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Year 11 Mock GCSE Exam Revision. Equipment. Specifications. What is a specification?
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Year 11 Mock GCSE Exam Revision
Specifications What is a specification? Description or detailed instruction provided in conjunction with product plans or a purchase order. Specifications may stipulate the type of materials to be used, special construction techniques, dimensions, colors, or a list of the qualities and characteristics of a product. Give a specification point – WHY have you chosen this point? Quality Environment Market ALWAYS make sure that all your ideas refer to your specification in some way. NEVER draw an idea that has no relevance to your secification
Injection Moulding What is Injection Moulding? The process is used to produce large quantities of identical plastic items. One of the most common types of thermoplastics used in injection moulding is high impact polystyrene (HIPS).Small components such as pens, bottle tops, milk crates and disposable razors can be made through this as well as larger parts such as kit car parts. All parts are created from one central processing unit, so labor is saved, and costs are reduced.
Plastic Dip-Coating What is Plastic Dip-Coating? Process used to cover metal with plastic. The metal, usually in rod form, is heated in an oven until it is hot, then dipped into a container of plastic powder, which is blown with air in order to create an even spread. The plastic melts onto the metal and sticks to it. The coated metal is put back into the oven until the plastic becomes smooth and shiny, then removed and left to cool. • Advantages • Quick process • Same results time after time • Effective finish • Durable finish – withstand everyday activity.
Materials - Plastics Plastics are often divided into 2 groups – THERMOPLASTICS and THERMOSETTING PLASTICS Acrylic – strong, flexible, can be manipulated into any shape with heat, abrasion resistant, cleaned easily. ABS – strong, rigid, tough, ABS is not heat resistant and can boil when exposed to excessive amounts of heat and burst into flames. Polyurethane - This forms the basis of many paints and varnishes because it is very tough and has water resistant qualities Polythene - Can be moulded into almost any form due to its excellent moulding qualities. Used for the production of bottles, bowls, toys, tube etc... It is available in large sheets. There are two types: High density which is rigid and hard, and low density which is tough and flexible. Machine parts are generally made from high density polystyrene whilst bottles are made from the low density polystyrene
Materials - Metals Metals are split into 2 groups FERROUS and NON FERROUS. Ferrous = Metals that contain iron Mild Steel (Tough. High tensile strength. Can be case hardened. Rusts very easily. Most common metal used in school workshops. Used in general metal products and engineering.) Stainless steel (Tough, resistant to rust and stains. Used for Cutlery, medical instruments.) Non-Ferrous = Metals that do not contain iron Aluminum (Ductile, soft, malleable, machines well. Very light. Used in window frames, aircraft, kitchen ware.) Copper (Ductile, can be beaten into shape. Conducts electricity and heat. Used in electrical wiring, tubing, kettles, bowls, pipes.)
Materials - Woods Woods are classified into two main groups, softwoods and hardwoods . Trees are either coniferous (bears cones and have needle shaped leaves that stay green all year round) or deciduous (has flat leaves that fall in autumn). The timber that comes from the coniferous tree is known as softwood and the timber that comes from deciduous trees is known as hardwood. Although the terms suggest that softwoods are soft and easy to cut and shape and that hardwoods are hard and more difficult to shape this is not the case. For example, balsa wood which is noted for its lightness and softness, is actually classified as a hardwood.
Woods - Softwood PINE - Is a relatively cheap wood used in the building trade and for furniture. It is pale in colour, quite easy to cut and shape, and machines relatively well. Advantages of Softwood…… Disadvantages of Softwood…….
Woods - Hardwoods MAHOGANY - Is quite expensive and is used for good quality furniture and hardwood windows. It is light brown in colour and more difficult to use compared to pine. OAK - This is an expensive material and is used in for making quality, expensive furniture. Steel fittings such as hinges will stain oak so it is important to use brass ones. TEAK - A hardwood that contains oils which means it is resistant to decay. This is often used to make garden furniture or for wood block flooring.
CAD/CAM CAD – Computer Aided Design CAM – Computer Aided Manufacture Why do we use CAD? The main purpose is so that we can have a visual 3D representation of the design in front of use. The 3D environment enables us to manipulate it in ways that aren’t possible when looking at a rendered paper drawing. You can place the design into the environment virtually, and then place forces and stresses upon that object to see how it would react in an everyday situation. Test it without having to spend time making it A 3D model can be sent to a CAM output to be machined. These usually come in the form of a Laser Cutter, Milling Machine or more sophisticated machinery in industry. Drawings are more economical and efficient Sizes an be changed instantly to fit the surroundings.
CAD/CAM • What is CAM – Computer Aided Manufacture • What is CNC – Computer Numerical Control Machine • A CNC is powered by a series of codes that tell the machine to produce an object. These codes are generated automatically from a CAD program such as PRO-Desktop. It tells the machine to move in the Z axis, the Y axis and the X axis. • Advantages of CNC machines are: • CNC machines can be used continuously 24 hours a day, 365 days a year and only need to be switched off for occasional maintenance. • CNC machines are programmed with a design which can then be manufactured hundreds or even thousands of times. Each manufactured product will be exactly the same. • Modern design software allows the designer to simulate the manufacture of his/her idea. There is no need to make a prototype or a model. This saves time and money. • Disadvantages of CNC Machines are: • Old traditional skills are being lost, as these are all computer controlled • A lot of people are becoming unemployed as they are not needed in the workplace due to only one person needed to control this.
Heat Treatment Process • The process of heating and cooling metal can be used to change its properties and characteristics • Annealing – heat introduced to relieve stresses • Normalising Steel – heat to between 700 – 900 degrees, soak at that temperature, then cool in air. This makes the steel a lot more tougher • Tempering Steel • Health and Safety • High temperatures – correct safety precautions taken, goggles, clothes • Chemicals released through the process potentially harmful • Bright lights from the flame and the heating process – hazardous to eyes
British Standards • British Standards provide designers and manufacturers with a precedent to design to. ALL products and components made HAVE to comply with British Standards. • The British Standards Institution publishes BSI and ISO (International Standards Organisation) data about many aspects of technology such as signs and graphics, and tools and components. • The BSI also make available standard information on people, anthropometric data, and the way people use things such as controls and displays, ergonomic data. • Advantages: • All products are safe and easy to understand • There will be no confusion when creating designs for products – everyone will be confirming to the same standards • Can you think of any more?
Environment THINK ABOUT….. Packaging – reducing this, what are the effects on reducing packaging for the environment? Transportation issues – reduce the carbon footprint. Effect on the environment of using less energy in the heating of homes - IMPORTANT
