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Flashcards in Plastics Deck (19)
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1
Q

What is a thermoplastic?

A

Its a plastic that can be re-shaped by heating it.

2
Q

What is a thermosetting plastic?

A

Its a plastic that cannot be re-shaped by heating.

3
Q

What material are majority of are plastics, and what does that mean?

A

They are all mainly synthetics and this means they are man-made chemical process.

4
Q

Name 2 types of thermoplastics and their properties:

A

PET- usually in transparent form, used for bottles and food containers.
HDPE- strong and stiff with excellent chemical resistance, used for bowls, buckets and pipes.

5
Q

Name 2 types of thermosetting plastics and their properties:

A

Polyester resin- hard, brittle, strengthened by laminating it with fibre glass. Used for boat hulls, garden furniture, car bodies.
Urea Formaldehyde- tough, attractive, good heat insulator. Used for electrical fittings, waterproof glue.

6
Q

What are the main facts about injection moulding?

A
  • Not identical cross section
  • very common
  • electrical goods
  • put granules in hopper, pushed in chamber by rams, bands soften into liquid under pressure then put in mould, then is cooled.
7
Q

What are the main facts about extrusion moulding?

A
  • has uniformed cross section
  • granules/powder are put in hopper through a heated cylinder, die fitted to end of extruder shapes the plastic, cooled as it leaves the die
8
Q

What are the main facts about blow moulding?

A
  • shapes with one open end-hollow

- warm condensed air is forced against the softened sheets causing it to expand in a mould or dome.

9
Q

What methods are used to change the shape of manufactured boards?

A
  • line bender
  • vacuum forming
  • extrusion/injection moulding
10
Q

What are the main facts about line bending?

A
  • radiant heat from electric element
  • enclosed in channel
  • acrylic laid across support opening turnover every so often
11
Q

What are the main facts about vacuum forming?

A

-make mould>put on tray>lower tray>put plastic on top of chamber>heat>make sure its malleable>remove heater>raise tray into plastic>switch on vacuum(remove air)>blow air back in>clean edges!!

12
Q

What is glass reinforced polyester(GRP)?

A

Its layers of fibre matting are placed over a former, and a liquid resin is poured over. The resin hardens to produce a rigid material. Further layers can be added. GPR is used for larger and more complex shaped, such as boots.

13
Q

What are advantages and disadvantages of GRP?

A

ads - double strong, resistant to all weather, oil and water, easy to form and very cheap
disads- fibre glass fumes/particles are hazardous and you must wear protective gear.

14
Q

Name 3 types of glues:

A
  • contact adhesive
  • epoxy resin
  • hot glue stick
15
Q

What is the dry time, material uses on and uses and a type of this glue of contact adhesive?

A
  • used on wood, metal, plastics
  • dry time = instant
  • waterproof, med strength, good for plastic laminates
  • left to touch dry then pressed together.
16
Q

What is a brand of contact adhesive glue?

A

evostick

17
Q

What is the dry time, material uses on and uses and a type of this glue of epoxy resin?

A
  • used on wood, plastics, metal
  • 1/2 - 6 hours
  • waterproof, strong joint
  • 2 tubes = resin + hardener, mixed together applied and then need to be held when drying
18
Q

What is the dry time, material uses on and uses and a type of this glue of hot glue stick?

A
  • used on wood, metal, plastics
  • dried on cooling
  • waterproof, weak, only suitable for modelling temporary things
  • comes in a stick form
19
Q

What is a brand of epoxy resin?

A

aridite