A Precision Assembly In Plastic Injection Mould.

(1)

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

A Precision Assembly in Plastic Injection Mould

Thesis submitted in accordance with the requirements of the Universiti Teknikal Malaysia Melaka for the Degree of Bachelor of Engineering (Honours)

Manufacturing (Process)

Husaini Bin Abdullah

Faculty of Manufacturing Engineering April 2008

(2)

UTeM Library (Pind.1/2007)

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PSM

JUDUL:

A Precision Assembly in Plastic Injection Mould

SESI PENGAJIAN: Semester 2 2007/2008

Saya Husaini Bin Abdullah

mengaku membenarkan laporan PSM / tesis (Sarjana/Doktor Falsafah) ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:

1. Laporan PSM / tesis 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 / tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi.

4. *Sila tandakan (√) SULIT TERHAD TIDAK TERHAD

(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia yang termaktub di dalam AKTA RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)

(TANDATANGAN PENULIS) Alamat Tetap:

4, Persiaran Mayang Pasir,

11900 Bayan Lepas, Pulau Pinang.

Tarikh: 25 Mach 2008

(TANDATANGAN PENYELIA) Cop Rasmi:

Tarikh: _______________________

* Jika laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.

(3)

FAKULTI KEJURUTERAAN PEMBUATAN

Rujukan Kami (Our Ref) : 15 Mei 2008

Rujukan Tuan (Your Ref):

Pustakawan

Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) Taman Tasik Utama, Hang Tuah Jaya,

Ayer Keroh, 75450, Melaka Saudara,

PENGKELASAN LAPORAN PSM SEBAGAI SULIT/TERHAD

- LAPORAN PSM SARJANA MUDA KEJURUTERAAN PEMBUATAN (PROSES): Husaini Bin Abdullah

TAJUK: A Precision Assembly in Plastic Injection Mould

Sukacita dimaklumkan bahawa tesis yang tersebut di atas bertajuk “A Precision Assembly in Plastic Injection Mould” mohon dikelaskan sebagai terhad untuk tempoh lima (5) tahun dari tarikh surat ini memandangkan ia mempunyai nilai dan potensi untuk dikomersialkan di masa hadapan.

Sekian dimaklumkan. Terima kasih.

“BERKHIDMAT UNTUK NEGARA KERANA ALLAH” Yang benar,

………..

MOHD AMRAN BIN ALI

Pensyarah,

Fakulti Kejuruteraan Pembuatan

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

Karung Berkunci 1200, Ayer Keroh, 75450 Melaka Tel : 06-233 2421, Faks : 06 233 2414

(4)

DECLARATION

I hereby declare that this report entitled_“A Precision Assembly in Plastic Injection Mould” is the result of my own research except as cited in the references.

Signature :

Author’s Name : Husaini Bin Abdullah

(5)

APPROVAL

This report is submitted to the Faculty of Manufacturing Engineering of UTeM as a partial fulfillment of the requirements for the degree of Bachelor of Manufacturing Engineering (Process). The members of the supervisory committee are as follow:

Mohd Amran Bin Ali (PSM Supervisor)

(6)

ABSTRACT

This project describe the method that was used to assemble plastic injection moulding. This project was done in the Manufacturing Workshop in Universiti Teknikal Malaysia Melaka (UTeM) that located at Fasa B. The material that been used in this mould project was Acrylic. This acrylic material was choose because of the characteristic that are transparent. The purpose of this project is to assemble plates that been provided to be one completed plastic injection moulding. The problem has been investigate such as machining with wrong dimension, off set, over cut, not enough cut, standard part cannot fit into plate and sharp edges. As a result, the plate must be remachining to get an actual dimension according to the drawing that been provided. Type of machining that been use in this project such as, milling machine, lathe machine, Computer Numerical Control (CNC) machine and Electrical Discharge Machine (EDM) wirecut. This project started from checking all plates to find out any defect or machining error or out of dimension in plastic injection mould. Every plate will be using quality measurement tool. It will be remachine if any defects found at mould plate. Various machines will be use such as milling machine, EDM machine, CNC, chamfering machine, drilling machine and lathe machine. During this project, all of learning outcome will be implement in every aspect of work. In order to get accurate result in measurement, various equipment have been used including vernier calliper, micrometer, high gauge, and Coordinate Measuring Machine (CMM). In this project also use a quality measurement equipment to get an accurate dimension. The equipment that involve in this project such as vernier caliper, micrometer, height gauge and Coordinate Measuring Machine (CMM). As a result, the measuring plate have been easier assembled with various mould component and finally one completed mould set was produce.

(7)

ABSTRAK

Projek ini akan memperihalkan tentang cara untuk menggabungkan acuan suntikan. Secara amnya, projek ini akan dijalankan di bengkel pembuatan Universtiti Teknikal Malaysia Melaka (UTeM) yang terletak di kompleks Fasa B. Dalam projek ini, bahan yang digunakan untuk membuat acuan ialah acrylic. Acrylic adalah bahan yang diperbuat daripada plastik. Bahan ini dipilih kerana sifatnya yang lutsinar. Tujuan projek ini dijalankan ialah untuk menyambung plat-plat yang dibekalkan menjadi satu acuan yang lengkap. Ini kerana plat-plat yang dibekalkan mempunyai masalah seperti dimensi yang salah, terpotong lebih, tidak cukup potong dan sebagainya. Maka plat-plat tersebut perlu di mesin semula untuk mendapatkan ukuran sebenar mengikut lukisan yang disediakan. Jenis mesin yang terlibat di dalam projek ini adalah mesin pengisar mesin pengejat, mesin pengawalan berangka komputer dan mesin penyahcas elektrik Projek ini dimulakan dengan menyemak kesemua plat untuk mengetahui kerosakan, kesilapan memesin, dan terkeluar daripada dimensi yang ditetapkan. Setiap plate akan menggunakan alat pengukuran yang berkualiti. Ianya akan dimesin semula jika terdapat kerosakan. Pelbagai mesin digunakan seperti mesin pengisar mesin pengejat, mesin pengawalan berangka komputer dan mesin penyahcas elektrik. Sepanjang projek ini, segala hasil pembelajaran akan digunakan dalam setiap aspek kerja. Untuk mendapatkan pengukuran yang tepat, pelbagai peralatan mengukur digunakan termasuk angkup venier, tolok skru mikrometer, tolok tinggi dan mesin pengukur koordinasi. Hasilnya, plat yang telah diukur, mudah untuk dicantumkan dengan pelbagai komponen acuan dan akhirnya satu set acuan lengkap telah dihasilkan.

(8)

ACKNOWLEDGEMENTS

Assalamualaikum w.b.t. and warm greeting,

First of all, thank to ALLAH SWT for His blessings and for the strength given to me to finish this Projek Sarjana Muda.

I would like to extend my heartfelt gratitude to all that have been contributed to the success of this Projek Sarjana Muda. I wish to acknowledge and express my gratitude and appreciation to my supervisor, Mr. Mohd Amran b. Md Ali for his supervision, encouragement, suggestion and assistance through the research, technician and my parent whose constant encouragement, faith and confidence besides continuously moral support.

I also would like to convey my biggest thanks to Universiti Teknikal Malaysia Melaka (UTeM) and Fakulti Kejuruteraan Pembuatan (FKP) especially Professor Dr. Mohd Razali b. Muhamad, Dean of Faculty of Manufacturing Engineering, my PSM panel and all the lectures in the faculty.

It is a pleasure for me to express huge gratitude to all technician especially Mohd Farihan Bin Mohammad Sabtu and Muhammad Azwan bin Abdul Kadir who construct and guide through completing this research while conducting the machining process in manufacturing workshop as their kindness and willing really regards me with pleasure. I could offer here only an inadequate gesture of my appreciation and all of your good deeds will always be in my mind.

(9)

TABLE OF CONTENTS

Abstract………...

Abstrak………

Acknowledgement………..

Table of Contents………... List of Tables……….. List of Figures………. List of Abbreviations………..

i ii iii iv viii ix xv 1. INTRODUCTION……… 1.1 Background……..……….……….. 1.2 Objective of project………. 1.3 Problem Statement……….…..……… 1.4 Scope of the project………. 1.5 Project Overview….……….…..……….

1 1 3 3 4 4 2. LITERATURE REVIEW……….………...

2.1 Mould………... 2.1.1 Two Plate Mould……….. 2.1.2 Three Plate Mould……… 2.2 Characteristic of Injection Moulding……….….. 2.2.1Impression………..………..

2.2.2Runner.………...………..

2.2.3Gate………..

2.2.4 Air Vent………

2.3 Acrylic……….

2.3.1 Properties of Acrylic……….... 2.3.2 Advantages of Acrylic……….. 2.4Conventional Machine……….

5 5 5 8 10 10 10 11 12 13 14 16 16

(10)

2.4.1Milling Machine………... 2.4.1.1 Type of Milling Machine……….. 2.4.1.2 Vertical Milling Machine……….. 2.4.2 Clasification of Milling... 2.4.2.1 Peripheral Milling……… 2.4.2.2 Face Milling………. 2.4.2.3 End Milling………... 2.5Lathe Machine………. 2.5.1 Component of Lathe Machine... 2.5.1.1 Bed and Ways... 2.5.1.2 Head Stock... 2.5.1.3 Tail Stock... 2.5.1.4 Carriage... 2.5.1.5 Feed Rod... 2.5.1.6 Lead Screw... 2.5.1.7 Crossfeed slide... 2.5.1.8 Accessories and Attachments... 2.5.1.9 Lathe Chuck... 2.6Advance Machining………. 2.6.1Computer Numerical Control (CNC)……….. 2.6.1.1 Movements... 2.6.1.2 Tool Changes... 2.6.1.3 Drilling... 2.6.1.4 Drilling Cycle……….. 2.6.1.5 Parametric Programming………. 2.6.2 Electrical Discharge Machining (EDM)………... 2.6.2.1 Wire EDM Cutting... 2.6.2.2 Possible Shapes... 2.6.2.3 Advantages of Wire EDM cutting... 2.7 Measuring Equipment...

16 17 18 19 19 19 20 20 21 21 22 22 23 23 24 24 24 25 26 27 28 29 30 30 31 32 34 35 35 36

(11)

2.7.1 Vernier caliper... 2.7.2 Coordinate Measuring Machine (CMM)... 2.7.2.1 Machine Body... 2.7.2.2 Machine Probe……….. 2.7.2.3 Physical Principle………... 2.7.3 Height Gauge………... 2.7.4 Micrometer……….. 2.7.4.1 Types………... 2.7.4.2 Reading an Inch System Micrometer………... 2.7.4.3 Reading a Metric Micrometer………...

3. METHODOLOGY………...……

3.1 Introduction………... 3.2 Flow Chart of Mould Assembly……… 3.3 Selection of Component……… 3.4 Assemble Moveable Half……….. 3.5 Checking……… 3.6 Machining………... 3.7 Assemble Stationary Half………... 3.8 Checking……… 3.9 Assemble………... 4. PROBLEM ANALYSIS AND MOULD ASSEMBLY……….. 4.1 Introduction………

4.2 Assembly drawing……….. 4.3 Problem Analysis………... 4.3.1 Sprue Bush………. 4.3.1. Measurement method……… 4.3.1.2 Machining Method………. 4.3.2 Shoulder Guide Bush Over Than Plate and Offset……….. 4.3.2.1 Procedures……….. 4.3.3 Core Plate……….

36 38 39 40 42 42 45 45 46 47 48 48 49 51 51 52 52 53 54 54 55 55 55 59 59 60 62 64 66 74

(12)

4.3.3.1 Method………... 4.3.4 Sprue Bush Loose………. 4.3.4.1 Measurement method………... 4.3.4.2 Machining Procedures………. 4.3.5. Cavity plate 2………. 4.3.5.1 Measurement Procedure………. 4.3.5.2 Machining Procedure………... 4.3.6 Socket Head Cap screw M6 x 25……… 4.3.6.1 Procedure……… 4.3.7 Socket Head Cap Screw M8 x 15……….. 4.3.7.1 Procedure………... 4.3.8 Thread………. 4.3.8.1 Procedure……….. 4.3.9. Sharp Edge………. 4.3.9.1 Procedure……….. 4.3.9.2 Result……… 4.3.10 Oil, Scratch and Mark………... 4.3.10.1 Procedure………

4.4 Mould Assembly………

4.4.1 Moveable Half………. 4.4.1.1 Procedure……….. 4.4.2 Fix Half……….. 4.4.2.1 Procedure……… 4.4.3 Align Moveable Half and Stationary Half……… 5. DISCUSSION……… 5.1 Introduction……….. 5.2 Machining Error………... 5.3 Standard Part……… 5.4 Scratches………..

5.5 Overcut or not enough cut……… 75 76 77 78 80 81 82 84 84 87 87 89 89 91 92 93 94 95 97 97 100 113 115 124 125 125 126 128 128 129

(13)

5.6 Chamfering………... 6. CONCLUSION & RECOMMENDATION………...

6.1 Conclusion………

6.2 Recommendation……….. References………. Appendix A Garnt Chart of PSM 1..……….. Appendix B Garnt Chart of PSM 2………

130 130 130 131 132 134 135

(14)

LIST OF TABLES

(15)

LIST OF FIGURES

2.1.1.1Clamping Unit

2.2.2.1Two Plate Injection Moulding 2.3.2.1 Cooling System

2.4 Water Cooling Located Inside the Mould 2.5 Three Plate Mould

2.6 Concept of 3 Plate Mould 2.7 Impression

2.8 Sprue and Runner 2.9 Gate

2.10 Air Vent

2.11 Acrylic Material

2.12 Vertical Milling Machine 2.13 Face Milling

2.14 Lathe Machine Component 2.15 CNC machine

2.16 CNC spindle 2.17 CNC magazine 2.18 Drilling Process 2.19 EDM machine 2.20 EDM wire cut

2.21 Product from EDM Process 2.22 Vernier Caliper Parts

2.23 Coordinate Measurement Machine (CMM) 2.24 CMM probe

2.25 Height Gauge 2.26 Scriber 2.27 Micrometer 5 6 7 8 8 9 10 11 12 12 14 18 19 21 26 28 29 30 32 34 35 37 38 41 42 44 46

(16)

3.1 Process Flow chart 3.2 Selected Acrylic Plate 3.3 Moveable Half Mould

3.4 CMM

3.5 EDM

3.6 Stationary Half Mould 3.7 Marking Mould 3.8 Complete Mould 4.1 Assembly Drawing 4.2 Bill of Material

4.3 Guide Piller and Shoulder Guide Bush 4.4 Ejector Pin, Locating Ring and Sprue Bush 4.5 Straight Guide Bush

4.6 Product Dimension 4.7 Sprue Bush Area 4.8 Sprue Bush

4.9 CMM Control Panel 4.10 Point to Measure 4.11 Initial Point 4.12 End Point 4.13 Result 4.14 Parting Tool

4.15 3 Jaw Lathe Machine 4.16 After Cutting Process

4.17 Shoulder Guide Bush Location 4.18 Guide Bush Shoulder

4.19 Guide Bush not enough cut hole 4.20 Parallel Bar

4.21 Workpiece on parallel bar 4.22 Edge finder

49 51 51 52 53 53 54 54 55 56 56 57 57 58 59 59 60 60 61 61 62 62 63 64 64 65 65 66 66 67

(17)

4.23 Clamp in milling chuck 4.24 Display of DRO

4.25 X-axis button 4.26 zero button 4.27 Enter Button 4.28 Y-axis button

4.29 All X,Y, Z-axis set zero 4.30 X-axis 2mm

4.31 Y-axis 2mm 4.32 4 Fluid End Mill 4.33 Tool Position 4.34 Machining Process

4.35 Shoulder Guide Bush Fit into the Hole 4.36 Radius Area

4.37 File Area

4.38 core insert fit into core plate 4.39 Loose sprue bush

4.40 mild steel 4.41 Washer Area 4.42 Result

4.43 Facing Process 4.44 Parting process 4.45 washer

4.46 Cavity Insert Location 4.47 Measure Cavity Insert 4.48 Measure cavity plate 2 4.49 Result

4.50 Dial Gauge 4.51 Boring process

4.52 Cavity insert fix into cavity hole

67 68 68 69 69 70 70 71 71 72 72 73 73 74 75 75 76 76 77 77 78 78 79 80 81 81 82 82 83 83

(18)

4.53 M6 x 25 locations

4.54 Socket Head Cap screw M6 x 25 4.55 Cutting Process

4.56 M6 screw that been cut 4.57 Cut off area

4.58 Ejector pin Socket Head cap screw M8 x 15 location 4.59 Cutting Process

4.60 Result

4.61 All M8 x 15 fit into hole 4.62 Damage Thread

4.63 Threading Tool 4.64 Tappering process 4.65 Result

4.66 Sharp edge

4.67 Chamfering machine 4.68 Chamfering Process 4.69 Repeating Process 4.70 Before chamfering 4.71 After Chamfering 4.72 Oil, scratch and mark 4.73 Denurated alcohol 95% 4.74 Workpiece

4.75 Cleaning Process 4.76 Clean Plate

4.77 Moveable Half Flow Chart 4.78 Ejector Base Plate

4.79 Socket head cap screw M6 x 25 4.80 Ejector Pin

4.81 Ejector Pin with Ejector Plate

4.82 Ejector Base Plate with Ejector Plate

84 84 85 85 86 87 87 88 88 89 89 90 90 91 91 92 92 93 93 94 94 95 95 96 97 100 100 101 101 102

(19)

4.83 Core insert 4.84 Core plate

4.85 Core insert with core plate 4.86 Stripper plate

4.87 Stripper plate with core plate 4.88 Backup plate

4.89 Guide piller

4.90 Backup, Core Plate and Stripper Plate with Guide Piller 4.91 Ejector plate with backup, core plate, stripper plate 4.92 Spacer Block

4.93 Join spacer block 4.94 Bottom Clamping Plate

4.95 Socket head cap screw M10 x 100 4.96 Joint bottom clamping plate 4.97 Guide bush

4.98 Guide bush location 4.99 Set screw m6 x 10

4.100 Set screw M6 x 10 location 4.101 Socket head cap screw M6 x 25

4.102 Joint Socket head cap screw M6 x 25 with ejector pin 4.103 Complete movable half

4.104 Fix Half Flow Chart 4.105 Guide bush shoulder 4.106 Cavity plate

4.107 Guide bush shoulder with Cavity plate 4.108 Cavity inserts 1

4.109 Cavity insert 1 with cavity plate 2 4.110 Cavity inserts 2

4.111 Cavity Plate 1

4.112 Cavity Inserts 2 with Cavity Plate 1

102 103 103 104 104 105 105 106 106 107 107 108 108 109 109 110 110 111 111 112 112 114 115 115 116 116 117 117 118 118

(20)

4.113 Cavity plate 1 with cavity plate 2 4.114 Top clamping plate

4.115 Socket head cap screw M6 x 25

4.116 Socket head cap screw M6 x 25 with top clamping plate 4.117 Sprue bush

4.118 Sprue bush in the locating ring 4.119 Locating ring

4.120 Counter sunk cap screw M4 x 8

4.121 Counter sunk cap screw M4 x 8 location 4.122 Complete fix half

4.123 Align fix half and stationary half 4.124 Complete set of mould

5.1 Datum and reference point 5.2 Digital Readout (DRO) 5.3 Clamping Area

5.4 Radius in core insert 5.5 Silicon area

119 119 120 120 121 121 122 122 123 123 124 124 125 126 127 127 128

(21)

LIST OF ABBREVIATIONS

CMM - Coordinate Measurement Machine EDM - Electric Discharge Machine CAD - Computer Aided Design CAM - Computer Aided Machining CNC - Computer Numerical Control NC - Numerical Control

(22)

CHAPTER 1 INTRODUCTION

1.1 Background

Injection moulding is a process in which a polymer is heated to a highly plastic state and forced to flow under high pressure into a mold cavity, where it solidifies. The moulded part, called a moulding, is then removed from the cavity. The process produces discrete components that are almost always net shape. The production cycle time is typically in the range 10 to 30 seconds, although cycles of one minute or longer are not uncommon.

Mould consists of various type of component. Such as locating ring, sprue bush, guide bushes and guide pillar, ejector system, sprue puller, return pin and ejector rod. Mould is devided into two parts. moveble half dan stationary half. Moveable half consist of several component that which are core plate, support plate, space block, top ejector plate, bottom ejector plate and bottom clamping plate, meanwhile stationary half is consist of top clamping plate and cavity plate. There are two type of mould, firstly two plate mould, and three plate mould.

In this project, the 2 plate mould was chosen in order to produce a cup mould. The purpose is to assemble the cup mould and define any defect on the mould and proceed to remachine the mould back if any defect is found. Mould are usually made from pre hardener metal, but in this project, acrylic material was used as a mould. Acrylic is a

(23)

useful, clear plastic that resembles glass, but has properties that make it superior to glass in many ways. Common brands of high-grade acrylic include Polycast, Lucite and Plexiglass. There are two basic types of acrylic, extruded and cell cast. Extruded or "continuous cast" acrylic is made by a less expensive process, is softer, can scratch easier and may contain impurities. Cell cast acrylic is a higher quality acrylic and it has been use for jet and airplane glass. The advantages using acrylic mould in this project, the mould is transparent and clear. This mean every process in injection mould can be see clearly.

Conventional machine has been used in this project. Variety machine such as milling and lathe were use to remachine the defect area. The machining process that are learn at the last semester such as drilling, boring, facing, surfacing and others are practiced in this project.

Measurement equipment such as verniar caliper, high gauge, dial indicator and Coordinate Measurement Machine (CMM) has been implemented in this project. This is to ensure the accuracy of each plate. Accuracy is very important in injection moulding, it is because it will influent the size of product.

(24)

1.2 Objectives

The main objective of this project is to assemble the plastic injection mould. To achieve this project there are five objectives:

1. To find out any defect, machining error, out of dimension in plastic injection mould.

2. To fix all mould plates at movable half and stationary half.

3. To align all the guide pin and guide bush between moveable half and stationary half.

4. To fix all mould components and inserts to the reference follow the assembly drawing.

5. To assemble all plates, component and insert for producing one set of mould.

1.3 Problems Statement

After machining, all plates of injection mould need to be assemble into one mould. However, there are some plates and components cannot assembly in one mould. Due to that, procedure of mould assembly should be prepared for industrial guide.

There are many sources, why plastic injection mould cannot assembly. Firstly the method to assemble between moveable half and stationary half is not documented. The wrong method to assemble the mould was use. To solve this problem, procedure of assembling mould should be documented.

Secondly, some plate may be machine with wrong dimension. For example offset, over cut, not enough cut and etc. To ensure that all plate were machine accurately, all plate should be checked using measurement tool such as vernier caliper, micrometer, and CMM.

(1)