Higher Level Leaving Certificate Engineering

Revision Notes 2011(Answer Question 1 - Section A and Section B and four other questions)

Question 1 Section A and Section B are CompulsorySection A (50 marks – 5 marks per question)

(Short Questions – Summary of the Course, look over past exam papers)

Safety symbols, safety with toxic materials, effects of toxic materials, methods of disposal of waste plastic, basic first aid requirements, personal protection, methods of safeguarding machinery, colour code of safety signs, mechanical, electrical and human failures, work space clearances, electrical hazards; principles of protective devices and systems, earthing; single and three phase systems, correct use of equipment, chemical hazards, poisonous, corrosive, combustible and explosive, fire protection methods and equipmentRed (prohibition signs to include danger and fire safety), Yellow (alerts to a caution or possible danger), Green (positive action to safe condition, emergency exit or first aid), Blue (denotes mandatory or information signage)

Highly Flammable

Toxic Corrosive Explosive Harmful Harmful to the environment

Radiation Poison Biohazard Electrical General Laser Oxidising

Fire Extinguishe

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Fire Emergency Telephone

Fire Alarm Call Point

Fire Hose Reel

Fire Ladder Fire Fighting Equipment

Corrosion, mechanisms of corrosion, electrolytic action, influencing factors, minimising corrosion, sacrificial protection, oxidation, electro-chemical

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corrosion, environment corrosion, protective coatings against corrosion (paint, plastic dipping, lacquer), anodising of aluminium, hot dipping, electro painting, galvanising, design features, environment, anodic and cathodic protection

Joining materials with adhesives, preparing materials for joining with adhesives, joint design, types of adhesives, safety hazards when using adhesives, advantages of adhesives

Joining Methods – Mechanical Joining (screw fasteners, compression joints, riveting, sheet metal folding), Welding, Bonding (soldering, brazing, adhesive bonding)

Manufacturing processes – fabrication, drop forging, calendaring, casting (pattern), sand casting, investment ‘lost wax’ casting, die casting, gravity die casting, pressure die casting, continuous casting, extrusion, drop forging, press forming, blanking, piercing, punching, bending, drawing, deep drawing, thread rolling, rolling, drawing, stamping, profile key cutting

Robots in industry – assembly lines, multipurpose capabilities, production with robots, advantages & disadvantages, work envelope, safety, degrees of movement

Machining – generating, forming, shaping, turning, milling, grinding

Pneumatic symbols – 3/2 valve (three port valve), 5/2 valve (five port valve), double & single acting cylinders, push button switch, roller switch, lever switch, plunger switch, solenoid operation, pressure sensitive switch, air supply, exhaust, spring return, reservoir, shuttle valve, flow regulator

Forces - torsion, shear, compression, tension, bending

Thread forms – buttress, acme, square

Electrical symbols – LDR, LED, capacitor, thermistor. Electronic terms – heat sink, breadboard

Separation of ores – pyrometallurgy, hydrometallurgy, thermo-electrometallurgy

Ore dressing/ore concentration – flotation, magnetic separation, gravity concentration, amalgamation, metal extraction – leaching, electrolysis, smelting & refining, reduction, reduction-oxidation

Mining – open cast mining, underground mining, open pit mining, dredging, solution mining

Types of materials – polymers, metals, elastomers

Properties of materials – tensile strength, shear strength, malleability, creep, hardness, toughness, ductility, elasticity, electrical conductivity, thermal conductivity, thermal expansion, compressive strength, density, proof stress,

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magnetic characteristics, resistance to corrosion, colour, machinability, melting point

Crystal defects (vacant site, substitute defect, interstitial defect), line defects dislocation), covalent bonding, ionic bonding, metallic bonding, crystal patterns - FCC, BCC, CPH, slip in BCC & FCC, crystalline & amorphous structures, dendritic growth, allotropy, crystal structures

Computer terms – CPU (central processing unit), DVD (digital versatile disc), CD-RW (compact disc rewriteable) , E-mail (electronic mail), RAM (random access memory), ROM (read only memory), LAN (local area network), ULR (uniform resource locator), HTML (hypertext mark-up language), WWW (world wide web), HTTP (hypertext transfer protocol), ISP (internet service provider), Input Device (keyboard, mouse, joystick, scanner, webcam, microphone, digital camera), Output Device (monitor, printer, speaker, sound card), Hardware (physical parts) & Software (programs)

Measuring instruments – limits, tolerance and allowances, limits & fits – (hole & shaft basis of fits), clearance, transition and interference fitsLinear measuring instruments – vernier callipers, micrometer, slip gauges, sine bar, precision cylinders & precision balls, gap gauge, plug gauge, screw thread measuring

Mechanisms – cams & follower, gears (rack & pinion, worm & wormwheel, bevel gears, helical gears, spur gear, gear train, idler gear), crank and slider, chain and sprocket, lever, linkage, quick return mechanism, bell crank, pulley, ratchet and pawl

Motion – linear, rotary, reciprocating, oscillating

PCB (printed circuit board), uPVC (unplasticised polyvinyl chloride), SPST switch (single pole, single throw switch), DPDT (double pole, double throw switch), HSS (high speed steel), CPU (central processing unit), LAN (local area network), IC (integrated circuit), CD-RW (compact disc re-write), VDU (visual display unit), LED (light emitting diode), LDR (light dependant resistor), E-mail (electronic mail), ISP (internet service provider), LCD (liquid crystal display), DOS (disc operating system), RAM (random access memory), ROM (read only memory), HD (high definition)

Corrosion of Metals – Oxidation, electro-chemical corrosion, sacrificial/cathodic protection, stress corrosion, protection against corrosion (corrosion resistance, anodising of aluminium, painting, plastic coating, hot dipping, powder cementation, metal spraying, metal cladding, electro-plating), corrosion prevention factors

Properties of materials – tensile strength, compressive strength, shear strength, creep, hardness, toughness, brittleness, elasticity, malleability, electrical conductivity, heat conductivity, melting point, resistance to corrosion

Inventors3

Albert Fryer The first incinerators for waste disposal were built in Nottingham by Manlove, Alliott & Co. Ltd. in 1874 to a design patented by Albert Fryer

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Joseph-Armand Bombardier

In 1922, he invented his very first snowmobile. He would later go on to invent several other types of snowmobiles, and finally in 1959, he invented the first practical and successful snowmobile.

Heinrich Hertz Discovered that ultraviolet light altered the lowest voltage capable of causing a spark to jump between two metal electrodes.

John P Holland Irish engineer who invented some of the first submarines.Viktor Kaplan Austrian engineer who invented a water turbine with adjustable

blades.Eli Whitney US inventor who patented the cotton gin and then manufactured

muskets using power-driven tools to produce interchangeable parts.

Igor Sikorsky Born in Kiev, Russia in May 1889. His most important contributions came in the area of helicopter design especially his single rotor design.

Theodore Maiman He invented the first operable laser. Laser beams are today being used in medicine, industry, electronic data processing & communications.

Dugald Clerk Born in Glasgow in 1859. He is identified with the internal combustion engine and the two-stroke engine.

Michael Faraday British physicist and chemist whose discoveries include electromagnetic induction and the laws of electrolysis. The unit of capacitance, the farad, is named after him.

Henry Maundslay In 1780 he used a revolving cutting tool to mill a slot in a lock. He mounted the tool on an arbour and set it up between centres on a lathe.

Gustaf Dahlen In 1902 he developed acetylene gas and demonstrated gas welding for the first time.

Simon Stevins A Flemish mathematician and engineer – he founded the science of hydrostatics, introduced decimal fractions laying the foundations for the decimal system of weights and measure. He developed methods of stopping invasions by designing sluice openings in dikes which could be opened and therefore flooding the lowlands.

Willhelm Roentgen In 1895 he produced X-rays in a high voltage discharge tube. The results have significant importance in engineering and medicine.

Chester Carlson In 1939, he developed the photocopier on a Xerox machine.Germain Sommeiller

In 1887 invented the compressed air drill, he was alsochief designer for Mont Censis tunnel in the Alps from Italy to France.

Jack Kilby In 1958, he co-invented the integrated circuit where complete sets of electronic components could be embedded, and connected, to create a complex circuit, ie. the microchip.

Thomas Edison Tin foil phonograph. A prolific producer, Edison is also known for his work with light bulbs, electricity, film and audio devices.

Alexander Graham Bell

1876, at the age of 29, invented his telephone. Among one of his first innovations after the telephone was the "photophone," a device that enabled sound to be transmitted on a beam of light.

John Logie Baird Mechanical television (an earlier version of television). Baird also patented inventions related to radar and fiber optics.

Henry Ford improved the "assembly line" for automobile manufacturing, received a patent for a transmission mechanism, and popularized the gas-powered car with the Model-T.

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James Dyson Born in Norfolk in England in 1947, he invented the use of cyclone technology in vacuum cleaners. This bagless system does not clog orlose suction. The Dyson Airblade hand dryer was launched in 2006.

George Atwood The first accelerometer, originally known as the Atwood machine, was invented by the English physicist George Atwood (1746-1807) in 1783.

Timothy Berners-Lee

Sir Timothy John "Tim" Berners-Lee born 8 June 1955 is a British engineer and computer scientist is credited with inventing the World Wide Web, making the first proposal for it in March 1989.

George Eastman American inventor and philanthropist, who played a leading role in transforming photography. He is the inventor of the first film in roll form in 1884 and the Kodak camera in 1888.

Pneumatic Symbols

Section B

Specialist Topic 2011 (50 marks)

“Basic principles and processes in the operation of Incineration Technology”

Incineration (thermal treatment) - disposal of waste by controlled burning Solid, liquid & gaseous wastes are converted into a small amount of ash & a large volume of exhaust gases Gases are cleaned before being released into the atmosphere Heat produced is recovered & used Energy from Waste (EfW) or Waste to Energy (W2E) plants.

Waste Types - Standard domestic rubbish usually called municipal solid waste (MSW) Industrial & chemical wastes Contaminated material from healthcare Residues from animal processing) Small plants handling waste from a single factory or hospital large plants processing the waste of entire cities.

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Combustion - Combustion or burning is the reaction of a material with oxygen fuel + supply of oxygen + high temperature are needed for combustion

Fuel - The main fuel type in waste is organic material Biological such as paper, timber, food waste and animal fats Petrochemical such as plastics and solvents.

Oxygen - Combustion is the reaction where a fuel combines with oxygen and is broken into simpler oxide molecules To burn properly there must be enough oxygen to react with all the fuel Reaction only occurs when oxygen comes into direct contact with the fuel For solid and liquids fuels this can only occur at the surface so it is best to break the fuel up into small particles or droplets.Temperature - Reaction with oxygen will only occur at a high temperature = ignition temp.

Combustion By-Products - If a fuel is burnt completely then: All carbon in it is converted to carbon dioxide All hydrogen is converted to water Any sulphur is converted to sulphur dioxide Any nitrogen into nitrous oxides All released as gases Complete combustion can only take place if: Enough oxygen is supplied Fuel & exhaust gases reach a high enough temperature for a sufficiently long time - called the dwell time Incomplete combustion of organic material produces solid carbon or soot.

Ash - If fuel contains other elements, such as metals, it will produce a solid residue or ash Amount of ash produced varies with the fuel composition but is usually less than 10% of the weight of the original fuel Some of the ash will be in the form of very fine particles and will remain suspended in the exhaust gases = fly ash Depending on the fuel fly ash may contain a range of heavy metals such as arsenic, cadmium, chromium, mercury Remainder of the ash is called bottom ash Contaminant levels tend to be lower.

Dioxins and Furans - If combustion is incomplete and the fuel contains chlorine then dioxins and furans will be released Dioxins are produced by the incomplete combustion of any organic materials containing chlorine To prevent their release very high temperatures must be reached and maintained Burning of rubbish in bonfires is one of the main sources of dioxins Temperatures reached are not high enough to give complete combustion.

Incineration Objectives - Achieve complete combustion of the waste: Controls fuel & air supply & temp Maintain required temp & dwell time Extract as much heat as possible from the exhaust gases Thoroughly clean the exhaust gases to ensure that only minimal amounts of harmful substances are released into the atmosphere.

Waste Supply - Sufficient waste to run the incinerator must be stored at the site The way it is stored will depend on the waste type Solid wastes are usually stored under negative pressure to minimize the release of odours May be sorted to remove any non-combustibles such as metals Mixed thoroughly to give a consistent fuel It may mechanically processed to reduce the moisture content or to break it into evenly sized pieces for easier handling and burning = Refuse Derived Fuel (RDF) Supply of waste to the combustion chamber is controlled and usually automated.

Combustion Chamber - Key part of the system where the burning actually takes place Different designs depending on the waste type Common Features to ensure

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complete combustion Adjustable forced supply of air usually sucked in Too little means incomplete combustion, too much low temperatures Thorough mixing of the waste and released gases with supplied air Controllable supply of a secondary fuel such as natural gas Used at start up and during operation to achieve required temperature Chamber design ensures exhaust gases have required dwell time.

Flue Gas Cleaning - Flue gas cleaning is done is two or more stages: Scrubbing and particle removal are always done Wet scrubbing sprays a fine mist through the flue gases Active carbon absorbs heavy metals such as cadmium, mercury, arsenic Water is collected and treated to removed pollutants.

Energy Extraction - Hot exhaust or flue gases are passed through heat exchangers in a boiler to produce high pressure steam This steam can be used to drive a turbine which in turn runs a generator producing electricity Each tonne of MSW produces around 650kWh of electricity and 2MWh of heat and is equivalent to 0.25t of oil or 0.4t of coal Heat from the steam condenser can be used to supply a local demand In Europe - used for heating.

Incineration Components

1. Waste Supply 2. Combustion Chamber 3. Boiler4. Scrubber 5. Fly Ash Filter 6. Draft fan7. Stack with Emissions Monitoring 8. Bottom Ash Collection. 9. Fly Ash Collection

Static Hearth - Liquid and gaseous wastes which will produce minimal ash are burnt in static hearth incinerators Typically organic solvents and vapours from chemical or

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pharmaceutical manufacture Several in Ireland e.g. Roche in Clarecastle Combustion chamber is a long cylinder Waste and air fed in by jets to create a swirling flow through the chamber Chamber length and swirling ensure sufficient dwell time.

Rotary Kiln - Hazardous solid waste is usually burned in rotary kilns Combustion chamber is an angled rotating cylindrical drum Rotation give good mixing of waste with air and flame Waste fed in at one end Ash removed Gases released are burnt in a secondary chamber

Moving Grate - MSW is normal burnt in moving grate incinerators Combustion chamber has an inclined moving metal grate air fed up through the grate Waste moves slowly down grate burn as it moves Ash falls off end into bunker.

Particle Removal - Fly ash can be removed by either filters or Electrostatic Precipitators (ESP) Baghouse filters use tightly woven fabrics Same idea as a vacuum cleaner bag Filters are cleaned regularly Up to 99% effective.

Fluidized Bed - Wastes with a uniform composition and high moisture content are burnt on fluidized bed incinerators Sewage sludge is typical burnt this way Fluidized beds are also used in power plants burning high moisture content fuels such as peat and biomass (willow) Instead of a grate there is a bed of sand Suspended on upward blowing jets of air Gives thorough mixing and a long dwell time Chamber is a vertical cylinder, sand is reused.

Flue Gas Monitoring - A large number of parameters are monitored continuously to ensure correct operation Total Organic Carbon (TOC) which is a measure of how much carbon is not fully burnt Other more difficult to measure pollutants are measured six monthly Dioxins, furans and heavy metals Strict limits must be met & all data reported to EPA.

Ash Disposal - Bottom Ash and Fly ash are usually treated separately Bottom Ash is first cooled and then processed to remove any metals For MSW bottom ash is then graded into different sizes & used as a construction aggregate Fly Ash & residues from scrubbers can contain highly levels of toxic materials Must be stored long term in a secure landfill to prevent release into the environment.

Role of Incineration - EU landfill directive has firm targets for the reduction of the amount of biodegradable waste going to landfill Currently Ireland landfills ~ 1.5 million tonnes of biodegradable waste Must be reduced to ~ 450,000t by 2016 Landfills cause methane emissions – 25 times more damaging than CO2 Risk of pollutants leaching into water table Incineration is one means of achieving target Reduces volume of material sent to landfill Material landfilled doesn’t decompose Reduces fossil fuel requirement.

Advantages of Incineration - Only practical method of disposing of wastes which cannot go to landfill If incineration is not available locally such material has to be exported Significantly reduces waste to be landfilled and associated pollution risks Produces useful energy from waste Reduces fossil fuel consumption and greenhouse gas (GHG) emission Can be more efficient that recycling Costs, energy usage and GHG emissions in the collection, transport and processing Waste is treated where it is generated.

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Disadvantages of Incineration - Incorrect operation releases harmful levels of pollutants In proper operation small amounts of fine particles and pollutants are released Emissions now one thousandth of 1990 levels Produces relatively large amounts of fly ash Approximately 4% of original waste weight, which must be dumped in secure landfills Could reduce the incentive to recycle Recyclable waste is a valuable fuel for incinerators Large capital investment could hamper future waste technology Require long term operation to recoup costs.

Incineration in Europe - Well established technology in Europe All Western European countries except Ireland have numerous plants Over 50% of all MSW in Denmark is incinerated Countries with high incineration rates also have high recycling rates.

Question 2 - Material Testing (50 marks)Advantages of mechanical testing, why are mechanical tests used

Destructive TestingToughness - Izod and Charpy (how the test piece is held)Hardness – Brinell and Vickers (type of indentor)

Principle of the test Type of indentor How the test piece is held Advantages Expected results

Tensile Testing - Draw graph (stress v strain), Stress, Strain, Proof Stress, Young’s Modulus, Elastic Limits, Modulus of Elasticity, Tensile Strength, Ultimate Tensile Strength, Upper Yield Point, Fracture Point, Specimen used in test, Necking, Cup & Cone, strength of materials in tension, compression, shear, bending, torsion

Non Destructive Testing (NDT)Visual Inspection / Thermal Testing / Ultrasonic / Radiographic or X-Ray / Magnetic Particle / Dye Penetrant / Eddy Current Testing

Name the test, purpose/principle of the test, what materials (ferrous/non ferrous metal), test procedure, type of flaws (surface, just below surface, internal), expected resultsWhy NDT’s are used, advantages of NDT,

Fatigue, fatigue failure, creep, micro and macro examination, ductile and brittle fracture, thermal and electrical conductivity, expansion, specific heat capacity, environmental exposure tests

Question 3 - Equilibrium Diagram (50 marks)Differences between metals and non-metals; chemical symbols; the importance of alloys, Physical properties of metals, outline of systems of mining for ores, description

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of the ores from which iron, copper, lead, zinc, aluminium, tin, silver, gold and other metals originate.

Label regions on Iron - Carbon Diagram and describe structure - ferrite, pearlite, austenite, cementite, martensite, eutectoid point, solidus line, liquidus line, solvus line, solid, liquid, critical points, structural changes, percentage of carbon, alloy, eutectoid alloy, binary alloy, equilibrium, inter-metallic compoundClassification, properties and uses of carbon steels, cast irons and alloy steelsHeat Treatments - Hardening, Flame Hardening, Induction Hardening, Age Hardening, Case Hardening, Pack Carburising, Nitriding, Annealing, Normalising, Tempering, Quenching Media (oil, water, brine, air, cooling in a furnace), Stress Relieving, Soaking, Pre-heating and Post-heating, Safety in Heat Treatments, Re-Crystallisation, Upper and lower critical temperatures, eutectic and eutectoid points, allotropy of carbon steelInstruments for measuring temperature in furnace – thermo-electric or thermocouple pyrometer and optical pyrometer, seger cones, describe how they operate

Blast furnace (iron), electric arc & basic oxygen furnace (steel,) open hearth furnace, cast iron, cupola furnace, cast iron classification, cast iron moulding, grey cast iron, white cast iron, whiteheart, blackheart, pearlitic iron

Non Ferrous Metals – copper, bronze, brass, aluminium, lead, tin, zinc, nickel, magnesium, tungsten, molybdenum, titanium

Question 4 - Thermal Equilibrium Diagrams (50 marks)Be able to label diagrams, state what lines represents, eutectic point, eutectoid point,solvus line, liquidus line, solidus line, solvus line, liquid region, solid region, pasty region, cooling curve, latent heat of fusion, ratio solid to liquidSolid solution alloys - Substitutional Solid Solution and Interstitial Solid Solution

Microstructure, factors affecting grain size, re-crystallisation, macroscopic examination of specimens, the structure of ingots and castings, atomic lattices, equilibrium diagrams for simple eutectics and solid solutions, ways in which metals combine to form alloys: eutectic and eutectoid

Stages of Metal Solidification. Allotropy of iron – BCC FCC BCC

Atomic imperfections in metals, line defects in crystals (dislocation), slip in BCC and FCC, crystal point defects (vacant site (vacancy), substitute defect, interstitial defect), solidifying metal, dendritic growth, allotropy - FCC, BCC, CPH, crystalline & amorphous structure, bonding of atoms – covalent, ionic/electrovalent, metallic, states of matter (solid, liquid, gas)

Question 5 – Welding (50 marks)Manual Metal Arc Welding (MMA), Gas Welding, Tungsten Arc Gas Shielded Welding (TAGS), Metal Arc Gas Shielded Welding (MAGS), Electro Slag Welding, Oxy Acetylene Welding, Submerged Arc Welding, Resistance Welding, Resistance Spot Welding, Resistance Seam Welding

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Name the process, equipment required, method of operation, applications/uses

MMA - function of electrode, function of slag, electrode coating, bridge rectifier, transformer, transformer circuit, AC/DC power supply, ground clamp, safety (flashback arrestor), installing a welding facility, safety in setting up a welding facility

TAGS – non consumable tungsten electrode, inert gas shields the weld, filler metal is required and is feed by hand, used to weld aluminium and stainless steel

MAGS – electrode is a bare wire and is fed continuously from a spool through the welding gun, weld is shielded by inert gas, no slag, often performed by robots, used for car assembly

Oxy Acetylene - identify and explain equipment, dissolved acetylene, oxidising, carburising and neutral flames, gas hose pipes, flashback arrestors, welding torch, gas pressure regulators, pressurised cylinders of gas, dissolved acetylene

Multi-run, single run welds, function of the slag, electrode coating, safety precautions when welding, preparation of materials for welding, transformer, rectifier

Advantages of Robots, work envelope, applications, advantages of robots, safety factors when using robots, industries where robots are used, work envelope, advantages of using robots in electrical circuit industry, pneumatic control with robots,

Joining of materials – mechanical fastenings, soldering, brazing, welding, adhesives

Question 6 – Polymers / Polymerisation (50 marks)Natural plastics (amber, animal horn, natural rubber, shellac), Modified natural plastics (cellulose, casein), synthetic plastics (by products of coal)

Stabilisers, catalysts, promoters, inhibitors, plasticisers, colour pigments, antioxidants, flame, retardants, lubricants, fillerscross-linking, van der vaals forces, monomers, elastomers

Additional, condensation polymerisation and copolymerisation + diagram

Manufacturing with Plastics - vacuum forming, blow moulding, injection moulding, compression moulding, rotational moulding, transfer moulding, calendaring, extrusion, welding, machining, lamination, foaming, spreading

Name process, type of polymer used, describe process, application, end product

Three main groups of polymers – thermoplastics, thermosetting, elastomers – chemical bonding, internal structure and properties, Properties of common plastics

Additives – fillers, plasticizers, colour pigments, stabilisers, antioxidants, flame retardants, lubricants

• Thermoplastics (polyethylene, ABS, acetals, polypropylene, PVC, polystyrene, acrylics, PTFE, polyamides, polymethymethacrylate, cellulose acetate, nylon)

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• Thermosetting Plastics (bakelite, amino plastics, phenolic resin, epoxy resin, polyester resin, polyurethanes, silicones, elastomers)

Methods of waste disposal.

Question 7 (50 marks) Milling – parts of milling machine, types of milling machines (horizontal, vertical

universal, turret) milling cutters, up-cut & down-cut milling, gang & straddle milling, work-holding (direct clamping, machine vice, dividing head, rotary table, magnetic chuck

Shaping – parts of shaping machine, shaping operations, set-up of machine, work holding, quick-return feature, table feed mechanism

Precision Grinding – parts of grinding machine, grinding wheel (abrasive, bond, grade, structure), wheel mounting, loading, glazing, dressing of grinding wheel, balancing of grinding wheel, surface & cylindrical grinding, internal grinding, work-holding (magnetic chuck, universal vice, sine chuck)

Turning – parts of the lathe, wedge, rake & clearance angle, shear plane, chip formation (continuous, discontinuous, BUE), measuring forces on cutting wheel (dynamometer), tool wear (flank, crater, spalling/chipping, plastic deformation), tool life, machinability, cutting forces, surface finish, Cutting forces - orthogonal (axial, tangential force) and oblique cutting (axial, tangential & radial force), working holding (collet chuck, faceplate, three & four jaw chuck, mandrels, turning between centres, lathe steadies), processes (parallel turning, facing, form turning, drilling, parting off/grooving, boring, taper turning, knurling, screw cutting), cutting data (cutting speed, spindle speed, cutting depth, feed rate)

Cutting Fluids – reduce friction & head between work & tool, flush away chipsWork-holding – magnetic chuck, chuck block, universal vice, sine chuckCutting Tool Material – Carbon steel, high speed steel, cemented carbide, cast alloys, ceramics, cubic boron nitrideMachinability, power consumed in cutting, relation between tool life and cutting speed, diamond, prolonging tool life, cutting fluidsForming and generating, safety when machiningMetrology - direct and comparative measurements (measuring instrument & gauges), standards of measurement, grades of accuracy, systems of limits, types of fit - clearance, interference fit, limits & fits, determination of limits and tolerances from given data., interchangeability of parts and selective assembly. limit gauges, measurement of screw threads; use of thread form gauges, and profile projector, sine bar, slip gauges, precision balls and rollers, specification of surface finish

Computer aided design (CAD), Computer aided manufacture (CAM)

CNC machining – G codes, M codes, canned cycles, pecking, absolute & incremental dimensioning, test run, tool part position, advantages (identical pieces, very accurate, mass production), safety features of a CNC lathe (test run, acrylic guard, emergency stop, CNC will not operate if acrylic guard is open), compare CNC to manual lathe, stepper motor

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Question 8 (50 marks)Mechanisms – Gears (rack & pinion, worm & wormwheel, bevel gears, helical gears, gear train, idler gear), crank and slider, cam & follower, ratchet & pawl, universal joint, pulleys, tooth belt and pulley, non return valve, dividing head, slider crank mechanism, quick return mechanism, power hacksaw, cam and follower, clutchKnow about the mechanisms that you used in your projectMechanical Joining – screw fastenersElectronic circuits – explain how the circuits operates, integrated circuit, solenoid, capacitor, light emitting diode (LED), switches (push button, slider, toggle), light dependant resistor (LDR), variable resistor, diode, transistor, battery, bulb, motor

Resistor Motor diode Bulb / Lamp Battery Capacitor

Variable resistor

Push Button Switch

On/OffSwitch

Relay LED Transistor LDR - Light Emitting Diode

Measuring instruments – limits, tolerance and allowances, limits & fits – (hole & shaft basis of fits), clearance, transition and interference fitsLinear measuring instruments – vernier callipers, micrometer, slip gauges, sine bar, precision cylinders & precision balls, gap gauge, plug gauge

Higher Level EngineeringProject 150 marks 25% (October 2010 – March 2011)Practical 150 marks 25% (May 2011)Theory 300 marks 50% (9th June 2011)

Answer Question 1 Section A and Section B (Specialist Topic) and four other questions.

Draw diagrams in pencil to help illustrate your answer. Label the diagrams.

Practice drawing diagrams, these will help you on the day of the exam. Use the book to draw a diagram, close the book and see can you draw and label it without the book.

Start each question on a new page and label all parts clearly.

Use graph paper for all graphs. Draw the graphs in pencil.

Start with your favourite question. It will give you confidence.

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Equipment needed – pencil, eraser, sharpener, ruler, calculator, pen (and a spare pen) and a few colouring pencils. Draw all diagrams and graphics in pencil.

Checkout www.examinations.ie for exam papers and marking schemes.

Do practice the past exam papers.

Check out www.etta.ie for exam tips, specialist topic.

Don’t leave the exam early, do an extra question if you have extra time. Once you come out you can’t go back in.

Don’t change your level on the day of the exam, you won’t be familiar with the structure of the paper or the topics.

Remember you have 50% of the exam already completed with project and practical.

Make out some key notes on flash-cards to read over the morning of the exam.

Get a good night sleep the night before, eat a good breakfast. Bring in a bottle of water to the exam.

Best of Luck!

HEALTH AND SAFETYBasic first aid requirements, personal protection Methods of safeguarding machinery and working areas with particular emphasis on moving parts colour codes; mechanical, electrical and human failures; work space clearances Electrical hazards; principles of protective devices and systems; earthing; single and three phase systems; correct use of equipment Chemical hazards: poisonous, corrosive, combustible and explosive Fire protection methods and equipment Statutory safety provisions; accident statistics.

CLASSIFICATION AND ORIGIN OF METALSTable of the Elements: differences between metals and non-metals; chemical symbols; the importance of alloys Physical properties of metals General appreciation of historical developments Outline of systems of mining for ores Description of the ores from which iron, copper, lead, zinc, aluminum, tin, silver, gold and other metals originate The extraction of metals from ores; important methods of ore dressing and process metallurgy.

STRUCTURE OF METALSMicrostructure; factors affecting grain size; recrystallisation Macroscopic examination of specimens The solidification of metals; dendritic structure; the structure of ingots and castings; atomic lattices Equilibrium diagrams for simple eutectics and solid solutions Ways in which metals combine to form alloys: eutectic and eutectoid.

IRON AND STEEL15

The important steel making processes The production of cast iron The structure of plain carbon steel; influence of carbon content; equilibrium diagrams Classification, properties and uses of carbon steels, cast irons and alloy steels.

NON-FERROUS METALSProduction of copper and aluminum from their ores Properties and uses of non-ferrous metals and alloys Classification of brasses, bronzes, gunmetal, bearing metal and aluminum and zinc based alloys.

HEAT TREATMENT OF METALSHeat treatment of plain carbon steels; equilibrium diagram; critical points; structural changes Types of quenching media Stress relieving Case hardening by the pack carburising method Carburising, nitriding, flame and induction hardening Types of furnace and methods of temperature measurement Heat treatment of alloy steels Outline knowledge of age hardening.

CORROSION OF METALSThe mechanism of corrosion, electrolytic action; influencing factors Methods of minimising corrosion; protective coatings; design features; environment; anodic and cathodic protection.

MATERIALS TESTINGStrength of materials in tension, compression and shear; bearing, bending and torsion Stress-strain diagrams; Young’s Modules Proof stress Determination of the strength of components in tension, compression, shear and bearing Methods of testing materials; tensile, hardness, impact, ductility and fatigue NDT using liquids, magnetism, sound, and radiation General appreciation of creep, thermal and electrical conductivity, expansion, specific heat capacity and environmental exposure tests.

PLASTICSOutline of the sources, physical structure, manufacture, classification and main forms of supply of plastics Methods of waste disposal Properties and use of the common thermoplastics polyethylene, polypropylene, PVC, polystyrene, acrylics, PTFE, cellulose acetate, nylon and the thermosetting plastics phenolic resin, polyester resin, epoxy resin, polyurethanes Processing of plastics: injection moulding, extrusion, vacuum forming, blow moulding, compression moulding, calendaring, spreading and laminating.

JOINING OF MATERIALSTheory of adhesion: Classification of adhesives; forms of supply and use Joining of metals & plastics Mechanical fastenings Soldering & brazing Fusion welding: oxyacetylene & electric arc Use of fluxes & fillers in gas welding Differentiation between AC & DC electricity; principle of transformer Specialised welding: inert gas shielded; automatic; resistance Welding of plastics.

MACHININGBasic construction, specification and cutting action of lathe, shaping machine, milling machine and precision and precision grinding machines Work holding methods Cutting tool nomenclature The mechanics of machining; forces acting on the cutter; the importance of the rake angle Type of chip formation Machinability Power

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consumed in cutting Relation between tool life and cutting speed Types of cutting fluid, lubricant and methods of application Principles of taper turning and of multistart and left hand screw threads Principles of simple indexing Structure and classification of grind wheels; surface finish.

METROLOGYStandards of measurement; grades of accuracy Systems of limits; types of fit Determination of limits and tolerances from given data Interchangeability of parts and selective assembly Limit gauges Measurement of screw threads; use of thread form gauges, and profile projector Principles involved in using sine bar, slip gauges, precision balls and rollers Specification of surface finish.

MANUFACTURING PROCESSESPrinciples involved in manufacture by fabrication, casting, forging, rolling, drawing, extruding, pressing and machining Properties and common forms of supply of manufacturing products General appreciation of the main factors relating to quality control.

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