TOPIC OF PRESENTATION
Noman Asif (2010-IM-112)
Ramiz Raja (2010-IM-132)
Ali Muhammad (2010-IM-149)
Introduction of the industry
Introduction to the process
Equipment and tools used
Process on the job
• Sharp Electric industry G.T Road
• Vendor of Boss industry.
Washing Machine & parts manufacturing.
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.
Typical parts are fittings, containers, bottle tops,
housings, and more.
For glass rubber also injection molding is used.
Most common plastic “finishing” process.
Injection molding process is primary manufacturing
Mold is a hollowed out block used when components are to
be made from plastics or rubber glass etc.
The mold is made from metal, usually either steel or
Designing and making mold for injection molding is more
complicated than making extrusion die
Main functions of mold
- to give desired shape to the part
- cool and cure the material
- eject the part properly
- to distribute the melt
- to withstand clamping forces and
Types of plastics:
Can be reused e.g. PP
Can not be reused
• Granulated or powdered plastic is fed from a
hopper into the injection molding machine.
• The rotating screw inside barrel carries the
plastic along the barrel to the mold.
• Heaters surround the barrel melt the plastic as it
travels along the barrel.
• The screw is forced back as the melted plastic
collects at the end of the barrel.
• Once enough plastic has collected a hydraulic
ram pushes the screw forward injecting the
plastic through a sprue into a mould cavity.
• The mould is warmed before injecting and the
plastic is injected quickly to prevent it from
hardening before the mould is full.
• Pressure is maintained for a short time to prevent the
material creeping back during setting (hardening).
• This prevents shrinkage and hollows, therefore giving a
better quality product.
• The moulding is left to cool before removing (ejected)
from the mould. The moulding takes on the shape of the
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
Full automation is possible with injection molding
More uniform melting
High initial equipment investment
High startup and running costs
Difficulty in designing molds
Contamination of raw material affect the quality of final
• Requires high pressures
• Problems with required heating/cooling of the plastic
• Rehl for The holy Quran
• Used broken tables, chairs etc. are
crushed in crusher.
• Crushed parts are melted.
• Small grains are made.
What is polypropylene??
Thermoplastic polymer used in a wide
variety of application including packaging
and labeling chairs, tables etc.
Melting point 130-171C
Low moisture absorption
Easy to maintain and clean
Can be recycled
Alternatives of PP
• polystyrene (low-cost material)
• 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)
• 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
• Injection molding process is a manufacturing process
used to manufacture parts from plastic, rubber and
• First of all raw material is melted then injected in the
mold and product is ready.
• Polypropylene is used for table chair and rehl as raw
• Polypropylene is cheap, has low melting point can be
• In injection molding less material is wasted, and final
product is of low cost.