Effect Of Process Parameters Of Injection Molding … · Effect Of Process Parameters Of Injection Molding Process Using ... Liquid injection moulding ... M.-C. Jeng / Wear 206

International Journal of Scientific Research and Engineering Studies (IJSRES)

Volume 2 Issue 7, July 2015

ISSN: 2349-8862

www.ijsres.com Page 64

Effect Of Process Parameters Of Injection Molding Process Using

Polycarbonate Lexan Ls1 And Comparison Of Surface Roughness

With PVC

S. Rajesh

S. Ranjith Khumar

Y. Karthikeyan

Mechanical Engineering,

Kumaraguru College of Technology, Coimbatore

Abstract: In this project the process parameters of

injection molding process was found and comparing the

surface roughness values of polycarbonate material with

polyvinyl chloride which has been already in use in our lab.

Polycarbonate is in this experiment because it’s having high

tensile strength and high melting point than PVC. In this

project the process parameters of injection molding process

like melt temperature, mold temperature, filling time,

clamping force, ram speed and etc… was found out and

from this results we can find out which one is the best one in

given conditions and results were discussed and graphs are

plotted.

Keywords: polycarbonate, poly vinyl chloride, surface

roughness, melting point, process parameters.

I. INTRODUCTION

Injection molding process development, industry is

searching for lighter weight, higher strength, faster

productivity and safer materials to meet the demands of

structural design and economic benefit. Injection molding is a

manufacturing technique for making parts thermoplastic

material. The injection molding process was studied

extensively in attempt to create plastic component at the

highest quality possible. This project is to get optimize

parameter in injection molding process. The present study

analyses the Wear behavior of polycarbonate reinforced with

20 wt. % short glass fibers. The specimens were prepared

under different molding conditions, with varied filling time,

melt temperature, and mould temperature.

Injection molding, a cyclic process, is completed in an

injection molding machine fig 1. The machine comprises a

clamping unit, an injection unit, a hydraulic unit and a control

unit. The clamping unit holds, opens and closes the mold

automatically and Ejects the molded product at the end of the

cycle. The molding process is generally divided into three

stages: "filling, packing holding and cooling fig 2, during

"filling, the screw moves forward and pushes the melt into the

mold cavity, as shown fig 2a. Once the mold is completely

filled, the process switches to the packing-holding stage,

during which additional polymer is added under a certain

pressure to the mold to compensate for the shrinkage

associated with the material cooling and solidification, as

shown in Fig. 2b.The packing-holding stage continues until

the gate, which is a narrow entrance to the mold, freezes,

isolating the material in the mold from that in the injection

unit. During the cooling stage, the polymer inside the mold

continues to cool down, and at the same time, plastication

takes place inside the barrel, resulting in the melting and

conveying of polymer to the screw tip, due to the screw

rotation, as shown in Fig 2c. The screw rotation ceases after a

sufficient amount of melt is generated in front of the screw.

When the part in the mold becomes rigid enough, the mold

opens, and the part is ejected, as shown in Fig the process is

then repeated.

Types of injection molding processes are,

Reinforced injection moulding

Liquid injection moulding

Gas assists injection moulding

Fusible core injection moulding

Rapid injection moulding

Micro injection moulding

Applications are,

Car bodies

High Speed Train cabs

Aircraft propellers

Jet engine blocker doors



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Figure 1

Figure 2

Figure 3

II. EXPERIMENTAL PROCEDURES

The experimental procedures contain different steps to

accomplish the project and calculations and graphical

representations are shown in this paragraph.

A. MATERIALS

In this study, the material used to prepare the

experimental specimens consisted of polycarbonate.. The

polycarbonate was a commercial blend (General Lexan LS1),

the average fiber diameter was 12 mm, with a density of 1.35

g cmy3. The figure shows the material.

Figure 4: Polycarbonate lexan ls1

The PVC materials also have been use in this experiment

and the surface roughness test was taken against

polycarbonate.



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B. MODEL

In this experiment the model would have been done by

using polycarbonate. The figure has shown a model.

Figure 5: Model

C. INJECTION MOLDING MACHINE

In this experiment the vertical injection molding machine

was used. It’s having different specifications and values. The

experimental setup has shown in the diagram. For

thermoplastics, the injection molding machine converts

granular or pelleted raw plastic into final molded parts via a

melt, inject, pack, and cool cycle. A typical injection molding

machine consists of the following major components Injection

system

Hydraulic system Mold system, clamping system

Control system, Injection molding machines can be

generally classified into three categories, based on machine

function:

General-purpose machines

Precision, tight-tolerance machines

High-speed, thin-wall machines

a. EXPERIMENTAL SETUP

Figure 6: injection molding machine

b. SPECIFICATIONS OF INJECTION MOLDING

MACHINE

Shot capacity 75gms

Heater capacity 1.75KW

Clamp force 12 tone

Injection 4.5 tone

Max mould size 250*250mm2

Min mould thickness 120mm

Max mould thickness 400mm

Max mould opening 130mm

Max daylight gap 400mm

Motor power 3HP

Oil tank capacity 60L

Weight 600kg

D. METHODOLOGY

The methodology contains six steps to make a project

those are,

E. SURFACE ROUGHNESS MEASUREMENT

In this project the surface roughness measurements have been

taken for both PVC and Polycarbonate and results were

tabulated. From this surface roughness values we could have

been found and conclude that which material made specimen

was having good surface roughness and which one is efficient.

a. SETUP

The surface roughness tester SJ201 was used in this

experiments which was made by MITUTOYA Company.

b. SPECIFICATIONS

Speed 0.25mm/0.5mm-measuring

0.8mm –returning

Measuring range 12, 5 mm

Mass 190g

Type of probe inductive

Stylus diamond cone

Tip radius 2μm

Force 0, 75 m N



ISSN: 2349-8862


No of sampling lengths x1, x3, x5,X L*

Auto sleep after 30 seconds

Resolution/range depend upon measuring

Range

Code no 178-930D

III. RESULTS AND DISCUSSIONS

In this experiment the different process parameters of the

injection molding process were found by using mold flow

plastics insight software. The results contain filling analysis,

and material data’s, specific heat values and thermal

conductivity data’s and process parameters.

A. FILLING ANALYSIS

Filling phase: Status: V = Velocity control

P = Pressure control

V/P= Velocity/pressure switch-over

B. MATERIAL DATA’S

Polymer 1: PC lexan ls 1: MRC Polymers

Coefficients:

Liquid phase Solid phase

------------------------------------------------

b1 = 0.0009 b1 = 0.0009 m^3/kg

b2 = 5.7710E-07 b2 = 2.0550E-07 m^3/kg-K

b3 = 1.8007E+08 b3 = 2.7969E+08 Pa

b4 = 0.0045 b4 = 0.0025 1/K

b5 = 409.1500 K

b6 = 3.5500E-07 K/Pa

b7 = 0.0000 m^3/kg

b8 = 0.0000 1/K

b9 = 0.0000 1/Pa

C. SPECIFIC HEAT VALUES

Tabulated data:

Temperature Specific Heat

T (K) Cp (J/kg-K)

----------- -------------

324.1500 1281.0000

348.1500 1426.0000

373.1500 1541.0000

393.1500 1636.0000

401.1500 1699.0000

409.1500 1814.0000

418.1500 1945.0000

443.1500 2012.0000

468.1500 2064.0000

493.1500 2112.0000

518.1500 2150.0000

543.1500 2195.0000

D. THERMAL CONDUCTIVITY VALUES

Temperature Thermal Conductivity

T (K) K (W/m-K)

---------------- -------------------------

304.1500 0.1710

331.1500 0.1700

351.1500 0.1840

372.1500 0.1860

392.1500 0.1970

412.1500 0.2110

432.1500 0.2510

452.1500 0.2430

472.1500 0.2520

511.1500 0.2480

531.1500 0.2550

551.1500 0.2460

E. PROCESS PARAMETERS

Fill time = 4.9000 s

Cooling time = 20.0000 s

Velocity/pressure switch-over by = Automatic

Packing/holding time = 10.0000 s



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Ram speed profile:

% shot volume % ram speed

---------------------------------

100.0000 100.0000

0.0000 100.0000

Pack/hold pressure profile:

Duration % filling pressure

---------------------------------

0.0000 s 80.0000

10.0000 s 80.0000

20.0000 s 0.0000

Ambient temperature = 25.0000 C

Inlet melt temperature = 270.0000 C

Ideal cavity-side mold temperature = 66.0000 C

Ideal core-side mold temperature = 66.0000 C

From these results and values we have obtained process

parameters of injection molding process for a given specimen.

IV. GRAPHS AND MODEL SIMULATION

In this experiment there are different steps involved in a

simulation of model using mold flow plastics insight.

A. MATERIAL SELECTIONS

Figure 7

Figure 8

B. MESHING OF MODEL

Figure 9



ISSN: 2349-8862


C. TEMPERATURE DISTRIBUTION OF MODEL

Figure 10

D. CLAMPING FORCE

Figure 11

E. PRESSURE INJECTION

Figure 12

F. RAM SPEED

Figure 13

V. CONCLUSION

SURFACE ROUGHNESS TESTING FOR PVC:

In this test the PVC specimen was been tested and the

different roughness values (Ra) were obtained by using

different locations of the model.

TOP SURFACE:

locations Roughness in μm,

1 3.14

2 3.78

3 3.16

4 3.53

5 3.17

Table 1

BOTTOM SURFACE:


1 2.19

2 2.93

3 2.14

4 2.11

5 2.05

Table 2

SURFACE ROUGHNESS TESTING FOR

POLYCARBONATE:

In this the surface roughness measurement of

polycarbonate has been measured.

TOP SURFACE:


1 3.34

2 3.61

3 3.14



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4 4.18

5 4.01

Table 3

BOTTOM SURFACE:


1 4.33

2 3.45

3 4.34

4 5.23

5 3.98

Table 4

These are the roughness values obtained from the

experiment. From these we can conclude that the

polycarbonate having high surface roughness than PVC

and the different process parameters values obtained

using mold flow plastics insight software.

The melting temperature and tensile strength of poly

carbonate is high.

These are conclusions can be made from the above

results.

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Effect Of Process Parameters Of Injection Molding … · Effect Of Process Parameters Of Injection Molding Process Using ... Liquid injection moulding ... M.-C. Jeng / Wear 206