Lab 5 - Injection Moulding Laboratory Manufacturing Process PDF

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

LAB REPORT COURSE NAME

Manufacturing Process 1

COURSE CODE

MDJ13303

LAB No.

5

Injection Moulding Faculty of Mechanical EngineeringTechnology LEVEL OF COMPLEXITY 1

2

3

4

5

6

KNOWLEDGE REPETITION APPLICATION ANALYSIS EVALUATION SYNTHESISE

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

LABORATORY REPORT Course Name

Manufacturing Process 1

Course Code

MDJ13303

Lab No.

Semester

SEM 2 2021/2022

SA

Title of Experiment

Injection Moulding

Date of Experiment

13 April 2022

Date of Submission

18 April 2022

Instructor’s Name

En Muhamad Nur Bin Misbah (Name and Matric No)

LOSHINI A/P GUNALAN 212051525

Marks Objectives

5

Introduction

20

Methodology

10

Results & Discussions

45

Conclusions

15

Others (Format, References, Appendix)

5

TOTAL

100

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

Table of Contents 1.0 Objectives ……………………………………………… 4 2.0 Introduction ……………………………………………. 4 - 6 3.0 Methodology …………………………………………… 7 4.0 Discussion ……………………………………………… 8 - 12 5.0 Conclusion ……………………………………………… 11 6.0 References ……………………………………………… 11

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

INJECTION MOULDING LABORATORY

1.0 OBJECTIVE 1. To introduce plastic injection moulding machines and accessories. 2. To introduce the injection moulding process for plastic technology.

2.0 INTRODUCTION Injection moulding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mould cavity where it cools and hardens to the configuration of the mould cavity. Complex shape and good dimensional accuracy can be achieved because the material is molten when injected into the mould. The main component of the injection moulding machine is: 1. The plasticating unit: The major tasks of the plasticating unit are to melt the polymer, accumulate the melt in the screw chamber, inject the melt into the cavity and maintain the holding pressure during cooling. The main element of the plasticating unit is: 

Hopper – to load material

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Screw – to feed, compress and inject material

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Heating band – to melt material.

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Check valve – to prevent polymer melt backflow into screw channel. A highquality check valve allows less than 5% of the melt back into the screw channel during the injection.

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Nozzle – is at end of the plasticating unit and fits tightly against the sprue bushing during injection

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

Figure 1: Plasticating unit 1. The clamping unit: The job of the clamping unit in an injection moulding machine is to open and close the mould tightly to avoid flashing during filling and holding.

Move plate

Fixed plate

Tie Bar

Mould

Figure 2: Clamping unit 2. The mould Cavity: The central point in an injection moulding machine is the mould. The mould distributes polymer melt into and throughout the cavities, shapes the parts, cools the melt, and ejects the finished product. The mould is custom-made and consists of the following elements: 

Sprue and runner system

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Gate

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Mould cavity

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Cooling system

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Ejector system

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

During mould filling, the melt flows through the sprue and is distributed into the cavities by the runners. There are two types of runner arrangement: 

Symmetric runner arrangement – all cavities fill at the same time. The disadvantage of this balanced runner system is that flow paths are long, leading to high material and pressure consumption

Cavities

Runner

Sprue

Figure 3: Symmetric runner system



Asymmetric runner arrangement – lead to parts of different quality. Equal filling of the mould cavities can also be achieved by varying diameters.

Cavities

Runner Sprue

Figure 4: Asymmetric runner system

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

3.0 MATERIAL & EQUIPMENT

1. Injection Moulding Machine 2. ABS (Acrylonitrile butadiene styrene)

4.0 PROCEDURE

1. Switch on the main panel switch on the body of the injection moulding machine. 2. Feed the polymer resin into the hopper. 3. Set up the temperature according to material melting temperature or refer Appendix A for temperature guidance. 4. Set up the injection parameter (injection pressure, injection speed and injection quantity). 5. Set up packing pressure and cooling time. 6. Press the semi-auto or auto button to start the injection moulding process.

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

5.0 DISCUSSION a. Briefly describe the Injection Molding process.

 Injection moulding is a method of injecting heated and molten plastic materials into a mould, and then cooling and solidifying to obtain moulded products. The method is suitable for the mass production of products with complicated shapes and takes a large part in plastic processing. The process of injection moulding is divided into 6 main steps as shown below.

The process proceeds as shown above and products can be made successively by repeating the cycle. b. Labels Injection Molding machine below.

A. Sprue B. Adapter C. Valve D. Barrel linear E. Hopper

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

c. List and explain two (2) defects that may occur in Injection Molding parts.

i.

Flash occurs when a thin layer of material is forced out of the cavity at the parting line or ejector pin. This excess material remains attached to the moulding and must usually be removed manually. Causes, worn or poorly fitting cavity/mould plates. Includes mould plate deformation and obstructions (grease, dirt, debris). Insufficient clamp force. The machine clamping force must be greater than the pressure in the cavity (i.e., the clamping opening force) to adequately keep the mould plates closed.

ii.

A short shot is an incomplete filling of the mould cavity, resulting in the production of an incomplete part. If the part is a short shot, the plastic will not fill the cavity. The flow freezes off before all the flow paths have filled. Causes flow restrictions due to channel freezing or inadequate runner design.

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

d. Discuss two (2) advantages and two (2) disadvantages of the Injection Molding process.

Advantages

Disadvantages

1. Fast production and highly efficient.

1. Small runs of parts can be costly.

Injection moulding can produce a surprising Owing to the complexity of the tooling and number of parts per hour. The speed depends the fact that all previous material must be on the complexity and size of the mould, and removed from the machine before the next each cycle time is between 15-120 seconds.

product can be made, the setup time can be quite long. As a result, low-volume parts have traditionally been considered too expensive for injection moulds.

2. Product consistency.

2. Part design restrictions.

Injection moulding is a repeatable process; in Plastic components should be designed with other words, the second part you make will injection moulding attention and should be the same as the first, and so on. This is a comply with the fundamental guidelines of huge advantage when trying to produce high injection moulding, for example, keep away tolerances and part reliability in high from undercuts and sharp edges as tons as volumes.

possible, use uniform wall thicknesses to save you inconsistencies withinside the cooling technique ensuing in defects like sink marks and draft angles are advocated for higher demoulding.

e. Name one (1) material used to produce parts or products in the Injection Molding process.



Polypropylene.

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Manufacturing Process I [DPT 110]

Semester 2, 2021/2022

f. Name and sketch three (3) types of mould used in the Injection Molding process.



Cold-runner, two plate mould



Cold-runner, three-plate mould

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Manufacturing Process I [DPT 110]

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Semester 2, 2021/2022

Hot-runner mould

6.0 CONCLUSION

Injection moulding has a great many applications for manufacturing, particularly for producing high volume parts. While the tooling and moulding can be expensive, the cost of production, once this is completed, is low. Providing the ability to produce nearidentical parts, injection moulding is used for parts in a variety of material types.

7.0 REFERENCES 1. S. Kalpakjian, S.R. Schmid (2014). Manufacturing Engineering and Technology. 7th Ed. Prentice-Hall International 2. John Schey (1999), Introduction to Manufacturing Processes, McGraw-Hill. 3. Mikell P. Groover (2007), Fundamentals of Modern Manufacturing, 3rd ed., John Wiley & Sons, Inc 4. https://www.plastikcity.co.uk/blog/advantages-disadvantages-of-injection-moulding/ 5. https://www.twi-global.com/technical-knowledge/faqs/what-is-injection-moulding

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