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PLASTICS (FORMATION TECHNIQUES (MOULDING (injection moulding
1 We inject…
PLASTICS
FORMATION TECHNIQUES
Extrusion.This technique has four stages:
1.We put thermoplastic,in granular form into a previously heated cylinder
2.We apply pressure by means of a large,rotating screw,which forces the melted material out .through nozzle
3.We cool the shaped material slowly in a refrigerated water bath until it's solid
4.Finally,we collect the pieces of platics through a feeder system
LAMINATION
Thermoplastic produced by the extruxion method is passed through a series of hot cylinders to produce sheets of varying thickness
VACUUM FORMING
1.We put thermoplastic into a mould
2.We then use a heater to heat the mould and soften the plastic
3.We extract the air below the sheet so that the plastic is pulled against the inside walls of the shaped mould,and the desired form is created
4.We leave the mould to cool,then remove de object
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MOULDING
injection moulding
1 We inject melted thermoplastic into a mould
2 When the material has cooles and solidificated , we extract it from the mould
Blow moulding
1 We put a tubular-shaped piece of plastic into a hollow mould wich has the same shape as the object that we want to make
2 We close the mould and blow pressurised air into it,so that the plastic adheres to the sides of the mould and takes its shape
3 When the object is cold, we remove it from the mould.
Compression
1.We put thermostable plastic,wich can be in granular form,into the base of a cavity mould.
2.The outer part of the covity mould shaped the same is closed to compress the material inside.We then heat it and it becomes soft and malleable
Properties of platics
Mechanical:malleability,ductility,machanical resistence
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Other properties:low density,impermeability
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Ecological properties
Mechanical recycling.We make new products from plastic granules .The process has five stages:
1 Separation and crushing. We separate the plastics according to
type and then they' re crushed
2 Floating. We wash the plastics and then dry them by centrifugal force.
3 Agglutination. The material is compacted and then incorporated into other materials
4 Extrusion. We melt the material, and then it's extruded into long filaments
5 Pellestesing.The filaments are then reduced to granules that we call pellets.
Chemical recycling. We apply chemical processes to make new
materials from the original components of plastic residues.
Definition
Plastics are materials formed by polymers. The polymers in plastics are
made from long chains of carbon atoms.
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