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Volume No.04, Issue No. 05, May 2015 ISSN (online): 2394-1537

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PARAMETRIC EFFECT DURING PLASTIC

INJECTION MOLDING PROCESS ON

POLYPROPYLENE MATERIAL

Himanshu Arora1, Dhirendra Pratap Singh

2, Sunil Kumar

3,

1M.Tech Student,

2HOD Mechanical Department, Subharti Institute of Technology & Engineering,

Swami Vivekanand Subharti University, Meerut, (India)

3Assistant Professor,

Faculty of Engineering and Technology,

Gurukula Kangri Vishwavidyalaya, Haridwar, (India)

ABSTRACT

Today’s Plastic Injection molding process as one of the most widely used processes for producing plastics

products. As in other forming processes, the characteristics of plastic injection molding procedures are

significantly affected by the quality of the plastic products by the different levels for its process parameters. To

find the effect of various level for the process parameters is becoming a research issue and is now known as

finding the efficient frontier of the parameters. The effect of parameters in plastic injection molding process and

its influence on product quality and costs. The main aim of this paper is to study the effect of different

parameters on polypropylene work material for a plastic injection molding process during manufacturing of

bottle cover. In this paper study of parameter like injection molding temperature, injection molding pressure

and cooling time used to find the effect on polypropylene work material in plastic injection molding process with

a number of experiments have been conducted in pre-planned way on injection molding machine to understand

the effect of various parameters on weight of product.

Keywords: Plastic Injection Molding Process, Polypropylene, Parameter Effect

I. INTRODUCTION

With the continuous progress of manufacturing techniques for latest products, better and better quality of

products is required for the survival in the present market. The plastic injection Molding is the most important

process for plastic parts mass production. Among the all plastic products about one fourth are made by injection

molding. Selecting the proper plastic injection molding process settings is necessary because during production

the behavior of the plastic material is highly affected by the process parameters. Consequently, the process

parameters govern the quality of the part produced. A sufficient amount of research has been directed towards

determining the process parameters settings for the plastic injection molding process. There are number of

parameters that affect the properties of plastic product. There are different processing parameters for all

different materials. Melting temperature, injection pressure and cooling time are the main processing

parameters. Therefore, the setting of process parameters for plastic products has a noticeable influence on their

quality and cost. As a raw material plastic is used in plastic injection molding process such as low density

polyethylene, nylon, polypropylene, flexible PVC, polystyrene and machine used for the injection process is the

injection molding machine. [1]

International Journal of Science, Technology & Management www.ijstm.com

Volume No.04, Issue No. 05, May 2015 ISSN (online): 2394-1537

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In plastic injection molding process raw material is melted in the injection molding machine and then forwarded

into the mould with the help of reciprocating screw where it cools and solidifies into the final product part. The

reciprocating screw is mounted on gear box in the barrel; barrel contains heaters for heating the raw material. In

the injection process raw material is melted by heat and pressure. While forwarding material the material enters

the grooves of reciprocating screw. After cooling and solidification final product is obtained. [2]

The work material used in this research is Polypropylene. Polypropylene is a thermoplastic polymer having

chemical formula (C3H6)n and chemical name of poly(1-methylethylene). It is a very versatile material; it offers

very great combinations of properties such as light weight, strong, high heat resistance as well as stiffness and

flexural retention. By these properties polypropylene is easily fabricated. The polypropylene has many variants

but the material used is homopolymer polypropylene. [3]

II. EXPERIMENTAL PLANNING

Fig.1 show the plastic injection molding machine set up used for conducting the number of experiment. The

plastic injection molding machine is of three types hydraulic, mechanical and electric, these types are classified

by their driving systems. The machine mainly consists of two main parts injection unit and clamping unit. Many

types of injection machine are available in the market but the most widely used machine is horizontal plastic

injection molding machine. In plastic injection molding process the plastic material usually in the form of

powder or pallet are fed from hopper which directs the raw material to the injection chamber. The material

moves forward from hopper to injection chamber by piston and cylinder arrangement. In injection chamber raw

material first enters into the barrel and raw material melts in the injection unit due to external heaters of the

barrel. The molten plastic material is then injected into the mould cavity through the nozzle and allows it to cool

and solidifies into the mould, after that it will remove from the mould cavity.

Polypropylene raw material used for production of final product i.e. bottle cover. Polypropylene (PP) is a linear

hydrocarbon polymer, expressed as (C3H6)n.

The polypropylene has many variants but the material used in the manufacturing of the bottle cover is

homopolymer polypropylene of H110MA grade. The electronic weighing machine is used for Weight

measurement after plastic injection molding process. The weighing machine used for the experiment is

electronic type having the weight limit 0.01 gm to 200gm.

III. RESULTS AND DISCUSSION

Two major parameters e.g. melting temperature and injection pressure are studied in current work mostly

affected the weight of final product.

Fig. 3 shows the S/N ratio response curve for melting temperature of final Product. It clears from the figure that

during experiment S/N ratio behaves differently at four level of temperature. For weight of the product lower the

best value calculated. So the effective value of melting temperature is 2150C.

Fig. 4 shows the S/N ratio response curve for injection pressure of final Product. It clears from the figure that

during experiment S/N ratio first increases up to 55mpa injection pressure and then decreases. For weight of the

product lower the best value calculated. So the effective value of injection pressure is 65MPa.

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IV. FIGURES

Fig.1 Plastic Injection Molding Machine Fig. 2 Final Product Used for Experiments

Fig. 3 S/N Ratio Curve of Melting Temperature for Weight (Gram)

Fig. 4 S/N Ratio Curve of Injection Pressure for Weight (Gram)

V. CONCLUSION

The effect of various factors has been identified and believed can be a key factor in helping to produce best

quality and less cost in plastic injection molding process parameters. In plastic injection molding process of

Polypropylene, for weight melt temperature and injection pressure are found to be the most significant factor

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Volume No.04, Issue No. 05, May 2015 ISSN (online): 2394-1537

121 | P a g e

which contributes. The results show that, for polypropylene the best combination of processing parameters in

terms of weight are 2150C melting temperature, 65MPa injection pressure. This paper shows that by optimizing

the melting temperature & injection pressure we can reduce weight of material used in production. This research

will improve the performance of injection molding machine as well as reducing the cost also. By carrying out

experimental tests the best combination of process parameters was found that would provide the lowest weight

of specimens made of polypropylene homopolymer material. On this basis, it was found that melting

temperature and injection pressure are the two most influential process parameters affecting the process. Other

parameter of this process is still under research and need more involvement of multidisciplinary science and

technology to achieve improvement.

REFERENCES

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Moulding- A Review”, international journal for research in applied science and engineering technology

Vol. 2 Issue IV, April 2014.

[4]. S. Kamaruddin, Zahid A. Khan, K. S. Wan; “The Use Of The Taguchi Method In Determining The

Optimum Plastic Injection Moulding Parameters For The Production Of A Consumer Product”; Jurnal

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[5]. Mr. A.J. Yadav, Mrs. S.V. Dravid, Mr. V.D. Rajput, “taguchi technique in optimization of injection

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