Advanced GCE A2 7822-3

GCE

Oxford Cambridge and RSA Examinations

Advanced Subsidiary GCE AS 3822-3

Advanced GCE A2 7822-3

Design & Technology

Mark Schemes for the Units June 2008

3822-3/7822-3/MS/R/08

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OCR (Oxford, Cambridge and RSA Examinations) is a unitary awarding body, established by the University of Cambridge Local Examinations Syndicate and the RSA Examinations Board in January 1998. OCR provides a full range of GCSE, A level, GNVQ, Key Skills and other qualifications for schools and colleges in the United Kingdom, including those previously provided by MEG and OCEAC. It is also responsible for developing new syllabuses to meet national requirements and the needs of students and teachers. This mark scheme is published as an aid to teachers and students, to indicate the requirements of the examination. It shows the basis on which marks were awarded by Examiners. It does not indicate the details of the discussions which took place at an Examiners’ meeting before marking commenced. All Examiners are instructed that alternative correct answers and unexpected approaches in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and skills demonstrated. Mark schemes should be read in conjunction with the published question papers and the Report on the Examination. OCR will not enter into any discussion or correspondence in connection with this mark scheme. © OCR 2008 Any enquiries about publications should be addressed to: OCR Publications PO Box 5050 Annesley NOTTINGHAM NG15 0DL Telephone: 0870 770 6622 Facsimile: 01223 552610 E-mail: [email protected]




CONTENTS

Advanced GCE Design and Technology: Product Design (7822)

Advanced GCE Design and Technology: Systems and Control (7823)

Advanced Subsidiary GCE Design and Technology: Product Design (3822)

Advanced Subsidiary GCE Design and Technology: Systems and Control (3823)

MARK SCHEMES FOR THE UNITS

Unit/Content Page 2520/01 2521/01 Product Design 1 1

2520/02 Product Design 1 6

2521/02 Systems and Control Technology 1 14

2524/01 Product Design 2 20

2525/01 Systems and Control Technology 2 33

Grade Thresholds 40




2520/01 2521/01 Mark Scheme June 2008

2520/01 2521/01 Product Design 1

Section A 1 (a) Justified design requirements include:

• balanced to avoid strain on wrist when full • hold sufficient water to complete watering task, not be to heavy when full • able to pour correct amount of water without flooding small plants • lightweight so as not to add overall weight when full • flat base to avoid spilling • easy to fill at the tap to avoid wastage.

No marks awarded for statements referring to obvious product function eg must hold water.

For three justified design requirements 1 x 3 [3]

(b) Examples could be:

• correct balance to avoid wrist fatigue, enable easy pouring • handle size, grip • handle size, span • size of container – weight when full.

For three examples described (up to 2 marks) with sketch (1 mark) 2 x 3 [6]

(c) Reasons could include:

• usually injection moulded – not cost effective for small batch • minimal assembly • large demand for cans • one piece (possibly two) product.

For three reasons 1 x 3 [3]

(d) Issues included in discussion could be:

• value for money • fashion • build integrity • high tech improvements, need to upgrade • if known, can plan budget. Examples could be: • products such as iPod, light bulbs, razors, mobile phone • examples of throwaway culture eg pens.

P relevant points/issues up to 3 marks Q quality of explanation up to 2 marks S specific example/evidence 1 mark [6]

Total [18]

1




2520/01 2521/01 Mark Scheme June 2008

2 (a) Reasons could be: • population increase • more cultures developing ‘western’ life styles • greater use of electronic products • greater demand for manufactured products • wider expansion of global industrialisation • climate change • rise in temperature • demand for air conditioning equipment • increased energy demands • demand for water • irrigation etc • pumping/distribution • desalination plants.

For four reasons 1 x 4 [4]

(b) Descriptions could include:

As a guide: Wind

clear sketch/flow chart 1 mark wind direction 1 mark turns turbines 1 mark generator produces energy. 1 mark [4]

Nuclear

clear sketch/flow chart 1 mark uranium or mention of power from atom 1 mark heats water 1 mark water turns turbine to generate energy. 1 mark [4]

(c) Issues included in discussion could be:

• environmental issues • health and safety issues • lifestyle implications • political issues (oil, nuclear) • international rivalries • competing for scarce energy services • emerging industrial rations • SE Asia • India/China • demand for nuclear technology • N Korea/Iran. Examples could be: • specific environmental examples relating to energy production eg Chernobyl

P relevant points/issues up to 3 marks Q quality of explanation up to 2 marks S specific example/evidence 1 mark [6]

2




2520/01 2521/01 Mark Scheme June 2008

3 (a) Justified design requirements include: • stable in use so as not to collapse when pressed on • easy to erect and fold down so as not to waste time or frustrate user • flat surface for efficient ironing of clothes • area to place iron safely to avoid accidents • smooth curved edges so as not to snag and damage clothes.


(b) Ways could include:

• broad customer surveys/questionnaires • user groups • specific market research • look at success of existing products on market.

For three ways 1 x 3 [3]

(c) Example could be:

• plug • light bulb • batteries • screw etc • high value production • multitudes of uses. Example 1 mark Benefits could include: • ease of replacement • longer life of product • manufacturers do not need to make every part/cost implication.

Well explained 2 marks 3 x 2 [6]

(d) Issues included in discussion could include:

• wide choice • variable options – finish, assembly style • assembly workforce not required, reduced cost to consumer – increase in

sales • use of standard components • can collect immediately, no wait/additional cost for delivery • increased packaging if with purchase of an assembled product • implications for disposal of packaging waste • recycling or landfill disposal.

Examples could be: • specific self assembly example – table, desk, bed • cost examples of stores – IKEA MFI.

P relevant points/issues up to 3 marks Q quality of explanation up to 2 marks S specific example/evidence 1 mark [6] Total [18]

3




2520/01 2521/01 Mark Scheme June 2008

4 (a) Justified design requirements include: • comfortable to wear for long periods, no chaffing • stretch to accommodate a range of wrist sizes or have a range of bands • distinctive colour/logo to highlight for charity • low cost production to maximise profit for charity • durability • larger visual display and impact • charity profile seen larger. For three justified design requirements 1 x 3 [3]

(b) Reasons could be:

• simple product, lends itself for high volume production • colour/lettering choice • high production – low cost item • fashion item • small product easy to transport to sales venues.


(c) Checks could be:

• visual check to look for rough/sharp edges • visual check/computer sensor check for correct colour distribution • sample (eg 1 per 1000) selected for stretch/recover test • sample dimensional check using gauges to ensure product within

tolerance.

Limited response eg visual check 1 mark

For three checks well described 2 x 3 [6]

(d) Issues included in discussion could be: • fixed costs • variable costs • market interest • region to be sold

Examples could be: • specific product breakdown eg MP3 player • profit margins eg charity products.

P relevant points/issues up to 3 marks Q quality of explanation up to 2 marks S specific example/evidence 1 mark [6] Total [18]

4




2520/01 2521/01 Mark Scheme June 2008

5 (a) Justified design requirements include: • easy to remove lid for speed of cooking • contents clearly described to ensure correct purchase • suitable material to ensure will accept hot water without deformation • clear instructions for use to ensure satisfactory meal • comfortable to hold (insulated?) to allow safe usage.

No marks awarded for statements referring to obvious product function eg must hold pot noodles (hot food snack).


(b) Reasons could-include:

• litter concerns • health & safety concerns eg vermin • environmental/disposal concerns • carbon footprint, energy costs of production.


(c) Explanation could include:

• speed of operation, instant viewing of data • accuracy, no error unless human input error • automatic ordering when stocks are low, lessens disruption of production • easy to check current status of any aspect of stock.

For three benefits well explained 2 x 3 [6]

(d) Issues included in discussion could be:

• last resort action • support in Health and Safety issues • support in faulty goods issues • support in trade description issues

Examples could be: • specific use of legislation eg Trade Descriptions Act, Sale of Goods Act • other legislation eg MOT

P relevant points/issues up to 3 marks Q quality of explanation up to 2 marks S specific example/ evidence 1 mark [6]

Total [18]

5




2520/02 Mark Scheme June 2008

6

2520/02 Product Design 1

1 (a) (i) Oily timber, strong, often easy to work, hardwearing(durable) good appearance, stable/non warping,, close grained, resistant to rotting, water resistant, doesn’t splinter - 1 mark for each. [4]

(b) Detailed description of the process to include: Marking out (1) Cutting to length (1) Name of suitable fixing for slats (+ 1 with accurate sketch) (1/2) Name of suitable joint for frame (+ 1 with accurate sketch) (1/2)

Details for cutting out (1) Detail for drilling/slotting (1) clamping and glueing (1) finishing (two different processes) (2) correct name of tools (upto three marks) (2)

[8]

(c) Discussion could include: material cost and availability size

processes to be carried out machinery, equipment - cost, availability thickness of section to be formed appearance in terms of grain/finishes etc strength of finished product sustainability P Critical examination of issues (3) Q Quality of explanation (2) S Supporting examples/evidence (1) [6]





2 (a) (i) Eg aluminium, steel, brass, suitable alloys, cast iron. [2]

(ii) Different properties required e.g strength, toughness, cost, appearance, corrosion resistance. [2]

(b) Die casting (high pressure) Mention should be given to: High carbon steel mould (1) mould design – female, rounded corners, tapers/draft angles,

the use of retractable cores, surface finish – 1 mark for each – (3) molten aluminium (1) poured (1) forced under pressure (1) water cooled (1) cooling time/solidifies (1) ejection from the mould/removal (1) fettling/finishing (1) [8]

(c) Discussion could include: reduced cost, ease of maintenance/replacement less storage/warehouse space required less need for specialist workers availability of material and equipment P Critical examination of issues (3) Q Quality of explanation (2) S Supporting examples/evidence (1) [6]

7





3 (a) (i) Polypropylene, polycarbonate, ABS, Polystyrene (HIPS), HDPE,(not acrylic). [2] (ii) Stiffens the body of the barrel, improves appearance, provides a

hand hold/rolling. 1 mark for point + 1 mark for explanation [2] (b) Detailed description of blow moulding eg: Hopper (1) Plastic pellets (1) heating/molten (1/2) parizon (plastic tube) extruded (1) parizon gripped between split mould (1) air blown in – parizon fills mould (2) cooling (water) (1) ejection of moulding (1) removal of sprue/waste (1) [8] (c) Discussion should focus on form vs function. Points could include manufacturing

constraints on design, functional constraints, aesthetic increase sales, practicality, use of colour, suitability to the environment, finish, size

P Critical examination of issues (3) Q Quality of explanation (2) S Supporting examples/evidence (1) [6]

8





4 (a) (i) Lightweight, stiff, easily printed on to, readily available, absorbent, low cost, recyclable, durable, easy to work [3]

(ii) Die cutting, stamping, pressing. [1]

(b) Artwork/origination (1)

image setter - colour separation, film images (4 colours) produced for each colour (3) CMYK (1) plate/screen/flexo sheet (1) attach to press (+ separate rollers) (2) inks applied (1) drying (1) quality checks (1)

[8] (c) Discussion could include: environmental concerns, wastage, expectancy from consumers (throw away

society)litter, energy waste, pollutants used during manufacture, energy usage in production and transport etc.


9





5 (a) (i) Eg flexible, strong, lightweight, easy to print onto, readily available, tear resistant, relatively thick, durable, application of varnish [2]

[4] (b) Screen

• artwork/origination (1) • image setter - colour separation, film images produced for each colour,(3) • silk screens coated with light sensitive emulsion (1) • screens produced by exposure to uv light (pmt) (1) • accept use of stencils (1) • screen washed to develop image (1) • screens (mesh) attached to printer sign (1) • blanks carefully positioned using registration marks (1) • ink applied using squeegee/pressure (2) • paper/substrate placed in position (1) • repeated for each colour (1) • signs left to dry before application of second colour (1)

[8]

(c) Discussion could include: new materials such as smart materials, processes such as lamination and varnishing producing improved aesthetics, new laminates enable drinks cartons etc.


10





6 (a) Eg cool to wear, absorbent, very comfortable, elegant drape, strong, elastic (creases drop out), non-static, easily dyed, lightweight, lustrous, soft handle. [4]

(b) yarns collected/wound(twisted) onto reel (2) Interlacing of two threads at right angles (1) ,mention of warp and weft marks. (2)

The warp yarns lie in the length direction of the fabric whilst it is being woven. (1) The weft is woven in between the wrap across the width of the fabric (west to east) (1)

Sketch of warp and weft (1) In satin weave the warp floats over four or more wefts and remains under only one (between 4 and 7). (1) Adjacent warps are arranged as randomly as possible so that no twill line is generated (1) The result is a smooth shiny fabric. (1)

[8] (c) Discussion could include: cost of raw materials, labour costs, complexity of design, fashion, availability, machinery used, transport, target market,

P Critical examination of issues (3) Q Quality of explanation (2)

S Supporting examples/evidence (1) [6]

11





7 (a) (i) Eg nylon (polyamide), polyester, cotton (not fabrics) [2] (ii) parachute clips, buttons, Velcro, snap lock, poppers, protective pads, flexible

cords, mesh, buckles, draw strings [2]

(b) With right sides together insert webbing strap into the reinforcement triangle. Leave gap in stitching (1) Rucksack turned inside out (1) (Checking that it is not going to catch in the seam)

Machine 2 sides. Turn and press. (1) Stitch reinforcement (double stitch) stitches to secure the strap. (1)

With right sides together insert the triangle between the side panel and back panel of bag. (1) Machine in place. (1) Neaten with overlocking on inside. (1) Iron/press (1) Tidy up loose stitches (1) Turn to right side. (1)

[8]

Seam allowance (1)

Webbing (1)

12





(c) For the manufacturer Ethical issues, economic issues, issues relating to communication, new machinery needed, new opportunities, costs, characteristics of materials, purpose/function

Critical examination of issues (3) Quality of explanation (2) Supporting examples/evidence (1) [6]

13





14

2521/02 Systems and Control Technology 1

1 (a) (i) Injection moulding. [1] (ii) Reasons are:

• accuracy of part fit • display housing • quality control by tooling • assembly by robot. 1 mark each.

[2]

(b) Two benefits are:

• low power • low current • flat front • backlit • multi-message capability. • easy to read 1 mark each.

[2]

(c) (i) Disadvantages could be:

A Two analogue components can give tolerance problems,

accuracy depends on quality of discrete components, hand soldering.

[1]

(ii)

B Single package, easier to place and flow solder, range wider. [1]

(d) (i) If the output from Vr1 is set higher than the output from the voltage regulator it will keep output low (1) if battery voltage falls below the reference voltage (1) the output will go high (1).

[3]

(ii) Stabilize voltage regulator or smoothing.[1] Holds ref voltage steady[1]

[2]

(e) Points could be:

• food hygiene regulations • sell by dates • packaging life • length of storage • fridges and coolers at below 5 degs • transportation and delivery • correct temp for food type • ambient conditions • handling • customer views. • Or any other temperature sensitive product. Any three correct points. Two qualified correctly (2). Specific example (1).

[3]

Total 18 marks





Accurate, faster switching, reliability. 2 (a) (i) [1] (ii) V=IR R=6-2/0.02 [1] = 200R [1]or Vled=2 = 200R. [2] (iii) Reverse bias means diode allows minimal current through as

it is backwards to conventional current or voltage at cathode higher than the anode.

[1]

(iv) R2 should be made a trimmer, variable resistor (2) Fixed

resistor (1) only. [2]

(b) (i) Drawing of square wave (1) indicated negative going pulse (1). [2] (ii) Uncontrolled gain-or similar[1] No feedback resistors[1] [2] (iii) Use of debouncing circuit or schmitt (1) Connections

correct[1] [2]

(c) Points could be:

• sensor types • accuracy • weather • vandalism • type of animal • height above ground • connections • communication • regulations. Any three correct points. Two qualified correctly (2). Specific example (1).

[3]

Total 18 marks

15





3 (a) Broader base, webs give strength, stability, torsion reduced 1 mark each.

(i) [2]

(ii) Cushions prevent vibration breaking foundation (1) allow

small sway, weight absorption (1). [2]

(b) Drawing should show- vane system (1) attached to rear of turbine

(1) on a rotating mount facing wind (1), drawing quality (1). [3]

(c) (i) Non metallic sleeve type, flange with rubber pads, universal

jointed shaft (1), fixings (1). [2]

(ii) Drawing should show gearbox input shaft with twice as many

teeth on gear (1) as gearbox output shaft (1), idler gear (1). [3]

(d) Points could be:

• alternative energy types • feasibility • cost • political issues • public opinion. Any three correct points. Two qualified correctly (2). Specific example (1).

[3]

Total 18 marks

16





4 (a) Suitable material could be cast iron, stainless steel, chrome molybdenum steel (1).

(i) [1]

(ii) Plates give rigidity to joints, less force on individual rivets,

enable thinner struts to be used, replacement of struts possible. 1 mark for each correct reason.

[2]

(b) (i) 520:1. [1] (ii) 260 teeth in half turn- one turn of worm = 1 tooth - 260/100

therefore quarter turn will be 130/100 (1) = 1.3 minutes or 1min 18secs (1).

[2]

(iii) Slow, high torque, will stay open or closed. [1] (c) (i) A Spin freely.

B Fixed to shaft. C Spin freely.

[1]

[1]

[1] (ii) Drawing should show

grub screw stake keyway and key spline fixing collar adhesive (1) quality of drawing (1).

[2]


• wear and tear • environmental conditions • maintenance programme • HSE • replacement plan • lubricants • painting • cost • safety of operatives. Any three correct points. Two qualified correctly (2). Specific example (1).

[3]

Total 18 marks

17





5 (a) Pneumatics is a suitable system- lift heavy skylights, large system capability, could be part of other systems, quiet, reliability.

(i)

1 mark each.

[2]

(ii) Most efficient is A (1) because of smaller cylinder and better

MA (1). If B is chosen for a correct reason then[1] [2]

(b) (i) Both 3-port valves connected to 5-port [2] If only one [1], flow

controls connected correct way round [2].If only one side of FCVs correct[1] Allow max 3 if all correct but wrong connections to 5-port.

[4]

(c) (ii) The two push button 3-port valves. [1] (iii) There would be no need for employee operation, costs,

errors, correct environment maintained [1]

(iv) 0 1 0 (1).

1 0 0 (1). [2]


• height • pipe runs • compressor site • water and oil traps • sensor location • connection to electrical system • earthing • cylinder location • operating pressure. Any three correct points. Two qualified correctly (2). Specific example (1).

[3]

Total 18 marks

18





6 (a) Cushioned cylinders have inbuilt restriction. Over last centimetre of stroke slowing it down.This will prevent unsafe spillage of molten metal, underfilling of mouldl[1] Prevents splashing on return to vat[1]

(i) [2]

(ii) Drawing should have:

fixing to cylinder (1) fixing to floor (1) swivel pin (1) quality of drawing (1).

[4]

(b) (i) And function:

connection from port 2 to port 1 to complete 3ps together (2) connections to 5p (2).

[4]

(ii) Use of bi-directional restriction from 5 port dcv (1) on both

outstroke and instroke (1). [2]

(c) Points could be:

• remote control • operator safety • HSE regs • fumes • PPA • size and Weight • radiation. Any three correct points. Two qualified correctly (2). Specific example (1).

[3]

Total 18 marks

19





20

2524/01 Product Design 2

1 Fig 1 shows outdoor play equipment designed for children. (a) (i) Answers could include:

• Sustainable material • Easily worked with most tools • Warm feel compared to metal • Initially more cost effective than hardwood • Aesthetic reasons.

2 x 1 [2]

(ii) Answers could include: • Less waste • Smaller section of timber can be used • Easier to get curved shapes • Cross grain eliminated • Increased stability/structural strength • Defects in timber can be eliminated.

2 x 1 [2]

(iii) Answers could include: • Sharp edges • Smooth surfaces/no splinters • Height above ground • Safety surfaces • Head/finger traps • Hanging/strangulation with ropes • Non-toxic finishes.

4 x 1 [4]

(b) (i) For treatment, answers could include: • Pressure treatment • Pressure tanks • Liquid preservative • Mention of preservative ‘forced’ into timber • Safety issues connected to preservatives during treatment • Time allowed for timber to ‘soak’.

Give credit for the use of dipping tanks. Brushing/spraying techniques would secure a maximum of two marks for a treatment method. There is no split in the marks and candidates could gain maximum marks for a very detailed answer in just one of the process.

4 x 1 [4]

(ii) For lamination, answers could include: • Timber inspected for defects • Timber prepared to size length/section • Jigs • Pressure applied and sustained • Rapid setting adhesives (accept gluing) • UV light curing • Time allowed for curing of adhesive.

4 x 1 [4]





(c) Discussions could include: • Economics of scale, manufacturer may not be able to or want to order material

in bulk therefore cost of material may be more. An example may be a named material or product such as an item of clothing

• Cash flow, the item may not be paid for until delivery of the goods to the customer. Evidence supporting this type of answer might be: the manufacturer having to wait to recoup the layout; costs this may lead to a shortage of available capital to the manufacturer

• Guaranteed sale, manufacturer has a contracted sale and therefore is certain of selling the item. Evidence supporting this type of answer might be: less waste as stock does not go out of fashion or damaged waiting to be sold; less warehouse space required again leading to a saving of money

• Bespoke products generally command a higher retail value and the manufacturer could charge more for them. Evidence supporting this type of answer might be: customers like unique goods and are prepared to pay more for them; this will lead to an increase in profit for the manufacturer

• Lead times might lead to lost sales, customers may not be prepared to wait for products. Evidence that might support this answer might be: those customers who are facing long delivery times might look to buy elsewhere or an ‘off the peg’ item. An example might be a piece of furniture/clothing that is made to order

• Tooling costs, manufacturer might have to build in tooling costs if needed for new job. Such as specialist machinery.

• Less storage space needed, no back stock, JIT. • Flexible or reliable supply chain needed.

P relevant points/issues up to 3 marks Q quality of explanation up to 3 marks S specific examples/evidence up to 2 marks [8]

Total: [24]

21





2 Fig 2 shows a practice cricket wicket.

(a) (i) Answers could include: • Low melt temperature • Little/no surface finish required • Good fluidity when molten • Good strength to weight ratio • Does not corrode easily.

2 x 1 [2]

(ii) Answers could include: • Bronze • Brass • Pewter • Iron.

2 x 1 [2]

(iii) Answers could include: • Safety visor • Leather apron • Leather gauntlets • Leather leggings • Suitable footwear/gators • Warming metal • Fume extraction • Sand not too wet.

4 x 1 [4]

(b) Answers could include: • Preparation of casting box • Pattern • Cope • Drag • Parting sand • Damping down • Levelling/strickling off sand • Locating pins • Feeder • Riser • Pouring basin • In gate.

8 x 1 [8]

(c) Discussions could include: • Environmental damage caused by extraction. Large tracks of land are mined to

remove ore. An example might be land damage caused by the removal of bauxite

• Spoil heaps caused by waste from conversion process. Mines produce a large amount of waste and this has to be disposed of. Supporting evidence for this argument might refer to the limited amount of mineral/metal extracted from ores compared to its bulk

• Environmental issues caused by the use of energy in the conversion process. In many instances a large amount of energy is required to extract materials

22





from the ore. Supporting evidence might talk of the amount of electricity used to extract aluminium

• Loss of habitat and the fact that a lot of extraction takes place in remote locations such as natural forest and the loss of these habitats are causing species to become endangered

• Noise and air pollution could be supported by explosives used in mining and heavy plant used to move material

• Contamination of land by toxic chemicals used in the conversion process. Chemicals used in the extraction and processing often contaminate land surrounding plants. This has to be removed, can be reused. There is also potential for water table pollution.

Must be linked to environmental issues P relevant points/issues up to 3 marks Q quality of explanation up to 3 marks S specific examples/evidence up to 2 marks [8]

Total: [24]

23





3 Fig 3 shows a vacuum formed acrylic bath.

(a) (i) Answers could include: • Lower in cost compared to cast iron • Lighter in weight compared to cast iron • Available in large sheet form • Available in a range of colours • Self finished surface • Easily cleaned • Warm surface • Holes can be cut on site.

4 x 1 [4]

(ii) Answers could include: • The top lip of the bath • The rolled edges on the lip • Rounded edge to prevent stress points • GRP (fibre glass) sprayed on underside after moulding • Metal frame added • Reinforcement strip under bottom of bath 1 mark is to be awarded for identifying a method of reinforcement The second mark being awarded for describing why it reinforces.

2 x 2 [4]

(b) Description could include: • Multiple heat sources – due to size • Zoned heating • Plastic softened • Pattern raised into softened plastic • Multiple air extraction points – due to size • Moulded by atmospheric pressure • Accept a ‘plug assist’ • Fan assisted cooling process – due to size • Trimming bath from sheet (although this is normally done at the end of the GRP

process) • Tapered mould/draft angle • No returns/undercuts • Mould release agents • Trimming of moulded bath.

(A simple ‘school based’ description of small sheet forming to score a maximum 4 marks for this section)

8 x 1 [8]

(c) Discussion could include: • More products can be designed by using plastics replacing ‘traditional

materials’. Examples and evidence could include: because of the properties of polymers it is possible to mould them and change their shape using a number of different repetitions manufacturing processes such as injection moulding

• Production costs can be reduced. Evidence and examples may include some of those given above but do not allow for repeats. Lead times are greatly reduced when compared to fabricated methods

24





• Product performance can be enhanced. Examples and evidence could include: plastics can be coloured by using either dyes or pigments. Dyes give transparent colours and pigments give opaque ones. A very wide range of colours can be obtained from clear to opaque black

• Weight saving eg car body panels • Corrosion resistant replacing steel panels with plastic • Design trends, the use of plastics in furniture etc eg 1970’s revival plastic

furniture • Recycled polymers can be added to raw polymers, this may lead to

environmentally friendly products but the quality of the plastic will generally degrade after each use

• Life cycle of products can be lengthened. Examples and evidence could include: plastics used in motor vehicles are very durable and corrosion resistant which also means they are very resistant to degradation

• Life cycle of product can be shortened. Examples and evidence could include: many plastics are degraded by heat and light, especially from the ultra violet light in sunlight. Adding protective agents can prevent this

• Environmental issues. Evidence might include: plastics are mostly made from limited natural resources which must be conserved. The manufacture of plastics may produce a lot of harmful pollutants. Old plastics are not always easy to dispose of and are generally buried in landfill sites.


Total: [24]

25





4 Fig 4 shows an Isometric drawing of a prototype Point of Sale display.

(a) (i) Answers could include: • Orthographic • Isometric • Assembly • Exploded • Oblique • Planometric • Sectional • Allow perspective but only once.

4 x 1 [4]

(ii) Descriptions could include: • Site trial with observation • Customer/client feedback • A test for rigidity or similar property • Stability with loading.

2 x 1 mark for test 2 x 1 mark for description [4]

(b) (i) Description and diagrams could include: • Etching/engraving/routing of ‘dies’ • Foiler – male part • Embosser – female part • Counterforce • Cold bed pressing • Flatbed or roller pressing acceptable.

4 x 1 [4]

(ii) Descriptions and diagrams could include: • Dies (could be made of copper/magnesium) • Chase (heat bed – 160°C) • Sheet made of plastic layer, coloured particles eg gold and wax • Tight (lines) or loose (blocks) release particles • Sheet fed onto die • Pressure applied • Die heated • Wax melts, particles adhere to sheet • Do not accept a gluing method.

4 x 1 [4]

(c) Discussions could include: • Quick production of models for testing. Evidence to support this could include

cars or aircraft in wind tunnels. Given to consumer groups for feedback on potential ideas

• That expensive materials do not need to be used for prototypes. Evidence could include the use of modelling plastics such as styrenes to represent final materials

• That a 3D model can be ‘handled’ by the designer and others. Evidence could include the use of prototypes by design teams to discuss possible changes to a design allowing for quick changes to be made

• CAD drawings can be sliced to produce prototypes. Evidence to support this could include the use of slice forms or stereo-lithography.

26






Total: [24]

27





5 Fig 5 shows a shop sign made from corrugated plastic (corriflute or correx).

(a) (i) Answers could include: • Lightweight so it can be easily suspended • Rigid (although better in one direction) • Weather resistant for outdoor use • Good surface to print onto • Self coloured background.

2 x 1 [2]

(ii) Answers could include: • Silk screening/Screen printing • Flatbed inkjet printing • UVR flatbed printing • Applied printing labels/sticky labels.

2 x 1 [2] (iii) Answers could include:

• Thermo-chromatic pigments that change colour with temperature • Holographic film • Lenticular plastic.

2 x 1 mark for material 2 x 1 mark for description [4]

(b) The answers for this question will reflect method chosen

Answers could include: • Design produced in a suitable package eg 2D Design • Designated colours for cut/vector • Designated colours for etch/raster • Hot wire/laser strength set • Cutter selected • Cutter/laser speed set • DPI set • Origin/offset set • Transferred to machine • Material placed on table of machine • Focus length set • Depth set.

8 x 1 [8] (c) Discussions could include:

• Ethical/moral such as religion, racism, cross gender, sexism, ageism etc • Environmental issues that might involve global warming supported by evidence

such as the use of CFC’s in products such as refrigerators and the problems with the safe disposal of, use of appropriate materials, carbon footprint

• Safety issues such as the use of potential hazardous chemicals. Evidence may include the use of lead based paints on toys. Plasticisers in bottles that may leech into drinks under certain circumstances such as PET bottles/UV light, thermo-chromatic pigments to warn of possible dangers such as hot liquids

• High energy use products. Evidence may include the use of standby buttons on electrical products such as televisions and DVD players that continually use energy whilst not being used

• Low energy use products that have been designed. Evidence might include low energy light bulbs with same light, less wattage and longer life. Low

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temperature washing powders that have been designed to be used at lower temperatures thereby saving energy

• Recycling issues that enable products to be recycled easily or reused at the end of the life cycle. Evidence may include the Dyson being easily broken down into recyclable pieces by the use of single materials. Motor vehicles that are designed so components can be reused. Refillable ink cartridges.

Discussions must be based on design issues and not centred on manufacturing issues not related to the design.


Total: [24]

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6 (a) (i) Any four, one mark each: • Durable/hardwearing • Washable/easy care • Stain resistant • Comfortable to wear • Crease resistant • Firm, stable fabric • Non-static • Non-irritating • Possibly waterproof/water resistant/not damaged by water. [4]

(ii) One mark for each reason: • to maintain shape, prevent stretching during wear • to strengthen – will be subjected to strain during wear • to improve appearance • to strengthen area around fastening, either button and button hole or

hook and bar. [2]

(iii) Any two, one mark each: • Box pleat • Inverted pleat • Gathers • Tucks • Darts. [2]

(b) Points to be included in answer, either in diagram or notes:

4cm 2cm

• Position of the lines, top and bottom, will need to be transferred to the fabric • Done using tailor tacks, tailor’s pencil, or hot drill • Fabric folded as shown • Pressed in place • Thermoplastic fabric may be used to permanently pleat the fabric/fixation by

resin for cotton fabrics • Machine may be used to fold and press pleats in place • Pleats held in place by tacking before waistband is attached • Quality control checks include checking pleats are all the same depth • Check pleats are correct distance apart • Check waist measurement is correct.

[8]

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(c) Discussion could include reference to: • Can adapt to demand of the orders coming in • Can meet colour requirements – if one colour selling well, can make just that

colour • Same applies to sizes • Batches can be repeated as many times as needed to meet requirements • Cost low compared to job production • Storage may be an issue • Staff become accomplished in one aspect of manufacture so quality improves • Staff have variety if batches of different products are made • Workers may become bored with repetitive work • Relatively small numbers of identical items made – can be making other items

as well as the trousers, so versatile • Work needs to be carefully planned to meet customers needs.

Range and relevance of issues relating to the question [3] Quality of the reasoning and explanation [3] Suitable use of examples and evidence to support the discussion [2]

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7 (a) (i) Any two, one mark each: • Thread • Zip • Poppers/ginger snaps/press studs • Bias binding. [2]

(ii) Any four points, one mark each:

• Hardwearing/durable • Waterproof • Not damaged by alkalis, bleach, water or toiletries • Will not rot/not affected by mildew • Easy to wipe clean/wash • No special finished needed • Not absorbent • Firm, stable fabric – will not stretch. [2]

(iii) Two marks, one for each method named:

• Transfer printed – design printed onto paper, then the colour transferred using heat

• Screen printed – a screen needed for each colour • Roller printed – pattern etched onto copper rollers, one for each colour • Woven in to the fabric using coloured yarns. [2]

(b) Any eight points in logical order, one mark each:

• Pattern pieces showing name of piece number to cut straight grain line seam allowance notches/dots position of fastenings

• Order of work may vary depending on how many pieces used. One example - • Stitch front to base and base to back – wrong sides together • Stitch flap to back – wrong sides together • Attach side panels – wrong sides together. Binding could be attached to upper

edge first • Attach bias binding to the rest of the edges of the case • Attach zip • Attach poppers. [8]

(c) Discussion could include reference to:

• Additional cost • Problems of storing chemicals • Additional process for workers to learn • Health and safety issues • Disposal of chemicals – environment • Will improve performance of product and may increase sales • Improve reputation of company • Additional testing required • More difficult to meet environmental requirements.

Range and relevance of issues relating to the question [3] Quality of the reasoning and explanation [3] Suitable use of examples and evidence to support the discussion [2]

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33

2525/01 Systems and Control Technology 2

(1) for 000 – 011, (1) for 100 – 111

C B A Q

1 (a) (i)

0 0 0 00 0 1 10 1 0 10 1 1 11 0 0 01 0 1 01 1 0 01 1 1 0 [2]

(ii)

As above or similar. (1) mark for each conversion up to three. [3] (iii) Easier fault-finding, only one chip needed, better packing density(all gates on a

chip used), or similar correct response 2 x (1). [2] (b) Pulses = 270/5 = 54 (1)

(1) for units (1) for tens and (1) for output gate. As above or similar. [4]

(c) (i) P = V x I So, P = 12 x 0.4 = 4.8 watts. [1] (ii) (12 – 2)/0.2 = 500 Ohms (1) Preferred value 510 Ohms (1). [2] (iii) Solid state (no moving parts), longer life, smaller size, cheaper or similar 2 x (1). [2]





P = Identify a range of relevant issues/points. (d) Q = Quality of explanation as to why these issues are relevant. S = Use of specific examples or supporting evidence.

Issues could include: Cost of implementation, just-in-time, long-term savings, bar codes, accuracy, reduce human error or other relevant points.

[3][3][2]

[Total: 24]

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2 (a) (i) Easier to install, less upheaval, no need for qualified electrician, less unsightly, position anywhere or similar correct response 2 x (1). [2]

(ii) Passive Infra Red senses the movement or heat of a person or thing (1) and

gives an output that can be used to switch other devices (1). [2] (b) (i) CR2032 [1] (ii) NP7-12 [1] (iii) PP3 [1] (c) (i) F1 is a 1A fuse used to protect the circuit in the event of a fault (1). [1] (ii) (1) for correct before bridge rectifier [2] (iii) Open gives I = 0.7/56 (1) = 12.5mA

Closed = (56 x 15)/71 (1) = 11.83 (1) So, 0.7/11.83 = 59mA (1) [4] (d) NiMH do not suffer with the memory effect, hold charge better, more environmentally

friendly. Any two, one mark each. [2] (e) P = Identify a range of relevant issues/points.

Q = Quality of explanation as to why these issues are relevant. S = Use of specific examples or supporting evidence.

Issues could include: Restricted access, carrying swipe card, keypads, need to remember numbers, feel secure, less theft or other relevant points.

[3][3][2]

[Total: 24]

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3 (a) (i) Reciprocating. [1] (ii) Hard-wearing and moisture in hands will cause most metal types to

rust/discolour. (1) for point and (1) for explanation. [2] (iii) Easier cooling, easier maintenance/replacement, easier to mount, cheaper for

manufacturer. Any one. [1] (b) (i) The mounting hole is slotted to allow for adjustment/tensioning. Either one (1).

Explanation (1). [2] (ii) Belt drives are quieter in operation, cheaper than other drives, allows for

slipping in the event of a jam or similar. Any two (1) each. [2] (iii) 14/70 = 1/5 (1) So, speed is 1200/5 = 240 rpm (1). [2] (c) (i) Needs a heavy base due to forces involved/keep it still when in use (1), casting

needs to be coated for protection, casting needs to be coated for aesthetic reasons, or similar (3 x 1). [3]

(ii) Holds a rotating device in position on the shaft, easier assembly/disassembly,

easier maintenance. Any one. [1] (iii) Because the circlip is the correct size to fit the slot in the shaft/bar/rod it must

be forced/sprung on so a certain amount of give is needed and spring steel gives this. [2]

(d) P = Identify a range of relevant issues/points.

Q = Quality of explanation as to why these issues are relevant. S = Use of specific examples or supporting evidence. Issues could involve: Spending too much, consumer trade protection, global purchasing , competitive pricing, can be done from home, increase in waste (packaging), more transport for deliveries, or other relevant points.

[2][3[[3[

[Total: 24]

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4 (a) (i) Reduced processes because no thread is needed to be cut in plastic. Self-tapping screw will cut its own ‘thread’. (1) for point and (1) for explanation. [2]

(ii) Tensile strength = F/A So, tensile strength = 80,000/π x 5² (1) = 1019N/mm² (1). [2] (b) (i) Anticlockwise. [1] (ii) 400 rpm Answer can be achieved without calculation. However,

16 (1) x 24 x 48 (1) x 400 = 400 rpm (1) 48 24 16 1 [2]

(iii) Change the chemical composition of the surface layer by absorption of carbon,

nitrogen, or a mixture of the two (1). The outer portion, or case, is made substantially harder than the inner portion, or core (1). [2]

(c) (i) The initial cost is great for moulds etc but as numbers increase the cost reduces

dramatically or similar response. (1) for point and (1) for explanation. [2] (ii) Shape of container/screw points/webbing etc. Any one. [1] (iii) (1) mark for sketch and (1) mark for explanation (x 2). Webs, screw fixing points,

thickening sections, bosses shape. [4] (d) P = Identify a range of relevant issues/points.


Issues could include: Identity theft, more security conscious people, fraud, gerbil / hamster bedding, scaremongering, poor security on landfill sites or other relevant points.

[3][3][2]

[Total: 24]

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5 (a) (i) Clean power source, can be used in adverse conditions. Any one. [1] (b) A - Filter (1) – filters air and removes water (1).

B - Pressure regulator with gauge (1) – allows the setting of line/secondary pressure (1). C – Lubricator (1) – Lubricates the air with mists of oil to protect moving parts (1). [6]

(c) (i) X = NOT valve. [1] (ii) Dough on platform, press valve Y (1). If dough on platform correct weight, air

bleed is covered and no action takes place. If dough underweight air bleed not covered (1) and air from valve X passes through valve Y (1) to cylinder Z and ejects the dough (1). [4]

(iii) (1) for valve (1) for operator.

[2] (d) P = F / A So, P = 1524 / (π x 25²) = 0.776N/mm². (1) 97% efficient, then

0.776 / 0.97 = 0.8N/mm² (1)

[2]

P = Identify a range of relevant issues/points. Q = Quality of explanation as to why these issues are relevant. S = Use of specific examples or supporting evidence.

Issues could include: Cleanliness of machines and areas, cleanliness of staff, educating staff, metal detection on all lines, temperature control for food and staff, wastage or other relevant points.

[3][3][2]

[Total: 24]

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6 A = unidirectional flow control valve or flow regulator (1) (a) B = reservoir (1) C = diaphragm valve or pressure sensitive valve. (1) [3]

(b) (1) for suitable fixing method to piston, (1) for suitable connection to valve crank, and

(1) correct operation. [3] (c) (i) No cup on air bleed so main air flows from diaphragm valve (1) to shuttle valve

and then to the 5-port valve 1 2 (1). Main air flows to the cylinder causing it to go fully negative and close the valve (1). Or similar suitable response. [3]

(ii) F = P x A So, 150/0.8 = A = 187.5mm² (1)

A = πr² . So, r = √ (187.5/π) = 7.725mm. (1) Diameter = 15.45mm (1) [3] (iii) The force of a double-acting cylinder will be different for out and in stroke due

to the area taken up by the piston rod. Since F = P x A the reduced piston area due to the piston rod will mean that for the same pressure a smaller force is exerted. [2]

(iv) A pneumatic cylinder will not be able to move variable amounts (1), it is either

in or out so an hydraulic piston would be required (1). [2] (d) P = Identify a range of relevant issues/points.


Issues could include: Make money / profit, supply a service, offer good food / drink, children’s health, profiteering, taking advantage of captive audience, servicing machines / breakdowns or other relevant points

[3][3][2]

[Total: 24]

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Grade Thresholds

Advanced GCE Design and Technology (7822, 7823) Advanced Subsidiary GCE Design and Technology (3822, 3823) June 2008 Examination Series Unit Threshold Marks

Unit Maximum Mark

a b c d e u

Raw 90 72 64 56 48 40 0 2518 UMS 90 72 63 54 45 36 Raw 120 96 84 72 60 48 0 2519 UMS 120 96 84 72 60 48

Raw 90 62 55 48 42 36 0 2520 UMS 90 72 63 54 45 36

Raw 90 60 53 47 41 35 0 2521 UMS 90 72 63 54 45 36

Raw 90 70 62 55 48 41 0 2522 UMS 90 72 63 54 45 36

Raw 90 71 63 55 48 41 0 2523 UMS 90 72 63 54 45 36

Raw 120 73 66 59 53 47 0 2524 UMS 120 96 84 72 60 48

Raw 120 85 78 71 64 58 0 2525 UMS 120 96 84 72 60 48

Specification Aggregation Results Overall threshold marks in UMS (i.e. after conversion of raw marks to uniform marks)

Maximum Mark

A B C D E U

3822, 3823 300 240 210 180 150 120 0

7822, 7823 600 480 420 360 300 240 0




The cumulative percentage of candidates awarded each grade was as follows:

A B C D E U Total Number of Candidates

3822 11.7 33.1 59.1 79.5 91.6 100 2987

3823 22.6 45.9 66.9 84.2 92.5 100 115 3822: 3389 candidates aggregated this series 3823: 167 candidates aggregated this series

A B C D E U Total Number of Candidates

7822 18.3 40.8 66.7 86.9 97.5 100 2747

7823 24.5 51.8 73.6 86.4 96.4 100 111 7822: 2747 candidates aggregated this series 7823: 111 candidates aggregated this series For a description of how UMS marks are calculated see; http://www.ocr.org.uk/exam_system/understand_ums.html Statistics are correct at the time of publication

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Advanced GCE A2 7822-3

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