Injection molding and blow molding are pivotal processes in mechanical engineering, particularly in the production of plastic components. These methods enable the efficient mass production of complex plastic parts and products, serving various industries. Injection molding involves injecting molten plastic into molds to create precise shapes, while blow molding uses air pressure to form hollow plastic objects.

1.  Introduction
 Injection molding
 Components of Injection Molding
 Injection Molding Process
 Injection Molding Machine Process
 Advantages
 Disadvantages
 Blow Molding
 Types of Blow Molding
 Extrusion Blow Molding
 Injection Blow Molding
 Components of Blow Molding
 Advantages
 Disadvantages
CONTENT
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2. INTRODUCTION
• Injection molding and blow molding are pivotal processes in mechanical engineering, particularly
in the production of plastic components.
• These methods enable the efficient mass production of complex plastic parts and products,
serving various industries.
• Injection molding involves injecting molten plastic into molds to create precise shapes, while
blow molding uses air pressure to form hollow plastic objects.
• Both processes play essential roles in modern manufacturing, offering versatility, cost-
effectiveness, and consistent quality.
• Understanding their principles, materials, and applications is crucial for mechanical engineers in
today's industrial landscape.
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3. Injection molding is a manufacturing process for producing parts by injecting material into a mold.
Injection molding can be performed with a host of materials mainly including metals, glasses, elastomers,
confections, and most commonly thermoplastic and thermosetting polymers.
Commonly used materials are: Polypropylene, Poly Vinyl Chloride, Acrylonitrile Butadiene Styrene, High-
density Polyethylene, etc.
INJECTION MOLDING
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4. COMPONENTS OF INJECTION MOLDING
 Clamping Unit
 Injection unit
 Drive unit
 Mold
 Hydraulic system
 Control system
 Hopper
 Heaters
 Cooling channels
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5. INJECTION MOLDING WORKING STEPS
Ejection
Mold
holding
and
cooling
Injection
Feeding
into hopper
Material
preparation
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6. INJECTION MOLDING MACHINE
WORKING
• Material granules are fed into hopper then melted down in barrel which is surrounded by the heaters.
• Melted material is injected into mold cavity and mold is held under pressure until the material cools and hardens.
• Once the material hardens, the mold is opened and the component is ejected by runner plate.
• And the process can be repeated.
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7. Cont…...
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8. ADVANTAGES & DISADVANTAGES
OF INJECTION MOLDING
Advantage:
 Fast production.
 Low labour cost.
 Design flexibility.
 Good colour control.
 High-output production.
Disadvantage:
 High initial equipment investment.
 High startup and running costs possible.
 Part must be designed for effective molding.
 Accurate cost prediction for molding job is difficult.
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9. • Blow molding is a process for producing hollow objects, primarily from thermoplastic materials.
• Bottles and packaging are the primary applications of blow molded parts.
• Blow molding is operated using low molding pressure & hence result in Low Internal Stresses.
• Commonly used materials are :Polypropylene, Poly Vinyl Chloride, Polyethylene Terephthalate, Polycarbonate, etc.
BLOW MOLDING
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10. COMPONENTS OF BLOW MOLDING
 Air hose.
 Extruder.
 Cooling line.
 Mold cavity.
 Parison.
 Mold half.
 Blow pin.
 Molten plastic.
 Die head.
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11. BLOW MOLDING PROCESS
• The blow molding process begins with melting down the plastic and forming it into a parison.
• The parison is a tube- like piece of plastic with a hole in one end in which compressed air can pass through.
• The parison is then clamped into a mold and air is pumped into it.
• The air pressure then pushes the plastic out to match the mold.
• Once the plastic has cooled and hardened the mold opens up and the part is ejected.
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12. TYPES OF BLOW MOLDING
i. Extrusion Blow Molding
ii. Injection Blow Molding
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13. EXTRUSION BLOW MOLDING
• In Extrusion blow molding (EBM), plastic is melted and extruded into a hollow tube (a parison).
• This parison is then captured by closing it into a cooled metal mold. Air is then blown into the parison, inflating it into
the shape of the hollow bottle, container or part.
• After the plastic has cooled sufficiently, the mold is opened and the part is ejected.
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14. INJECTION BLOW MOLDING
Injection Stage
• Molten polymer is injected into a heated preform
mold.
• The preform is the partly shaped product that
will be used to make the final hollow product by
being blown into shape.
• The preform consists of a fully formed neck with
a thick tube of polymer attached.
Blowing Stage
• The preform is passed to the hollow,
chilled blow mold.
• Compressed air is blown through the
core rod into the preform material,
inflating it and forcing it against the
sides of the mold.
•
Ejection
• The blow formed polymer is allowed
to cool.
• It is then removed from the blow
mold and stripped off the core rod.
• The product then passes to the
quality control section and is tested
for leaks.
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15. ADVANTAGES & DISADVANTAGES OF
BLOW MOLDING
Advantage:
 Low tooling cost.
 Fast production rate.
 Recycling.
 Little scrap generated.
 Ability to mold complex.
Disadvantage:
 Only for hollow parts.
 Defect may be seen.
 Thick parts can be manufactured.
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