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PLASTICS (Formation techniques (Extrusion (We put thermoplastic, in…
PLASTICS
Formation techniques
When we manufacture plastic obiects in Industry, the plastic Is avadable in different forms:
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Extrusion
- We put thermoplastic, in granular form, Into a previously heated cylinder.
2- We apply pressure by means of a large, rotating screw, whtch forces the melted metal out, through a nozzle.
- We cool the shaped material slowly In a refngerated water bath until. lt's solid.
- Finally, we collect the pieces of plastic through a feeder system
Lamination
Thermoplastic produced by the extrusion method ls passed through a senes of hot cylinders to produce sheets of varying thtckness
With that technique, we can produce different finishes, for example: glossy, matt or textured.
Vacuum forming
- We put thermoplasttc into a mould.
- We then use a heater to heat the mould and soften the plasuc.
3- We extract the air below the sheet so that the plastic ts pulled against
the instde walls of the shaped mould, and the desired form ts created.
- We leave the mould to cool, then remove the obiect
Moulding
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Compression
The outer part of the cavity
mould,
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We put thermostable plasuc, which can be in granular form,into the base of a cavity mould.
Blow moulding
We put a tubular-shaped piece of plastic into a hollow mould whichhas the same shape as the oblect that we want to make
We close the mould and blow pressurised air into it, so that the
such as fridges, the sides of the mould and takes its shape.
When the object is cold, we remove it from the mould.
Natural plastics
They are obtained directly from raw vegetable materials. 
Synthetic plastics
They are made from compounds extracted from
petroleum, natural gas and carbon, most of them are in this group.
En ergetic recycling. We can incinerate plastics and the energy that is produced is used tn industry, for heating or producing electricity.
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Properties of plastics
Strength, elasticity, rigidity and flexibtflty are charactenstics of many plasics. However, there are other properties that are common to the majority of plastics.
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other properties: low density, tmpermeabihty
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mechanical: malleabrlity, ductility, mechanical resistance
Ecological properties
We can recycle plastics.
There are three recycling
processes: chemical,
mechantcal and energetic.
Chemical recycling. We apply chemical processes to make new
matenals from the ongtnal components of plasuc residues.
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There are 5 steps:
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Extrusion. tve melt the matenal, and then tt's extruded into long
filaments
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Plastics are materials formed by polymers. The polymers in plastics are made from long chains of carbon atoms.
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