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DT > Cad cam > Flashcards

Cad cam Flashcards

1
Q

What is the most widely used material in commercial production?

A

Polymers

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2
Q

What are the two main sources from which polymers can be created?

A
  1. Natural polymers

2. synthetic polymers

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3
Q

Give 2 examples of natural polymers

A

Amber

Rubber

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4
Q

Which is more commonly used, natural or synthetic polymers?

A

Synthetic polymers

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5
Q

Name 3 carbon based materials used to make synthetic polymers

A
  1. Crude oil
  2. Coal
  3. Natural gas
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6
Q

What is the name of the process used to make synthetic polymers?

A

Polymerisation

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7
Q

What is the definition of polymerisation?

A

Polymerisation occurs when monomers are joined together to form chains of molecules called polymers.

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8
Q

Write out the word equation and diagram for polymerisation

A

Monomers ➡️ ➡️ ➡️ ➡️ polymer

Polymerisation should be written across the arrow and single circles should represent the monomers and circles joined in a line for the polymer

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9
Q

What are the two main types of synthetic polymer that you need to learn?

A
  1. Thermosetting

2. Thermoplastic

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10
Q

Can thermosetting plastics be recycled?

A

No

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11
Q

What is thermosetting?

A

When the polymers are heated and moulded into shape

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12
Q

If polymers made by thermosetting are reheated, do they soften?

A

If thermosetting polymers are reheated they cannot soften

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13
Q

Why can thermosetting polymers not soften on reheating?

A

They cannot soften as the polymer chains are interlinked.

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14
Q

What happens in the thermosetting process?

A

Individual monomers are joined together to form a massive polymer

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15
Q

Where are thermosetting polymers commonly found?

A

In resins or powder form.

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16
Q

Give three actual examples of thermosetting polymers

A

Polystyrene resin
Epoxy resin
Melamine formaldehyde

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17
Q

What will happen when thermoplastics are softened?

A

These polymers will soften when they are heated

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18
Q

When can thermoplastics be shaped?

A

Yes when the plastic is hot

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19
Q

After heating when the plastic is soft when will it harden again?

A

When it cools

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20
Q

Can thermoplastics be remoulded?

A

Yes they can be reshaped by heating them up

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21
Q

How is thermoplastics normally supplied?

A

Generally supplied in sheets form or in pellets for injection moulding.

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22
Q

Can thermoplastics be recycled?

A

Yes they can

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23
Q

Give three examples of thermoplastics

A

Polyethylene terephthalate

High density polystyrene

Low density polystyrene

Polystyrene

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24
Q

What does the diagram of thermosetting look like?

A

Links between the polymer chains to stop movement between them.

Make sure you know what this looks like as you may have to draw it.

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25
Q

What does the diagram of thermoplastics look like?

A

No links between the polymer chains

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26
Q

What is the thermoplastic polyethylene terephthalate used for?

A

Fizzy drinks bottles and oven ready meal trays

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27
Q

What is the thermoplastic high density polystyrene used for?

A

Bottles for milk and washing up liquids

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28
Q

What is the thermoplastic low density polystyrene used for?

A

Carrier bags and bin liners

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29
Q

What is the thermo plastic polystyrene used for?

A

Yoghurt pots, foam meat or fish trays, hamburger boxes and egg cartons, plastic cutlery, protective packaging for goods and toys

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30
Q

What are degradable plastics?

A

Bio based plastics

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31
Q

Are bio based plastics new?

A

No they have been around for some time but are now becoming much more widely used.

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32
Q

Why are more types of bio based plastics being developed?

A

Consumers are becoming more environmentally friendly and demand it

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33
Q

How are biodegradable plastics created?

A

Using renewable raw materials such as starches from corn and potato

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34
Q

What does biodegradable mean?

A

Will decay over time

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35
Q

An example of a thermosetting plastic is polyester resin. What is this used for?

A

Used as the plastic in fibre glass

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36
Q

What is fibre glass?

A

A plastic made from polyester resin which is laid up with glass fibres to form complex shapes up to the size of a boat hull.

37
Q

Is epoxy resin (Araldite) which is a strong multi purpose adhesive actually a thermosetting plastic?

A

Yes

38
Q

Give 2 other examples of thermosetting plastics

A

Melamine formaldehyde

Urea formaldehyde

39
Q

What is the thermosetting melamine formaldehyde used for?

A

Scratch and heat resistant laminate for kitchen work tops.

40
Q

What is urea formaldehyde used for?

A

Electric fittings and adhesives

41
Q

Why is urea formaldehyde good for electrical fittings and adhesives?

A

Rigid
Good strength
Good electrical insulator

42
Q

What is the advantages of plastics from a finishing viewpoint?

A

From a world wide manufacturing point of view, one of the appeals of plastics is that they are self finishing.

43
Q

What does self finishing mean?

A

When it comes out of the mould, water called flask is trimmed off and then it is ready for use.

44
Q

How does finishing of plastics compare with that of wood sand metals

A

Woods and metals need lots of finishing whereas plastics are ready to go.

Be able to give some examples of the finishing of woods and metals.

45
Q

Give three examples of elastomers

A

Styrene butadiene
Silicon rubber
Thermoplastic elastomers

46
Q

What does TPE stand for?

A

Thermoplastic elastomers

47
Q

What are elastomers used for?

A

Seals in plumbing
Covers for handles such as pliers
The rubbery grip on a toothbrush

48
Q

What does PLA stand for?

A

Polylactides

49
Q

What are polyactides?

A

Clear plastic similar to polythene in its properties

50
Q

What is the 3D printer plastic called?

A

Polyhydroalkanote

51
Q

What is the printer plastic polyhyroalkanote abbreviated to?

A

PHA

52
Q

What is polyhydroalkanote made from?

A

Plant sugars

53
Q

To be called as truly sustainable what terms must a plastic meet?

A

Environmentally, economically and socially sustainable.

54
Q

What aspects of the sustainability of plastics known as the three pillars of stability referring to?

A

Environmentally, economically and socially viable

55
Q

What are the three pillars of stability?

A

Environmentally, economically and socially sustainable.

56
Q

Do plastics contribute to the three pillars of stability?

A

Yes, they make a positive contribution.

57
Q

Why are plastics considered to make an immense contribution to environmental sustainability?

A
  1. Wpenergy saving potential
  2. Intrinsic recyclability
  3. Energy recovery options
58
Q

What do plastics do from the UK economy?

A
  1. Important part of the economy and make lots of money within the country
  2. Major export product and so bring money into the country
  3. Major employer who treats staff well and trains them
59
Q

Do plastics have a good environmental profile?

A

Yes. Only 4% of the worlds oil production goes into plastics and much less energy is used to produce it compared to other materials

60
Q

Hoy r plastics used in cars, aircraft, packaging and pipe work

A

Durable, hard wearing but still lightweight.

61
Q

What can happen to plastics once they have completed their use phase as a car bumper or a bottle?

A
  1. They can be recycled, or if this is nor economically or environmentally beneficial the caloric value of the plastic can be recovered through energy from waste incineration to provide a source of home grown power.
62
Q

Why are plastics considered as borrowing the oil?

A

Plastics are made from oil, but when they are finished in their use they can be recycled or burnt to provide power for homes. Oil would normally be used to power homes and so the plastic is just borrowing it before it is ultimately used to provide power.

63
Q

What properties to elastomers have which make useful?

A

They have good elasticity
They are distorted under pressure but will return to their original shape when the pressure is removed.

They extend reversibily

64
Q

What percentages can elastomers extend reversible?

A

5-700% depending on the type of material.

65
Q

Are elastomers classed as thermo setting or thermo plastics?

A

They can be of either type

66
Q

Why do plastics have such a bad reputation for the environment?

A

There has been 50 years of plastic production often from non renewable petroleum and natural gases which threaten the environment , human health, species maintenance and the very life of the ocean.

Thankfully different forms of plastic are now being made

67
Q

Comment on plastics and the impact on oceans and ocean life

A

1Research reveals that parts of the Pacific Ocean have 6x more plastic particles than plankton, the source of life.

68
Q

State a problem with fossil fuel based plastics

A

They are non biodegradable

69
Q

What does non biodegradable mean?

A

While degradable plastics can break down into minute pieces, non biodegradable ones may not completely degrade for 1000 years.

70
Q

Why is it such a problem that plastics don’t biodegrade?

A

They are mistaken for food by the tiniest of species as well as large marine animals

71
Q

Is plastics recycling in the world good?

A

No, plastic is one of the fastest growing parts of the waste stream and among the most expensive discarded material to manage.

72
Q

What is the plastics recycling rate compared to paper, metals and glass?

A

Plastics 6.9%
Paper 51.6%
Metals 36.3%
Glass 21.8%

73
Q

How much has single use plastics grown in the last 30 years?

A

From 0.14% to 5.7 %

74
Q

List the sort of chemicals added to plastics during the manufacturing stage. Why are they added?

A
  1. UPVC contains a chemical added to reduce the effects of sunlight (UV) on the material.
  2. Bio batch additives decrease the breakdown time of polymers from 100 years to decompose to 5 years.
  3. Water soluble polymers in the form of dishwashers tablets or small bags of soap solution that break down quickly to release their contents.
  4. Flame retardants
  5. Anti static agents
  6. Impact modifiers
75
Q

Give some uses of polyethylene terephthalate

A

Soda bottles, salada dressing bottles, bean bags, combs

76
Q

Give some uses of high density polyethylene

A

Milk jugs, grocery bags, motor oil container, shampoo and conditioner containers

77
Q

Give some uses of polyvinyl

A

Grocery bags, plumbing pipes, window frames, sewage pipes, cling film, shoes

78
Q

Give some uses of low density polyethylene

A

Sandwich bags, squeezable bottles, frozen food bags

79
Q

Give some uses of polypropylene

A

Tupperwares, kitchen wares, margarine tubes, bottle caps, disposable plates

80
Q

Give some uses of polystyrene

A

Polystyrene cups, plastic cutlery, plastic food boxes.

81
Q

How many numbers are seen on recycling symbols on plastics?

A

1-7 with some abbreviations?

82
Q

What does 1 with PETE stand for?

A

Polyethylene terephthalate

83
Q

What does 2 HDPE stand for?

A

High density polyethylene

84
Q

What does 3 with a v stand for?

A

Polyvinyl

85
Q

What does 4 with LDPE stand for?

A

Low density polyethylene

86
Q

What does 5 pp

A

Polypropylene

87
Q

What does 6 PS stand for?

A

Polystyrene

88
Q

What does 7 other stand for?

A

Miscellaneous

DT (7 decks)

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