Presentation on theme: "Technical aspects of designing and making"— Presentation transcript:
1Technical aspects of designing and making 2nd Part of A565 Theory
2What topics are covered in the exam? Designing & Product PlanningMaterialsTools, Equipment & ProcessesComputer ApplicationsIndustrial ProductionHealth & SafetyQualityProduct Evaluation
3Theory Questions… What are the main stages of the design process? Explain the differences between the 4 different types of strengthWhat is the main difference between softwoods and hardwoods?Name 4 good things about MDFWhy would you put a finish on wood?What is the main difference between the 2 different types of plastic?
4Designing & Production Planning Identification of a design needAnalysing a design briefResearch, data and analysisIdentification of complex associations linking principles of good design and technological knowledgeDeveloping a design specificationGenerating ideas and communicating designModelling and trialing techniquesDigital media and new technologiesProduction planningMaterial selectionMake productCritical evaluation skills
5Material PropertiesPerformance characteristics of different materials have to be considered when choosing what products should be made of, you need to know the definitions of the following properties;Hardness – resist cutting and indentationsToughness – withstand shocks such as hammeringStrength = 4 types include the ability to withstand...Being pulled apart or stretchedCrushed or compressedTwistedSheared as a result of sideways force like scissorsElasticity – can be stretched and then return to original lengthFlexibility – bend but not break and return to original shapeDuctility – can be stretched into wireDurable – can withstand bad weather conditionsMalleability – can be hammered, pressed into a shape
6Materials - HardwoodsThese come from ‘deciduous’ trees which shed their leaves in autumn. They are generally hard, tough, and durable and are reasonably expensive because they take longer to grow than softwoods.BeechUK, EuropeVery tough, hard, straight, polishes wellToys, chairs, toolsOakEuropeHeavy, hard, tough, good outdoors, finishes wellHigh-class furniture, boat building, floorsMahoganySouth America, AfricaEasy to work, wide boards availableIndoor furniture, veneers
7Materials - SoftwoodsSoftwoods come from coniferous trees that remain evergreen all year roundPine is the most common type;grown mainly in Northern Europe it is easy to work, knotty, durable, widely available and cheapIt is most commonly used for construction work and cheap furniture
8Materials – Manufactured boards These are wood-based materials that are made by compressing and bonding thin sheets of wood (plywood) or particles (chipboard or MDF) together with adhesive.Advantages over solid woods;More stable as they don’t have grainAvailable in large sheet sizesEasier to buy from DIY shopsLess expensiveTHEY DON’T GROW ON TREES!!
9Wood Finishes – Protect or Decorate DetailsExample ProductPaintsWater-based paints are not durable. Oil-based paints are tough, hard wearing and weatherproof. Acrylic paints are quick drying.VarnishesPolyurethane varnishes give clear, tough and hard-wearing finish = plastic coating that doesn’t go into wood. Can get them in quick-drying. ‘Yacht’ varnish provides waterproofing.StainsDo not protect wood. Used to enhance the look of wood by showing off grain or colouring it to look like different, more expensive wood or bright colour. Not easy to apply and can look patchy.WaxBeeswax is sustainable, natural finish for wood that leaves dull gloss shine. It is applied straight on bare wood after it has been sanded and sealed with oil.PolishingBuild up layers of clear polish, sanding between each coat, which enhances look of grain. Also used to seal wood before waxing.
11Materials - Plastics There are 2 ‘families’ of plastics; Key Terms; THERMOPLASTICS = such as acrylic, can be heated to make them soft so they can be shaped, this can be repeated many times.PLASTIC MEMORY = is the ability of thermoplastics to return to their original state after reheatingTHERMOSETTING PLASTICS = such as epoxy resin, can also be heated to make them soft so they can be shaped, but this can only be done once. They are particularly useful for making plastic products that are resistant to heatDYES = can be added to plastics to make them a specific colour all the way through unlike woods or metals that can only be coloured on their surface.
12Materials – THERMOPLASTICS MetalPicturePropertiesUsesAcrylicStiff, hard, clear, durable outdoors, easily machined and polished, good range of colours, does scratch easilyIlluminated signs, aircraft canopies, perspex sheet, car rear-light clusters, school projectsABSTough, high-impact strength, lightweight, scratch-resistant, chemical resistance, excellent appearance and finish. Good for injection mouldingKitchenware, safety helmets, car parts, telephones, food mixers, toysLow-density PolytheneRange of colours, tough, flexible, good electrical insulator and chemical resistanceWashing-up liquid, detergent and squeezy bottles, bin liners, carrier bags
14Theory Questions…What is the main difference between softwoods and hardwoods?Name 4 good things about MDFWhy would you put a finish on wood?What is the main difference between the 2 different types of plastic?What are the 2 parts of Araldite glue (epoxy resin)?What are the 2 main types of metals? What are the differences between them?What is the main difference between an alloy and an element?What is ‘work hardening’? And what is the heat treatment method that you can use to remedy it?Name 3 finishes that can be used to stop mild steel from rusting.
15Materials – THERMOSET PLASTIC MetalPicturePropertiesUsesUrea-FormaldehydeStiff, hard, brittle, heat-resistant, good electrical insulator, range of coloursWhite electrical fittings, domestic appliance parts, wood glueEpoxy resinGood chemical and wear resistance, resists heat to 250ºC, electrical insulatorAdhesives such as Araldite used to bond different materials such as wood, metal and porcelainPolyester ResinWhen laminated with glass fibre becomes tough, hard and strong, brittle without reinforcementGRP boats, chair shells, car bodies
16IRON Materials - Metals Key Terms; FERROUS metals contain iron, like steel – they rust and are magneticNON-FERROUS metals don’t contain iron, like aluminium and copper – they don’t rust and aren’t usually magneticIRONPURE METALS are made from one single elementALLOYS are made from mixtures of different elements
17Materials – FERROUS Metals PictureCompositionPropertiesUsesMild SteelAlloy of iron and % carbonHigh tensile strength, ductile, tough, poor resistance to corrosionGeneral purpose, nails, car bodies, nuts & bolts, girdersStainless SteelAlloy of steel with 18% chrome and 8% nickelResistant to corrosion , hard, tough, difficult to workSinks, dishes, cutlery, kitchenwareHigh-speed SteelMedium-carbon steel with tungsten, chromium, vanadiumRetains hardness at high temps. Can only be groundDrills, Lathe cutting tools
18Materials – NON FERROUS Metals PictureCompositionPropertiesUsesAluminiumPure MetalLight, soft, ductile, malleable, corrosion resistant, polishes wellAircraft bodies, saucepans, cooking utensils, cans, foils, packagingCopperCorrosion resistant, malleable, ductile, tough, good conductor of heat and electricity, easily joinedElectrical wire, printed circuits, central heating pipesBrassAlloy of 65% copper, 35% zincCorrosion resistant, heat and electrical conductor, casts well, polishes wellCastings, forgings, ornaments, boat fittings
21Heat Treatment of Metals Key Point – The properties of some metals can be altered to suit particular applications by the use of heat treatment, which involves heating and cooling the metal in a carefully controlled way.Hardening – make steel much harder but can be brittle. Do this by heating until cherry red and then quenched in oil.Tempering – make steel that has been hardened more tough. Do this by heating to certain temperature (between 230ºC – 300ºC) and then quench in oil.Case hardening – make outer surface of steel very hard. Do this by heating to cherry red, dipping in carbon powder, quench in water.Annealing – Relieve problems caused by work hardening (when you hit/bend a metal it can become fragile and brittle) Do this by heating it to a certain temperature (depending on type of metal) and then allowing it to cool as slowly as possible.
22Metal Finishes – Protect or Decorate DetailsExample ProductPrimers and PaintsThis creates a thin barrier between ferrous metal and oxygen. Must clean surface first and then apply evenly. Primer and then Paint.ElectroplatingFerrous metal is coated in thin layer of non-ferrous metal by fusing it on using electricity. The most common is chrome-plating on car parts.AnodisingUsed on aluminium, passing electricity through it thickens an oxide layer on it’s surface. Coloured dyes can be added to process – Maglites.Dip-coatingHeat metal to 180ºC in oven and then dip in thermoplastic powder. Good for making grippy handles on metal tools.PolishingPolishing compound is added to non-ferrous metal and then buffed to high shine. Can be protected with clear lacquer (spray-on varnish)
23Theory Questions… What are the 2 parts of Araldite glue (epoxy resin)? What are the 2 main types of metals? What are the differences between them?What is the main difference between an alloy and an element?What is ‘work hardening’? And what is the heat treatment method that you can use to remedy it?Name 3 finishes that can be used to stop mild steel from rusting.What type of material is an SMA? What does it do?What is an LCA? Why are they important?‘Knobs’, ‘screws’ and ‘nuts’ are all funny words but what are they all types of?In RM what does the word ‘wasting’ mean?What tool is used to make wood and metal components with cylindrical cross sections?
25SMART Materials Metal Picture Properties Uses Shape Memory AlloysSMAs can be bent to a shape at room temp. but will then return to original shape when heated to certain temp.Move parts in robots, open and close valves, teeth braces.Thermochromic pigmentThis is paste that can be added to acrylic paint. When it is heated the paint goes clear. When it cools the colour comes back.Kitchenware, baby feeding spoons, drink stirrers, and childrens’ toysThermochromic sheetThis is a black plastic material that when it reaches a certain temperature turns different colours.Electronic circuitry, food containers, children’s thermometer.
26Environmental & Sustainability Issues You need to know about;Selection of materials based on a consideration of the environment and sustainabilityThe application of the 6Rs: Reduce, Reuse, Rethink, Refuse, Repair and Recycle.‘Life Cycle Analysis’ (LCA).‘Design for disassembly’ and the importance of recovering parts and materials from end-of-life products.
30Design Issues – Making products easy and safe for humans to use Anthropometrics“The measurement of humans”
31Design Issues – Making products easy and safe for humans to use ErgonomicsUsing anthropometric data to design products so they are easier and more comfortable for humans to use
32How is ergonomics involved in the Design Process? Basic ProductAnthropometric DataProduct DesignerErgonomically designed chair
33Tools & Processes - WOOD MARKING OUTToolPictureUseSafetyPencilCreate lines that are clearly visible on wood and can be erasedSharp pointSteel RuleMeasure accurately and draw straight linesNoneTry SquareMarks line at 90º to square edgeMarking GaugeScratches parallel lines to edge
34Tools & Processes - WOOD WASTING (CUTTING & SHAPING)ToolPictureUseSafetyCoping SawCut curved lines in thin wood and plasticSharp bladeTenon SawCut straight lines in thicker woodScroll SawSame as coping saw but faster because it’s electricSharp blade but moves faster. Blade can snap which makes scary BANG!Band SawCuts curved and straight lines very quickly in wood and plasticVERY DANGEROUS! Not for students as it can cut bits off! You must be trained
35Tools & Processes - WOOD WASTING (CUTTING & SHAPING)ToolPictureUseSafetyJig SawCut curved lines in wood – good for cutting holes of weird shapesMust clamp wood down and careful what you are cutting underneathHand DrillCut holes in thin wood, plastic or metalNot muchCordless Rechargeable DrillCut holes in wood, plastic, wood – VERY MOBILE! Make sure work doesn’t move – wear goggles, no loose clothesPillar DrillPowerful way to drill holes in most things – as long as they fit on bedMake sure work is clamped – wear goggles, no loose clothes, long hair
36Tools & Processes - WOOD WASTING (CUTTING & SHAPING)ToolPictureUseSafetyTwist DrillCut holes in wood, metal and plastic. Fit in a chuck.Must clamp work down and careful what you are cutting underneathSaw Tooth Bit (Forstner Bit)Cut holes in wood which have smooth sides and flat bottomsWood can burn and catch fire so drill slowly and clamp stronglyHole SawCuts large discs out of quite thin wood – you can’t stop halfwayChuck &Chuck KeyUsed to fit drill bits in pillar drillsMake sure chuck is done up tightly and then remove key before turning on!
37Tools & Processes - WOOD WASTING (CUTTING & SHAPING)ToolPictureUseSafetyFilesShape and smooth metal, plastic and wood. Have lots of ‘teeth’Clamp workChiselsUsed to cut and shape wood. Often used to make joints. Hit with mallet.Super sharp! Always point chisel away from body and clamp workWood PlanesRemove shavings from wood to make surfaces flat and right size.Plane blade is super sharp so keep away from body and clamp workWood-Turning LatheUsed to make cylindrical shapes and bowls from woodBig stuff spinning quickly and very sharp tools! Goggles etc.
38Tools & Processes - WOOD WASTING (CUTTING & SHAPING)ToolPictureUseSafetyPower RouterCutting grooves, fancy edges and complex shapes in woodReally dangerous because of exposed spinning blade and lots of stuff flying offCNC Milling MachineExample 1Cutting really complex shapes very accurately and quickly in woodFollow safety procedures for machine – all guards working?
39Tools & Processes - METAL MARKING OUTToolPictureUseSafetyScriberCreate lines that are clearly visible on metal by scratching the surfaceSharp pointCentre PunchMarks centre of hole to be drilled by making a dent for bit to fit intoHave to hit it with a hammer – so mind your fingers!Engineer’s SquareMarks line at 90º to square edgeNoneDividersScratch circles and arcs of different sizes on metalSharp points
40Tools & Processes - METAL WASTING (CUTTING & SHAPING)ToolPictureUseSafetyHack SawCut straight lines in metal and plastic – small teethSharp bladeTin SnipsCut straight lines and curved lines in thin metal sheetSharp blades with scissor actionBench ShearsSame straight lines in slightly thicker metal sheet = long handleSharp blade with scissor action – very dangerous!Wire WoolRemoves scratches on the surface of metal ready for finishingWash hands after so filings do not go in eyes
41Tools & Processes – METAL & PLASTIC WASTING & SHAPINGToolPictureUseSafetyMetal Work LatheMake work with a cylindrical profileBig stuff spinning quickly and very sharp tools! Goggles etc.Milling MachineCut grooves and remove very precise layers of materialLarge powered tool with spinning cutter – goggles and guards neededVacuum Forming MachineMould plastic into different shapes by sucking around mouldGrill area gets hot so keep hands out and don’t touch work until coolStrip heaterUsed to bend plastic along a lineFilament gets very hot – wear gloves
42Theory Questions… What type of material is an SMA? What does it do? What is an LCA? Why are they important?‘Knobs’, ‘screws’ and ‘nuts’ are all funny words but what are they all types of?In RM what does the word ‘wasting’ mean?What tool is used to make wood and metal components with cylindrical cross sections?Which is the simplest wood joint? Why is this weaker than a hidden-dowel joint? Why are mitre joints sometimes used?Why are injection moulding machines used in industry?What is the main difference between soldering/brazing and welding?Explain 5 reasons for why CAD is so goodExplain 3 reasons for why CAM is so good
43FIXING – WOOD JOINTS Tool Picture Use Butt Joint The simplest of all wood joints. PVA glue is used to stick plain ends together and then held in place until dry. This is also the weakest joint and usually needs to be strengthened with pins, screws, knock-down fittings, a metal plate etc.Mitre JointPretty simple joint. Ends are cut at 45º and then glued together. Attractive joint as it hides end grain, used for picture and mirror frames. Can be strengthened with nails, screws or staplesHidden Dowel JointMore advanced joint – holes need to be drilled in both surfaces and then small dowel is glued in place. Can be used in lots of situations – use this in the exam if you can!!If you’re keen then check out these other joints – they might ask you to name them (only 1-2 marks)
44Tools & Processes – INDUSTRIAL PictureUseSafetyPLASTICInjection Moulding MachineVideo 1 Video 2Making lots of identical complicated plastic shapesIndustrial machines have loads of safety equipment and fail safesBlow Moulding MachineMaking hollow plastic shapes like bottlesPLASTIC & METALExtrusion mouldingMake long rods with various cross-section shapesMETALDie-castingMaking lots of complicated metal shapes
45Joining Materials Tool Picture Use Safety PLASTIC Tensol Cement Sticking Plastics togetherNasty stuff – irritant and toxic, wear gloves and gogglesWOODPVA Wood GlueGluing wood together – used lots in joints to strengthen themNot much – clamp work will help joinMETALSoldering& BrazingIts like gluing 2 metals together with metal glue – fairly versatileVery hot process so gloves, apron etc. need to be wornWeldingUsed to permanently melt 2 metals together – very strong but tricky to doVery hot process so gloves, apron etc. need to be worn. Also need to wear welding mask to protect eyes
54Computer Aided Design (CAD) Designers can use computer packages like 2D Design, Autocad, Google SketchUp to design, Model and Test ideas before they go into production. It is particularly useful because;Computers can be used to make changes to a design and edit it without having to redraw it.Computers can be used to produce very accurate drawings and dimension exactly to what is drawn.Computers can produce photorealistic models without having to make themYou can see what it will look like in 3D – spin it around so you can see all anglesComputers can show or simulate how a product will behave without having to undertake expensive testing.
55Computer Aided Manufacture (CAM) Designers can use machines that are controlled by computers to cut and shape material. They are called Computer Numerically Controlled (CNC). This is good news because;Computers do not make mistakes if programmed properly.Computers give reliable and consistently high standards of manufacture.Computers achieve quicker production times. Complex shapes and designs can be created easily.CNC LatheCNC Miller/RouterLaser Cutter
56Theory Questions…Which is the simplest wood joint? Why is this weaker than a hidden-dowel joint? Why are mitre joints sometimes used?Why are injection moulding machines used in industry?What is the main difference between soldering/brazing and welding?Explain 5 reasons for why CAD is so goodExplain 3 reasons for why CAM is so goodWhat is main differences between; one-off, batch, and mass production?How does rapid-prototyping work?What is Globalisation? Why is it a good/bad thing?Give 5 examples of health & safety equipment that could be used in a factory.What does the ‘corrosive’ safety symbol look like?
57Basic Production Methods What we do to a material in order to make something is called a process, but a method is how we apply that process to manufacture one or more products. A designer has to decide which production method should be used to make their products based on the numbers and quality required. There are 3 main methods;One-off ProductionUsed to produce one or two very special products, usually by highly skilled craftsmen who are paid lots of money. It is very time-consuming as each part is made individually and therefore is very expensive. Products have a ‘hand made’ feel and therefore are usually considered high quality.
58Batch ProductionBatch production is used where a number of identical products are made, and special tools are normally used to make them. The size of the batch can be anything from 10 – but can be repeated at any time if more orders are made. Production processes like injection-moulding and die-casting are often used as once the moulds are made for the parts they will be suitable for future re-orders. These moulds are expensive to make at first but this cost is spread over the number of products made so becomes cheaper as more are made. The workers are not as skilled as those in one-off production and therefore are paid less. Using moulds, jigs and templates improves consistency but as products are usually hand assembled by low-skilled workers this can result in lower build quality.
59High-Volume Production Sometimes referred to as ‘mass-production’ – this deals with the production of very large numbers of identical products. A lot of specialist equipment is needed and it is very expensive to set up therefore it is only economical to use this method if large numbers of products are made. This is a very fast method of production and only a few skilled workers are needed to maintain and manage the machine. Assembly lines are often used which keep production almost continuous. Robots are used to improve build quality, accuracy and consistency. This type of production was first used by Henry Ford when he made the Model T.
61Rapid PrototypingCAD packages allow the designer to view a 3D image of a new design on-screen. A number of systems are now available to quickly turn these designs into models which can be handled and used for market research purposes. These machines are called rapid-prototypers. First computer software breaks the 3D drawing into thin horizontal slices. These ‘layers’ are then sent to the machine in sequence where they are built up to make the model. One of these rapid-prototyping systems is called stereo-lithography which uses a laser to harden layers of liquid plastic resin to make the 3d shape.
62GlobalisationThis is where companies become multi-national, this means they make products in countries all over the world and can also sell their products all over the world.This is good because;They can make products cheaper as labour costs are often less and also they are closer to raw materialsFactories can be closer to new markets – for example Nissan (Japan) make cars in the UK to sell in Europe to save on transport costsIt can be bad because;Labour laws in emerging economies (like China, India etc.) are not as strict and this can lead to mis-treatment of workersCompanies often have to ship products long distances which can be very bad for the environment because of all the CO2 produced
63Health & SafetyUnderstand the importance of personal safety when engaged in designing and making activities, including:Personal protective equipmentMachine guardsDust and fume extractionWaste disposalUse the link above to learn theory and complete activityYou also need to know about simple risk assessmentRisk = (How dangerous it is) X (How likely it is to happen)
64C.O.S.H.H. Control of Substances Hazardous to Health The COSHH Regulations (2002) states general requirements on employers to protect employees and other persons from the hazards of substances used at work by risk assessment, control of exposure, health surveillance and incident planning. There are also duties on employees’ to take care of their own exposure to hazardous substances and prohibitions on the import of certain substances into the European Economic Area.
65Safety Symbols Blue signs are mandatory – you must do what they say Black and Yellow signs are warningsRed diamonds are warnings of hazards
66QualityIt is important that you know that products need to be a certain quality to be sold commercially.Design – they have to be designed in such a way that they will perform the correct functionManufacture – they need to be made so they are both safe and don’t fall apart.To do this the correct materials need to be chosen and the product must be made accuratelyQuality ControlTo help with this process companies will check a certain number of the products. This is called inspection, and would generally include checks on;Accuracy of sizesOverall appearanceSurface finishThe consistency, composition, and structure of the materials