Section 2 - Intro to Materials + Systems Flashcards
(102 cards)
1
Q
Overview of different properties of materials
A
- The properties of a material determine what is useful for. Thinking about these properties are super important when it comes to designing a new project product
- Materials have working properties
- They also have physical properties
2
Q
What are some examples of working properties of materials?
A
- strength
- hardness
- toughness
- elasticity
- malleability
- ductility
3
Q
What is strength of a material?
A
Strength is the ability to withstand forces without breaking. For example:
- The rope in a tug-of-war resists pulling forces
- Bridge supports resist compression forces
- A surfboard resists forces trying to bend it
- Fabrics that contain Kevlar fibres are really strong and resistant to abrasion - so they’re used in motorcycle clothing
4
Q
What is hardness of a material?
A
- This is the ability to resign scratching, abrasion or denting.
- It’s very important for tools that cut, like files and drills.
5
Q
What is toughness of a material?
A
- If a material is tough, it is hard to break or snap – the material changes shape a bit instead.
- Armour and bullet-proof vests need to be tough.
6
Q
What is elasticity of a material?
A
- Elastic materials can stretch and bend and return to their original shape.
- A spring has good elasticity
7
Q
What is malleability of a material?
A
- Materials that are malleable can be bent and shaped.
- Most metals are malleable – they can be hammered into thin sheets without breaking.
8
Q
What is ductility of a material?
A
Ductile materials can be drawn into a wire
9
Q
What are some examples of physical properties of materials?
A
- Electrical conductivity
- Thermal conductivity
- Fusibility
- Density
- Absorbency
10
Q
What is electrical conductivity of a material?
A
- Electrical conductors let electricity travel through them easily. Electrical insulators don’t.
- Electrical wires need to be conductors, but the coating around the wires must be insulating.
- Metals are good electrical conductors. Plastics tend to be good insulators.
- Some fabrics are blended or coated with an electrical conductor material (e.g. a metal) – gloves can have electrically conductive fingertips so you can still operate touch screens with them on.
11
Q
What is electrical conductivity of a material?
A
- Thermal conductors let heat travel through them easily. Thermal insulators don’t.
- Metals are good thermal conductors. Plastic, board and wood are good thermal insulators.
- Pans must be made from good thermal conductors, but the handles are often made from thermal insulators.
12
Q
What is fusibility of a material?
A
- Materials with a high fusibility have low melting points – only a small amount of heating is required to convert these materials to liquids.
- For example, solder has a high fusibility – this allows it to melt before the metals that are being soldered together (which have a lower fusibility).
13
Q
What is density of a material?
A
- The density of a material is a measure of its mass per unit volume.
- A table made of solid metal would likely be heavier to carry than an identical table made of plastic. This is because metal tends to be denser.
- Density often has units of kg/m^3
14
Q
What is absorbency of a material?
A
- Fibres and fabrics that are absorbent are good at soaking up moisture. Paper towels are a good example.
- Absorbent materials can be dyed easily, but they also dry slower and are vulnerable to stains.
- Natural fibres (e.g. wool, cotton and cellulose fibres that make up paper) are absorbent.
- Synthetic fibres (e.g. polyester and lycra) are not absorbent.
15
Q
What are properties of non-metals?
A
Nonmetals tend to have a very different set of physical properties to metals.
Compared to metals, they are generally:
- More brittle
- Not always solid at room temperature
- Poor electrical conductors
- Dull looking
- Less dense
16
Q
What are properties of metals?
A
Metals tend to have similar basic physical properties to one another. They’re usually:
- Strong
- Malleable
- Good conductors of heat electricity
- Not very fusible (have high melting and boiling points)
17
Q
What is an alloy?
A
- Alloys are a mixture of two or more metals, or a metal mix with one or more elements.
- The alloy is a new material – it has different properties to the individual metal it’s made of.
- Alloys are developed to have a specific set of properties. This is often done with future products in mind.
18
Q
What are the 5 types of paper?
A
- cartridge paper
- layout paper
- tracing paper
- grid paper
- bleed-proof paper
19
Q
What is cartridge paper?
A
It is high-quality and has a textured surface – it is great for sketching with different drawing materials like pencils, crayons and inks.
20
Q
What is layout paper?
A
It is thin and translucent (you can see light through it) and is used for general design work – particularly sketching ideas.
21
Q
What is tracing paper?
A
It is semi transparent, and is used to copy images.
22
Q
What is grid paper?
A
It may have a square or isometric pattern printed on it. Square grid paper is useful for orthographic and scale drawings and isometric paper is good for isometric drawings.
23
Q
What is bleed-proof paper?
A
It is used by designers when drawing with felt tip and a marker pens. The ink doesn’t spread out (bleed) – it stays put.
24
Q
What is the weight of paper and board measured in?
A
The weight of paper and board is measured in gsm (grams per square metre).
Above 200 gsm, it’s not paper anymore – it’s board (also known as card or cardboard).
25
Why is board often used in packaging?
Because of its low cost compared to other packaging materials, and it's high strength-to-weight ratio
26
What are the 6 types of boards?
- solid white board
- ink jet card
- corrugated card
- duplex board
- foam core board
- foil-lined board
27
What is **solid white board**?
It has a high quality bleach surface, which is ideal for printing. It's used loads for primary packaging – packaging for individual items.
28
What is **ink jet card**?
It is card used for ink jet printing. It's designed so that the ink doesn't bleed – this allows the printed image to be sharply defined and have a high quality.
29
What is **corrugated card**?
It is made up of a fluted inner core sandwiched between two outer layers (the liner), which can be printed on. The flutes add strength and rigidity – this is useful in a lot of secondary packaging to protect products during transit.
30
What is **duplex board**?
It has a different colour and texture on each side. It's often used where only one surface is seen, so that only one side needs to be smooth for printing. This board is often used for food packaging.
31
What is **foam core board**?
It is made by sandwiching expanded polystyrene foam between 2 thin layers of card. It's stiff, lightweight and the thin outer card layer can be scored. It's good for making models and mounting posters.
32
What is **foil-lined board**?
It is a board with an aluminium foil lining. It is often used to package food – the foil keeps flavours in, and air and moisture out.
33
What is primary packaging?
packaging for individual items
34
What is secondary packaging?
it is used to contain lots of the same item
35
What are the 2 types of wood?
hardwood and softwood
36
What is timber?
It is sawn chunks of solid wood that are used as building materials.
37
What are softwoods?
Softwoods grow in colder climates and are fast-growing – this makes them fairly cheap and readily accessible. The trees have leaves like needles, are usually evergreen and have cones (e.g. pine).
38
What are examples of softwoods?
Pine, spruce, larch
39
What are pine trees like?
Pine is yellow with brown streaks. It's quite strong and cheap – but knotty, which makes it harder to work with. It's used for telegraph poles, fences and cheap furniture.
40
What are larch trees like?
Larch has an attractive yellow to reddish-brown colour. It's harder, tougher and more durable than most softwoods. It's also resistant to rot, which makes it good for decking, cladding the outside of building, and fence posts.
41
What are spruce trees like?
Spruce is a reddish brown colour. It's hard and has a good strength-to-weight ratio – but is also knotty and not very durable. It's used for structural purposes both outside and in – aircraft, crates and ship masts.
42
What are hardwoods?
- Hardwoods usually grow in warm climates and are slow growing - so they're generally more expensive than softwoods.
- The trees have broad, flat leaves and are usually deciduous (they lose their leaves in autumn).
- The wood tends to have a tighter grain and be denser and harder than softwood, although there are exceptions to this, e.g. balsa
43
What are Oak trees like?
- Oak is light brown.
- It's tough, durable and very strong.
- It also has attractive grain markings, especially when quartersawn and finishes well, so it's used in a lot of interior panelling, flooring and furniture.
- However, it does corrode steel screws and fittings.
44
What are Mahogany trees like?
- Mahogany is a red-brown colour.
- It's durable and easy to work with, but it's expensive, so it's used for good quality furniture.
45
What are Beech trees like?
- Beech is pinkish-brown.
- It's hard enough to resist being dented, and can be bent using steam.
- It's used for chairs and toys.
46
What are Balsa trees like?
- Balsa is a white or tan colour.
- For a hardwood, it has a very low density and is very soft.
- Its softness makes it easy to cut and shape - this combined with a high strength-to-weight ratio, makes it great for modelling
47
What are Ash trees like?
- Ash has a pale cream colour.
- It's tough and absorbs shock well, so it's used for tool handles and wooden sports equipment (e.g. baseball bats).
- It's also attractive so is used for furniture.
48
What are the 2 basic groups of metals?
- Some metals are pure metals and others (alloys) are mixtures of a metal with another element
- Both types of metal can be classified into two basic groups - **ferrous** and **non-ferrous.**
49
What are ferrous metals?
- These metals or alloys are mostly made up of iron.
- Because of this, almost all of them are magnetic.
- Protective coatings (e.g. paint, enamel) are often applied to prevent ferrous metals from rusting.
- An exception to this is stainless steel - it's resistant to rust so doesn't need to be coated.
50
What are 3 example of ferrous metals?
- **cast iron** (iron +2-3% carbon + silicone)
- **low-carbon steel** (aka mild steel) (iron + 0.05-0.35% Carbon)
- **high-carbon steel** (aka tool steel) (Iron + 0.5-1.5% Carbon)
51
What are the properties and uses of cast iron?
**Properties:**
Very strong if compressed, but brittle and not malleable
**Uses:**
Bench vices, car brake
disks, manhole covers
52
What are the properties and uses of low-carbon steel?
**Properties:**
Quite strong and cheap, but rusts easily and can't be hardened.
**Uses:**
Car bodies, screws, nuts, bolts, nails, washing machines
53
What are the properties and uses of high-carbon steel?
**Properties:**
Harder than low-carbon steel, can be hardened. Not as easy
to work though and it rusts.
**Uses:**
Tools, e.g. chisels,
files, saws, drills
54
What are non-ferrous metals?
These metals or alloys don't contain iron so don't rust - useful if they're likely to be exposed to moisture.
55
What are 5 example of non-ferrous metals?
- aluminium
- brass (65% Copper + 35% Zinc)
- copper
- tin
- zinc
56
What are the properties and uses of aluminium?
**Properties:**
Lightweight and corrosion-resistant, but expensive and not as strong as steel (although strong for its weight). Hard to join.
**Uses:**
Aeroplanes, cans, ladders
57
What are the properties and uses of brass?
**Properties:**
Quite strong, corrosion-resistant, malleable, ductile and looks good (nice golden bronze colour).
**Uses:**
Electrical parts, door handles, taps
58
What are the properties and uses of copper?
**Properties:**
Relatively soft, malleable, ductile and a very good electrical conductor.
**Uses:**
Electrical wiring, pipes.
59
What are the properties and uses of tin?
**Properties:**
Soft, corrosion-resistant, malleable and ductile. Has a low melting point.
**Uses:**
Foil, tin cans (tin-plated steel), alloying metal in solder
60
What are the properties and uses of zinc?
**Properties:**
Not very strong, corrosion-resistant.
**Uses:**
Coating steel (e.g. on nails, buckets and watering cans).
61
How are alloys formed?
Alloys are formed when one or more elements are combined with a metal.
62
What are 3 examples of alloys?
- High Speed Steel
- Brass (copper + zinc)
- Stainless steel (iron + carbon + chromium + nickel)
63
What is High Speed Steel?
- High speed steel contains iron, more than 0.6% carbon and other metals including chromium, tungsten, and vanadium.
- It keeps its hardness when heated to high temperatures, so it's used in high speed cutting tools that get hot when used.
64
What is Brass (copper + zinc)?
- Brass is harder and stronger than both copper and zinc.
- It is malleable, ductile and a good electrical conductor (like copper), and is resistant to corrosion (like zinc).
65
What is Stainless steel (iron + carbon + chromium + nickel)?
- Cast iron and mild steel (iron + carbon) are strong but rust (corrode) easily.
- Adding chromium and nickel increases strength, toughness and ductility, and decreases rust.
- It is used in surgical equipment, sinks and cutlery.
66
What are the 2 types of plastics/polymers?
thermoforming and thermosetting plastics
67
What are thermoforming plastics like?
- Thermoforming plastics don't resist heat well - they're easily formed into different shapes by heating, melting and remoulding.
- This means they're easy to recycle - they're ground down, melted and re-used.
68
What are 6 types of thermoforming plastics?
- Acrylic (PMMA)
- High-density polyethylene (HDPE)
- Polyethylene terephthalate (PET)
- High impact polystyrene (HIPS)
- Polyvinyl chloride (PVC)
- Polypropylene (PP)
69
What are the properties and uses of Acrylic (PMMA)?
Hard, stiff and shiny. Resists weather well. Can be used to make motorcycle helmet visors, baths, signs, etc. Quite brittle (not tough)
70
What are the properties and uses of High-density polyethylene (HDPE)?
Stiff and strong but lightweight. Used for things like washing-up bowls, baskets, folding chairs and gas and water pipes.
71
What are the properties and uses of Polyethylene terephthalate (PET)?
PET is a polyester that is light, strong and tough. Used to make see-through drink bottles and fibres for clothes.
72
What are the properties and uses of High impact polystyrene (HIPS)?
Rigid and fairly cheap. Used for vacuum forming, fabricating boxes, model kits and smoke detector casings.
73
What are the properties and uses of Polyvinyl chloride (PVC)?
Quite brittle, cheap and durable. Used for blister packs, window frames, vinyl records and some clothing.
74
What are the properties and uses of Polypropylene (PP)?
Quite tough and flexible. Can be made in a wide variety of bright colours. Used for plastic chairs - its flexibility makes it comfortable.
75
What are thermosetting plastics like?
- Thermosetting plastics resist heat and fire (so they're used for electrical fittings and pan handles).
- Thermosetting plastics (unlike thermoforming plastics) undergo a chemical change when heated and moulded to make a product - they permanently become hard and rigid.
- This means they're non-recyclable - they can't be melted and reshaped again.
76
What are 5 types of thermosetting plastics?
- Epoxy Resin (ER)
- Urea-Formaldehyde(UF)
- Melamine-Formaldehyde (MF)
- Phenol-Formaldehyde (PF)
- Polyester Resin (PR)
77
What are the properties and uses of Epoxy Resin (ER)?
Rigid, durable, corrosion-resistant and a good electrical insulator. Used for circuit boards and wind turbine rotor blades.
78
What are the properties and uses of Urea-Formaldehyde(UF)?
Hard, brittle and a good electrical insulator. Used for things like plug sockets and cupboard handles.
79
What are the properties and uses of Melamine-Formaldehyde (MF)?
Strong and scratch-resistant. Used to laminate chipboard and for plates and bowls.
80
What are the properties and uses of Phenol-Formaldehyde (PF)?
Hard and heat-resistant, it's very easily moulded into bottle caps, snooker balls, etc. Also mixed with other materials to form a composite
81
What are the properties and uses of Polyester Resin (PR)?
Hard, stiff, cheap and a good electrical insulator. Added to glass
fibres to form glass-reinforced plastic, e.g. for kayaks. Waterproof, so used in shower stalls and garden furniture.
82
What are the 2 types of textiles/fabrics?
natural or synthetic fibres
83
What are Natural Fibres?
- They come from natural sources
- Natural fibres can be harvested from plants and animals - cotton comes from plants and wool from sheep.
- These are renewable resources (i.e. you can always produce more of them). They are also biodegradable (can be broken down by microorganisms in the ground when disposed of) and recyclable - natural fibres are therefore fairly sustainable.
- In general, natural fibres are absorbent and strong when dry, but have poor resistance to biological damage, e.g. from moths and mould.
84
What are 3 types of natural fibres?
- cotton
- wool
- silk
85
What are the positive and negative properties of cotton?
**positive:**
Strong, hard-wearing, absorbent, comfortable to wear, feels quite cool in hot weather, easy to wash & add colour to, doesn't cause allergies, non-static, fairly cheap.
**negative:**
Creases easily, high flammability, poor elasticity, can shrink when washed, dries slowly
86
What are the positive and negative properties of wool?
**positive:**
Warm, absorbent, good elasticity, low flammablity, crease-resistant available in lots of fabric weights.
**negative:**
Can shrink when washed, dries slowly,
can feel itchy, fairly expensive.
87
What are the positive and negative properties of silk?
**positive:**
Smooth, resistant to shrinking/ stretching, absorbent, good drape, low flammability, comfortable to wear, lightweight, sun-resistant.
**negative:**
Creases easily, might not wash well, weak when wet, expensive.
88
What are synthetic fibres?
- Synthetic fibres are made from polymers (long chain molecules). These molecules come mainly from coal and oil - non-renewable fossil fuels. Synthetic fibres are therefore much less sustainable than natural fibres.
- Synthetic fibres can be given many different properties. In general, they're resistant to biological damage, and can be changed by heating to form different shapes and
textures. However, they're not very absorbent, so they can be hard to dye.
89
What are 3 types of synthetic fibres?
- Elastane
- Polyester
- Polyamide
90
What are the positive and negative properties of elastane?
**positive:**
Extremely elastic (stretches up to 7 times its length), strong, hard-wearing, lightweight, keeps its shape well, resists sun/biological damage.
**negative:**
Not absorbent, high flammability, not biodegradable.
91
What are the positive and negative properties of polyester?
**positive:**
Strong (even when wet), hard-wearing, low flammability, good elasticity, cheap, resists creasing, dries quickly, resists biological damage.
**negative:**
Not absorbent, not biodegradable, damaged by strong acids, melts as it burns (so harmful if clothes catch fire).
92
What are the positive and negative properties of polyamide?
**positive:**
Strong, hard-wearing, warm, good elasticity, crease resistant, resists biological damage, fairly cheap.
**negative:**
Not very absorbent, damaged by sunlight, melts as it burns.
93
What are yarns?
Yarns are threads that are woven or knitted to make fabrics.
94
What are yarns made of?
- Yarns are made of fibres (tiny hairs). These come in either short lengths (staple fibres) or longer lengths (filaments).
- Yarns made from filaments are smooth, while yarns made from staple fibres tend to be hairier.
- Yarns are available in different thicknesses. A 1-ply yarn is a single yarn, a 2-ply yarn is two yarns twisted together, a 3-ply yarn is three yarns twisted together... and so on..
95
What are the three main ways of turning fibres/yarns into a fabric?
weaving, knitting
or bonding
96
What are woven fabrics?
WOVEN FABRICS are made by interlacing
(crossing alternately over and under) two sets of yarns.
97
What are knitted fabrics?
KNITTED FABRICS are made by interlocking one or more yarns together using loops. The loops trap air, so they insulate. They stretch more than woven fabrics.
98
What are non-woven fabrics?
- NON-WOVEN FABRICS are layers of fires (not yarns) held together by bonding or felting.
- They don't fray, and can be cut in any direction - which means there's little waste when laying out patterns
- However, they don't stretch and aren't very strong.
99
How are woven fabrics made?
Different woven fabrics are made by interlacing two sets of yarns - the weft, which travels from right to left and the warp, which travels up and down the weave
100
What is the simplest weave?
- The simplest weave is the plain weave - the weft yarn passes over and under alternate warp yarns, making it unpatterned
- It's hard-wearing - strong and holds its shape well.
- It has a smooth finish (making it good for printing on).
- It's the cheapest weave to produce and is used to make loads of fabrics, especially cotton-based ones.
101
What is the edge of a woven piece of fabric called?
The edge of a woven piece of fabric, where
the weft yarns wrap around the warp yarns, is called the **selvedge**
102
