Investigating the influence of materials on the durability of composite products in the injection molding technology

ABSTRACT TOPIC NAME INVESTIGATING THE INFLUENCE OF MATERIALS ON THE DURABILITY OF COMPOSITE PRODUCTS IN THE INJECTION MOLDING TECHNOLOGY This graduation project aims to sample two differ

MINISTRY OF EDUCATION AND TRAINING

HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY AND EDUCATION

FACULTY FOR HIGH QUALITY TRAINING

CAPSTONE PROJECT ELECTRONICS AND TELECOMMUNICATIONS

ENGINEERING TECHNOLOGY

INVESTIGATING THE INFLUENCE OF MATERIALS

ON THE DURABILITY OF COMPOSITE PRODUCTS

IN THE INJECTION MOLDING TECHNOLOGY

LECTURER: Ph.D NGUYEN VAN THUC STUDENT: TRUONG THIEN TRIEU

VO QUOC TRUNG

LE DUC KHAI

S K L 01 0 8 5 1

MINISTRY OF EDUCATION AND TRAINING

HO CHI MINH CITY UNIVERCITY OF TECHNOLOGY AND

EDUCATION _

FACULTY OF MECHANICAL ENGINEERING

GRADUATION THESIS

Ho Chi Minh city, July 2023

INVESTIGATING THE INFLUENCE OF MATERIALS

ON THE DURABILITY OF COMPOSITE PRODUCTS IN

THE INJECTION MOLDING TECHNOLOGY

Supervisor: Ph.D NGUYEN VAN THUC

Student’s name: TRUONG THIEN TRIEU MSSV: 19144210

VO QUOC TRUNG MSSV: 19144212

LE DUC KHAI MSSV: 19144130 Academic year: 2019-2023

HO CHI MINH CITY UNIVERCITY OF TECHNOLOGY AND

EDUCATION FACULTY FOR HIGH QUALITY TRAINING

INJECTION MOLDING TECHNOLOGY

Supervisor: Ph.D NGUYEN VAN THUC

Student’s name: TRUONG THIEN TRIEU MSSV: 19144210

VO QUOC TRUNG MSSV: 19144212

LE DUC KHAI MSSV: 19144130 Academic year: 2019-2023

Ho Chi Minh city, July 2023

HO CHI MINH UNIVERSITY OF TECHNOLOGY AND

EDUCATION

SOCIALIST REPUBLIC OF VIETNAM

Independence - Freedom - Happiness

HIGH QUALITY TRAINING FACULTY

GRADUATION PROJECT TASKS

Semester II/School year 2023

Instructor: Ph.D Nguyen Van Thuc

Student: Truong Thien Trieu MSSV: 19144210 DTx: 0948955598

Vo Quoc Trung MSSV: 19144212 DTx: 0778764800

Le Duc Khai MSSV: 19144130 DTx: 0979057015

1 Project ID number: 22223DT331

-Topic name: INVESTIGATING THE INFLUENCE OF MATERIALS ON

THE DURABILITY OF COMPOSITE PRODUCTS IN THE

INJECTION MOLDING TECHNOLOGY

2 Initial figures and documents:

- Mold set MAU THU WELDLINE, domestic and foreign documents

3 Main contents of the project:

- Learn the theory of composite materials

- Learn about injection molding parameters

- Create injection molding patterns

- Analysis report and experimental sample

5 Project delivery date: 15/03/2023

6 Date of submission of the project: 15/07/2023

7 Presentation Language:

Protection presentation: English  Vietnamease 

(Sign, specify full name)

Permitted to present the research project: ………

(Instructor sign, specify full name)

- Topic name: INVESTIGATING THE INFLUENCE OF MATERIALS ON THE DURABILITY OF COMPOSITE PRODUCTS IN THE INJECTION MOLDING TECHNOLOGY

- Supervisor: Ph.D Nguyen Van Thuc

- Student name: :

Truong Thien Trieu MSSV: 19144210 DTx: 0948955598

Address: Alley 9/10, Street 22, Phuoc Long B, Thu Duc

- Thesis submission date: 15/07/2013

- Commitment: “I hereby declare that this graduation thesis is the result of our own research and implementation We have not copied from any published articles without proper citation of the original sources If there is any violation, we take full responsibility for it”

Ho Chi Minh City, 15th July 2023 Signature

THANK YOU

I would like to extend my sincere appreciation and gratitude to Ph.D Nguyen Van Thuc and all the professors in the faculty committee for their invaluable support and guidance, which have been instrumental in helping our team successfully complete our graduation project to the best of our abilities

Ph.D Nguyen Van Thuc, your expertise and mentorship have played a crucial role

in our project's success Your deep knowledge, insightful feedback, and unwavering commitment to our development have challenged and inspired us to achieve our best

We are truly grateful for the time and effort you have dedicated to ensuring our project's excellence

To all the professors in the faculty committee, we are immensely thankful for your valuable input, constructive criticism, and encouragement throughout the journey Your expertise and diverse perspectives have enriched our project and broadened our understanding of the subject matter Your unwavering support and belief in our potential have motivated us to push boundaries and strive for excellence

We are humbled and honored to have had the opportunity to work under your guidance and supervision Your dedication, passion, and commitment to our academic growth have made a lasting impact on our development as aspiring professionals

We would also like to express our gratitude to the entire faculty for providing us with a conducive learning environment and the necessary resources to carry out our project effectively Your unwavering support and commitment to fostering our academic growth have been invaluable

Once again, we extend our heartfelt thanks to Ph.D Nguyen Van Thuc and all the professors in the faculty committee for their invaluable assistance and support throughout our journey We are truly grateful for the opportunity to learn from your expertise and for your unwavering belief in our abilities Your guidance has shaped

us into better individuals and has prepared us for future endeavors

TÓM TẮT ĐỒ ÁN TÊN ĐỀ TÀI

NGHIÊN CỨU ẢNH HƯỞNG CỦA VẬT LIỆU ĐẾN ĐỘ BỀN CỦA SẢN PHẨM

COMPOSITE TRONG CÔNG NGHỆ KHUÔN ÉP

Đồ án tốt nghiệp này nhằm lấy mẫu hai loại nhựa Polyamide 6 (PA6) khác nhau

gồm PA6 có 30% sợi thủy tinh và PA6 không có sợi thủy tinh (PA6 0%) Quá trình

lấy mẫu sẽ được thực hiện để thu được các mẫu nhựa có độ dày và hình dạng cụ thể,

chuẩn bị cho các thử nghiệm tiếp theo

Sau khi lấy được các mẫu nhựa, chúng sẽ trải qua quá trình kiểm tra độ bền kéo để

đánh giá độ bền của chúng Thử kéo sẽ tác dụng lực kéo tiêu chuẩn lên mẫu nhựa và

ghi lại các thông số như lực kéo, độ giãn dài, độ cứng tối đa Bằng cách so sánh kết

quả thử nghiệm giữa hai loại nhựa PA6, chúng ta có thể đánh giá và so sánh tác động

của sợi thủy tinh đến độ bền và cơ tính của nhựa

Sau khi hoàn thành thử nghiệm độ bền kéo, các mẫu sẽ được đưa vào Kính hiển vi

điện tử quét (SEM) để nghiên cứu đặc điểm bề mặt của chúng SEM cho phép chụp

ảnh bề mặt mẫu với độ phóng đại cao, cung cấp thông tin chi tiết về cấu trúc và hình

dạng của nhựa Qua phân tích ảnh SEM, chúng ta có thể quan sát và đánh giá được

sự phân bố sợi thủy tinh trong mẫu nhựa PA6 30% và sự khác biệt so với mẫu nhựa

PA6 0%

Kết quả thu được sẽ bao gồm dữ liệu phân tích thống kê, biểu đồ và hình ảnh liên

quan Ví dụ: chúng sẽ bao gồm các thông số kiểm tra độ bền kéo, biểu đồ ứng

suất-biến dạng, kết quả kiểm tra độ bền kéo và cuối cùng là tối ưu hóa bằng ANN và GA

Các thông số kiểm tra độ bền kéo sẽ bao gồm lực tối đa, độ giãn dài và độ cứng,

là các chỉ số cơ bản về tính chất cơ học của nhựa PA6 Các thông số này sẽ giúp đánh

giá độ bền và hiệu suất của các mẫu và cho phép so sánh giữa PA6 có và không có

sợi thủy tinh Các biểu đồ ứng suất-biến dạng sẽ minh họa hành vi của vật liệu dưới

các lực tác dụng, cung cấp cái nhìn sâu sắc về các đặc tính đàn hồi, dẻo và biến dạng

của chúng

Student’s name

ABSTRACT TOPIC NAME

INVESTIGATING THE INFLUENCE OF MATERIALS ON THE DURABILITY

OF COMPOSITE PRODUCTS IN THE INJECTION MOLDING TECHNOLOGY

This graduation project aims to sample two different types of Polyamide 6 (PA6) plastics, including PA6 with 30% glass fiber and PA6 without glass fiber (PA6 0%) The sampling process will be carried out to obtain plastic samples with specific thickness and shape, in preparation for further testing

Once the plastic samples are obtained, they will undergo tensile testing to evaluate their strength The tensile test will apply standard pulling forces to the plastic samples and record parameters such as maximum force, elongation, and stiffness By comparing the test results between the two types of PA6 plastics, we can assess and compare the impact of glass fiber on the strength and mechanical properties of the plastic

After completing the tensile testing, the samples will be subjected to Scanning Electron Microscopy (SEM) to study their surface characteristics SEM allows high-magnification imaging of the sample surfaces, providing detailed information about the structure and shape of the plastic By analyzing SEM images, we can observe and evaluate the distribution of glass fibers in the PA6 30% plastic samples and the differences compared to PA6 0% plastic

The obtained results will consist of statistical analysis data, charts, and relevant images For example, these will include tensile strength test parameters, stress-strain diagrams, tensile strength test results, and ultimately, the optimization using ANN and GA

The tensile strength test parameters will include maximum force, elongation, and stiffness, which are essential indicators of the mechanical properties of the PA6 plastics These parameters will help evaluate the strength and performance of the samples and enable a comparison between PA6 with and without glass fiber The stress-strain diagrams will illustrate the behavior of the materials under applied forces, providing insights into their elasticity, plasticity, and deformation characteristics

TABLE OF CONTENTS

GRADUATION PROJECT TASKS i

COMMITMENT ii

THANK YOU iii

ABSTRACT iv

TABLE OF CONTENTS v

LIST OF TABLES vi

LIST OF DIAGRAMS, DRAWINGS vii

LIST OF ACRONYMS viii

CHAPTER 1: INTRODUCTION 1

1.1 Overview of research in the subject area: 1

1.1.1 Domestic 1

1.1.2 Foreign 2

1.2 Reason for choosing a topic 3

1.3 Topic objective 3

1.4 Research methodology 3

1.5 Subject and scope of study 4

CHAPTER 2: THEORETICAL BASIC 5

2.1 Introduction of PA6 (Polyamide 6) 5

2.1.1 Define of PA6 5

2.1.2 Physical properties of PA6 5

2.1.3 Chemical properties of PA6 6

2.1.4 Application of PA6 6

2.2 Overview of Glass fiber 6

2.2.1 Formation process 6

2.2.2 The composition of glass fibers 7

2.2.3 Properties 7

2.2.4 Classification 8

2.2.5 Application 8

2.2.6 Glass fiber manufacturing 9

2.3 PA6 GF30% properties and applications (Polyamide 6 including glass fiber 30%) 10

2.3.1 Properties: 10

2.3.2 Application: 11

2.4 Technical specification of PA6 and PA6 + GF30% plastic 11

2.4.1 Technical specification of PA6 11

2.4.2 Technical specification of PA6 + GF30% plastic 12

2.4.3 Comparision between PA6 and PA6 + GF30% 13

2.5 Overview of injection molding technology 15

2.5.1 Definition 15

2.5.2 Injection molding machine 15

2.5.3 Possible defects after the Injection Molding process 24

2.5.4 Advantages and disadvantages of Injection Molding Technology 24

2.6 Mechanical Testing 25

2.6.1 Definition 25

2.6.2 Mechanical testing 25

2.6.3 ASTM D2240 standard and Shore hardness testing method 28

2.7 Surface inspection using SEM 35

2.7.1 Overview of SEM (Scanning Electron Microscope) 35

2.7.2 The history of Scanning Electron Microscope 36

2.7.3 The operating principle and image formation in SEM 37

CHAPTER 3: EXPERIMENTAL AND SELECTION PROCESS 40

3.1 Process of forming tensile test specimens 40

3.2 Experimental process 41

3.3 Selection process 47

CHAPTER 4: ANALYSIS AND EVALUATION OF THE RESULTS 48

4.1 Results before and after parameter selection 48

4.1.1 Before selection process 48

4.1.2 The finalized set of parameters 50

4.2 Comparison 56

4.3 SEM analysis 56

4.4 Optimization process 58

CHAPTER 5: CONCLUSION AND RECOMMENDATION 67

5.1 Conclusion 67

5.1.1 Comparison and optimization 67

5.2 Recommendation 70

REFERENCES 72

APPENDIX 74

LIST OF TABLES

Table 2.1: Technical specifications of Libolon PA6 N200 plastic 12

Table 2.2: Technical specifications of Akulon K224 – G6 PA6 plastic 12

Table 3.1: Detailed information for each of these Durometer types 33

Table 3.2: Shore durometers of common materials 34

Table 3.3: The minimum value table for the parameter set of PA6 30%GF at normal temperature 42

Table 3.4: Five levels of utilization in the univariate table 43

Table 3.5: Univariate value table for PA6 + 30% glass fiber plastic 43

Table 3.6: Strength testing data of PA6 with 30% glass fiber 45

Table 4.1: The experimental parameter table of PA6 30%GF 48

Table 4.2: The final parameter table for PA6 30% GF 50

Table 4.3: The final parameter table for PA6 0% 53

Table 4.4: Comparison between the network output and experimental testing data for PA6 30%GF 62

Table 4.5: Comparison between the network output and experimental testing data for PA6 0% 63

Table 4.6: The Pareto table of optimized results for PA6 30%GF 65

Table 4.7: The Pareto table of optimized results for PA6 0% 66

Table 5.1: A table comparing the theoretical results and the actual outcomes for PA6 30%GF 68

Table 5.2: A table comparing the theoretical results and the actual outcomes for PA6 0% 69

Table 5.3: Comparison table of optimized parameters between the two plastic types 70

LIST OF DIAGRAMS, DRAWINGS

Chart 4.1: The results of the parameter “ Filling time” of PA6 30%GF 51

Chart 4.2: The results of the parameter “ Packing time” of PA6 30%GF 51

Chart 4.3: The results of the parameter “ Melt temperature” of PA6 30%GF 52

Chart 4.4: The results of the parameter “ Mold temperature” of PA6 30%GF 52

Chart 4.5: The results of the parameter “ Filling time” of PA6 0% 54

Chart 4.6: The results of the parameter “ Packing time” of PA6 0% 54

Chart 4.7: The results of the parameter “ Melt temperature” of PA6 0% 55

Chart 4.8: The results of the parameter “ Mold temperature” of PA6 0% 55

Chart 5.1: The correlation of strength between PA6 30%GF and PA6 0% 68

Chart 5.2: Comparison between actual and theoretical tensile strength for PA6 30%GF 69

Chart 5.3: Comparison between actual and theoretical tensile strength for PA6 0% 69

Figure 2.1: Nylon 6 (PA6) 5

Figure 2.2: Glass fiber 7

Figure 2.3: PA6 reinforced with glass fiber 30% 11

Figure 2.4: Horizontal Injection Molding Machine 15

Figure 2.5: Vertical Injection Molding Machine 16

Figure 2.6: Structure of the Injection Molding Machine 16

Figure 2.7: Plastic Injection Molding system 17

Figure 2.8: Clamping and injection phase 18

Figure 2.9: Cooling and Product Ejection phase 19

Figure 2.10: Universal Compression Testing Machine 25

Figure 2.11: Structure of Universal Compression Testing Machine 26

Figure 2.12: The deformation of the tensile specimen 27

Figure 2.13: Shore D durometer 30

Figure 2.14: Shore A and Shore D indentor 31

Figure 2.15: The Shore hardness scales 32

Figure 2.16: Scanning Electron Microscope 36

Figure 2.17: Description of the different types of radiation 38

Figure 3.1: Mold set MAU THU WELDLINE 40

Figure 3.2: Tensile test specimen 41

Figure 3.3: The sample is fractured into two pieces 44

Figure 4.1: The glass fiber structure within PA6 56

Figure 4.2: A close-up view of the magnified glass fibers 57

Figure 4.3: PA6 plastic structure 57

Figure 4.4: Magnify the location of fracture 58

Figure 4.5: The architechture of feedforward network 59

Figure 4.6: The data input is in matrix format for PA6 30%GF in MATLAB 59

Figure 4.7: The data output is in matrix format for PA6 30%GF in MATLAB 59

Figure 4.8: Results after training 60

Figure 4.9: The R-squared results of PA6 30%GF 60

Figure 4.10: The R-squared results of PA6 0% 61

Figure 4.11: The fitness function 64

Figure 4.12: The optimized result for PA6 30%GF 64

Figure 4.13: The data input is in matrix format for PA6 0% in MATLAB 65

Figure 4.14: The data output is in matrix format for PA6 0% in MATLAB 65

Figure 4.15: The optimized result for PA6 0% 66

LIST OF ACRONYMS

GF Glass Fiber

GA Genetic Algorithm

CHAPTER 1: INTRODUCTION 1.1 Overview of research in the subject area:

In another study, Nguyen Tien Cuong, Nguyen Hoang Duong, Nguyen Huu Nieu, Duong Tu Tien, 2011 “Research into fabrication pa6/clay-nanocomposites in order

to make water lubricated stern tube bearings” Jourmal of Science and Technology Development, 14(1), 39-45 The study produced PA6/Clay-nanocomposite with mechanical properties equivalent to (20%-30%)GF composite Using a self-made mixer MLKNHU01 with a capacity of 500g/batch, the research utilized various equipment such as injection molding machines, tensile and bending testing machines, and impact testing machines The results showed that, compared to PA6, the mechanical and thermal properties of PA6/clay-nanocomposite in a water-saturated state, such as tensile strength, increased by 30%, bending strength increased by 9%, impact resistance increased by 15%, and heat deflection temperature (HDT) increased

by 40% Furthermore, compared to Russia's Carpon, PA6/clay-nanocomposite exhibited better properties as mentioned above

1.1.2 Foreign

Research on PA6 (Polyamide 6) has been conducted worldwide in various fields Some studies have focused on the mechanical and physical properties of PA6, including the mechanical strength and durability of PA6 under tension, impact, high temperature, etc This research has provided important information on the properties

of PA6 and helped improve the production process

A study on the influence of chemical foaming on the structure and selected properties of glass fiber reinforced PA6 (Natalia Konczal, Bartosz Nowinka, Marek Bieliński, 2022) focuses on the effect of chemical foaming argents on the structure, analyze through SEM imaging and selected properties of PA6 reinforced with glass fibers (30-60% wt%) The density, tensile properties and Charpy impact strength were determined The result showed that the foaming process of PA6 moldings containing a high content of glass fiber caused a decrease in their specific tensile strength and did not contribute to a significant change in the specific impact strength Smaller pores have been observed in the material containing higher glass fiber content.Chemical foaming of PA6 containing a high glass fiber content contributed

to the change of mechanical properties and density reduction Materials with such properties can be used in the automotive, machine and aviation industries

Kroll, M., Langer, B, and Grellmann, W (2012) "Toughness Optimization of Elastomer-Modified Glass-Fiber Reinforced PA6 Materials" Jounrnal of applied polymer science, 127(1), 57-66 In this study, they investigated the influence of humidity and EPR-g-MA content on the fracture behavior of glass fiber reinforced PA6 material The transition temperature from brittle to ductile (Tbtt) was determined Two characteristic temperature at the points of Ts and Te were determined Which were the intercept between elastic and elastic–plastic deformation on the one hand and the starting point of dominating stable crack propagation with strong plastic deformation on the other hand Characteristic brittle-to-tough transition temperatures Tbtt could be calculated as the arithmetic average of these two points The result showed that, moiture affects the glass transition temperature and significantly decreases strength and stiffness in the main application temperature range The addition of elastomeric material has altered the transition from brittle to ductile process towards lower temperatures The Jid values have demonstrated that they are within the range of the transition of strength after water absorption in some cases

Other studies have focused on developing PA6 with special properties, including heat and flame resistance, high flexibility, antimicrobial properties, etc These studies are also being conducted to investigate the application of PA6 in fields such as healthcare and the environment

In addition, research has also focused on the production process of PA6, with the aim of reducing emissions and optimizing the production process New production methods have also been developed to increase efficiency and reduce production costs

1.2 Reason for choosing a topic

There are several reason why we choose that topic First, Composite products are

a rapidly developing field in the industry This is also means that there will be many opportunities for research in this area

Second, studying the materials that influence the durability of composite products

in injection molding is necessary to improve product quality and reduce production costs

Third, this research can also help businesses producing composite products enhance competitiveness in the market, it may also open up new research directions

in the field of composite materials and can also have applications in other fields, such

as healthcare, energy, etc

1.3 Topic objective

Studying the changes in PA6 material between heat-treated and non-heat-treated conditions, the difference between PA6 GF30% and PA6 0% and the effect of weld lines on their properties and durability In this study, samples of two different types

of plastics, PA6 GF30% and PA6 0%, were compressed and tested under both treated and non-heat-treated conditions The data were analyzed and evaluated through SEM imaging

1.5 Subject and scope of study

Issues and areas related to PA6 (Polyamide 6 including GF30% and 0%), the influence of weldline on the properties of plastic

CHAPTER 2: THEORETICAL BASIC 2.1 Introduction of PA6 (Polyamide 6)

2.1.1 Define of PA6

PA6 stands for Polyamide 6, also known as Nylon 6 It is a synthetic engineering plastic with superior properties, typically used in mechanical and industrial applications

PA6 is a high-strength plastic that is relatively stiff yet also has some flexibility It has good resistance to abrasion and impact, and is also heat-resistant and chemical-resistant, making it suitable for use in a wide range of applications PA6 also has high dynamic strength, making it suitable for use in dynamic applications

PA6 can be fabricated into various products such as fibers, films, wires, fabrics, and other engineering plastic products It can be reinforced with glass fibers to increase its stiffness and strength, and can also be synthesized with other types of polyamides such as PA66/PA6

Figure 1 Nylon 6 (PA6)

2.1.2 Physical properties of PA6

- The melting temperature is 220oC and the phase transition temperature is 40-50oC

- The molecular weight limit is around 105 g/mol

- The density is 1.13 g/cm3

- It has good load-bearing capacity at high temperatures

- It has good chemical properties and wear resistance

- It has a low coefficient of friction

- It is stiff and impact-resistant

2.1.3 Chemical properties of PA6

- Nylon 6 is not resistant to acid and base environments

- The amide group can be hydrolyzed to form amine and carboxyl

- They are easily hydrolyzed in acidic environments, and bases can either break down the polymer chain or completely hydrolyze them into individual monomers

- Hydrolysis of Nylon 6 in an acidic or basic environment

Nylon-6 can also be used to manufacture machine parts such as gears, connecting parts, and drive parts in engines It is also used in electrical circuit breakers, wire coil cores, and plugs

It is used to make thin film coatings, casing for electrical devices, and coverings for electrical wires It is also used as the basic fiber in grass cutting machines or fishing lines, in tires for vehicles, and in making molds for various types of containers

2.2 Overview of Glass fiber

2.2.1 Formation process

Glass fibers are formed based on silica or glass formula and are compressed into many small diameter fibers suitable for further weaving process The method for producing fiberglass was invented by Games Slayter at Owens-Illinois Glass Co (Toledo, Ohio) Including the Mineral Fiber Group: glass fibers, carbon fibers,

ceramic fibers; stable thermal synthetic fiber group: Kermel fibers, Nomex fibers, Kynol fibers, Apyeil fibers

2.2.2 The composition of glass fibers

In glass fibers, the main component is fiberglass Fiberglass is formed by melting glass and can be blown into small and short fibers using a high-temperature hot air stream This is the fiberglass

Figure 2.2.2 Glass fiber

There is now a type of glass fiber that is extremely small, formed by 200 small fibers combined together, with a size at that time only as big as a hair strand It has very strong heat retention properties, for example, the heat retention ability of a 3cm thick glass fiber insulation material can be equivalent to a 1m thick brick wall The sound insulation ability of glass fiber is also very good Therefore, it is used as a material for insulation, soundproofing, shock absorption, and filtering in many industries today

2.2.3 Properties

Thermal properties

Fabrics of woven glass fibers are useful thermal insulators because of their high ratio of surface area to weight However, the increased surface area makes them much more susceptible to chemical attack By trapping air within them, blocks of glass fiber

make good thermal insulation, with a thermal conductivity of the order of 0.05 W/(mK)

Mechanical properties

The strength of glass is typically tested and reported for "virgin" or pristine fibers, referring to those that have just been manufactured The freshest and thinnest fibers exhibit the highest strength because thinner fibers tend to be more ductile The extent

of surface scratching directly affects the resulting tenacity, with greater scratches leading to reduced strength Glass, being amorphous in structure, possesses consistent properties along and across the fiber Humidity plays a crucial role in tensile strength

as moisture easily adsorbs and can worsen microscopic cracks, surface defects, and diminish tenacity

In contrast to carbon fiber, glass has a greater capacity for elongation before breaking Thinner filaments can withstand more bending before fracturing The viscosity of molten glass holds significant importance in successful manufacturing During the drawing process, where hot glass is pulled to reduce the fiber diameter, the viscosity needs to be relatively low If the viscosity is too high, the fiber may break during drawing Conversely, if the viscosity is too low, the glass will form droplets instead of being drawn into fiber form

2.2.4 Classification

Glass fibers can be divided into 5 types:

A - Glass, also known as alkali glass A-Glass fibers have the ability to resist chemicals and have some similarities to window glass Outside of the United States,

it is used to manufacture processing equipment

C - Glass, also known as chemical glass C-Glass has a very good ability to resist chemical impacts

E - Glass, also known as electrical glass Electrical glass is an excellent insulating material

AE - Glass, alkali-resistant glass S-Glass, also known as structural glass

S - Glass is used for its mechanical properties

2.2.5 Application

Glass fiber is an extremely versatile material due to its lightweight, good strength, weather resistance, and various surface shapes In the 1930s, the development of

glass-reinforced plastic was extensively studied and developed in the industry It was particularly focused on in the aerospace industry During World War II, glass fiber was developed to replace the cast plywood used in aircraft, and its use was expanded

to the automotive and sports equipment fields

Tank

A fiberglass tank can have a capacity of up to 300 tons Better tanks can be made using woven mats or filament winding, with fibers oriented at a right angle to the hoop stress applied to the sidewall Such tanks are often used to contain chemicals because the plastic lining has the ability to resist chemical corrosion

House building

Fiberglass-reinforced types of adhesives are also used to produce building components such as laminate roofing panels, door frames, window awnings, chimney pipes, bracing and door supports

Pipiline

GRP and GRE pipes are widely used in many aboveground and underground piping systems, including systems for desalination, water treatment, water distribution networks, chemical processing plants, fire suppression, hot and cold water, wastewater, liquefied gas, etc

Specific applications of fiberglass include: equipment handles, traffic lights, ship hulls, water pipes, helicopter rotor blades, antenna shells and structures, vehicle parts

or entire bodies, and so on

2.2.6 Glass fiber manufacturing

To manufacture glass fiber, use the following steps:

Prepare the raw materials: Glass fibers are made from a combination of silica (silicon dioxide), limestone, soda ash, and other additives

Melting: The raw materials are heated in a high-temperature furnace until they melt and form a viscous liquid called molten glass

Fiber formation: The molten glass is then forced through tiny openings called spinnerets As the molten glass passes through the spinnerets, it is rapidly cooled with

a stream of air or gas, which solidifies it into fine fibers

Coating: To improve the strength and handling properties of the fibers, they are coated with a protective material Typically, a polymer coating is applied to the fibers

Collection: The fibers are collected on a conveyor belt or a rotating drum, forming

a continuous strand of glass fibers

Further processing: The continuous strand of glass fibers can undergo additional processes such as cutting, bundling, and winding onto spools, depending on the desired application

Quality control: Throughout the manufacturing process, quality control measures are implemented to ensure the fibers meet the required specifications

2.3 PA6 GF30% properties and applications (Polyamide 6 including glass fiber 30%)

PA6 GF30 stands for Polyamide 6 reinforced with 30% glass fibers It is a strength engineering plastic that has improved stiffness, strength, and thermal resistance compared to standard PA6

high-The addition of glass fibers to PA6 results in a composite material that has a higher modulus of elasticity, better dimensional stability, and improved creep resistance PA6 GF30 is commonly used in applications that require high strength, stiffness, and dimensional stability, such as automotive parts, electrical and electronic components, and industrial machinery

PA6 GF30% can be processed using various methods such as injection molding, extrusion, and compression molding The glass fibers can be oriented in a specific direction to further improve the mechanical properties of the material

2.3.1 Properties:

- High tensile strength: With the reinforcement of glass fibers, PA6 GF30 has higher tensile strength than conventional PA6 This helps to increase load-bearing capacity and reduce deformation during use

- High hardness: PA6 GF30 also has higher hardness than conventional PA6 due to reinforcement by glass fibers This improves impact resistance and bending resistance

of the material

- Good heat resistance: With the improved heat resistance properties of conventional PA6, PA6 GF30 can withstand higher temperatures and is used in applications that require high temperatures

- Good dimensional stability: Glass fibers help improve the dimensional stability of the material, reducing deformation during use and ensuring the accuracy of product dimensions

- Good wear resistance: PA6 GF30 has good wear resistance, increasing the durability and lifespan of the product

2.3.2 Application:

- PA6 GF30 (30% glass fiber reinforced Polyamide 6) is commonly used in applications that require high strength, rigidity, and dimensional stability Some of the common applications of PA6 GF30% are: automotive industry, electrical and electronic industry, industrial machinery, sports equipment, aerospace industry

Figure 2.3.1 PA6 reinforced with glass fiber 30%

2.4 Technical specification of PA6 and PA6 + GF30% plastic

The following is table of technical specifications for two types of plastics:

2.4.1 Technical specification of PA6

Table 2.4.1 Technical specifications of Libolon PA6 N200 plastic

STT Technical data Standard Unit Value

5 TensileYield Strength ASTM D638 MPa 85.9

9 IZOD Notched Impact

14 Melting Index 2700C, 1.2kg - g/10min 8.76

15 Surface resistance ASTM D257 Ohm 3.0x10^14

16 Volume resistance ASTM D257 Ohm*cm 1.02x10^15

17 Dielectric strength ASTM D149 kV/mm 12.5

18 Dielectric constant at 1 MHz ASTM D150 kV/mm 5.29

2.4.2 Technical specification of PA6 + GF30% plastic

Table 2.4.2 Technical specifications of Akulon K224 – G6 PA6 plastic

STT Technical data Standard Unit Value

(dry/cond)

1 Mold Shrinkage, parallel ISO 294-4 % 0.3 / *

2 Mold Shrinkage, transverse ISO 294-4 % 0.9 / *

3 Tensile Modulus ISO 527-1/-2 MPa 9700 / 6000

4 Stress at break ISO 527-1/-2 MPa 185 / 110

7 Flexral Strength ISO 178 MPa 290 / 165

8 Charpy notched impact strength

11359-E-4/°C 0.2 / *

16 Coeff of linear therm

expansion (normal)

ISO 1/-2

Ohm.m 1E13 / 1E11

22 Surface resistivity IEC

62631-2-1

Ohm - / 1E14

23 Electric strength IEC 60243-1 kV/mm 30 / 25

24 Water absorption Sim to ISO

2.4.3 Comparision between PA6 and PA6 + GF30%

PA6 (Nylon 6) and PA6 + GF30% (Nylon 6 with 30% Glass Fiber Reinforcement) are both variations of polyamide-based plastics, but they have distinct differences in their properties and applications

Strength and Stiffness

- PA6: PA6 offers good tensile strength (50-80 MPa) and moderate stiffness (elastic modulus of 1.5-3.0 GPa) It is suitable for applications requiring strength and durability

- PA6 + GF30%: With the addition of 30% glass fiber reinforcement, PA6 + GF30% exhibits significantly higher tensile strength (100-150 MPa) and stiffness (elastic modulus of 6-10 GPa) It provides improved mechanical performance and rigidity compared to PA6

Dimensional Stability

- PA6: PA6 has moderate dimensional stability with some shrinkage during the cooling process It may require careful consideration in applications with tight tolerances

- PA6 + GF30%: The addition of glass fibers in PA6 + GF30% improves its dimensional stability, reducing shrinkage and providing better retention of shape and size

Surface finish

- PA6: PA6 typically exhibits a smoother surface finish in molded parts

- PA6 + GF30%: The addition of glass fibers can result in a slightly rougher texture

on the surface of molded parts

Application

- PA6: PA6 is commonly used in various applications such as automotive components, consumer goods, electrical connectors, and industrial parts that require strength and durability

- PA6 + GF30%: PA6 + GF30% is often preferred in applications that demand higher mechanical performance, such as automotive structural components, electrical and electronic parts, and industrial machinery

2.5 Overview of injection molding technology

2.5.1 Definition

Injection molding is a technology of manufacturing products by injecting molten material into a mold Injection molding can be performed on a wide variety of materials, mostly metals (commonly referred to as pressure casting), glass, elastomers, blends, and most commonly plastics heat ductile and thermosetting

2.5.2 Injection molding machine

We can classify plastic molding machines in various way such as:

- Clamping force: including types of 50, 100,…, 8000 tons

- Maximum shot weight per cycles: including 1, 5, 8, 10,…, 56, 120 oz

- By type of piston or screw

- For the screw type: there are horizontal or vertical screw types

Structure of the Injection Molding Machine

Figure 2.5.1 Horizontal Injection Molding Machine

Figure 2.5.2 Vertical Injection Molding Machine

An injection Molding Machine consists of the following main components: a clamping system, a mold, an injection system, a hydraulic system and a control system

Figure 2.5.3 Structure of the Injection Molding Machine

Clamping system

This system is responsible for both opening and closing the mold and also for moving the mold and generating enough force to hold the mold during the filling and injection process This system is a linear system

Common types of clamping systems is include mechanical clamping, hydraulic clamping and hybrid machanical – hydraulic clamping system

Figure 2.5.4 Plastic Injection Molding system

The injection system consists of three main parts: the hopper, the heating cylinder, and the screw, including the screw head and nozzle The material is fed in the form

of small plastic pellets The hopper serves to contain these raw materials and will enter the heating cylinder The heating cylinder works to make the material flow out

in a liquid form It is heated by thermoforming sheets

The screw consists of three stages, the material feeding section is used to transfer the raw material forward, and at the end of this section the plastic begin to melt

The compression section is the middle of the screw is used to conpress the liquid material

The metering section is mixing zone homogenizes the material before injection into the mold

The nozzle is the part that connect the screw head and the mold sprue The nozzle must have a suitable shape for the flow of the material and be tightly attached to the sprue during the injection molding process

The hydraulic system is responsible for supplying energy to open and close the mold, holding the load while clamping the mold, rotating the screw shaft, and creating force for the injector pins to release the mold The hydraulic system includes apump, valves, hydraulic motor, piping system and storage system

The control system is responsilbe for ensuring stable and repeatable machine operation It controls and displays various parameters such as temperature, pressure, injection speed position and speed of the screw shaft and position of the hydraulic system

Plastic Injection Molding process

The processing time for the injection molding process is very short, typically ranging from 2 seconds to 2 minutes and consists of the following four stages:

Claming and Injection phase

Figure 2.5.5 Clamping and injection phase

a Plasticization process b Plastic Injection process

Clamping phase, Before pumping plastic into the mold, the two mold halves must

be tightly clamped, one fixed half and one movable half The hydraulic clamping unit

pushes the two mold halves together and exerts enough force to hold the mold tightly closed while the material is being injected into the mold

Injection phase, During this process, the plastic pellets are melted by heat and pressure The melted plastic is then rapidly injected into the mold The amount of material injected is called the shot The injection time is very difficult to calculate accurately, however, the injection time can be estimated by the shot volume, injection pressure, and injection power

Cooling and Product Ejection phase

Figure 2.5.6 Cooling and Product Ejection phase

a Cooling phase b Product Ejection phase

Cooling phase, The molten plastic inside the mold begins to cool as soon as it contacts the inner surface of the mold As the plastic cools, it solidifies into the desired shape of the product However, during the cooling process, shrinkage of the product may occur The mold cannot be opened until the cooling process is complete The cooling time may depend on the maximum wall thickness of the product

Product Ejection phase, After sufficient cooling time, the product can be ejected from the mold using an ejection system attached to the rear half of the mold Once the product is ejected, the mold can be closed to begin the next cycle

Injection molding parameters

Filling time

Filling time in the context of injection molding technology plays a crucial role in the overall manufacturing process It refers to the duration required to fill the mold cavity with molten material during the injection molding cycle

During filling time, the molten material, typically plastic, is injected into the mold

at a controlled rate and pressure This process ensures that the material flows smoothly and evenly throughout the mold cavity, taking the desired shape and forming the final product The duration of the filling time is carefully calculated and optimized to achieve the desired quality, accuracy, and structural integrity of the molded part

Several factors affect the filling time in injection molding The viscosity and temperature of the molten material, the design of the mold, the complexity of the part geometry, and the injection pressure are some of the critical parameters that influence the duration Through extensive testing, analysis, and simulation, manufacturers strive to find the optimal filling time that ensures efficient material flow while minimizing defects such as air traps, voids, or uneven filling

Accurate control of the filling time is essential for achieving consistent and quality molded parts Too short of a filling time can lead to incomplete filling, resulting in inadequate part formation and weak structural integrity On the other hand, excessive filling time can cause overpacking, leading to excess material, warpage, or part distortion

high-To optimize the filling time, manufacturers utilize advanced injection molding technologies and software simulations These tools allow for the precise calculation and adjustment of filling parameters, ensuring that the molten material is injected with the ideal flow rate and pressure, resulting in defect-free and dimensionally accurate parts

Filling press

Filling press is a crucial component in injection molding technology, playing a determining role in the process of injecting molten material into the mold It is a device that directly influences the smooth and uniform flow of the material

The filling press operates by applying pressure to the molten material from the material feeding system This pressure creates a pushing force, propelling the material

from its initial position into the mold cavity This ensures that the molten material is accurately and completely filled into the mold

The filling press needs to be precisely adjusted to ensure that the filling process occurs at the correct time and pressure Insufficient pressure can result in incomplete filling or inadequate material flow, while excessive pressure can lead to overpacking

or undesired stress on the product

The adjustment and control of the filling press are often performed through automated control systems Parameters such as filling pressure, filling velocity, and filling time are programmed and adjusted to meet the specific requirements of the injection molding process This ensures accuracy and consistency in the filling process, resulting in high-quality molded parts

The filling press not only plays a critical role in ensuring successful filling but also affects the final product quality A well-functioning filling press ensures accuracy and consistency in the dimensions, shape, and structure of the molded parts

Packing time

In injection molding technology, packing time is a crucial factor in the plastic injection process It refers to the duration during which the plastic material is injected into the mold to create the final plastic products

The injection process begins once the mold is securely closed and the plastic material is fed into the injection molding machine During this stage, the plastic material is introduced from a supply source, either through a hopper or a conveying system, and is pushed into the mold cavity using the machine's injection drive system The packing time is adjusted to ensure that the required amount of plastic is injected into the mold at the desired rate and quantity This process involves fine-tuning parameters such as pressure, injection velocity, and injection time Accurate control of the injection time is crucial in achieving good plastic product quality and ensuring dimensional accuracy and shape integrity

The packing time needs to be optimized to ensure that the plastic material is adequately filled into the mold without causing overpacking or underpacking issues

It also impacts the production time and efficiency of the injection molding machine The packing time may vary depending on the type of plastic, the size of the product, and specific requirements Precise adjustment and control of the injection

time are essential factors in achieving efficient plastic injection processes and quality products

high-Packing pressure

In injection molding technology, packing pressure is a critical parameter during the injection phase It refers to the force applied to the molten plastic material as it is injected into the mold cavity

The packing pressure plays a significant role in ensuring the proper filling of the mold and achieving high-quality plastic products It is controlled and regulated based

on various factors such as the type of plastic, the geometry of the mold, and the desired properties of the final product

During the injection process, the plastic material is melted and then injected into the mold under high pressure The packing pressure must be sufficient to overcome the resistance within the mold cavity, including the flow resistance of the plastic material and any restrictions or complexities in the mold design

Optimizing the packing pressure is crucial to avoid common issues such as insufficient filling, flow marks, or part defects Insufficient pressure may result in incomplete filling of the mold, leading to voids or incomplete part formation On the other hand, excessive pressure can cause excessive shear stress on the plastic, leading

to degradation or part deformation

The appropriate packing pressure is determined through a combination of theoretical calculations, simulations, and practical trials It is adjusted to achieve the desired flow characteristics, part quality, and dimensional accuracy The injection pressure is typically set by the machine operator based on the specific requirements

of the molding process

Controlling and monitoring the injection pressure throughout the injection phase ensures consistent part quality and helps prevent issues such as flash, sink marks, or warpage It requires a balance between the injection pressure, injection speed, and other process parameters to achieve optimal results

Melting temperature

Melt temperature, also known as melt temperature, is a fundamental parameter in injection molding technology that refers to the temperature at which the plastic material transforms from a solid state into a molten state It is a critical factor in

achieving proper flow and filling of the mold cavity during the injection molding process

Each type of plastic material has a specific melt temperature range that is recommended for optimal processing The melt temperature is typically determined based on the polymer's thermal properties, including its melting point and melt flow index It is crucial to operate within the appropriate melt temperature range to ensure the plastic material is sufficiently melted and flows smoothly into the mold

Maintaining the correct melt temperature is essential for several reasons Firstly, it affects the viscosity of the molten plastic, which influences the flow behavior and fillability of the mold cavity A higher melt temperature generally results in lower viscosity and improved flowability, while a lower melt temperature can increase viscosity and potentially lead to incomplete filling or flow-related defects

Secondly, the melt temperature also affects the material's thermal degradation Excessive melt temperature can cause the plastic material to degrade, resulting in the deterioration of its physical and mechanical properties On the other hand, insufficient melt temperature can result in poor fusion between molten layers and compromised part strength

To control the melt temperature, injection molding machines are equipped with heating elements and temperature controllers The plastic material is heated to the appropriate temperature range before injection, and the melt temperature is closely monitored and maintained throughout the injection molding process

It is important for operators to optimize the melt temperature for each specific plastic material and product This optimization process may involve trial runs, adjustments, and evaluations to achieve the desired flow characteristics, part quality, and dimensional accuracy

The procedure includes measuring the total length of the sample, marking the midpoints on the sample, at positions appropriate for a 135mm length The sample is then inserted into the grips at the marked positions and tightened securely It is important not to overtighten the grips, as it can cause surface structure failure of the product When the tensile test begins, the upper and lower grips of the universal testing machine gradually apply pulling force from both ends, resulting in the sample being pulled until it fractures At this point, we obtain the data and the corresponding graph displayed on the computer

2.5.3 Possible defects after the Injection Molding process

- Deformation error: due to excesive injection pressure

- Warpage issue: the reason is uneven cooling rate

- Blisters: reasons can include injection temperature being too high, excessive moisturein the materials and uneven cooling rate

- Short shot: insufficient plastic, low filling speed

- Sink Marks: caused by uneven cooling or shinkage of the materials

- Weld lines: due to insufficient injection pressure, too slow injection speed, poor mold design, improper mold cleaning, uneven mold temperature, unsuitable plastic materials

2.5.4 Advantages and disadvantages of Injection Molding Technology

Advantage:

- Complex shapes: The injection molded parts can hold very precise tolerances on extremely small parts, which cannot be achieved through normal machining at an economical cost

- Speed and scale: The plastic molding process can quickly produce large quantities

of parts in batches, with a single mold containing multiple cavities to produce identical products in one molding cycle Therefore, it is very suitable for mass production

- Durability: when molded, plastic is an extremely durable material That is why it is used to create parts that form the casing or outer shell of devices

- Product control: The inspection of the exterior of plastic products after molding is much simpler compared to other non-plastic products

Disadvantages:

- Limitations in design: Because the mold must be opened and pushed out, there are some designs that cannot be molded or are extremely difficult to mold

- High upfront costs: To use injection molding technology to create a desired product

in terms of size, tolerance, appearance, etc., the first step is to invest in designing a complete and accurate set of molds Therefore, the cost is often much higher