Materials Flashcards
1
Q
describe tension force and example products
A
- when an object is stretched/pulled apart in opposite directions
- springs in a trampoline have high tensile strength - they resist being permanently stretched and return to their original length to throw you back into air
- suspension bridges use springs to support weight of the bridge
2
Q
describe compressive force and example products
A
- when an object is squashed due to compressive forces directed at one another
- occurs when a material supports weight above it eg. chair legs+ bridge supports
3
Q
describe shear force and example products
A
- causes parts of an object to slide past one another
- scissors/industrial cutting machines use shear force to cut materials
4
Q
describe torsion force and example products
A
- when an object is twisted
- propeller shafts resist torsion - allows them to transfer rotary motion without breaking/twisting
- wringing water out of cotton towels
5
Q
describe the primary processing of paper
A
- trees are cut down and taken by lorry to a paper mill
- the bark is stripped off
- the wood is cut into smaller pieces by a chipper
- the bits of wood go through chemical or mechanical pulping
- the pulp is washed and bleached to desired colour
- the pulp is pressed flat between rollers, dried, and cut to size
6
Q
describe the sizes of paper and how they relate to each other
A
- sizes start of A0 and half in size/area each time
- e.g. A4 is half the size of A3
7
Q
describe the properties and use of cartridge paper
A
- high quality & has a textured surface
- good for sketching with different drawing materials (pencils, crayons, inks)
8
Q
describe the properties and use of layout paper
A
- thin+ translucent
- good for general design work/ sketching ideas
9
Q
describe the properties and use of tracing paper
A
- semi-transparent
- used to copy images
10
Q
describe the properties and use of grid paper
A
- has a square grid/ isometric pattern printed on it
- grid - orthographic+ scale drawings
- isometric - isometric drawings
11
Q
describe the properties and use of bleed-proof paper
A
- used when drawing with felt-tips/ marker pens
- ink does not bleed (spread out)
12
Q
describe the properties and use of foil-lined board/ tetrapak
A
- board with an aluminium foil lining
- used for food packaging - foil keeps flavours in and air+moisture out
13
Q
describe the properties and use of foam core board
A
- expanded polystyrene foam is sandwiched between two thin layers of card - increases strength+ rigidity by lamination
- stiff+ lightweight, outer card layers can be scored
- used for making models, mounting posters
14
Q
describe the properties and use of duplex board
A
- one side is solid white board - visible side, smooth for printing, high quality
- one side is cardboard
- used for food packaging
- outside appears high-quality
- cheaper as one side is cardboard
15
Q
describe the properties and use of corrugated card
A
- made of a fluted inner core sandwiched between two outer layers/liners
- the flutes add strength/rigidity by lamination - used for secondary packaging to protect products during transit
- air held in fluted layer provides insulation+ cushioning
- outer liners can be printed on
- is flexible/can be bent without breaking but is rigid enough to keep its shape
- negative - stronger materials are bulkier so could increase transport costs
- used for food packaging (pizza boxes), delivery boxes
16
Q
describe the properties and use of ink jet card
A
- used for ink jet printing - ink does not bleed so the printed image is sharply defined+ high quality
17
Q
describe the properties and use of solid white board
A
- high quality, bleached surface ideal for printing
- used for luxury primary packaging (packaging for individual items)
18
Q
describe properties+ examples of thermoforming plastics
A
- don’t resist heat - easily formed into diff shapes by heating/melting/remoulding
- recyclable - are ground down/melted +reused
- acrylic (PMMA) - hard/stiff/shiny, weather resistant, used for helmet visors/baths/signs
- also PVC/ HDPE
19
Q
describe properties+ examples of thermosetting plastics
A
- resist heat/fire - used for electrical fittings/pan handles
- undergo a chemical change when heated then moulded - become permanently hard/rigid
- non-recyclable - cannot be melted+reshaped
- polyester resin (PR) - hard/stiff, cheap, electrical insulator, waterproof so used in shower stalls/garden furniture, added to glass fibres to form glass-reinforced plastic
- also epoxy resin/ urea formaldehyde
20
Q
describe the properties of softwoods
A
- grow in cold climates
- fast growing - therefore cheap+ readily available
- leaves are like needles+ have cones
- leaves are evergreen
21
Q
state examples of softwoods (3)
A
- PINE - strong, contains lots of knots so harder to work with, used for telegraph poles/fences/cheap furniture
- LARCH - hard/tough/durable, resistant to rot so good for decking/fences
- SPRUCE - hard, high strength to weight ratio, contains lots of knots, used fir crates/ship masts
22
Q
describe the properties of hardwoods
A
- grow in warm climates
- slow growing - therefore rarer+ expensive
- broad/flat leaves
- deciduous - lose their leaves in autumn
- most have a tighter grain - dense/hard (except balsa)
23
Q
state examples of hardwoods (5)
A
- OAK - tough/durable/strong, attractive grain, good finish, corrodes steel screws/fittings, used for flooring/furniture
- MAHOGANY - durable, easy to work with, expensive, used for good-quality furniture
- BEECH - hard, can be bent using steam, used for chairs/toys
- BALSA - low density/soft so easy to cut/shape, used for modelling
- ASH - tough, attractive, shock-absorbent, used for tool handles/sports equipment
24
Q
state examples of manufactured boards (3)
A
- MDF
- plywood
- chipboard
25
state the stock forms that paper+board come in (3)
sheet
roll
ply - refers to no. paper layers
26
state what units papers and boards are measured in
paper: gsm (grams per square metre)
board: gsm, thickness measured in microns
27
describe how paper is modified to increase rigidity
folded/bent - lamination
28
describe smart materials +examples
* react to changes in their environment (stress, light, temp)
* thermochromic/photochromic pigment, shape memory alloy
29
describe modern materials +examples
* developed recently as a result of new technology
* graphene, titanium, LCD, nanomaterials, carbon fibre, glass-reinforced plastic GRP, metal foam
30
describe composite materials +2 examples (GRP/CRP)
substance made from 2+ different materials bonded together
* **glass reinforced plastic**: glass fibres coated in thermosetting resin, stronger+tougher, heat-resistant, easy to mould (boats/ surf boards)
* **carbonfibre reinforced plastic**: carbon fibres coated in thermosetting resin, lighter, stronger+tougher than GRP but more expensive (helmets/ sports equipment/ laptops)
