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2. Injection Molding
PRESENTED BY :
Fahad Rafiq
2014-UET-KIT-Mech-21
Cell No:
+923334040537

3. D.R AQ Khan Instetute Mianwali
Subject Code : 244
Name Of Subject : Manufacturing Technology
Name of Unit : Molding
Topic : Injection Molding

4. INJECTION MOULDING
3 Major Functional Units: Injection, Mold, Clamping

5. CORPORATE TRAINING AND PLANNING
Historical Background
• A single-action hydraulic injection machine was
designed in the U.S.A. in 1870 by Hyatt
• Heating-cylinder design was first recognised in a
patent issued to Adam Gastron in 1932.
• Large-scale development of injection moulding
machinery design towards the machines we know
today did not occur until the 1950's in Germany

6. CORPORATE TRAINING AND PLANNING
Injection Moulding Process
– Over View
Solid Wide neck, Flat Product is made like
bucket, cabinets, Automobile & Industrial
parts etc.by injecting molten thermoplastic
material in to a closed mould which is
relatively cool.

7. Process Studied
"Injection molding”
DEFINITION:
Injection molding is a manufacturing process for
producing parts from both thermoplastics and thermosetting
plastic or other materials.
 For this purpose injection molding machine is used.
 Used for manufacturing of variety of parts from small
components to entire body panel of cars.
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8. What Is Plastic Injection
Moulding
Injection moulding is often ranked as the one of the
commonly used processes in the production of plastic
items. The popularity of plastic injection moulding is
often due to the fact that it is a fast process which can
be used to produce vast quantities of identical plastic
items ranging from disposable consumer goods to
high precision engineering components.

9. INJECTION MOLDING
• Injection molding is one of the most commonly
used processing method for the plastic
components
• It is defined as
“ A manufacturing process for forming objects,
as of plastic or metal, by heating the
molding material to a fluid state and injecting it
into a mold “.

10. INJECTION BLOW MOLDING
• The injection blow molding is used for the production
of hollow objects in large quantities . The main
applications are bottles, jars and other containers.
• The process is divided into three sections
i) Injection
ii) Blowing
iii) Ejection

11. What is Injection Moulding?
• Injection moulding is a manufacturing process
for making parts from thermoplastic materials
• Thermoplastics are materials, such as
polystyrene, that can be formed into different
shapes once heated and pressured in a mould
• An engineer/industrial designer will design
the desired product and then a mouldmaker
will make a mould from metal
• Used to manufacture a range of parts such as
body panels for cars vido

12. • Blow moulding is a manufacturing process
similar to injection moulding
• Hollow plastic parts are formed through the
use of blow moulding vido
What is Blow Moulding?

13. Main Differences
Injection Moulding
• Makes solid parts
• Thermoplastic is injected
into a mould
• A part’s thickness is
influenced by the mould and
core relationship
• 90% of the time spent on the
job is needed for making the
mould
Blow Moulding
• Makes hollow parts
• Thermoplastic is a sheet/
parison that is pushed into a
mould by air
• A part’s thickness will differ
from place to place
• 50% of the time spent on the
job is needed for making the
mould

14. Main Differences
Injection Moulding
• Minimising the presence of
air in the injected plastic is a
key concern
• When the plastic cools at the
end of the process the
machine opens and the part
is released
• Parts tend to be solid plastic
parts or components
Blow Moulding
• As a hollow interior is
required, air is needed to
force the plastic to expand
• The process may end in the
first mould or the air may be
injected in another section
of the machine
• Parts tend to be hollow
containers such as bottles

15. Injection Moulding

16. Blow Moulding
Extrusion Blow Moulding – one of 3 types of Blow Moulding

17. CORPORATE TRAINING AND PLANNING
Type of Injection Moulding Machine
• Hand Injection Moulding M/C
• Plunger type Injection Moulding M/C
• Reciprocating Screw Type Injection
Moulding M/C

18. CORPORATE TRAINING AND PLANNING
Hand Injection Moulding Machine
vertical machine consists of Barrel, Plunger, Band
Heaters along with energy regulator, Rack & Pinion
system for Injecting the material by the plunger, a
torpedo and nozzle.

19. CORPORATE TRAINING AND PLANNING
Plunger Type Injection
Moulding Machine
Vertical & Horizontal Plunger Type Injection Moulding Machine

20. CORPORATE TRAINING AND PLANNING
The Reciprocating Screw
• The feeding zone
• The compressing (or transition) zone
• The metering zone

21. CORPORATE TRAINING AND PLANNING
Machine components

22. CORPORATE TRAINING AND PLANNING
The Injection Process
• Plasticises the material by reciprocating Screw.
• Injects the molten material to a closed mould
– via a channel system of gates and runners.
• Cools the Mould.
• Refills the material for the next cycle.
• Ejects the Product.
• Closes the Mould for further cycle.

23. CORPORATE TRAINING AND PLANNING
Injection Moulded Items

24. CORPORATE TRAINING AND PLANNING
Injection Moulded Items

25. CORPORATE TRAINING AND PLANNING
Injection Moulded Items

26. CORPORATE TRAINING AND PLANNING
Machine operation sequence
The mould closes and the screw begins moving forward for
injection.
The cavity fills as the reciprocating screw moves forward, as a
plunger.

27. CORPORATE TRAINING AND PLANNING
Machine operation sequence
The cavity is packed as the screw continuously moves forward.
The cavity cools as the gate freezes off and the screw begins to
retract to plasticize material for the next shot.

28. CORPORATE TRAINING AND PLANNING
Machine operation sequence
The mould opens for part ejection
The mould closes and the next cycle begins

29. INJECTION MOLDING (CONTINUED)
 It is used to process thin walled plastic
parts for a wide variety of shapes and
products .
BASIC PRINCIPLE
Plastic material is melted in a heated
chamber and then injected in the mold ,
where it cools and finally the finished
plastic part is ejected out of the cavity .

30. INJECTION MOLDING MACHINE
• The raw material in the form of powder/pellets is
introduced through hopper into the cylinder

31. • Advantages
– More uniform melting
– Improved mixing or additives and dispersion
throughout the resin
– Lower injection pressure
– Fewer stresses in the part
– Faster total cycle
Reciprocating Screw Injection Molding Machine

32. Machine parts
• Hopper is a tapered container working with a hopping
motion to transfer grains into cylinder
• Inside the cylinder there is a piston /plunger which is
used to move the material from cylinder into the mold
• Heating arrangement is placed above and below the
cylinder .
• The mold is in two halves , it has a mold cavity and the
mold has two ejector pins.

33. Process
• As soon as the plastic is melted it will be pushed
by the piston into the sprue through which the
material would go into the mold cavity .
• The cavity will be filled by the pressure of the
piston and the mold should not be opened until
the plastic solidifies.
• When the plastic solidifies the ejector pins are
hydraulically moved backwards .

34. Stages of Injection molding
• Clamping : The two halves of mold are tightly closed
before the molten plastic is injected.
• Injection : Injection of raw material from hopper into
cylinder to the cavity is called the injection stage.
• Cooling : The material is cooled for at least 30-60 sec
• Ejection : The 2nd mold plate moves back by ejector
pins and the product is tapped out

35. Mold of REHL
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36. Mold for Chair
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37. Types of plastics:
Thermoplastics
Can be reused e.g. PP
Thermosetting plastics
Can not be reused
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38. 38

39. 39

40. Advantages:
• High production rate
• Can process a wide range of materials
• Relatively low labor
• Less or no finishing of parts required
• Scrap material can be recycled and reused
• Low operation cost
• Smooth surfaces
• Full automation is possible with injection molding
• More uniform melting
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41. CORPORATE TRAINING AND PLANNING
Advantages of Injection Moulding Process
• Parts can be produced at high production rates.
• Large volume production is possible.
• Relatively low labour cost per unit is obtainable.
• Process is highly susceptible to automation.
• Parts require little or no finishing.
• Many different surfaces, colours, and finishes are available.
• Good decoration is possible.
• For many shapes this process is the most economical way to
fabricate.
• Process permits the manufacture of very small parts which are
almost impossible to fabricate in quantities by other methods.

42. Disadvantages:
• High initial equipment investment
• High startup and running costs
• Difficulty in designing molds
• Contamination of raw material affect the quality of final
product
• Requires high pressures
• Problems with required heating/cooling of the plastic
material
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43. RECYCLING
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• Used broken tables, chairs etc. are crushed in
crusher.
• Crushed parts are melted.
• Small grains are made.

44.  The most commonly used thermoplastic materials are:
 Polystyrene (low-cost, lacking the strength and
longevity of other materials)
 ABS or acrylonitrile butadiene styrene (a co-polymer or
mixture of compounds used for everything from Lego
parts to electronics housings)
 Nylon (chemically resistant, heat-resistant, tough and
flexible - used for combs)
 Polypropylene (tough and flexible - used for containers
 PVC (more common in extrusions as used for pipes,
window frames, or as the insulation on wiring where it
is rendered flexible by the inclusion of a high
proportion of plasticiser).

45. Raw material used:
• Polypropylene PP
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46. What is polypropylene??
Thermoplastic polymer used in a wide variety of
application including packaging and labeling
chairs, tables etc.
Melting point 130-171C
266-340 F
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47. Why polypropylene????
• Low cost
• Flexible
• Tough
• Light weight
• Low moisture absorption
• Easy to maintain and clean
• Can be recycled
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48. FINAL PRODUCTS:
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49. Material wasted:
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Less material is wasted
Can be used again after melting

50. MATERIALS USED
• Acetate
• Acrylonitrile butadiene styrene (ABS)
• Cellulose acetate
• PVC ( poly vinyl chloride)
• Polycarbonate
• Polyesters
e.t.c.

51. APPLICATIONS
• It can be used to produce thin walled plastic products of
varying size and dimensions e.g.
• Medical devices such as surgical syringes
• Open container like buckets
• Plastic housings of different tools
• Daily use products such as tooth brushes

52. Any
question?

53. The end