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“Parametric Study of Injection Moulding Using Polypropylene

H200mk Grade”

Subodh Singh Tomar1, Ashish Kumar Sinha

2, Ashish Shrivastava

3

PG Scholar

1, Assistant Professor

2, Assistant Professor

3

Department of Mechanical Engineering

Oriental Institute of Science & Technology, Bhopal

India

ABSTRACT: This paper deals with the mechanical and thermal properties of polypropylene material of grade

H200MK that is homopolymer from reliance polymer industry, where PP material is basically a thermoplastic

resin that is obtained by the polymerization of propylene. The monomer is propylene (CH2=CH-CH3)., and it is

a semi crystalline material that is easily manufactured by the injection moulding machine. Initially the raw

material of PP (H200MK) is taken as a filler material and fed into the feeder of injection moulding machine and

then it goes to the further process cycle of machining by varying different parameters of injection moulding

machine such as temperature , holding pressure , hold on time , cooling time, injection pressure , injection

speed and at each parameter specimens are ready. The mechanical and thermal properties of these specimens

are tested on INSTRON 3560 Universal Testing machine where the mechanical properties such as tensile

property is tested and these tests were carried out by taking ASTM methods of plastic material.

Keywords: Polypropylene, ASTM, Injection Moulding, H200MK, Hold on pressure.

INTRODUCTION

1.1. POLYPROPYLENE

Polypropylene (PP), also known as polypropylene,

is a thermoplastic polymer used in a wide variety of

applications including packaging and labeling,

textiles (e.g., ropes, thermal underwear and carpets),

stationery, plastic parts and reusable containers of

various types, laboratory equipment, loudspeakers,

automotive components, and polymer banknotes. An

addition polymer made from the monomer propylene,

it is rugged and unusually resistant to many chemical

solvents, bases and acids.

The global market for polypropylene had a volume of

45.1 million tonnes, which led to a turnover of about

$65 billion (~ €47.4 billion).

1.2. CHEMICAL AND PHYSICAL

PROPERTIES

Most commercial polypropylene is isotactic and has

an intermediate level of crystalline between that of

low-density polyethylene (LDPE) and high-density

polyethylene (HDPE). Polypropylene is normally

tough and flexible, especially when copolymerized

with ethylene. This allows polypropylene to be used

as an engineering plastic, competing with materials

such as ABS. Polypropylene is reasonably

economical, and can be made translucent when

uncolored but is not as readily made transparent as

polystyrene, acrylic, or certain other plastics. It is

often opaque or colored using pigments.

Polypropylene has good resistance to fatigue. The

melting point of polypropylene occurs at a range, so a

melting point is determined by finding the highest

temperature of a differential scanning calorimetry

chart. Perfectly isotactic PP has a melting point of

171 °C (340 °F). Commercial isotactic PP has a

melting point that ranges from 160 to 166 °C (320 to

331 °F), depending on atactic material and

crystallinity. Syndiotactic PP with a crystallinity of

30% has a melting point of 130 °C (266 °F).

The melt flow rate (MFR) or melt flow index (MFI)

is a measure of molecular weight of polypropylene.

The measure helps to determine how easily the

molten raw material will flow during processing.

Polypropylene with higher MFR will fill the plastic

mold more easily during the injection or blow-

molding production process. As the melt flow

increases, however, some physical properties, like

impact strength, will decrease.

There are three general types of polypropylene:

homopolymer, random copolymer, and block

copolymer. The comonomer is typically used with

ethylene. Ethylene-propylene rubber or EPDM added

to polypropylene homopolymer increases its low

temperature impact strength. Randomly polymerized

ethylene monomer added to polypropylene

homopolymer decreases the polymer crystallinity and

makes the polymer more transparent.

1.3. MECHANICAL PROPERTIES

The mechanical properties of semi‐crystalline

polymers strongly depend on the degree of

crystallinity, the crystallite size and the concentration


of tie‐chains. The tie‐chains connect the adjacent

crystals (lamellae). In addition, the (average)

molecular weight and the molecular weight

distribution (MWD) also affect the mechanical

properties. Nucleating agents can reduce the cycle

time in the injection moulding process, increase the

stiffness, increase the tie‐chain concentration,

improve the clarity, promote the β phase etc. Single

crystals (lamellae) are highly anisotropic because of

the nature of bonding between atoms and molecules,

strong covalent bonds along the chain vs. weak

Vander Waals interaction etc between chains,

Random formations of spherulite structure in the 3D

space create an isotropic composition. Therefore,

even if the individual crystals are anisotropic, the

differences in the properties tend to average and,

overall, the material is isotropic. Note that the degree

of crystallinity and molecular orientation are affected

by the fabrication process that could lead to

anisotropic mechanical response in solid polymers.

Figure 1: Molecular Orientation of polypropylene

LITERATURE REVIEW

P. Postawa [1] The influence of thermal conditions

of the mould on properties of injection moulded parts.

Which give the Result of that the conditions of

cooling stage during injection moulding of

thermoplastics polymers for e.g. mould temperature

and cooling rate influence on structure properties.

Results shown that the same cooling channels in

different configurations can give another thermal

condition and in effect different structure. Presented

injection moulds that have been soundly designed

from the thermal point of view, help to bring down

the cost of production whilst ensuring greater

reliability. A large number of aids are currently

available to design engineers, together with the

results of theoretical and practical investigations,

which can be used in the thermal design of the mould.

In order to attain the specified aims of thermal mould

design, i.e precise maintenance of the target mean

cavity moulding surface temperature, uniform

distribution of the cavity temperature, short cycle

time for a high moulding quality.

T. Glomsakera [2] The response of mechanical

properties of injection-moulded parts at high strain

rates shows that mechanical loading of a

thermoplastic material like polypropylene at large

strains and different loadings rate may be reasonably

well simulated by use of a linear-elastic visco plastic

constitutive equation of von Mises type. However, it

is clear that these materials deviate from the von

Mises model, since their yield stress increases with

hydrostatic pressure and plastic dilatation occurs in

tension. Therefore a modified model with these

properties was implemented in LS-DYNA.

Simulations with this modified model, resulted in

improved agreement between simulations and

measurements for impact on a plate due to lower,

stiffness. For three-point bending the agreement was

poorer, possibly due to different strain hardening in,

compression and tension. In the unloading stage,

however, it is clear that the recoverable strain is non-

linear and at least one decade larger than predicted by

the linear elastic model.

Ranjusha J P [3] Effect Of Moulding Temperature

On The Properties Of Polypropylene/High Density

Polyethylene/Clay/Glass Fibre Composites are

analysis of moulding temperature on the properties of

composite based on PP/HDPE (80/20) was studied

which shows that the moulding temperature has

significant effect on the mechanical and thermal

properties of the composite. The optimum moulding

temperature depends on the desired

mechanical/thermal properties of the composite for its

application. The incorporation of nano clay and glass

fibres imp

roves the properties of PP/HDPE blends. The

enhancement in physical properties is well explained

by morphological characterization.

L.W. Seow, Y.C. Lam [4] Optimizing flow in plastic

injection molding The mold and part design of plastic

parts for injection molding is a complicated process,

considerations for producing a part ranging from cost

and speed of production to structural, ergonomics and

aesthetic requirements. One of the routines faced by a

designer when designing quality into a part is the

process of cavity balancing. This entails controlling

the plastic flow in the filling phase such that the melt

front reaches the boundaries of the mold at the same

time. This is done by adjusting the thicknesses of

various sections and can be a tedious trial and error

process. In this paper, a method is described whereby

the thickness-adjustment process can be automated.

An optimization routine is used to generate the

thicknesses necessary to balance the mold cavity. The

method is implemented on a PC through interfacing

of the Fortran code with the commercial software,

Moldflow ©. Using the method, good results have

been obtained for several basic geometric models

P.K. Bharti [5] Optimizing the plastic injection

moulding process in the determination of the process

parameters for injection molding. A number of

research works based on various approaches

including mathematical model, Taguchi technique

,Artificial Neural Networks (ANN),Fuzzy logic, Case

Based Reasoning (CBR), Genetic Algorithms (GA),


Finite Element Method(FEM),Non Linear Modeling,

Response Surface Methodology, Linear Regression

Analysis ,Grey Rational Analysis and Principle

Component Analysis using cavity pressure signals

have been described. A review of literature on

optimization techniques has revealed that there are, in

particular, successful industrial applications of design

of experiment-based approaches for optimal settings

of process variables. Taguchi methods and response

surface methodology are robust design techniques

widely used in industries for making the

product/process insensitive to any uncontrollable

factors such as environmental variables. Taguchi

approach has potential for savings in experimental

time and cost on product or process development and

quality improvement. There is general agreement that

off-line experiments during product or process design

stage are of great value. Reducing quality loss by

designing the products and processes to be insensitive

to variation in noise variables is an ovel concept to

statisticians and quality engineers.ANN, GA, and

CBR are emerging as the new approaches in the

determination of the process parameters for injection

molding. A trained neural network system can

quickly provide a set of molding parameters

according to the results of the predicted quality of

molded parts. However, the time required in the

training and retraining for aneural network could be

very long. By using GA approach, the system can

locally optimize the molding parameter seven without

the knowledge about the process. In practical use, the

convergence rate to an optimal set of process

parameters could be very slow in some occasion.

CBR systems can determine a set of initial process

parameters for injection molding quickly based on the

similar case(s) without relying heavily on the expert

molding personnel.

Babur Ozcelik [6] Influence of injection parameters

and mold materials on mechanical properties of ABS

in plastic injection molding Are shows, changing of

mechanical properties of ABS material was optimized

by ANOVA and regression analysis with respect to

injection parameters and two mold materials. The

most important parameter affecting the elasticity

module, tensile strength and tensile strain at yield,

tensile strain at break was melt temperature and its

effect was determined for steel as 84.90%, 86.78%,

50.05% and 42.99%, respectively. The other

parameter affected by flexural module (73.26%) was

injection pressure. In case of aluminum mold

material, percentages of injection pressure were

found as 44.21% for elasticity module, 35.32% for

tensile strength at yield and 36.93% for izod impact

limit, and percentages of melt temperature were

89.39% for tensile strain at yield and 98.29%for

flexural module, respectively. The most important

parameter affecting tensile strain at break was

packing pressure by 52.48%.The elasticity module,

tensile strength at yield, flexural module and izod

impact strength for steel and flexural module for

aluminum mold materials gave linear relationships

(based on values of r2) with injection parameters

whereas other mechanical properties resulted in non

linear relationships. Values of elasticity module and

tensile stress at yield for Al mold were higher than

that of steel mold when melt temperature and cooling

time were high, there was hardly any difference

observed for values of tensile strain at yield and at

break. Value of flexural modules and izod impact

strength were found to be higher for Al mold when

melt temperature and cooling time were low.

OBJECTIVES

The huge applications of polymer material subjected

to the mechanical and thermal properties are evolving

at a rapid pace as these materials are having

widespread applications ,the response of polymer

material subjected to a tensile test in day to day uses

are vast generally in automotive industries that is an

excellent example for the application of Mechanical

and Thermal response , the automobile industry is

therefore rapidly growing in this field creating a

widespread demand for the polymer material.

The main topics of this thesis of the behavior of the

polypropylene under the mechanical properties,

specially this thesis deals with the following topics.

1. To produce the specimen by plastic injection

moulding by changing its different

parameters such as injection pressure,

cooling time, temperature, hold on time,

made different specimen and then compared

to obtain the specific mechanical and

thermal property such as tensile property.

2. To test the specimen of PP material for

comparing the improvement with the

existing material.

II. EXPERIMENTAL SETUP

2.1. POLYPROPYLENE GRADES

It is obvious from the points discussed so far that the

properties of end products are decided by various

parameters, viz.,

Temperature, pressure, speed and time set on

the machine

Moulds

Resin properties

In order to derive the properties of similar resins,

ASTM has devised standards, wherein they are

injection moulded under identical conditions and

tested.


Figure 2: Universal Testing machine

2.2. TENSILE TESTING, ASTM D638

Tensile properties are most widely specified and are

used as an indication of strength of polymers. It

measures the ability of a with stand the force that

tends to pull it apart and the extent of deformation

before breaking. Tensile properties are also widely

used for defying the measures for quality of

production their designing and engineering behavior.

2.3. TENSILE STRENGTH

Tensile strength is defined as the maximum tensile

stress sustained by a test piece during the tension test

or ultimate strength of a material subjected to tensile

loading.

In other words, it is a measurement of the ability of a

material to withstand force that tends to pull it apart

and to determine to what extent the material stretches

before breaking. It is expressed in N/mm2.

Figure 3: Injection Moulding Machine

2.4. TENSILE MODULUS

The ratio of tensile stress to the corresponding strain

at maximum load within proportional limits is the

tensile modulus. It is an indication of the relative

stiffness of a material. It is expressed in N/mm2.

Tensile strength

Elongation at yield

The elongation produced in the gauge length of the

test piece up to the yield point called.

Elongation at yield= change in length (elongation)

Original length (gauge length)

Table 1shows the specification of test specimen used

in experiment purpose. Material used in this

experiment is Polypropylene.

Table 1: Sample Details

Sample details Parameters

Length 115 mm

Rate 1 100 mm/min

Standards ASTM D638

Temperature (deg

C) 25

Humidity (%) 55

Table 2 shows the different levels of experiment.

Injection speed, temperature, injection pressure,

cooling time, hold on pressure and hold on time are

the variable parameters taken on this experiment.

Table 2: All parameters at different level

Le

vel

Inject

ion

Spee

d (%)

Tem

perature

(0c)

Inject

ion

Press

ure

(%)

Cool

ing

Tim

e

(Sec)

Hold

On

Press

ure

(%)

Ho

ld

On

Ti

me

(Se

c)

1 37 205 30 20 25 3

2 40 210 40 40 40 5

3 50 215 50 60 50 9

III. RESULTS AND DISCUSSIONS

Table 3: Comparison table of mechanical

properties at different temperature Level

Temper

ature

level

Maxi

mum

load

(N)

Tensi

le

stren

gth

(N/m

m2)

Ten

sile

strai

n

(%)

Tensil

e

Exten

sion

(mm)

Mod

ulus

(N/m

m2)

Level-1 1410.3

2 34.73

10.6

5 17.04

1395.

07

Level-2 1429.0

9 35.19

10.3

8 16.61

1470.

48

Level-3 1460.3

1 35.96 9.21 14.74

1500.

96


Figure 4: Tensile Strain at different level

Figure 5: Maximum load at different level

Figure 6: Tensile Strength at different level

Figure 7: Tensile Extrusion at different level

Figure 8: Modulus at different level

Tensile strain – According to varying the

temperature from 190oC-235

oC of injection moulding

the tensile strain is decreasing 10.65% to 9.21% by

decreasing the injection temperature because the

molecular bonding of polypropylene material is weak

due to high temperature so it shows less tensile strain

comparative to low temperature of pp material as

mentioned in figure 4.

Maximum load- It observe that by decreasing the

temperature 235oC to 190

oC the load bearing capacity

is increases 1410.32 N to 1460.31 N because at lower

temperature the density of polypropylene material is

high comparing to higher temperature as shown in

figure 5.

Tensile strength- As we seeing that by decreasing

the temperature 235oC to 190

oC at different level the

molecular structure of pp material become dense due

to which the tensile strength is increases 34.73

N/mm2 to 35.96 N/mm

2 because at low temperature

there is a dense material form in pp and at high

temperature, the molecular structure will changes

with minimizing the density due to which the strength

will goes down as shown in figure 6.

Tensile Extension – It indicates that as lowering the

injection temperature parameter 235oC to 190

oC the

density of pp will increases along with the tensile

extension will decreases 17.04 mm to 14.74 mm as

shown in figure 7.

Modulus – By decreasing the temperature at 235oC

to 190oC the modulus of elasticity is increases from

1395.07 N/mm2 to 1500.96 N/mm

2 which shows that

at lower temperature the higher elasticity of modulus

is formed and by increasing the temperature the value

of modulus is increases as shown in figure 8.


properties at different Injection Pressure Level

Pre

ssur

e

leve

l

Max

imu

m

load

(N)

Tensile

strengt

h(n/mm2)

Ten

sile

strai

n(%

)

Tensile

Extensi

on(mm

)

Modulu

s(N/mm2)

Lev

el-1

1439

.12 35.44

10.2

3 16.36 1351.99

Lev

el-2

1457

.06 35.88 8.97 15.33 1365.31

Lev

el-3

1472

.06 36.25 9.58 14.35 1387.92


Figure 9: Maximum load at different level of

injection pressure

Figure 10: Tensile strength at different level of

injection pressure

Figure 11: Tensile Extension at different level of

injection pressure

Figure 12: Tensile strain at different level of

injection pressure

Figure 13: Modulus at different level of injection

pressure

Maximum load- By decreasing the injection pressure

at 50% to 25% we observe that the packing of pp

material is become dense due to which at higher

pressure level the load beating capacity increasing

from 1439.12 N to 1472.06 N of maximum

comparing to the lower pressure as mentioned in

figure 9.

Tensile Strength – The tensile strength is increasing

from 35.44 N/mm2 to 36.25 N/mm

2 by increasing the

injection pressure and is continuously decreases by

decreasing the injection pressure at 50% to 25%. As

mentioned in figure 10.

Tensile extension- The density of pp material is

increases at 235oC due to which the tensile extension

is 14.35 mm and a deformation is decreases but at

lower pressure 190oC the density of pp material is

also affected and it decreases at lower temperature

pressure level due to which the tensile extension is

16.36 mm also increases as shown in figure 11.

Modulus – It observe that the tensile modulus is

related to the load bearing capacity from 1439.12 N

to 1472.06 N which shows that the tensile modulus is

increases at 1351.99 N/mm2

to 1387.92 N/mm2 the

injection pressure at 50% to 25 % as shown in figure

12.

Tensile strain – The tensile strain from 8.97% to

10.23% indicates that there is some optimum value at

intermediate pressure level because we observe that

as we increases the injection pressure from 25% to

50% there is some decreasing slope is formed in

tensile strain but when it reaches to its intermediate

value which is the optimum value of tensile strain is

formed at that injection pressure level and as further

increasing the injection pressure from its optimum

value there is some changes is formed which shows

that beyond the intermediate pressure level the tensile

strain is also increases at the higher pressure level as

shown in figure 13.


properties at different Holding Pressure Level

Hold on

pressure

Maximum

Load

(N)

Tensile

stress at

Maximum

Load

(MPa)

Extension

at Break

(Standard)

(mm)


Level-1 1461.59 35.1 13.02

Level-2 1465.3 36 13.11

Figure 14: Maximum load at different hold on

pressure

Figure 15: Tensile stress at different hold on

pressure

Figure 16: Extension at break at different hold on

pressure

Maximum load- It indicates that by increasing the

hold on pressure at 15% to 50% the packing of pp

material become dense due to which the maximum

load bearing capacity is increasing at1461.59 N to

1465.3 N higher holding pressure level as shown in

figure 14.

Tensile stress- The tensile stress is directly

proportional to the load bearing capacity so at higher

holding pressure there is a maximum load is beard

due to which the maximum tensile stress is

decreasing 36 N/mm2 to 35.1 N

//mm

2 and at

decreases the holding pressure at 50% to 15 % the

load as well as tensile stress is also decreases as

shown in figure 15.

Tensile extension- By increasing the holding

pressure at 15% to 50% the deformation and an

extension is goes down from 13.11 mm to 13.02 mm

comparing to the lower holding pressure as shown in

figure 16.

Table 6: Comparison Table of mechanical

property on different injection speed

Le

vel

Mech

anical

Load

(N)

Tensile

Strength(

N/mm^2)

Tensi

le

Strai

n(%)

Tensi

le

Exte

nsion

(mm)

Mod

ulus

(N/m

m^2)

1 1451.8

5 37.07 9.38 15.00

1502.

80

2 1461.5

2 37.35 9.65 15.44

1530.

88

Figure 17: Mechanical load at different injection

speed

Figure 18: Tensile strength at different injection

speed


Figure 19: Tensile Strain at different injection

speed

Figure 20: Tensile Extension at different injection

speed

Figure 21: Modulus load at different injection

speed

Mechanical load – It observe that the load is

increasing from 1451.85 N to 1461.52 N by

increasing the injection speed at 20% to 50% because

when the injection speed is increases the molecular

structure of pp material become closely packed as

shown in figure 17.

Tensile strength - As we increases the injection

speed from 20% to 50% the high density polymer is

formed due to which there is a higher tensile strength

is increasing from 37.07 N/mm2 to 37.35 N/mm

2

occurs comparatively to the lower injection speed as

shown in figure 18.

Tensile strain – At different increasing level of

injection speed from 20% to 50% indicate that the

decreases in the tensile strain from 9.65 mm to 9.38

mm is formed because at higher injection speed the

denser pp material is formed , due to which the lower

strain is occurred as shown in figure 19.

Tensile extension- The tensile extension from 15.44

mm to 15 mm of pp material graph is continuously

decreases whole increasing the injection speed at

20% to 50% as shown in figure 20.

Tensile modulus- Modulus is a properly which

depend upon the stress and strain which acting on the

material and we have seen that the as increases the

injection speed at 20% to 50% the stress also increase

which show that by increasing the injection speed the

modulus also increases as shown in figure 21.

Table 7: Comparison Table of mechanical

property on different injection speed

Le

vel

Hold

on

Pres

sure

(N/m

m2)

Inject

ion

Spee

d

(mm/

min)

Ho

ld

on

Ti

me

(m

in)

Injec

tion

Press

ure

Coo

ling

Tim

e

(sec)

Tempe

rature

(0C)

1 101.

1 92.6

95.

7 88. 96.8 87.7

2 104.

6 88.8

90.

4 95.0 89.7 90.4

3 106.

4 94.3

89.

7 110

104.

3 90.1

Figure 22: HDT at different level of hold on

pressure

Figure 23: HDT at different level of injection

speed


Figure 24: HDT at different level of hold on Time

Figure 25: HDT at different level of injection

pressure

Figure 26: HDT at different level of cooling time

Figure 27: HDT at different level of temperature

It observe that by testing the specimens, which is

produced by changing the different parameters of

injection moulding process as we identify that there is

some changes seen in Heat Deflection Temperature in

testing the specimens of different parametric values

of injection moulding by investing all the parameters

they are such as the hold on pressure by increasing it

the HDT temperature also increases which show in

fig.22, in injection speed we have seen that by

increasing it there is a continuous increasing curve is

formed which is shown in fig.23 , By taking holding

time parameter in this the HDT temperature is drop

for some time then it shows slightly constant curve it

means for a certain time the temperature fall than it

will be sustains by increasing the holding time as

shown in fig.24 as increasing the Injection pressure

the HDT is also increases because as the pressure

increases there is a densely closed packing pp

material formed as shown in the fig 25 if the cooling

time increases there is also the sudden drop of

temperature observe for the intermediate pressure

than the temperature also increases as increases in the

cooling time shown in fig.26 and finally by

increasing the moulding temperature the heat

deflection temperature also increases and when it

reaches at a certain temperature there is some

constant curve is shown which is indicated in the

'fig.27.

Figure 28: Comparison between maximum load at

different parameters

Figure 28 shows the comparison between maximum

loads at different parameters. In case of Temperature

maximum load in level 3 1460.31 N. in case of

injection pressure maximum load is 1472.06 in level

3. In case of hold on pressure 1465.3 N at level 2. In

case of injection speed maximum load is 1461.52 N

at Level 2.

Level-1

Level-2

Level-3

Maximum load (N) *Temp

1410.32 1429.09 1460.31

Maximum load (N)

*Injection Pressure

1439.12 1457.06 1472.06

Maximum Load (N) *Hold on Pressure

1461.59 1465.3

Mechanical

1370 1380 1390 1400 1410 1420 1430 1440 1450 1460 1470 1480

Max

imu

m L

oad

(N

) Maximum Load (N) v/s All Levels


Figure 29: Comparison between Tensile Strength

at different parameters

Figure 29 shows the comparison between Tensile

strength at different parameters. In case of

Temperature Tensile strength in level 3 35.96 N/mm2.

in case of injection pressure Tensile strength is 36.25

N/mm2 in level 3. In case of injection speed tensile

strength is 37.35 N/mm2 at Level 2.

Figure 30: Comparison between Tensile Strain at



strain at different parameters. In case of Temperature

Tensile strain in level 3 9.21%. In case of injection

pressure Tensile strain is 8.97% in level 2. In case of

injection speed tensile strain is 9.38% at Level 1.

Level-1 Level-2 Level-3

Tensile strength (N/mm2)

*Temp

34.73 35.19 35.96

Tensile strength (N/mm2) *Injection Pressure

35.44 35.88 36.25

Tensile Strength(N/

mm2) * Injection

Speed

37.07 37.35

33 33.5

34 34.5

35 35.5

36 36.5

37 37.5

38 Te

nsi

le S

tre

ngt

h (

N/M

M^2

)

Tensile Strength v/s All Levels

Level-1

Level-2

Level-3

Tensile strain (%) *

Temp 10.65 10.38 9.21

Tensile strain (%) *

Injection Pressure

10.23 8.97 9.58

Tensile Strain(%) * Injection

Speed

9.38 9.65

8

8.5

9

9.5

10

10.5

11

Ten

sile

Str

ain

(%

)

Tensile Strain v/s All Levels


Figure 31: Comparison between Tensile

Extensions at different parameters


Extension at different parameters. In case of

Temperature tensile extension is 14.74 mm at level 3.

In case of injection pressure tensile extension is 14.35

mm in level 3. In case of hold on pressure tensile

extension 13.02 mm at level 1. In case of injection

speed tensile extension is 15 mm at Level 1.

Figure 32: Comparison between Modulus at


Figure 32 shows the comparison between Modulus at

different parameters. In case of Temperature Modulus

is 1500.98 N/mm2 at level 3. In case of injection

pressure Modulus is 1387.92 N/mm2 in level 3. In

case of injection speed Modulus is 1530.88 N/mm2 at

Level 2.

IV. CONCLUSION

The mechanical and thermal response of

polypropylene materials of grade H200MK was

investigated experimentally in this thesis. The

mechanical response of thermoplastic polymer

material is strongly related to its microstructure. The

microstructure is also affected by fabrication, e.g.

injection moulding, and the processing conditions.

The anisotropy and in- homogeneity of injection

moulded parts can be a challenge trying to predict

their mechanical response. Due to the complexity of

the molecular and composite structure of these

polypropylene compounds, making an accurate

simulation requires highly well‐defined material

models. It means the material model should be able to

describe the most important features of the material

behavior, e.g. mechanical strain rate, tensile strength,

extension and thermal heat deflection temperature. It

should be noted, however, that with this rather

complex material behavior it is often difficult to

separate the effects, but however experimental results

show the changes with respect to the variation in all

the parameters and these are concluded below-

1. It is observed that maximum load bearing

capacity is improved by the variation of injection

pressure as compared to other variable

parameters.

2. It is observed that the tensile strength is

increased by the variation of injection speed.

3. It is seen that the tensile strain depends upon the

temperature, the rate of strain suddenly changes

with the change in temperature.

REFERENCES

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Tensile Extension

(mm) *Temp 17.04 16.61 14.74

Tensile Extension

(mm) * Injection Pressure

16.36 15.33 14.35

Tensile Extension

(mm) * Hold on Pressure

13.02 13.11

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Speed

15 15.44

0 2 4 6 8

10 12 14 16 18

Ten

sile

Ext

en

sio

n (

mm

)

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1351.99 1365.31 1387.92

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1502.8 1530.88

1250

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1350

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du

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(N/M

M^2

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Web References: https://www.acpo.com/polypropylene/

http://ppmb.net/html_news/About-

Polypropylene-(PP)-6.html

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pp/polypropylene.html

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ii/S0735193310001636

http://pranjal-dew42.blogspot

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ing-flow-in-plastic-injection-molding-

jYcQ7EnPMa.in/

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