PLASTIC MATERIALS
PLASTIC MATERIALS
Consists of long chains of molecules, mostly made of the element carbon
THE ORIGIN OF PLASTICS
NATURAL PLASTICS
SYNTHETIC PLASTICS
THE TRANSFORMATION OF PLASTICS
During the manufacturing process, fillers may be added to reduce the cost of production and enhance certain properties of the raw materials
Chemical additives can aslso be used, such as plasticizers which increase the flexibility and the resistance of the final product.
PROPERTIES OF PLASTICS
Physically resistant
good electrical, thermal and acoustic insulators
Ductible because they can be pulled to make theads
Malleable because they can be pressed into the sheets
light
Impermeable
recyclable
Chemical recycling
mechanical recycling
Energy recovery
Non-biodegradable plastic
biodegradable plastic
THE CLASSIFICASTION OF PLASTICS
CLASSIFICATION BY INTERNAL STRUCTURE
Thermoplastics
Thermosetting plastics
Elastomers
Industrial plastics
Polyethylene terephthalate
High-density polyethylene
Polyvinyl chloride
low-density polyethylene
Polypropylene
Polystryrene
Moulded
Expanded
Methacrylate
Teflon
Cellophane
Nylon
PLASTIC FORMING TECHNIQUES
Plastics products are typically made from powder, pallets, or resins.
Various techniques can be used to form plastic products, but the most important ones are extrusion, calendaring, vacuum forming and moulding
EXTRUSION
Thermoplastic material, usually in the form of pallets, is added to an extursion machine
Inside the cylinder, there is a screw that turns and pushes and pushes the plastic out through a die.
When the plastic leaves the machine, it is hardened in a bath of cool water
CALENDARING
In the calendering process, thermoplastic material is passed betwween rollers to make thin sheets.
VACUUM FORMING
A sheet of thermoplastic material is placed over a mould.
The sheet of plastic is heated until it becomes soft
The air under the sheet is sucked out to create a vacuum.
The sheet is cooled and removed from the mould
MOULDING
Blow moulding
Injection moulding
Compression moulding
MODIFICATION TECHNIQUES
measuring-marking-cutting-drilling-filling and sanding-joining
MEASURING
Carpenter´s square
measuring tape
ruler
Protactor
DRAWING MARKS AND LINES
CUTTING
Scissors
HACKSAW
utility knife