Plastic and Processes Theory'

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PLASTIC
Plastic and Processes Theory. Knowledge and
Understanding.
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PLASTICS can be divided into TWO main categories
THERMOPLASTIC and THERMOSETTING plastic .
PLASTIC
THERMOPLASTIC

• Recyclable
• Dont resist heat very well
• Easily shaped and reshaped over and over.

Examples Acrylic, ABS, Polystyrene and
Polythene.
THERMOSETTING

• Non-recyclable
• Resists heat and fire very well
• Hard to reshaped.

Examples Epoxy resin, Urea-formaldehyde,
Polyester resin.
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MATERIALS
POLYESTER
Polyesters (PET) is produced in numerous forms
such as sheets and three-dimensional shapes.
thermoplastics may change shape after the
application of heat, it is strong, lightweight
and waterproof. USE home furnishings such as bed
sheets, bedspreads, curtains, ropes, fabrics for
conveyor belts, safety belts, coated fabrics and
cushion padding.  
NYLON
Durability its high tenacity fibbers are used
for seatbelts, tire cords, ballistic cloth and
other uses. High elongation, excellent abrasion
resistance, highly resilient (nylon fabrics are
heat-set) High resistance to insects, fungi and
animals, molds, mildew, rot, many chemicals and
rain  
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Plastic Theory.
1. Plastics are divided into two groups, they are
Thermoplastic
Thermo set plastic
2. Describe the difference between the two groups

• Thermoset plastics can only be heated and shaped
  once.
• Thermoplastics can be heated and shaped many
  times .Making them ideal for recycling.

3. What type of plastic would you use for
electrical products
Thermoset plastic.
4. Give a reason for your choice
Thermoset plastics can only be heated and shaped
once making them more resistant to heat and
electrical fires.
PLASTIC
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Plastic Theory.
5. Name and briefly describe two methods of
shaping plastic  
Blow Moulding
FEED BACK
Parison
How are they made?

• Blow moulding of plastic bottles.
• A molten polymer is extruded into a hollow,
• tube-shaped parison.
• A split mould is closed around the parison, which
  is expanded against the sides of the mould by a
  stream of air.
• Once the plastic has solidified, the mould is
  opened and the shaped bottle released.
•  

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Plastic Theory.
Injection Moulding
Materials used
Products made
How it works.

• Granules of plastic are poured into a hopper.
• 2. A motor turns a thread which pushes the
  granules along the heater section which melts
  then into a liquid.
• 3. The liquid is forced into a mould where it
  cools into the shape.
• 4. The mould then opens and the shape is removed.

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Plastic Theory.
Vacuum Forming
How is it works?
FEED BACK

• Mould Facts.
• The mould must have sloping side so that it can
  be easily removed later.
• The mould should be greased before use for easy
  removal later.