large scale manufacture:polymers Flashcards
1
Q
injection molding
A
Injection molding
- Granules fed in to hopper
- Granules heated and plasticised
- Dragged forward with screw
- Injected into mould
- Cooled in the mould
- Removed with injector pins
2
Q
what is injection molding used for ?
A
Used to make…
- Complex 3d shapes
- Chairs
- Lego bricks
- Lunch boxes
3
Q
Extrusion
A
Extrusion
- Plastic forced through die (not into a mould like injection moulding)
- Continuous stream of polymer pushed through
- Creates long sections of polymer
(Similar to injection moulding)
4
Q
what is extrusion used to make?
A
Used to make…
- Tubes
- Gutters
- Sections
- Rods
5
Q
blow molding
A
Blow Moulding
- Start with the extrusion process
- Polymer then goes into split mould
- Air blow into extruded polymer to make it fill the mould
- Cooled in the mould
- Removed
(Similar to extrusion)
6
Q
what is blow molding used to make?
A
Used to make…
- Drinks bottles
- Large containers
- Water butts
7
Q
rotational molding
A
Rotational Moulding
- Polymer powder placed into mould
- Mould is heated and rotated continuously
- Once coated then cooled
- Mould opened and product removed
8
Q
what is rotational molding used to make ?
A
Used to make…
- Large toys
- Insulated containers
- Bins
- Kayaks
9
Q
compression moulding
A
Compression Moulding
- Heated slug placed inside two pre heated moulds
- 2 halves of mould pushed together with hydraulic press to shape slug
- Part allowed to cool
- Removed using ejector pins
Slug: Block of polymer
OFTEN USED WITH THERMO SETTING PLOYMERS
10
Q
what is compression moulding used to make
A
Used to make…
- Cups
- Bowls
- Plug sockets
11
Q
vacuum forming
A
Vacuum Forming
- Mould placed on machine bed
- Polymer sheet clamped above mould and heated
- Mould pushed into polymer
- Vacuum removes air and shapes polymer around mould
- Allowed to cool
- Removed and trimmed
12
Q
what is vacuum forming used for?
A
Used to make…
- Yoghurt pots
- Trays
- Baths
