) SULIT TERHAD (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan) (Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia sebagaimana yang termaktub dalam AKTA RAHSIA RASMI 1972) TIDAK TERHAD Disahkan oleh: AlamatTetap: No.18, Jalan Makmur 50, Cop Rasmi: Taman Damai Jaya, Johor Bharu. Tarikh: ** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai SULIT atau TERHAD.

3 DECLARATION I hereby, declare that this report entitled Design Analysis of A Baby Stroller by Using Design for Manufacturing and Assembly Method (Boothroyd Dewhurst) is the result of my own research except as cited in the references. Signature :... Name Date : AZIE NOOR MARLIA BINTI RUSLAN :...

4 APPROVAL This report is submitted to the Faculty of Engineering Technology of UTeM as a partial fulfillment of the requirements for the degree of Bachelor of Engineering Technology Product Design (Hons.). The member of the supervisory is as follow:. (Project Supervisor)

5 ABSTRAK Projek ini menggunakan kaedah rekabentuk untuk proses dan pemasangan supaya dapat mengkaji rekabentuk kereta sorong bayi (Sweet Cherry SCR 8 Series) dalam aspek pembuatan, proses pemasangan dan juga kepayahan ketika memegang dan memasang komponen. Masalah yang dikenal pasti dalam kajian ini adalah pada bentuk kereta sorong bayi yang banyak menggunakan screw pengikat dan juga penggunaan kedua-dua belah tangan untuk menggerakkan penyelak bagi melipat kereta sorong bayi tersebut. Objektif projek ini adalah untuk mengurangkan komponen disamping mengekalkan fungsi kereta sorong tersebut, untuk membuat perbezaan kadar kecekapan oleh rekabentuk asal berbanding dengan rekabentuk baru, dan juga untuk mengurangkan jumlah waktu pemasangan setelah analisis rekabentuk dan pemasangan dijalankan. Melalui kajian yang telah dijalankan, terbukti dengan menggunakan kaedah ini, kos pemasangan dapat dikurangkan sebanyak s, iaitu 23% lebih baik daripada yang sebelumnya. Kos untuk satu bahgian juga dapat dikurangkan sebanyak RM Bilangan bahagian juga dapat dikurangkan daripada 179 bilangan kepada 149 bilangan sahaja. Indeks DFA juga meningkat daripada 9.6 kepada Kelebihan penggunaan kaedah ini telah dibuktikan melaui rekabentuk baru untuk kereta sorong bayi i

6 ABSTRACT This project implemented the design for manufacturing and assembly (DFMA) methodology in order to study the design analysis of a baby stroller (Sweet Cherry SCR8 Series) in aspect of part for manufacturing, assembly process and also handling and insertion difficulties. The problem identified in this study is on the features of the stroller that shows a lot of fastener being used and also the usage of both hands in moving the fold latch to fold the stroller. The objectives of this project are to reduce part while maintaining the function of the baby stroller, to compare the efficiency of the original design and after redesign, and also to reduce total assembly time with a new product design of a baby stroller after DFMA analysis. The study has proven to save assembly time by s which is 23% more efficient than the original design. Further ado, the total cost per product for manufacturing has saved RM The number of parts reduced from 179 parts to be 149 parts. The DFA index is also improved from 9.6 to The advantages of using DFMA method has been proved in the redesign of the baby stroller. ii

7 DEDICATION To my beloved parents and my brothers. iii

8 ACKNOWLEDGEMENT First and foremost I offer my sincerest gratitude to my adorable supervisor, Madam Nurul Ain Binti Maidin, who has supported me throughout my project study with her patience and knowledge sharing. I attribute the level of my degree to her encouragement and effort and without this thesis, too, would not have been completed or written. One simply could not wish for a friendlier supervisor. In my daily life I have been blessed with my beloved parent, Mr Ruslan Bin Mohd Dom and Mrs Kintan Binti Abdul Rahman. I owe them a deep sense of gratitude but not to forget with my handsome big brothers, Mr Ahmad Mohammad Bin Ruslan and also Mr Ahmad Muazzam Bin Ruslan that keep pushing me to success whenever I felt that I am not the best. I thank profusely both of my roommates, Ms Khalilah Binti Khalid and also Ms Nurul Aima BintiMazlan for their kindness and co-operation throughout my study period. iv

9 TABLE OF CONTENTS Abstrak Abstract Dedication Acknowledgement Table of Content List of Tables List of Figures List Abbreviations, Symbols and Nomenclatures i ii iii iv v ix x xiii CHAPTER 1: INTRODUCTION Background Problem Statement Objectives Scope of Project 3 CHAPTER 2: LITERATURE REVIEW Design for Manufacturing and Assembly (DFMA) Design for Assembly (DFA) DFA Methods 7 v

10 2.2.2 DFA Guidelines DFA Product Simplication Software (BDI) Design for Manufacturing DFM Guidlines DFM Concurrent Costing Software DFMA Methodologies Boothroyd-Dewhurst Method History of A Baby Stroller Types of Stroller Sweet Cherry SCR8 Series 23 CHAPTER 3: METHODOLOGY Introduction Flowchart Formulation of Project Research for Literature Review Part Identification of Baby Stroller Run The Analysis by Using Boothroyd-Dewhurst DFMA Sotware Redesign of The Baby Stroller Generate Project Report 30 CHAPTER 4: RESULT & DISCUSSION 31 vi

11 4.1 Baby Stroller Information Bill of Materials Original Design for Sweet Cherry SCR8 Series Exploded View of The Original Design Structure Chart of The Assembly Sequences Design for Analysis (DFA) of The Original Design DFM Analysis of original Design Suggestion for Redesign of Baby Stroller Redesign Exploded View of Redesign Bill of materials Structure Chart of Redesign DFA Analysis of Redesign DFM Analysis of Redesign DFMA Analysis and Discussion Design Comparison Research Limitation 64 CHAPTER 5: CONCLUSION & RECOMMENDATION Conclusion Recommendation of Future Work 66 vii

12 REFERENCES 67 APPENDICES 69 viii

13 LIST OF TABLES Table 2.1 Type of stroller nowadays Table 4.1 Table 4.2 Table 4.3 Bill of materials (BOM) for original design DFA analysis of front bar part and handle part DFA analysis result for original design of Sweet Cherry SCR 8 Series Stroller. Table 4.4 Table 4.5 Table 4.6 Table 4.7 Table 4.8 Table 4.9 DFM concurrent costing for front bar B of the original design Suggestion for redesign parts Bill of material for redesign DFA analysis for redesign (front bar and handle) of the baby stroller. DFA analysis result for redesign of Sweet Cherry SCR 8 stroller DFM concurrent costing for front bar of redesign for baby stroller Table 5.1 Percent reduction for DFA analysis ix

14 LIST OF FIGURES Figure 2.1 Time to deliver comparison between DFMA and CAE with Traditional Methods Figure 2.2 Figure 2.3 Figure 2.4 Typical steps taken in a DFMA study using DFMA software Manual Handling and Manual Insertion Estimated Times Relative Cost Of Different Assembly Method By Type And Production Volume Figure 2.5 Figure 2.6 Figure 2.7 Figure 2.8 Production ranges for each type of assembly method Standardize part Geometry feature of tangle an untangled Symmetrical part for ease of insertion Figure 2.9 Provision of air- relief passages to improve insertion into blind holes Figure 2.10 Features affecting part handling Figure 2.11 Figure 2.12 Figure 2.13 Figure 2.14 Figure 2.15 Figure 2.16 Figure 2.17 Figure 2.18 Figure 2.19 Provision of chamfer to allow easy of insertion Horse-Drawn Baby Carriages (1700s) Handles and Forward-Facing Carriages The Pram The Reversible Baby Carriage The Umbrella Stroller The Jogging Stroller Modern stroller Sweet Cherry SCR 8 Series Stroller Figure 3.1 DFA Procedure. x

15 Figure 3.2 The Parameter in DFM. Figure 4.1 Figure 4.2 The original design of Sweet Cherry SCR 8 Series Stroller Exploded view of the original design for Sweet Cherry SCR 8 Series Stroller. Figure 4.3 The structure chart of the original design of the Sweet Cherry SCR 8 Series. Figure 4.4 Figure 4.5 The evaluation properties interface in DFA analysis. The breakdown of time per product for original design of the Sweet Cherry SCR8 stroller (DFA) Figure 4.6 Figure 4.7 Figure 4.8 Breakdown cost for front bar of the Sweet Cherry SCR8 stroller. Distribution bar chart for the total cost Redesign of Sweet Cherry SCR8 stroller Figure 4.9 (a) Exploded view of front bar sub-assembly and bill of materials Figure 4.9 (b) Exploded view of handle sub-assembly and bill of material. Figure 4.10 Figure 4.11 Figure 4.12 Figure 4.13 Figure 4.14 Structure chart of redesign. Breakdown of time per product for redesign Breakdown of the cost for redesign of the baby stroller Comparison of DFMA for original and redesign of the baby stroller The comparison for breakdown of cost per product for original and Redesign. Figure 4.15 Figure 4.16 Design comparison of front bar Design comparison of handle xi

16 LIST OF ABBREVIATIONS, SYMBOLS AND NOMENCLATURE DFMA = Design for Manufacturing and Assembly DFA = Design for Assembly DFM = Design for Manufacturing CAE = Computer Aided Engineering xii

17 CHAPTER 1 INTRODUCTION Nowadays hundreds of stroller models are available with different branded and quality. This made the features of the stroller to be different and unique depends on the designer and company intention to be focused. However, the manufacturing process is the important things to be considered as it will affect the price of the product itself. Hence, this project focused on analyzing the design of a baby stroller in order to reduce cost then improve the manufacturing and assembly process with a new design of a baby stroller after the analysis. This chapter basically explain on how the project being made starting from the background study, problem statement, objective, scope, organization of the project, and lastly result expectations. 1.1 Background Design for Manufacturer and Assembly in which being known as DFMA generally is a combination of Design for Assembly (DFA) and Design for Manufacturing (DFM). Through history of DFMA, it had been used before the Second World War by Ford and Chrysler that using DFM philosophy in their design and manufacturing process of the weapons, tanks and other military products. Early 1970 s the researching job of this new technology had been done by Professors Peter Dewhurst and Geoffrey Boothroyd who originated the Boothroyd Dewhurst, Inc. (BDI) in Initially on comprehensive work studies, relating part characteristics to handling, fitting times and degrees of difficulties etc., their work was genesis of the concept of scoring designs for DFA or DFM. Currently Boothroyd Dewhurst methodology was the inspiration for many of its successors around the world. 1

18 In essence, unstructured DFA and DFM guidelines and rules are transformed into a structured form that can be applied using paper-based spreadsheet type analysis or computer software. For DFA, a formalized step-by-step process being used to produce a design metric that assesses the design efficiency related to its assemblability. The main steps involved are based on general DFA concepts in which choose assembly method (manual or automatic) analyze the design for ease of assembly and improve the design and reanalyze. Boothroyd Dewhurst s, Inc. DFMA software is designed to be used at the concept design stage. The aim is to optimize design for manufacture and assembly before commitment to detail design and manufacture. The DFMA package contains a DFA module and DFM module. Normally the DFA module is used first, working from a concept drawing. The aim is to improve design efficiency by eliminating of unnecessary parts, and choosing more efficient assembly methods. This is followed by DFA, which provides estimates of time and cost for assembly, as well as other operations. Through redesign, the design efficiency figure is improved. This provides a relative measure between design alternative which should influence the final design concept chosen. Meanwhile for DFM module is used to evaluate design alternative from a manufacturing cost perspective. This project fundamentally focused on the design analysis of Sweet Cherry SCR 8 Series Stroller by implementing DFMA method. Hence, Boothroyd Dewhurst methodology had been used to complete this project. 1.2 Problem Statement Nowadays, there are a lot of distinct process which all influence product cost, quality and productivity of system that cause a huge losses to Business Company. This is because a lot of product is made up of fasteners and redundant features (Othman, 2010). Boothroyd Dewhurst DFA method could help to overcome the problem by suggested the idle possible way to assemble a product with remove fastener. In a production of a baby stroller, from the features show a lot of fastener such as screw, rivet and many more as the structure need to be foldable. Hence, this project had analyzed the design for assembly to 2

19 reduce parts as well as the cost of production and come out with some improvement of the design in an efficient way. 1.3 Objective (a) (b) (c) To reduce part while maintaining the function of the baby stroller. To investigate the efficiency of the original design and after redesign (comparison) To reduce total assembly time with a new product design (redesign) of baby stroller after DFMA analysis 1.4 Scope In order to achieve the objective of the project, the scope had been list as shown below: (a) Study of design for assembly of a baby stroller that focusing on mechanical parts only by using Boothroyd Dewhurst method. (b) Evaluate a baby stroller as a case study, analyze and redesign the product using Boothroyd Dewhurst method. (c) Solid Works software being used for drawing of each part and assemble of the original and redesign of the baby stroller. 3

20 CHAPTER 2 LITERATURE REVIEW As the time flies an organizations need to learn in order to improve their adaptability and efficiency toward future. Through this idea with the help of new technologies and philosophies of compete with other competitors literally could enhance the development process with a good results to achieve target. Currently there are a lot of tools that could be used to help production team to solve their problem at an early stage. Hence, this chapter will review the past research from other sources with citation. 2.1 Designs for Manufacturing and Assembly (DFMA) Design for Manufacturer and Assembly (DFMA) is a tool that helps in minimizing production cost by breaking the product down to be the simplest components and parts. Concurrent Engineering (CE) is intended to cause developers from the outset, to consider schedule, quality, cost, user demand and all elements of product cycle from conception to disposal. Both of this Production Oriented Design (DFMA and CE) could run activities simultaneously in a parallel form as being showed in Figure 2.1 below. They were using simulation techniques that could give a fully understanding among team member to find errors along the process and fix it before the development ends. 4

21 (Sources: Junior, O.C. at. all, The White Goods Part Designed Based on DFM/DFA Concepts in a Concurrent Engineering Environment) Figure 2.1: Time to deliver comparison between DFMA and CAE with Traditional Methods There are two major concept in DFMA process in which design for assembly (DFA) and also design for manufacturing (DFM). DFA is the design of the product for ease of assembly (Boothroyd, 1994). It is an analysis method that brings together multidisciplinary teams to evaluate and validate product design with respect to the manufacture and assembly of its components parts. Meanwhile DFM is to design that is based on reducing the cost of production and time to market for a product, while maintaining appropriate level of quality the material and tooling side of the new product. Hence, DFMA refers to working on both concepts together. Figure 2.2below shows the typical steps taken in DFMA study using DFMA software. 5

22 (Sources: Boothroyd,G., Dewhurst,P., and Knight, W., Product Design for Manufacturing and Assembly, 2 nd Edition, Marcel Dekker Inc) Figure 2.2: Typical steps taken in a DFMA study using DFMA software DFMA can be used effectively to reduce part count in the assembly that brings to simplify the assembly process, lower manufacturing overhead cost, minimize assembly time, and improve quality by reducing the possibilities for introducing a defect. Also the amount of labor can be reduced once the component of parts becomes fewer and simpler assembly processes. When the part count had been reduced, automatically the development cycle become shortened as the philosophy encourages simplifying the design and using standardize component whenever possible. 6

23 2.2 Designs for Assembly (DFA) Generally, there are two objective of DFA in which to minimize part count and to have remaining parts of a nature that they are easily assembled together. The DFA method accomplishes the objective by: (a) Providing a tool for the designer and even design team which assures that considerations of product complexity and assembly take place at the earliest design stage. This eliminates the danger of focusing too much the whole things during early design on product function with insufficient regard for product cost and competitiveness. (b) Guiding the designer to simplify the product so that the cost of assembly and parts can be saving equally. (c) Gathering information normally possessed by the experienced design engineer and arranging it conveniently for use by less-experienced designers. (d) Forming a database that comprises of assembly times and cost factors for numerous design situations and production conditions DFA Methods The analysis of a product design for ease of assembly depends to a large extent on whether the product is to be assembled manually, fixed or hard automation, soft automation (robotic), or a combination of these. (a) Manual assembly List of parts are assigned to workbenches where the component of product being assemble manually by workers with the aids of hand tools. Even though this is an idle method for assembly, there is usually an upper limit to the production volume, and labor costs remain higher. 7

24 (Sources: Boothroyd,G., Dewhurst, P., and Knight, W.,2002. Product Design for Manufacturing and Assembly, 2 nd Edition, Marcel Dekker Inc) Figure 2.3: Manual Handling and Manual Insertion Estimated Times 8