Thermoforming

process of injection moulding, blow moulding & vacuum forming

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  • Created by: saraswati
  • Created on: 06-05-09 12:31

INJECTION MOULDING

liquid plastic is forced into mould which is cooled to produce a wide range of products such as castings for electronic products & closures for packaging

1) granules are poured into the hopper

2) they are heated

3) screw pushes the softened granules forward

4) the plasticised material is forced into the mould

5) mould is cooled (water)

6) the ram is withdrawn

7) mould opens

8) hardened product is ejected from the mould with ejector pins

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BLOW MOULDING

used to produce hollow containers such as plastic bottles

1) extruded parison is inserted into a split mould

2) split mould closes, sealing the perison at one end

3) hot compressed air forces the plastic into the shape of the mould

4) mould is cooled & plastic hardens

5) mould opens & the product is ejected

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VACUUM FORMING

is used to produce trays & container such as chocolate bow trays, yogurt pots & blister packs

1) a mould is placed on the platen which is lowered(mould must be tapered - draft angle - without udercuts, so it can be removed)

2) a plastic sheet is clamped into place above the mould

3) heater is pulled over this plastic sheet

4 )when the sheet has softened the platen is raised

5) a pump expels the air which creates a vacuum causing the plastic to be forced over the mould

6) platen is lowered & the mould is removed

7) waste material is trimmed

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