Injection moulding process

this is very useful slide for cipet

1. ISO 9001
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CENTRAL INSTITUTE OF PLASTICS
ENGINEERING AND TECHNOLOGY

2. ISO 9001
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INJECTION MOULDING PROCESS -
RESOURCES
MATERIAL
MACHINE
MOULD
MAN POWER

3. ISO 9001
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MATERIALTHERMOPLASTIC
MATERIAL
THERMOSET
MATERIAL
PLASTIC MATERIAL

4. ISO 9001
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•HEAT •COOL
•SOLID
•PRESS.
IT CAN BE RECYCLED
THERMPLASTIC MATERIAL
•SOFT

5. ISO 9001
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•HEAT •HEAT
•SOLID
•PRESS.
•IT CAN NOT BE RECYCLED
•SOFT
•CHARCOAL
THERMOSET MATERIAL

6. ISO 9001
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Injection Moulding
Definition
Processwherebyheatsoftening,plasticsmaterial
isforced(injected)fromacyclinderintoacavity
whichisareplicaofarticle.Afterallowingfor
coolingfinishedarticlecanbeejectedoutfrom
thecavity.

7. ISO 9001
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Injection Moulding
Product
Batch process of constant dimension with close
dimensional control. Such as
•video cassettee,
•fuel pumps,
•gear box,
•small gears,
•automobile parts,
•pipe fittings disposable
syringes &
•other medical
equipments.
•bucket,
•mug,
•dustbin,
•cups,
•crates,
•moulding luggauge,
•cabinate for radios,
•taperecorders,
•housing for domestic
appliances,

8. ISO 9001
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Injection Moulding
Material
All thermoplastics like LDPE, HDPE, PVC, ABS,
Polycarbonate, etc.
Thermoset on specific requirement & cost
effective basis, Recommended MFI 8 to 10 and
above.

9. ISO 9001
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Injection Moulding
Rating
•Clamping Capacity in Tonnes

10. ISO 9001
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Injection Moulding
Major factor for consideration
•Type of Clampings
•L/D ratio and compression ratio,
•Shot weight
•Minimum and Maximum day light
•Size of platen and distance tie rod/
•Type of Drive.

11. ISO 9001
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MACHINE
HEATING
PRESURISING AND CONVEYING
MOULD CLAMPING
Figure -The basic Injection Moulding Cycle

12. ISO 9001
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MOULD
THE MOLD HAS 4 MAIN FUNCTIONS
RECEIVE & DISTRIBUTE THE MATERIAL
SHAPE FORMING
COOLING(Water & oil)
DISPOSAL

13. ISO 9001
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MANPOWER
TO SET UP A PROCESS
TO MONITOR AND TROUBLE SHOOT
TO OPARATE MACHINE

14. ISO 9001
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Injection Moulding
Types of Injection Unit
•Plunger
•Preplasticising
•Reciprocating screw

15. ISO 9001
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PLUNGER TYPE MACHINE
TYPES OF I.M MACHINES

16. ISO 9001
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VPLUNGER-PLUNGER TYPE

17. ISO 9001
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SCREW –PLUNGER TYPE

18. ISO 9001
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VIN LINE RESIPROCATING SCREW TYPE

19. ISO 9001
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Screw Rotation

20. ISO 9001
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The rotation of the screw produces
frictional and shear together with the
heat input from heater bands around
the barrel cause the material to melt.
These two sources of heat , combined
with the mixing effect of the screw ,
provide a homogenous melt
Screw Rotation

21. ISO 9001
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NOZZLE
It provides thermal & mechanical connection
from hot cylinder to cold injection mold
TYPES OF NOZZLES
An open channel with no mechanical
valve
An internal check -valve held closed by
spring
A shut off valve

22. ISO 9001
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SCREW-L/D RATIO
It is the ratio of the flight length to the dia.
of the screw
Generally L/D ratio varies 20:1 to 30:1
Generally L/D ratio for PVC is 16:1
The larger the L/D ratio greater opportunity
for mixing, resulting in better homogeneity of
melt
Greater the resident time of the plastic in the
barrel permitting faster cycles of larger shots
& more output

23. ISO 9001
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FEED ZONE: Promotes pumping/output rate
adequately-It can be 50 to 60% of L
COMPRESSION ZONE : Promotes shearing
and hence melting of polymers at the output
rate of feed zone-It can be 20 to 25% of L
METERING ZONE : Promotes homogenization
of entire melt stream emerging from
compression zone-It can be 20 to 25% of L
SCREW-VARIOUS ZONES IN SCREW

24. ISO 9001
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SCREW
SIGNIFICANCE OF LENGTH OF EACH ZONE
Longer feed zone creates greater potential
throughput
Longer compression zone results in less
shear heat & more to compress & melt the
plastic
Longer meter zone allows screw to develop
more pumping pressure and greater
opportunity to homogenize
Shorter meter zone allows less time to assure
uniform melt temperature and viscosity

25. ISO 9001
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CLAMPPING -TYPES
 HYDAULIC CLAMPING
 TOGGLE CLAMPING
 PNEUMATIC CLAMPING

26. ISO 9001
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Hydraulic Clamping
Toggle Clamping

27. ISO 9001
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28. ISO 9001
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HYDRAULIC Vs TOGGLE -COMPARISION
Much higher original
cost
Higher horse power
needed.Therefore
more expensive to
run
Unlimited stroke
potential
Direct readout of
clamp force
Lower original cost
Lower horse power
needed.More
economical to run
Limited stroke
potential
No Direct readout of
clamp force

29. ISO 9001
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HYDRAULIC Vs TOGGLE -COMPARISION
Easy adjustment of
clamp force
Easy mold setup
Varies stroke to mold
height
Clamp speed easily
controlled or stopped
at any point
Low maintenance as
parts are self
lubricated
More difficult
More involvement in
mold setup
Constant mold stroke
Clamp speed more
difficult to control and
stop
Higher maintenance
cost

30. ISO 9001
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POLYMER
MATERIAL
TEMP.RANGE 0
C
MOLD TEPMP.
Nylon-6 230-260 80-90
Nylon-6 with GF 230-280 70-90
Nylon-66 270-290
80-90
Nylon11 210-240 30-60
Polysulphon
33-400 100-160
LDPE 160-240 30-50
LLDPE 200-280 30-50
HDPE 160-220 30-50
EVA copolymer 160-230 30-50
PP homopolymer 220-280 20-70
PP,20% Talc 200-280 20-70
PP,copolymer 170-230 20-60
PP,20% glass 220-280 20-80
GPPS 170-280 20-70
GPPS with GF 210-280 60-80
HIPS 190-260 50-80
SAN 200-280 30-80
ABS 240-280 40-80

31. ISO 9001
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POLYMER MATERIAL TEMP.RANGE 0 C MOLD TEPMP.
PVC,Rigid 190-220 30-60
PVC,Soft 140-200 20-40
Acrylic 220-250 60-90
PET 280-295 5-15
PET,Not reinforced 235-280 20-70
PBT,30%GF 235-280 20-90
PET/PBT copolymer 235-280 20-90
PC 280-310 80-120
PC 40% GF 270-310 80-120
PPS 300-360 120-180
POM copolymer 180-230 60-120
PPO modified with GF 250-280 110-13
PPS/PS 270-300 70-110
PUR 170-220 10-30