Key term
CCEA A-Level Technology and Design 8900
Material Selection and Wood
Metals
Plastics
Composite and Emerging Materials
Processing Materials
Product Analysis and Design Communication
Design for Manufacture, Quality and Safety
Electronic Control SystemsOption A
Topic overviewControl systems, feedback and electronics safetyResistors, Ohm's law and power ratingsCapacitors and RC timingPotential dividers, sensors and comparatorsSwitches, pull-up and pull-down resistorsOutput devices and LEDsTransistors, Darlington pairs and thyristorsLogic gates, truth tables and flip-flops555 monostable and astable timers
Microelectronic Control SystemsOption A
Topic overviewMicrocontroller systems, ADCs and DACsStrain gauges and bridge circuitsOptical switches, encoded discs and Schmitt triggersOp-amp amplifiers and gainZener diodes and voltage regulatorsKarnaugh maps and binary countersSeven-segment, LCD and dot matrix displaysPIC flowcharts and programmingDC motors, stepper motors and driver circuits
Mechanical and Pneumatic ComponentsOption B
Topic overviewOpen and closed loop mechanical and pneumatic controlSafe working with compressed air and mechanismsLevers, linkages and momentsGear types and gear trainsPulleys, belts, chains and shaft fixingsCams, cranks and converting motionCompressed air supply and pneumatic valvesCylinders, shuttle valves, restrictors and reservoirsPneumatic circuits for logic, timing and speed control
Mechanical and Pneumatic SystemsOption B
Topic overviewHydraulics, system limitations and plant safetyTorque, work, power and air consumptionVacuum handling, proximity sensors and 5/3 valvesSequential and cascade pneumatic circuitsCam profiles and follower displacement diagramsGear geometry, pulley blocks and ratchetsToggles, treadles, shafts and couplingsFriction, brakes and clutchesBearings, lubrication and seals
Designing and Manufacturing ProductsOption C
Topic overviewResearch, questionnaires and specificationsIdea generation, critiques and computer simulationManufacturing planning and product evaluationCFRP, GRP, Kevlar and tungsten carbideSmart materials, nanotechnology and biophotovoltaicsIsometric, perspective and assembly drawingLaminating, steam bending, cutting and printing processesRisk assessment and product safety lawScales of production, JIT and cell productionQuality assurance, ISO 9001 and continuous improvementDesign influences and intellectual property rights
Product Design in Industry and SocietyOption C
Topic overviewLife-cycle environmental impact and climate changeThe 6Rs, waste and environmental legislationSustainable metals, plastics and degradable polymersProduct life cycles, consumer types and relaunchesCAD, CAM, 3D scanning and quick-change mouldingMarket pull, technology push and market strategyPrice, place and promotionJigs, fixtures and ICT in quality controlDesign for maintenance, inclusion and scale productionRendering, typography and presentationDyson, Baylis, Memphis and Apple
Product Development
Product and System Design and Manufacture
Processing Materials
Sand casting, die casting and extrusion
- 3 things to know
- AS 1 Paper 1
Overview
Patterns, moulding boxes, sprues, risers, cores and fettling in sand casting, pressure die casting of non-ferrous alloys, and extruding uPVC pipe and aluminium sections.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Why is a sand-casting pattern made slightly larger than the finished casting?
Key term
Describe how a sand mould is prepared in a two-part moulding box.
Questions from this subtopic
Each one with the model answer underneath.
- 1
What is the purpose of the pattern in sand casting?
Model answer
The pattern is a replica of the casting that is packed round with sand and then removed, leaving a cavity. Patterns are usually made of wood.
- 2
Why is a sand-casting pattern made slightly larger than the finished casting?
Model answer
Metal shrinks as it cools from liquid to room temperature. A shrinkage allowance on the pattern means the casting ends up at the right size, with extra left for machining.
- 3
Describe how a sand mould is prepared in a two-part moulding box.
Model answer
The pattern is placed in the drag and green sand is rammed firmly round it. The cope is added and rammed round sprue and riser pins, then the pins and pattern are removed.
- 4
What are the sprue and the riser in a sand mould?
Model answer
The sprue is the channel down which molten metal is poured. The riser lets air escape and holds a reserve of metal that feeds the casting as it shrinks.
- 5
How are the hollow water passages inside a cast engine block produced?
Model answer
A core of bonded sand is placed in the mould to occupy the space that must stay hollow. The core is broken out after the metal has solidified.
- 6
What is fettling?
Model answer
Fettling is cleaning up a casting after it is removed from the sand. The sprue, riser and any flash are cut off and rough surfaces are ground smooth.
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