Technical principles Flashcards

Question

Tough, close grained, hard, available in steamed (white colour) and un-steamed (pink tinge). Chairs, chopping boards, tools (mallet), steam bent laminated furniture, turned bowls

Answer 1

Polyurethane closed-cell foam blocks or sheets. Lightweight, easy to work using traditional woodworking tools, CNC miller/router, sands easily to allow intricate shapes and forms to be created. 3D modelling, prototypes

Answer 2

Prepare the Mould: Sand mixed with a bonding agent is packed into a flask to create the mould cavity. Add the Pattern: A pattern is placed in the sand to shape the mould cavity. Remove the Pattern: The pattern is carefully removed, leaving a hollow cavity in the sand. Pour the Molten Metal: Molten metal is poured into the mould cavity through a runner. Cool the Casting: The metal is left to solidify and cool within the mould. Break the Mould: The sand mould is broken apart to remove the solid metal casting. Redistribution Molten metal from a billet Railway carriage wheels, wood working clamps, vices, motor housings, bollards, drain covers, post boxes * Labour-intensive process. not a high- quality surface finish. * suitable for one-off or small-batch production.

Answer 3

Glycolide (Lactel and Ecofilm)

Answer 4

thermoforming, thermosetting and elastomer

Answer 5

can cause respiroty irritation and hardwood dusts are listed are carcinogenic both softwoods and hardwoods dust have workplace exposure limits of 5mg cubic metre employers should have ventilation systems and mask

Answer 6

Epoxy resin

Answer 7

a material which can be repeatedly reheated and reshaped, allowing it to be recycled after its initial use. Thermoplastics have long linear chain molecules held by van der Waals forces.

Answer 8

A material that allows the flow of electrical current ( good conductors have low resistance)

Answer 9

Drop Forging is a forging process where a hammer is raised and then ‘dropped’ onto the work piece to deform it according to the shape of the die. Forming billet spanners, pliers and screwdriver shafts Used for products that need to be tough and hard. * Maintains the internal grain structure which retains the strength. * Hot metal billet shaped on an anvil or die and then pressed into shape and cooled. * Suitable for mass production.

Answer 10

Bio-polymer (natural). Made from bacteria grown in cultures. Additive to promote degradation. Usually 1% added to thermoplastics. Packaging products such as film, carrier bags, vending cups, nappies, surgical stitches, pill coverings

Answer 11

Layout paper, cartridge paper, tracing paper, bleed proof paper, treated paper, watercolour paper, corrugated card, bleached card, mount board, duplex card, foil backed and laminated card, metal effect card, moulded paper pulp

Answer 12

Metals, woods, polymers, papers and boards, composites, smart materials and modern materials

Answer 13

a material which at room temperature can be deformed under pressure and then upon release of the pressure, wil return to its original shape. Elastomers have weak bonds which allow them to stretch easily. They can be stretched repeatedly and upon immediate release of the stretch, will return with force to the original length

Answer 14

Plywood, marine plywood, aeroply, flexible plywood, chipboard, MDF

Answer 15

Polymer is fed into the hopper The polymer is heated and moved along using a screw Molten polymer is extruded as a tube called a ‘parison’ The mould closes around the parison and air is injected in forcing the polymer to the sides of the mould The polymer is cooled, the mould opens and the finish product is ejected. Thermoplastic tube "parison' Drinks bottles, shampoo bottles, detergent bottles, etc. * Produces hollow thin-walled components. * High initial tooling cost. * Used for continuous production.

Answer 16

Bio-polymer (natural). Made from bacteria grown in cultures. Fully compostable. Packaging, medical uses such as slow-release medication patches, films, screws and bone plates

Answer 17

Extruded sheet with integral 'flutes' or corrugations. Lightweight and easily bent along the flutes. Signs (such as construction site signs, sale boards for estate agents), storage box construction, portfolio cases, small models

Answer 18

its a way of improving a material's properties to better suit the requirements of the final product.

Answer 19

Plain paper with a clear binder or dye layer applied to help hold the image on the paper surface. Photographic printing

Answer 20

Added to the preservative to give different coloured shades to enhance the aesthetics, e.g. outdoor decking. Can also be used on cheaper softwoods to make them look like hardwoods.

Answer 21

Can contain interlocking grain making it more difficult to work rich :dark red color indoor furniture shop fittings and cabinets veneers commonly used on manufactured boards

Answer 22

addition forming and wasting processes

Answer 23

Mount board

Answer 24

Involves a heated hollow mould which is filled with a charge or set weight of material. It is then slowly rotated, causing the softened material to disperse and stick to the walls of the mould. In order to maintain even thickness throughout the part, the mould continues to rotate at all times during the heating phase and to avoid sagging or deformation also during the cooling phase. Thermoplastic powder or granules Traffic cones, kayaks, water tanks, kerosene tanks, children's play equipment Seamless hollow components with a large wall thickness. * Mould continuously rotated through heating and cooling. * Large-scale batch or mass production.

Answer 25

Hard tough Blanking punches and dies, extruder dies, fine press tools

Answer 26

polymer turns into a fine powder with exposure to oxygen and is subsequently degraded by the action of micro-organisms

Answer 27

Biodegradable polymers can produce methane gas when they decompose in landfills. Methane gas is a greenhouse gas that contributes to global warming. Biodegradable polymers can take high temperatures to decompose and may leave behind toxic residues. Do not necessarily encourage a sustainable or recyclable culture.

Answer 28

how a material reacts to an external force. 11

Answer 29

Foil-backed and laminated card

Answer 30

Lubricant, Thermal antioxidants, Pigments, Antistatics, Flame retardants, Plasticisers, Fillers, Biodegradable Plasticisers, Bio-batch additives , Antioxidants, UV light stabilisers

Answer 31

Made from compressed fine cotton fibres to produce a rigid board Presenting artwork, picture mounting, modelling

Answer 32

Biopol (bio-batch additive)

Answer 33

Flexible polyvinyl chloride (PVC)

Answer 34

Low carbon steel

Answer 35

the metal is placed inside the die. The press then applies high pressure (3000 tons of force or higher on large presses) and the material is formed to match the shape of the die. In other words, press forming is a forming technology where a pressing force is applied to a material to deform it (by bending, stretching, etc.) to match the size and shape of the die Forming Sheet Metal seats, car body panels, boxes and containers * Shapes sheet metal into 3D forms. * Often used in conjunction with robots for lifting the sheet into place. * Suitable for mass production or large- scale batch production.

Answer 36

Glass reinforced plastic (GRP)

Answer 37

using a heat flow meter, a square-shaped material test piece is placed between two temperature -controlled plates. The temperature is increased at a controlled rate and the heat flow through the material is measured.

Answer 38

Reduce the likelihood of the polymer building up a static charge.

Answer 39

Pine, spruce, Douglas fir, redwood, cedar, larch

Answer 40

A material that doesn't allow the transfer of heat energy

Answer 41

Wood has sides and edges that are all planed square, straight and level, leaving a smooth finish, and is ready to use. The PAR board is about 3 mm smaller all round than the original rough- sawn nominal size and is the most expensive stock form to buy.

Answer 42

High-quality card with a thin metal effect layer applied to the outer surface for enhanced aesthetics. Can be embossed. Gift boxes and packaging, high- quality metal effect business cards

Answer 43

The mass of the material

Answer 44

Protect wood (especially for outdoor use) from fungal and insect attack. Wood can be pre-treated with a copper-based preservative, which penetrates the wood to protect the whole plank.

Answer 45

Cupping involves pressing a flat metal sheet (blank) into a shallow cup shape using a punch and die. Deep drawing extends this process, pulling the cup deeper into the die to create hollow, cylindrical shapes without fracturing the material. Forming Sheet Tube-like shapes such as fire extinguishers, aerosol cans, drink cans * Starts with a metal blank. * Metal is stretched into shape. * High initial tooling cost. * Used for large- scale mass or continious production.

Answer 46

Photochromic pigment

Answer 47

Cement powder, sand, aggregate particles and polymer or steel fibres mixed with water Lighter in weight than reinforced concrete, hard, tough, good at low temperatures and in freeze/thaw situations. Suspended floors, complex geometric shapes, pathways

Answer 48

Cement poweder, sand, aggregate particles mixed with water High compression strengh, low tensile strength, few surface defects, easy to mold Pathways, beams, blocks, driveways, house of foundations

Answer 49

Lubricants Thermal antioxidants Pigments Antistatics Flame retardants Plasticisers Fillers Biodegradable plasticisers Bio-batch additives Antioxidants UV light stabilisers

Answer 50

Off-white paper, usually with a slightly textured surface. Sketching, rendering in pencil ink and pastel

Answer 51

Hard outer skin but brittle core, good under compression 3.5% carbon Melting temperature 1149°C disc brakes, machine parts and engine blocks

Answer 52

Timber laminates and MF adhesive Good aesthetics, natural alternative to reinforced concretes, more lightweight than concrete alternatives, fire resistant, good structural stability, corrosion proof. Beams, bridges, domes, arches, decking, roof beams, rafters

Answer 53

Tough, corrosion resistant, good temperature resistance, low coefficient of friction. Safe working temperature 150 °C. Bearings, gears, curtain rails, textiles, boil-in-the-bag food packaging, car engine manifolds, cable ties

Answer 54

Carbon fiber reinforced plastic (CFRP)

Answer 55

Thin translucent paper with smooth surface sketching ,technical drawing and tracing

Answer 56

Natural wood comes from trees and is available only at the maximum width o f the tree. * To produce a wide desktop, natural wood planks need to be joined together. * Planks should be joined with the end grain going in opposite directions to minimise distortion.

Answer 57

Usually with carton board outer layers and a corrugated middle layer, giving the material the ability to provide protection against impact. Protective packaging, model making, prototyping ideas, food packaging such as takeaway boxes

Answer 58

the natural force between objects that causes the material to attract iron or steel

Answer 59

Ductile, high tensile strength, tough, malleable, poor resistance to corrosion 0.15%-0.3% carbon content melting temperature at 1427 nuts, bolts, washers, screws, car bodies, outer panels for white goods

Answer 60

Tough, available in thin sheet form. transparent good chemical resistance flexible Food wrapping, air pillow packaging, bubble wrap, carrier bags

Answer 61

Tungsten carbide

Answer 62

medium carbon steel

Answer 63

In the Rockwell test a preload weight is applied to the material sample using a diamond indenter which just breaks through the surface. An additional load is then applied to the test material and held for a predetermined length of time. The distance between the preload and applied load is then measured. The Brinell test uses a standard sized steel ball which is forced into the materials surface using a pre-set load. The diameter of the indent is measured. The smaller the indent, the harder the material. Vickers pyramid test is used for very hard materials and uses a diamond square-based pyramid to indent the surface of the material. Diamond is used as it will not deform under load. A microscope is used to measure the size of the indent. The smaller the indent, the harder the material.

Answer 64

Low melting point, good corrosion resistance. Melting temperature 420 °C. Galvanising steel as a protective coating for dustbins, buckets,farm gates; intricate die castings

Answer 65

Similar construction to plywood but is gap and void free, and uses specialist water and boil-proof (WBP) glue to provide resistance to moisture. Some higher-quality marine plywood is also resistant to fungal attack. Boat dashboards, boat lockers and panelling

Answer 66

Thermochromic pigment

Answer 67

Shape memory alloys (SMA), thermochromatic pigment, thermochromatic film, phosphorescent pigment, photochromic pigment, electroluminescent wire, piezo electric material

Answer 68

thicker than polymer film and is available in stock sheets of varying thicknesses - for example, foam board sheet is available in 3 mm, 5 mm, 10 mm and 20 mm standard thickness.

Answer 69

Corrosion resistant, good electrical and thermal conductor, low melting point 930°C, casts well. 65% copper, 35% zinc. Melting temperature 930 °C. Boat fittings, door furniture, cast valves and taps, ornaments

Answer 70

Hard, tough, high level of resistance to frictional heat. 18% tungsten, 4% chromium, 1% vanadium, 0.5-0.8% carbon. Tool blades, drill bits, milling cutters, router bits

Answer 71

Bio-polymer (synthetic). Fully compostable, water soluble. PLA and cellulose based. Biomedical applications, slow- release medication, bone repair fixings, detergent washing sachets

Answer 72

A material that allows light but diffuses the light making it blurry or cloudy

Answer 73

Natural rubber, polybutadiene, neoprene, silicone

Answer 74

A process which involves heating up a small area of plastic sheet so it can be folded or bent like paper. Usually this is done around a former. Thermoplastic sheet Acrylic boxes, shelves or point-of-sale displays Uses an electrically heated element that provides heat along a line. * Quite slow and labour-intensive, used in school or college workshops. * Suitable for one-off or limited batch production.

Answer 75

Milling, turning, flame cutting, plasma cutting, laser cutting and punching stamping

Answer 76

Gives off a small electrical charge when deformed. Increases in size (up to 4%) when an electrical current is passed through it Airbag sensors in cars, lighters barbecues, vibration damping in tennis racquets, musical greetings cards, pressure sensors

Answer 77

the ability to be drawn out under tension without cracking

Answer 78

Wood is impregnated to cure within the wood cell structure. Results in increased hardness, toughness and stability (often added to hardwood floor panels).

Answer 79

These are man-made and produced in large sheets, typically 1220 mm x 2440 mm. * Wide surfaces can be produced from one sheet without the need for joining processes.

Answer 80

Ferrous alloys: stainless steel, die steel non ferrous alloys- bronze, brazz, duralumin, pewter

Answer 81

A metal that does not contain iron. Non-ferrous metals are not magnetic and do not rust.

Answer 82

Degradation occurs because of the action of micro-organisms, which convert the material into water, carbon dioxide (CO2), biomass and possibly methane (CH4) The ability of a polymer to biodegrade is dependent on the structure of the polymer rather than the origin of the raw material.

Answer 83

Translucent paper, slightly thicker than layout paper. Copying images when sketching

Answer 84

High tensile strength, low elongation, good hardness, tough, electrical insulator, good cold resistance. Automotive industry such as tyres, tubes, hoses, gaskets, belts; balloons, toys, footwear

Answer 85

Laser cuting(cnc) is ideal for prototype or small-scale production because it an be used to cut, engrave and perforate papers and boards It: * is faster than traditional methods - gives repeated accuracy * provides a high level of detail| - allows the design to be quickly edited and then manufactured.

Answer 86

Melamine formaldehyde (MF)

Answer 87

Precious metal clay (PMC)

Answer 88

is a process by which a disc of metal is rotated at high speed and formed into a symmetrical part. Metal spinning does not involve removal of material but forming of sheet material over an existing shape. Forming Sheet Body of stainless steel kettles, saucepans, metal light shades * Product may show parallel lines where the sheet has been forced onto the mandrel * Suitable for mass production or small-batch production

Answer 89

The majority of polymers are made via the fractional distillation of crude oil, which is a non-renewable resource. Synthetic polymers are made from crude oil and take hundreds of year to decade Polymers are 'self-finishing' (can be pigmented during the manufacture process to give colour and therefore require no additional secondary finishing process). Can be grouped as a thermoforming, thermosetting and elastomer polymer

Answer 90

Oxy-degradable photodegradable and hydro-degradable additives help reduce the degradation time from hundreds of years to a few years or even months.

Answer 91

Malleable, low melting point 170-230°C, casts well. 85-99% tin, with the remainder consisting of copper and antimony. Melting temperature 170-230 °C. Tankards, flasks, goblets, photo frames, decorative items, candlesticks, sports trophies

Answer 92

Card with polymer film or foil applied to provide a water-resistant and/or heat-insulating layer. Drinks packaging, milk cartons, take-away box lids

Answer 93

Plywood made from high-quality timber such as birch. Available in very thin sheets, lightweight, easy to bend around a support frame. Gliders, laminated furniture, laser-cut projects, jewellery items

Answer 94

light (photodegradable) oxygen (oxy-degradable) water (hydro-degradable)

Answer 95

Transparent, tough, naturally biodegrades. Packaging film, membranes, photographic films

Answer 96

Changes colour with light intensity. Welding goggles, reactive spectacle lenses, security markers that show up under UV light

Answer 97

Abrasive wear can be easily tested by running a file over the surface of the material. The material with the fewest scratches is the hardest. A dot punch can be placed on the material and hit with a hammer. The larger the surface indentation, the softer the material. Again, maintaining the same force for each blow is difficult and can lead to inconsistent results.

Answer 98

This process can be used in industry for precision cutting metals. Lower-powered lasers are readily available in schools and colleges to cut manufactured boards and acrylic sheet. * Laser cutting uses the power from a high-powered laser beam that is directed through optics. * The laser head contains a lens that focuses the laser into a fine beam for cutting and engraving. * Laser beams usually have a very fine tolerance (can be less than 1 mm). * Laser cutting is more accurate and uses less energy than plasma cutting but cannot cut to the same thickness of material. * In industry, laser cutting is typically used to cut flat sheet material, but it is not able to cut to the same thickness as plasma cutting.

Answer 99

expose the material to environmental effects such as rain or sun. The material is simply placed outside in an area exposed to the elements. They can then be visually inspected for signs of surface corrosion.

Answer 100

Malleable, ductile, corrosion resistant, can be soldered. Melting temperature 1063 °C. Jewellery, electronic components, connectors,switch components

Answer 101

same size material- environmental conditions the same- same equipment- same force- same person

Answer 102

Urea formaldehyde (UF)

Answer 103

Rough-sawn, PSE, PAR, natural wood, manufactured boards and mouldings

Answer 104

a polymer that can be made from finite resources such as crude oil and contains additives that cause it to degrade more quickly than traditional polymers.

Answer 105

Thin sheets of MF polymer hard tough chemical resistant used for decorative coverin

Answer 106

Fluted PP sheet properties/ performance haracteristics and uses

Answer 107

Vacuum forming, thermoforming, calendering, line bending, lamination, injection moulding, blow moulding, rotational moulding, extrusion and compression moulding.

Answer 108

the ability of the material to withstand environmental decay

Answer 109

Rigid, heat resistant, chemical resistant, brittle. Safe working temperature 95 °C. Castings, used in lay-up process for glass reinforced plastic (GRP) for boat hulls, car parts, chair seats

Answer 110

Place the test material in a vice then hit it with a hammer. The more impact it can withstand, the tougher the material. Brittle materials will withstand less force The problem with this test is maintaining a consistent level of force with each blow.

Answer 111

Hard, tough, attractive grain pattern, fades to silver upon exposure outside Garden furniture, cladding, decking and fencing

Answer 112

Hard, tough, attractive grain, good weather resistance. Contains tannic acid, which will corrode steel screws or fixings. Furniture, flooring, boat building, lading, interior and exterior joinery

Answer 113

Ferrous, non-ferrous and alloys

Answer 114

Rigid, opaque, tough, hard, good weathering resistance, good chemical resistance. Safe working temperature 95 °C. Window frames, external doors, guttering and downpipes for buildings, water service pipes, bank cards

Answer 115

a material which when heated undergoes a chemical change whereby the molecules form rigid cross links. Thermosetting polymers cannot be reheated and reshaped, even at very high temperatures

Answer 116

Rigid polyvinyl chloride (uPVC)

Answer 117

Bio-polymer (synthetic) Made from corn kernels or cane sugar, fermented to produce lactic acid, then synthesised to produce polylactic acid. Packaging, single-use bottles, carrier bags, plant pots, disposable nappies, medical sutures, 3D printing

Answer 118

Polyhydroxyalkanoate (PHA)

Answer 119

usually very thin and flexible, such as celulose acetate used for photographic film.

Answer 120

Tiny particles that are mixed into the polymer in its molten state to give colour to the final processed product

Answer 121

Recycled paper pulp moulded when wet and dried to a specific shape. Usually smooth on the visible inside surface and rough textured on the outer surface. Moulded packaging products, eco-friendly packaging, egg boxes, fruit packaging

Answer 122

A heat treatment reduces some of the excess hardness and brittleness of a hardened metal, and increases the toughness and ductility. * The metal is heated to below the critical point for a given time then slowly air cooled. * The exact temperature wil determine the amount of hardness removed. * Tempering colour on the metal indicates the temperature at which brittleness is removed.

Answer 123

Available in absorbent, smooth, hot-pressed or the more textured cold-pressed and heavily textured rough Watercolour painting

Answer 124

High-density polyethylene (HDPE)

Answer 125

Used to pressure treat wood for roof joists, cladding etc. and exhibition stands. Wood can also be treated to make it harder and more resistant in high-wear situations such as flooring.

Answer 126

Original source of paper is wood pulp(grey) During manufacture, bleaches are added to make paper white The natural source makes paper and boards suitable for recycling they will biodegrade in landfills

Answer 127

These make the polymer more flexible, softer and easier to break down, which means faster degradation time.

Answer 128

pine, spruce, douglas fir, larch and cedar

Answer 129

gsm-- grams per square metre the lower the lighter the paper

Answer 130

gives greater immunity from decay and increased resistance to rot * increases strength and stability * helps preservatives to penetrate * makes wood less corrosive to metals.

Answer 131

Fibre cement

Answer 132

Combined heat and steam make strips of wood pliable so they can be shaped over a former. * Wood is placed into a steam box where it wil absorb the steam. * The wood is then bent over a former and clamped to it until it dries.

Answer 133

Layout paper

Answer 134

Aluminium composite board

Answer 135

Acrylonitrile butadiene styrene (ABS)

Answer 136

Tough, corrosion resistant, can be cast. 90% copper, 10% tin. Melting temperature 850-1000 °C Statues, coins, bearings

Answer 137

When a sheet metal component is put on top of a die and pressure is dropped on the metal forcing it to fit the die Forming sheet or plate Seams on metal edges, bending sheets for product casings or housings Does not include any punching or trimming of the metal. * Simple bending can be carried out in a school or college workshop. * Used for large- scale batches in industry.

Answer 138

Medium and high carbon steels are heated to alter their crystalline structure, holding them at this temperature for a given time and then quenching them in water, oil or salt-water baths. The hardening and subsequent quenching increase hardness but also increase brittleness.

Answer 139

a four-point probe method can be used to determine the electrical conductivity of materials. Four small diameter wires are stretched, parallel to each other, across a non-conductive polymer block. Ohm’s law can be used to calculate the resistance of the material sample.

Answer 140

A material developed through the invention of new or improved processes

Answer 141

The ability to resist stretching or pulling forces

Answer 142

a wood from a coniferous (cone bearing)tree.These trees are generally fast growing and tend to be evergreen

Answer 143

Cartridge paper

Answer 144

Bleed-proof paper

Answer 145

Oak, ash, mahogany, teak, birch, beech

Answer 146

Moulded paper pulp

Answer 147

Absorbs light energy during the day and re-emits the light when it is dark Fire exit signs, 'glow in the dark' products such as adhesive stars, masks, night lights, watch hands

Answer 148

Closed-cell polyethylene foam, tough, flexible, good impact resistance, impermeable to liquids. Protective packaging, swimming floats, gym and exercise mats, sound and pipe insulation, stage props

Answer 149

Changes shape in response to a change in temperature or electrical input, e.g. nitinol wire in dental braces can change at body temperature when placed in the mouth to mantain constant tension and if heated to a certain temperature it will return to its original shape Dental braces, self-closing windows, aeroplane wing flaps, bioengineering such as stents, bone plates and screws

Answer 150

Modern materials are not 'smart materials' because they do not react to external change.

Answer 151

involves heating up a sheet of plastic then raising a former or pattern up through the plastic while removing the air below to create a vacuum. This then causes atmospheric pressure outside the vacuum to ‘force’ the plastic down on to the former. Thermoplastic sheet up to about 6 mm in thickness Lightweight trays, box inserts and liners, takeaway coffee cups and yoghurt pots * Moulds are relatively easy to make but need a draft angle, air holes and rounded corners. * Not cost effective for one-off manufacture. * Small-scale batch and mass production.

Answer 152

From A0 (largest) to A8 (smallest) Each A is half the size of the previous A4 is half the size of A3

Answer 153

Polyester resin

Answer 154

Marine plywood

Answer 155

Granules that become mouldable at about 60 °C. Can be heated in water or with a hair dryer. Solidifies at room temperature. Also available in liquid form. Liquid at room temperature and solidifies at 2°C Modelling, shaping ergonomic handles, prototype mechanical parts

Answer 156

the ability of the material to be fused or converted from a solid to a liquid or a molten state by heat usually( essential for metal cast)

Answer 157

Hard, tough, straight grain, natural oils resist moisture, acids and alkalis. Outdoor furniture laboratoy benches traditional boat decks

Answer 158

Two outer layers of card with a foam middle core Mood board backing, presentation boards, modelling

Answer 159

Good flexibility at low temperatures, poor abrasion resistance, good thermal resistance and resistance to temperature extremes, good weather resistance, good lubricating qualities, electrical insulator. Flexible ice cube trays, bakeware, cooking utensils, seals for refrigerators, machinery lubricant, sealants, mould making, medical uses such as lubricants for prosthetics, aerospace applications tubing for drug delivery systems

Answer 160

Harder than, low-carbon steel but less ductile, malleable and tough 0.30-0.70% carbon content. 1425º-1540ºC melting temperature springs, gardening tools

Answer 161

Hard, similar strength to steels but more lightweight, high resistance to corrosion. Melting temperature 1668 °C. Hip replacements, joint replacements, tooth implants, spectacle frames, aircraft, spacecraft, golf clubs, bicycles, ship hulls

Answer 162

The ability to absorb impact force without fracture

Answer 163

Neoprene (polychloroprene rubber)

Answer 164

A material that allows light to pass through easily

Answer 165

Very tough, good chemical resistance, weather proof, available in translucent, low level of rigidity. Safe working temperature 65 °C. Squeezy detergent bottles, toys, carrier bags, bin liners, general packaging, food wrap film, food trays

Answer 166

a test using basic tools and equipment

Answer 167

(hydro-degradable) - polymer quickly breaks down with exposure to water and is subsequently degraded by the action of micro-organisms

Answer 168

Polypropylene (PP)

Answer 169

to select the most appropriate material for a product and make the tests fair

Answer 170

A metal containing mostly iron and carbon. Ferrous metals are magnetic and wil rust.

Answer 171

Wood has only one edge that is planed accurately; the rest are rough sawn Planing removes about 3 mm from the original nominal size.

Answer 172

Lightweight, ductile, malleable, corrosion resistant, electrical and thermal conductor, can be metal inert gas (MIG) and tungsten inert gas (TIG) heat welded. Melting temperature 660 °C. Drinks cans, aircraft bodies, bike frames, window frames, saucepans, cooking utensils, packaging, baking foil

Answer 173

Die casting is a process where molten metal is forced into a mould under high pressure. The mould is made from two strong steel dies that fit together to form the shape. The molten metal is heated in the machine and a ram forces a SHOT of metal through the GOOSE NECK into the mould, it is very fast and the pressure will allow extra detail on the cast. Zinc, Tin, Lead Hot-chamber machines: For metals like Zinc and Lead. Redistribution Molten metal from a billet Toy cars, collectible figures, decorative door knobs and handles * Lower melt point metals such as aluminium, aluminium alloys and zinc-based alloys. * Molten metal stored in a chamber then a shot of molten metal is forced into the die. - fast process -used for ver large-batch and mass production

Answer 174

the ability to be deformed and then returned to the original shape when force is removed

Answer 175

Treated paper

Answer 176

Straight grain, knotty, can contain resinous knots. Construction work, roof beams, and timber frames and interior joinery

Answer 177

Corn starch polymer

Answer 178

Urea formaldehyde (UF), melamine formaldehyde (MF), polyester resin, epoxy resin

Answer 179

transparent tough naturally biodegradable Biodegradable packaging film

Answer 180

The ability to be permanently deformed and retain the deformed shape

Answer 181

Similar to cartridge paper but it is bleed-proof so Spirit-based marker rendering c o l o u r s do not r u n .

Answer 182

Case hardening is used for hardening the surface of steels with less than 0.4 per cent carbon content. * Case hardening produces an outer casing of greater hardness, improved wear resistance and resistance to surface indentation, while the inner core of the metal retains the original 'softer' properties. * Case hardening is a two-stage process: 1) Carburising: this changes the chemical composition of the surface of low carbon steel so that it can absorb more carbon to increase surface hardness. * In industry, the steel is placed in a ceramic box that is packed with carbon. The box is heated to about 930-950°C, the carbon atoms diffuse into the material's structure to build up the surface carbon content. * The depth of the carbon layer is determined by the length of time the material is exposed to carbon. * The longer the time, the thicker the carbon layer. The product is then heated to about 760°C and then quenched. 2) Quenching: the hot metal is quenched in water to fast-cool it and seal the hard surface case while not affecting the properties of the inner core.

Answer 183

Veneers such as natural wood are laminated on to the board surface to enhance aesthetics

Answer 184

This process uses computer-controlled machines that stamp out sections of sheet material. * It uses the shearing action on a sheet of metal placed between an upper tool (punch) and a lower tool (die). * The process is suitable for small- and medium-size production runs, and it is normally used for processing metals from 0.5 mm to 6 mm thickness.

Answer 185

Hard, heat resistant, good electrical insulator, brittle Electrical fittings, adhesives

Answer 186

is traditional and inexpensive. * Wood is stacked in a shelter outside, protected from the rain. * Air circulates between the planks to remove excess moisture. * It is a slow process, taking up to one year. * The wood is used for outdoor products.

Answer 187

Polylactic acid (PLA)

Answer 188

Sheet is large flat sections of metal in varying thicknesses from less than 1 mm up to approximately 3 mm. * Plate is generally thicker than 3 mm and narrower than sheet metals. * Bar is solid form, flat bar, square bar, round bar or hexagonal bar. * Tube form is hollow in cross-section and can be square, rectangular (also caled box section), round or hexagonal. * Structural angular shapes such as H beams, L beams (angle), I beams, tee bar and channel.

Answer 189

When Smas are heated to a certain temperature( transition temperature) it will return to its original shape

Answer 190

Ductile, malleable, tough, corrosion resistant, good electrical and thermal conductor, can be soldered and brazed. Melting temperature 1083 °C. Electrical wire, printed electrical circuits, water pipes, hot water tanks, central heating pipes

Answer 191

Press forming, spinning, cupping and deep drawing, drop forging, wrought iron forging, bending, rolling, sand casting, gravity die casting, pressure die casting (hot chamber), pressure die casting (cold chamber) investment casting and low temperature pewter casting

Answer 192

Reduce the likelihood of combustion or the spread of fire (car engine components) or potential electrical fires such as plug sockets.

Answer 193

The ability to withstand deformation by compression without cracking( malleability increases with temperature)

Answer 194

The actual make-up or structure of the material. 4

Answer 195

Clay consistency material made up of fine metal particles. Works like ceramic clay, easily mouldable, easy to shape and form, sets hard once fired with a kiln or butane torch. Inexpensive compared to solid metals such as Silver. Jewellery, decorative items, small sculptures, fobs

Answer 196

The ability to resist sliding forces on a parallel plane

Answer 197

Available in translucent, good chemical resistance, tough, good fatigue resistance (hinge property). Safe working temperature 100 °C. Rope, folders, folio cases, food containers, medical equipment

Answer 198

polymer bonds are weakened and the polymer breaks down with exposure to ultraviolet (UV) light, such as UV rays from sunlight

Answer 199

Material is preheated and placed in a heated mould Mould is closed under pressure from the top plug The pressure pushes the polymer( like granules)into all areas of the mould Heat and pressure maintained until the polymer fits the mould Thermoset polymer charge Electrical light fittings, switches, plugs, picnic plates and cups Uses a pre- weighed 'slug' of polymer. * Polymer removed from moulds while still warm. * Large-scale batch production.

Answer 200

Reinforced concrete

Answer 201

Hard, rigid, available in translucent, tough. Safe working temperature 70 °C. Yoghurt pots, refrigerator linings, single-use drink cups, toilet seats, instrument control knobs

Answer 202

A material that doesn't allow light to travel through

Answer 203

Kevlar, precious metal clay (PMC), high density modelling foam, polymorph

Answer 204

Wood chips compressed with a resinn such as urea formaldehyde. Often veneered or covered with polymer laminate, kitchen worktops and units, shelving and 'flat pack' furniture

Answer 205

Piezoelectric material

Answer 206

Milling is used for small-sized, basic jobs such as a rough prototype or roughing out a small hole or channel. * Slow process and miling machines do not have as large a work area as computer numerically controlled (CNC) routers. * They can be operated manually or they can be CNC.

Answer 207

Izod impact test: a notched piece of material is held vertically in the vice of the machine. A pendulum is released from a set position. The energy absorbed is calculated from the height the pendulum swings to after it hits the piece. The material that absorbs the most impact is the toughest.

Answer 208

Straight grain, can corrode ferrous metals due to acidic nature, low density, good sound damping rot and insect resistant Exterior cladding, sheds, greenhouses, beehives, interior panelling

Answer 209

Aramid fibres with high cut- and heat-resistant properties. Body armour, cut-proof gloves and aprons, aerospace applications, surfboard components, puncture- resistant bicycle tyres

Answer 210

Materials that can be scored folded and cut with basic tools to form stuff like nets for packaging

Answer 211

Tough, hard, good chemical resistance, available in translucent. Safe working temperature 95 °C. Car light casings, computer numerically controlled (CNC) laser- cut items, lighting units, lighting covers,bath

Answer 212

Routering is used to machine slots and holes in wood, or to make decorative 'mouldings' on the edges, for example on a table top. * Can be manual plunge routers or computer numerically controlled (CNC).

Answer 213

The ability to resist forces that may bend the material

Answer 214

High speed steel( HSS)

Answer 215

Thin slices of wod less than 3 m used for Decorative coverings for manufactured boards

Answer 216

a wood from broad-leafed (deciduous) These trees are generally slow growing and lose their leaves in autumn.

Answer 217

Carbon fibres mixed with polyester resin Lightweight, corrosion resistant, tough, hard, good compressive strength, low thermal expansion. Sports equipment such as bicycle frames, tennis racquets, fishing rods, racing car bodies and parts, helmet, prosthetics

Answer 218

Work hardening is when the metal is 'cold worked' such as by bending, rolling or hammering. * the crystals within the metal are distorted and changed, leading to improved tensile strength and hardness in the worked area *When the metal crystals are distorted, they cannot move freely within the metal structure, which can result in less ductility, cracking or damage in the worked area * The effects of work hardening can be removed by annealing the metal.

Answer 219

Redistribution Molten metal from a billet Jewellery, key fobs and decorative components * Used for school or college projects. * Can be used with simple MDF moulds. * Suitable for one- off production or small batch (with aluminium moulds).

Answer 220

Add this:a polymer manufacturing process for a TV remote control' - make sure that, in the diagram, you draw the mould in the shape of the product.

Answer 221

A material that does not allow the flow of electricity

Answer 222

Aluminiu, copper, zinc, silver, gold, titanium, tin

Answer 223

* The stamped-out net is placed on to a folding table. * Some die cutters may include moving parts that help to bend or fold parts of a net automatically. For example, when making boxes, the die cut net is held firmly while the sides are bent up along the crease lines.

Answer 224

The ability to resist abrasive wear such as scratching and surface indentation

Answer 225

A bend test is used to determine how well a material can withstand cracking during one continuous bend. A test piece is placed in a bending machine and held; supported at the ends. A plunger loads the test piece at the centre and bends to a predetermined angle. The material is then inspected for cracks and defects. Cracks on the outer bend indicate the level of ductility Cracks on the inside of the bend indicate the level of malleability.

Answer 226

Polymethylmethacrylate (PMMA)

Answer 227

When a material's physical property changes in response to an input or change in the environment like light temp or electricity

Answer 228

The work to be machined is clamped on to the table of the machine. The table can run in the x direction (left and right horizontally), y direction (forwards and backwards horizontally) and z direction (up and down vertically) to cut slots, shape edges or thread holes.

Answer 229

Bleached card

Answer 230

Butadiene rubber (BR)

Answer 231

can be designed to degrade in as litle time as a few months to a couple years

Answer 232

A standard test piece of material is placed into a Tensometer machine and held in clamps at each end. One of these moves on a worm drive gear putting the piece under constant tension. The ostretch is measured before the piece ‘necks’ and reaches final breaking point.

Answer 233

Tracing paper

Answer 234

Available in translucent form, weather proof, tough, good chemical resistance. Safe working temperature 65 °C.

Answer 235

Celulose acetate

Answer 236

a man-made wood-based composite material. Manufactured boards are available in much larger sizes than solid wood.

Answer 237

forming - processes in which no material is removed, but materials are deformed to produce required shapes redistribution - processes where the material is changed from one form to another without loss of material e.g. liquid metal poured into a mould to take a solid shape wastage - processes that cut away material to leave the desired shape.

Answer 238

Carbon fibre reinforced plastic (CFRP), glass fibre reinforced plastic (GRP), tungsten carbide, aluminium composite board, concrete, fibre cement, engineered wood, e.g. glulam

Answer 239

Low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene (PP), high impact polystyrene (HIPS), acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), polyethylene terephthalate (PEl), nylon, rigid and flexible polyvinyl chloride (PVC)

Answer 240

MDF is compressed wood fibres, although sometimes urea formaldehyde is added as an additional resin. It has two smooth faces available in either standard grade or veneered with a layer of timber Model or mould making, furniture items such as bookcases, cabinets and desks

Answer 241

Lamination, steam bending, turning-milling and routering

Answer 242

Foam board

Answer 243

low carbon steel, medium carbon steel, cast iron

Answer 244

is expensive, using controlled temperature and humidity levels. * The wood is stacked on trolleys. * It is initially steamy in the kiln then becomes hotter and drier. * It is a quick process, taking up to a few weeks. * The wood is used for indoor products.

Answer 245

This is carried out on a centre lathe. * Work such as a bar can be held in a rotating chuck and machined to reduce the diameter, and to square or 'face off' the end, thread and drill. * Turning can be done manually or using computer numerically controlled (CNC) lathes. * The material is machined by cutting tools held in a tool post, which can be moved in and out, and along the bar.

Answer 246

Flexible plywood

Answer 247

Bio-polymer (synthetic). Fully compostable. PLA and cellulose based. Food film, bags, packaging wrap, bin bags, agricultural ground sheet, flower wrap

Answer 248

uses gravity to force the molten material into the mould. Redistribution Molten metal from a billet Alloy wheels, engine components, door knobs and handles * Lower melt point metals such as aluminium, aluminium alloys and zinc-based alloys * Relies on gravity to help the metal flow into the mould. * Used for thicker mould sections. * Used for very large-batch and mass production.

Answer 249

Polylactide

Answer 250

prosphorescent pigment

Answer 251

Tough, excellent wear resistance against friction, good thermal resistance against friction, electrical insulator Vehicle tyres, shoe soles, toys, conveyor belts, water and pneumatic hoses

Answer 252

Duplex card

Answer 253

An odd number of layers glued together with the two outer layers made from open-grained timber, which allows the sheet to flex. Bent and glued around a former to achieve a solid shape. Laminated furniture, curved panels

Answer 254

Used in engineered wood (e.g. manufactured boards) to enhance theproperties of the useable parts of trees such as sawdust, wood chips and fibres.Chipboard is made from compressing wood chips with a resin

Answer 255

similar to Injection Moulding but without the use of a hydraulic ram as the polymer is continually pushed through the die due to the archimedean screw Thermoplastic granules Solid rods, tubing, angle sections, curtain track * Like injection moulding except polymer is forced through a die. * Industrial production method. * Continuous production.

Answer 256

Sawdust and wood flour provide bulk to the product, meaning that less polymer is required. Mineral fillers such as chalk, clay and calcium carbonate help increase the thermal conductivity of the polymer, meaning it will heat up and cool down more quickly, which gives shorter mould cycle times.

Answer 257

Thermoplastic pallets thin polymer sheet and films * Heated rollers squash and stretch the polymer to make it thinner. * Industrial production method, carried out by specialist manufacturers. * Used for continuous production.

Answer 258

Adding wax or calcium stearate reduces the density of the molten polymer, making it less 'sticky' and allowing more complex shapes to be formed. Lubricants also allow the moulding temperature to be lowered, saving energy.

Answer 259

Hardwoods, Softwoods and manufactured boards

Answer 260

A cermet (mixture of ceramic and metal particles) Ceramic tungsten and cobalt metal Hard, tough, resistant to high temperatures, corrosion resistant Cutting tools such as drill bits router bits kitchen knifes

Answer 261

Translucent PP sheet

Answer 262

This bonds materials together. * It uses wood veneers or thin manufactured boards such as 3 mm plywood, which can be glued together and bent over a former so that, when dry, they form a thicker board in the shape of the former. * Held while drying by clamps or a vacuum bag.

Answer 263

Cement powder, sand, aggregate particles and low carbon steel rods (rebar) mixed with water High compression and tensile strength, consistency across the structure, few surface defects, fire resistant Buildings, bridge piles and bridge spans, retaining walls, grid floors

Answer 264

Pewter properties/ performance characteristics and uses

Answer 265

Materials is put in a hopper, mixed heated up whilst being moved by a archimedium screw then forced into a mould due to a hydraulic ram. It cools and hardens in the mould. Thermoplastic granules Electrical product casings (computers, TVs, vacuum cleaners, calculators) * Complex 3D shapes can easily be made. * Fast industrial production method * High initial tooling cost. * Used for large-scale mass or continuous production.

Answer 266

corrision resistent, low meting point, Melting temperature 232 °C. soft solder, coatings for food cans, rarly used in pure from

Answer 267

Materials properties of products and say why the property is needed

Answer 268

Fibre-based composite sheets (GRP, CFRP) Boat hulls, kayaks, train carriages, theatre and film props, theme park rides * Requires a former to mould around. * Polyester resin used as the polymer. * A top gelcoat is applied which may contain pigment. * CFRP requires an autoclave for the product to 'cure.

Answer 269

Engineered wood

Answer 270

Die casting is a process where molten metal is forced into a mould under high pressure. The mould is made from two strong steel dies that fit together to form the shape. Similar to hot chamber in the process except the molten metal is stored elsewhere and ladled into the machine for each SHOT. Mainly for Aluminium because it can pick up particles of steel from the chamber in the hot process Cold-chamber machines: For metals like Aluminium. Redistribution Molten metal from a billet Toy cars, collectible figures, decorative door knobs and handles * Lower melt point metals such as aluminium, aluminium alloys and zinc-based alloys. * Molten metal ladled into the shot chamber and hydraulically pushed into the chamber. * Used for very large-batch and mass production.

Answer 271

Tough, close grained, hard, available in steamed (white colour) and un-steamed (pink tinge). Chairs, chopping boards, tools (mallet), steam bent laminated furniture, turned bowls

Answer 272

Corrugated card

Answer 273

Prevent the polymer oxidising or discolouring due to excessive heat during processing.

Answer 274

A material made of two or more different materials enhancing the material properties

Answer 275

Tough polymer sheet. Can be folded millions of times. Virtually impossible to tear, water resistant. Packaging products, folders, boxes

Answer 276

The ability to withstand twisting forces from twisting/torsion

Answer 277

Low-density polyethylene (LDPE)

Answer 278

Hard, straight close grained, resists warping Furniture indoor panelling veneers used for birch faced plywood constructions

Answer 279

Aluminium sheets with a polyethylene core Lightweight, rigid, tough, malleable, good thermal and sound insulation, good vibration damping. Soundproofing panels in cars, buildings and boats

Answer 280

Thin copper wire coated in a phosphorescent material that glows in response to an alternating current Glow bracelets, interweaving for clothing, home decoration, outdoor decorative lighting

Answer 281

Resin is impregnated with fire-retardant cladding

Answer 282

Available in translucent, tough, flexible,good weathering resistance, goodchemical resistance. Safe working temperature 95 °C. Hose pipes, cable insulation, medical grade tubing, inflatable products, imitation leather, seat coverings

Answer 283

Pre-made mouldings such as skirting boards or wooden trims are readily available in standard lengths up to approximately 4 metres.

Answer 284

The ability to withstand being crushed by pushing forces

Answer 285

A test piece is secured in a vice and then it is attempted to bend to 90 degrees using a hammer or mallet. Cracks or surface damage on the outside of the bend indicate a lack of ductility. Cracks on the inside indicate a lack of malleability.

Answer 286

This process machines wood on a lathe. There are three turning methods: 1 turning between centres, used to machine a spindle such as chair legs and table legs 2 turning on a faceplate, used to machine items such as domes or bowls 3 turning in a chuck, used to grip the item while it is machined, such as drilling the end of a spindle or holding the base of a small bowl to allow access to the inside surface.

Answer 287

Allow plastics to become less hard and brittle at normal temperature use,e.g. added to LDPE food wrap, allowing the wrap to be stretched over the food product plasticisers also help in processing because they allow polymers to be easily formed at higher temperatures

Answer 288

stainless steel

Answer 289

changes colour in response to temperature change Room thermometers, medical thermometers for children, bath water thermometers, colour change mugs and kettles, food packaging to indicate food is hot to eat or cool for drinks, baby feeding spoons, battery charge indicator strips

Answer 290

Dense, closed-cell foam. Can be cut, shaped and sanded with standard workshop tools. Product modelling, formers for moulding and laminating

Answer 291

Thermoplastic sheet approx 6 mm Bath, food packaging, box, sandwich packaging Like vacuum forming, except for an additional. mould is pressed onto the surface of the polymer sheet at the same time as the vacuum is applied. * Good for fine detail such as moulding in logos. * Slow process, used in industrial production

Answer 292

Low-density polyethylene (LDPE) sheet

Answer 293

Polymer derived from renewable biological sources, such as plants or microorganisms, as opposed to fossil fuels. Cannot be recycled and may contribute to a throwaway culture. can be classified into two groups: Natural bio-polymers are made from natural materials such as cellulose, starch and polysaccharides. Synthetic bio-polymers are made from renewable resources but chemically engineered (synthesised) to break down more quickly.

Answer 294

Metal is a naturally occurring material and is mined from the ground in the form of ore. they are grouped as ferrous, non ferrous and alloys * Approximately 25 per cent of the Earth's crust is made up of metal ores. * Bauxite, which aluminium is made from, is the most common ore. * The raw metal is extracted from the ore through a combination of crushing, smelting or heating, with the addition of chemicals and huge amounts of electrical energy. * Metals can easily be recycled (due to their low melt point)

Answer 295

Granules: a smal particle of plastic. * Sheet: large flat sections of polymer in varying thicknesses. * Film: very thin sheet polymer. * Rods and other extruded forms, tubes, bars: rods and extruded forms can be a specific designed shape * Foam: solid form made by including air or other gases, such as styrofoam from expanded polystyrene. * Powder: very fine granule of polymer.

Answer 296

Oak, ash, mahogany, teak, birch and beech

Answer 297

Equivalent strength properties to mild steel but more light weight, ductile, becomes harder as it is worked. Aluminium with 4% copper, 1% magnesium and manganese. Aircraft parts, vehicle parts

Answer 298

Douglas fir

Answer 299

Cutters are used to cut out 'nets' or 'developments' that, when folded and assembled, will form a 3D shape such as a box.

Answer 300

Steel cutting dies (to cut the paper or board) and creasing rules (to crease areas for folds) are used to cut out the net shape from the sheet of paper or board, ready for assembly. (in industry some machines will cut, crease and fold the edges to create the 3D shape in one process.)

Answer 301

Hard, opaque, tough, heat resistant, food safe, chemical resistant Decorative laminates, picnic ware, buttons

Answer 302

Tough, hard, corrosion resistant. 18% chrome, 8% nickel. Melting temperature 1510 °C. Sinks, kitchenware, cutlery

Answer 303

Made by layering strands (SCL) or veneers (LVL] of wood with resins such asurea formaldehyde, pressing and heat curing them to produce a stable wood billet. SCL and LVL are less prone to defects such as warping, splitting or shrinking. and have greater load bearing properties

Answer 304

multimeter with the probes attached at a set distance between them. The higher the resistance, the lower the conductivity.

Answer 305

Make the Wax Pattern: Create a wax model of the product. Assemble the Tree: Attach wax patterns to a central sprue. Dip in Ceramic Slurry: Invest the tree in liquid ceramic. Stuccoing sand after for strength. Dry the Shell: Let the ceramic shell harden. Melt the Wax: Heat the shell to remove the wax. Preheat the Mould: Heat the shell to prevent cracking. Pour Molten Metal: Fill the hollow mould with metal. Cool the Casting: Let the metal solidify inside. Knockout: break the ceramic mould revealing the cast tree Finishing: Remove the parts from the tree and finish the edges. redistribution molten metal from a billet Cast jewlerry or collectable figures, hip replacement joints Used for intricate or awkward shapes that would be difficult or impossible to mould using any other casting process. * High quality, excellent finish. * Wax patterns are cast from a master mould, a repeatable quality process

Answer 306

Air and kiln

Answer 307

Malleable, ductile, corrosion resistant, can be soldered. Melting temperature 962 °C. Jewellery, cutlery, used for plating other materials

Answer 308

Straight or slightly wavy grain, few knots, stable, good resistance to corrosion veneers, plywood construction, joinery and construction work

Answer 309

Good thermal resistance, toughness, good oil and chemical resistance, excellent weather resistance, good abrasion resistance and electrical insulator. Wetsuits, laptop cases, industrial wire insulation, automotive applications such as shock absorber seals, hose covers, transmission belts, gaskets and door seals

Answer 310

Annealing is used to make the work-hardened metal easier to work by making it less brittle and more ductile. * The metal is heated and then cooled very slowly, allowing the metal crystals to grow and slowly move into place.

Answer 311

where metal is passed through rollers to reduce its thickness and shape it. This can be done using hot rolling or cold rolling, depending on the temperature and the desired properties of the final product. Forming billet Hot rolling: 1 beams, angle, bar, plate and channel, railway tracks Cold rolling: filing cabinets, chairs, steel drums, containers * Hot rolling metal results in uniform mechanical properties, np deformation stresses. * surface is usually coated with carbon deposits, which must be removed using acid pickling. * Cold rolling results in a material that has a tighter tolerance and better surface finish.

Answer 312

Wood is a natural material, which wil naturaly biodegrade if left in landfill. Wood fibres grow along the length of the tree or branch (grain) and these fibres consist of hollow cells (tracheids) supported by lignin resin. 2 types hardwood and softwood Wood expands and shrinks with changes in humidity. Wood is: * strong in the direction of the grain (along the grain) and weaker across the grain * converted (from the tree it is sawn into useable pieces) and then seasoned (air or kiln) to remove the excess moisture, 80-90 per cent, before use * seasoned to help prevent defects such as twisting, warping, cracks, cupping or bowing; to reduce the time taken t o season wood, trees should be felled in the winter when they grow less, have less sap and therefore contain the least moisture.

Answer 313

High-impact polystyrene (HIPS)

Answer 314

Made up of two layers of paper, with the exterior often coated to make it more water-resistant and to give it a glossy sheen and waxy feel. Food packaging such as juice or milk cartons, disposable cups, plates

Answer 315

is usually carried out on products such as large castings where there is a likelihood of internal defects or imperfections which might not be detected by other methods. There are two standard NDT methods: Ultrasonic testing: a transducer generates sound waves which are pulsed into the material. The intensity of the reflected waves is recorded on a display unit. They can show internal cracks or other defects and can be used on all types of materials. X-ray testing: an x-ray beam passes through the material and an image is projected onto a display screen. X-ray testing can be used to inspect integrated circuits (IC’s) and printed circuit boards (PCB’s) and to check for micro-voids in composite materials in products such as Formula One cars. It can also be used to detect faults in turbine blades or aeroplane engine blocks.

Answer 316

A material that allows the transfer of heat energy (high conductivity = quick transfer of heat)

Answer 317

Chemically treated to brighten the surface to make it suitable for high-quality printing. Greeting cards, high-quality packaging

Answer 318

tough attractive open-grain pattern which makes it more flexible tool handles, ladder, sports goods, laminating

Answer 319

the increase in material volume in response to heat increase

Answer 320

SMAs, e.g. nitinol

Answer 321

Resin is impregnated with fire-retardant cladding (e.g. for indoor flooring). which slow down the spread of fire.

Answer 322

Help reduce the environmental damage of the polymer from exposure to oxygen in the air. Also help prevent increased brittleness, surface cracks and pigment discolouration. Often used in polymer garden furniture.

Answer 323

Bio-polymer (natural). Made from potato starch. Single-use food items such as bowls, cutlery, food trays, serviettes, packaging beads or peanuts, bin bags

Answer 324

Work hardening, annealing, case hardening, hardening, tempering

Technical principles Flashcards

(381 cards)