PLASTICS MOULDING Flashcards
1
Q
VACUUM FORMING
A
used for: -blister packet -yogart pots -cups made from: -H.I.P.S (high impact polostirene) what you need: -5degree draft -vent holes -no undercuts -curved corners
2
Q
PROCESS OF VACUUM FORMING
A
- Thermoplastic is heated
- Table + mould is raised
- Air is sucked out
- Thermoplastic is forced down onto mould
- Thermoplastic is forced down into mould
- Form then un clampled + trimmed
3
Q
INJECTION MOULDING
A
used for: -lego -bottle tops made from: -polyethylene -polypropylene -nylon it is: -very expensive -only used for mass prodution -a 2 part mould
4
Q
PROCESS OF INJECTION MOULDING
A
- plastic granules go from HOPPER into into machine
- granules move through the heater where they are PLASTICISED
- plasticised material is forced into the cavity in the 2-part die
- component is cooled by water
- mould is separated, and the component is ejected
5
Q
BLOW MOULDING
A
used for: -plastic bottles -toy wheels made from: -HDPE -LDPE
6
Q
PROCESS OF BLOW MOULDING
A
- a hollow length of plastic in extruded between the two halves of the mould
- the 2-part mould closes, crimping the top of the tube
- compressed air is blown in, pushing the softened plastic out againsted the inside of the mould
- the component is ejected and waste trimmed off
7
Q
EXTRUSION
A
used for: -window frames -guttering -electrical trunking made from: -HDPE -PVC -ABS
8
Q
PROCESS OF EXTRUSION
A
- plastic put into hopper funnel
- plastic is heated
- pushed through a die to create a specific profile
- it goes through a cooling water bath the cut to length
9
Q
ROTATIONAL MOULDING
A
used for: -buoys -kayaks made from: -polyethylene -polypropylene
10
Q
PROCESS OF ROTATIONAL MOULDING
A
- plastic powder is poured into a mould
- mould is heated in an oven and is rotated on 3 axes
- the power melts and gradually coats the inside of the mould
- the mould is rotated while it is cooled by fans
- the mould is opened and the component ejected
