2024 CCEA GCSE Engineering and Manufacturing 0009 模擬試題連答案詳解

ABS is a thermoplastic polymer commonly used for power tool casings because it combines good impact toughness (resists cracking if dropped), is lightweight, and can be easily moulded into complex shapes with a good surface finish.

[1] correctly names a suitable material (e.g. ABS or another suitable thermoplastic). [1] correctly states a relevant property (e.g. toughness/impact resistance, low density/lightweight, electrical insulation). Max [2].

Injection moulding forces molten thermoplastic into a mould cavity under pressure; once the (relatively expensive) mould tool has been made, each cycle produces an identical casing half in a matter of seconds, making unit costs very low at high volumes despite the high initial tooling cost.

[1] correctly identifies injection moulding. [1] valid reason linked to high-volume production (e.g. fast cycle time, low unit cost at volume, high repeatability/identical parts). Max [2].

The workpiece must be securely clamped (e.g. in a machine vice bolted to the drill table, or with toolmakers' clamps) so that the cutting forces of the rotating drill bit cannot spin or grab the workpiece, which could cause serious injury. (Other valid precautions: tie back loose hair and remove loose clothing/jewellery that could catch in the rotating chuck; wear eye protection against swarf; never leave the chuck key in the chuck.)

[2] one clearly stated, genuinely relevant pillar-drill safety precaution (e.g. clamp the workpiece; remove chuck key before starting; tie back hair; wear eye protection). [1] if the precaution given is only generically workshop-related rather than specific to pillar drilling. Max [2].

A rechargeable lithium-ion battery can be charged and discharged repeatedly (typically hundreds of cycles) before it needs replacing, so the user avoids the repeated cost of buying disposable batteries and less battery waste is sent to landfill over the product's lifetime; lithium-ion cells also have a higher energy density than most disposable cell chemistries, giving longer running time for a given weight.

[1] identifies a genuine advantage (e.g. reusable/rechargeable, reduced running cost, reduced waste, higher energy density). [1] explains the advantage with a clear reason. Max [2].

A functional quality control check would involve inserting a test drill bit into the chuck and confirming that the jaws tighten evenly and grip the bit securely with no significant radial play, and that the chuck's key/keyless mechanism operates smoothly through its full range — any assembly that fails this check would be rejected or reworked before packaging.

[2] a specific, relevant quality control check on the chuck assembly (e.g. functional grip test, dimensional check of jaw travel against tolerance, visual inspection for damage). [1] for a vague/generic answer (e.g. 'check it works') without specific detail. Max [2].

Stage 1 (Injection): ABS granules are fed into a heated barrel where a rotating screw melts and mixes them; the molten plastic is then injected at high pressure through a sprue/runner system into the closed, cooled steel mould cavity, filling the shape of the casing half. Stage 2 (Cooling/dwell): pressure is maintained briefly to pack extra material in as the part shrinks slightly, then the plastic is left in the mould to cool and solidify fully into a rigid casing shape. Stage 3 (Ejection): once solid, the two halves of the mould tool open and ejector pins push the finished casing half out of the mould cavity, ready for the next cycle to begin.

[1] Injection stage correctly identified and briefly explained (melting + injecting into mould). [1] Cooling/dwell stage correctly identified and explained. [1] Ejection stage correctly identified and explained. [1] stages given in the correct chronological order with clear, exam-appropriate technical vocabulary. Max [4].

(a) stress = force ÷ cross-sectional area = 1000 N ÷ 5 mm² = 200 N/mm². (b) strain = change in length ÷ original length = 0.15 mm ÷ 150 mm = 0.001 (dimensionless, i.e. 0.1%).

[1] correct stress calculation (200 N/mm², formula shown). [1] correct strain calculation (0.001, formula shown). Max [2].

Young's modulus = stress ÷ strain = 200 N/mm² ÷ 0.001 = 200,000 N/mm². Converting to GPa (1 GPa = 1,000 N/mm²): 200,000 ÷ 1,000 = 200 GPa. This matches the typical textbook value for steel (approximately 200 GPa), confirming the result is physically realistic for this material.

[1] correct calculation of Young's modulus (200,000 N/mm², or equivalently 200 GPa, with correct method shown). [1] correctly compares the result with the typical value for steel (~200 GPa) and confirms consistency. Max [2].

(a) Along the 600 mm side: 600 ÷ 150 = 4 blanks fit. Along the 400 mm side: 400 ÷ 100 = 4 blanks fit. Total blanks per sheet = 4 × 4 = 16. Check by area: sheet area = 600 × 400 = 240,000 mm²; blank area = 150 × 100 = 15,000 mm²; 240,000 ÷ 15,000 = 16 — the two methods agree exactly, confirming no wasted area in this layout. (b) Cost per blank = £45.00 ÷ 16 = £2.8125, which rounds to £2.81.

(a) [1] correct method (fitting blanks along each dimension, or area ÷ area). [1] correct answer of 16 blanks. (b) [1] correct method (sheet cost ÷ number of blanks). [1] correct answer of £2.81 (accept £2.8125 unrounded). [1] working clearly shown/laid out for both parts. Max [5].

(a) Sheets required = 250 ÷ 16 = 15.625. Since a part-used sheet must still be bought whole, this rounds UP to 16 sheets (15 sheets would yield only 15 × 16 = 240 blanks, 10 short of the 250 needed). (b) Total cost = 16 sheets × £45.00 = £720.00.

(a) [1] correct division (250 ÷ 16 = 15.625). [1] correctly rounds UP to 16 sheets (not down), with reasoning shown. (b) [2] correct total cost of £720.00 (16 × £45.00). [1] working clearly shown throughout, applying the 'own figure rule' if a different (but internally consistent) number of blanks per sheet was carried forward from the previous question. Max [5].

1. Overall form: three hardened-steel jaws are arranged at 120° intervals around a central circular bore that accepts the drill bit shank; the jaws sit in angled slots machined into a cylindrical chuck body, converging towards the centre as they move forward.

2. Mechanism: an outer sleeve is threaded internally with a fine helical (spiral) thread that engages matching threads on the back of each jaw. Rotating the sleeve clockwise by hand causes all three jaws to move simultaneously and evenly inward along their angled slots, clamping onto the drill bit shank; rotating anticlockwise retracts the jaws to release the bit.

3. Materials: the jaws are specified in hardened tool steel, because they must resist wear and deformation from repeatedly gripping hard steel drill bit shanks under high clamping force. The chuck body is specified in medium carbon steel, which is tough and machinable, providing adequate strength for the threaded slots at a lower cost and lower weight than using hardened tool steel throughout.

4. Dimensions: maximum bit capacity = 13 mm diameter (labelled on the drawing at the jaw opening); total jaw travel = 15 mm (labelled along the jaw's angled slot, from fully open to fully closed).

5. Usability feature: the outer sleeve has a knurled (diamond-pattern grooved) surface finish, which increases hand grip and prevents the operator's fingers slipping when tightening or loosening the chuck, particularly when hands are dirty or slightly wet.

Assessed via a 4-band descriptive-sketch rubric (Excellent 10–12, Good 7–9, Satisfactory 4–6, Basic 1–3). Excellent: all five required elements present, technically accurate and internally consistent (e.g. dimensions plausible and consistent with each other), described with the precision and labelling detail expected of an annotated sketch. Good: four or five elements present with minor inaccuracy or missing labels/dimensions. Satisfactory: two or three elements present, described in general rather than specific/labelled terms. Basic: only one element present, or description too vague to represent a workable engineering sketch.

Materials: the steel components (chuck, gearbox housing) are highly recyclable, since scrap steel can be melted down and reprocessed repeatedly without significant loss of quality, which is a strong sustainability advantage. The ABS plastic casing is technically recyclable but, in practice, is often not recycled because it must first be correctly identified and separated from other plastics, and ABS production itself is derived from non-renewable petrochemical feedstocks.

Manufacturing: injection moulding of the ABS casing is energy-intensive to set up (heating the plastic, running the moulding machine), but once the mould tool exists, the process generates relatively little material waste per part because off-cuts/sprues can often be reground and reused in future moulding cycles, improving material efficiency at high volumes.

End-of-life: the rechargeable lithium-ion battery is a sustainability positive during use, since it avoids the repeated waste of disposable batteries, but the battery itself contains materials (lithium, cobalt) that require environmentally impactful mining and must be disposed of through specialist battery recycling schemes rather than general waste, or they pose a fire/environmental hazard. The fact that the product combines steel, ABS and a battery pack in one assembly can also make it harder to fully disassemble and separate materials for recycling at the end of the product's life, compared with a single-material product.

Overall, Product X shows genuine sustainability strengths — recyclable steel content and a reusable rechargeable power source — but these are offset by the environmental cost of battery materials and the practical difficulty of separating a mixed-material assembly for recycling, so its overall sustainability depends significantly on whether the manufacturer designs the product to be easily disassembled and whether consumers have access to appropriate battery recycling facilities.

Assessed against a 4-band QWC level of response grid (Band A 8–10, Band B 5–7, Band C 3–4, Band D 1–2). Band A: evaluates sustainability across all three areas (materials, manufacturing, end-of-life), with both positive and negative points supported by specific engineering reasoning, and a balanced, justified overall conclusion; fluent, well-organised use of specialist terminology. Band B: covers at least two of the three areas with reasonable balance and some specific reasoning; conclusion present but less developed. Band C: covers one or two areas, mostly one-sided or generic; limited specific reasoning. Band D: vague, unsupported assertions about sustainability with little engineering content.

1. Resistor = a rectangle or zig-zag line symbol → B. 2. LED = a standard diode symbol (triangle and bar) with two arrows pointing away, representing emitted light → C. 3. Push switch = a break in the circuit bridged by a movable contact → D. 4. Battery cell = a long line (positive) and short line (negative) → A.

[1] each for the correct letter: 1–B; 2–C; 3–D; 4–A. Max [4].

1. Single-acting cylinder has a rod extending from one end only, returned by a spring → B. 2. Double-acting cylinder has a rod extending from (effectively) both directions of travel with two ports for air in/out → C. 3. A 3/2 way manually operated valve is shown as a two-position switching box with flow-path arrows and a lever actuator → D. 4. Compressed air supply is shown as a circle with a triangle (representing the energy source) → A.

[1] each for the correct letter: 1–B; 2–C; 3–D; 4–A. Max [4].

A shape-memory alloy (such as Nitinol) can be bent or deformed at a lower temperature but will return to a pre-programmed ('memorised') shape when heated above its transition temperature, due to a reversible change in its internal crystal structure. This property is used in applications such as flexible eyeglass frames that return to shape after bending, dental braces that apply a gentle constant force as they try to return to shape, and self-closing valves/actuators that respond automatically to temperature change.

[1] correct explanation of the shape-memory property (returns to a pre-set shape when heated above a transition temperature). [1] a genuine, relevant application. Max [2].

A thermochromic material reversibly changes colour when its temperature rises or falls past a certain threshold, due to a temperature-dependent change in its molecular structure that affects how it absorbs/reflects light. This is used in applications such as novelty mugs and baby-feeding spoons that change colour to show a liquid is too hot, battery-level indicator strips, and temperature-sensitive safety warning labels.

[1] correct explanation of the thermochromic property (reversible colour change with temperature). [1] a genuine, relevant application. Max [2].

Polymorph (a low-melting-point thermoplastic, often supplied as small pellets) becomes soft, pliable and mouldable by hand when heated in hot water to around 60°C, and re-solidifies into a rigid shape as it cools back to room temperature; this cycle can be repeated many times by reheating. It is used to make custom, ergonomically fitted tool handle grips and quick prototype parts or casings. Compared with machining a traditional engineering material (such as aluminium or steel) into a custom shape, polymorph requires no specialist tooling, CNC machinery or workshop machining skills — it can be shaped by hand in minutes, making it much faster and cheaper for one-off or prototype applications.

[1] correct explanation of the polymorph property (softens/mouldable when heated in hot water, re-hardens on cooling, repeatable). [1] a genuine, relevant application. [1] a valid, clearly explained advantage over a traditional material for that application. Max [3].

Reactive glass contains light-sensitive compounds (e.g. silver halide particles) that undergo a reversible chemical change when exposed to UV light, causing the glass to darken in bright sunlight and become clear again in low light. It is used in self-tinting spectacle lenses and some vehicle sunroofs/windows. Compared with a traditional fixed-tint glass or a separate pair of sunglasses, reactive glass automatically and continuously adjusts its tint to match changing light conditions, improving user convenience and comfort without any manual action or additional product being required.

[1] correct explanation of the reactive/photochromic glass property (darkens with UV exposure, reversible). [1] a genuine, relevant application. [1] a valid, clearly explained advantage over a traditional material for that application. Max [3].

A vernier caliper (or digital caliper) fitted with internal measuring jaws, or an internal micrometer, can measure an internal diameter to a precision of 0.01 mm, far more precisely than a steel rule.

[1] a correct precision measuring tool named (vernier caliper, digital caliper, or internal micrometer). No credit for a steel rule or tape measure, which cannot achieve this precision.

Engineer's marking blue is a fast-drying blue dye/lacquer applied thinly to a metal surface before marking out; when a scriber cuts through the coating, it exposes the bright metal underneath, making the scribed lines much easier to see against the blue background than on bare, reflective metal.

[1] correct answer: engineer's marking blue (accept 'marking blue' or 'layout fluid').

A scriber (a hardened steel tool with a fine, sharp point) is used, held tilted slightly in the direction of travel and pressed firmly against a straight edge such as a steel rule or engineer's try square. It is drawn along the edge in a single continuous pass rather than several overlapping strokes, since multiple strokes make the line thicker/less precise and can cause the tool to wander from the true line.

[1] correctly names the scriber. [1] correctly explains use against a straight edge/square in a single firm continuous stroke for accuracy. Max [2].

The magnetic stand is attached to the lathe bed so the DTI's plunger/stylus lightly contacts the outer surface of the workpiece held in the chuck. The chuck is then rotated slowly by hand through one full turn while the dial is watched: if the workpiece is perfectly concentric (running true), the needle will not move; if it is off-centre, the needle will deflect back and forth, and the amount of deflection shows how far out of true the workpiece is. The workpiece can then be gently tapped/adjusted in the chuck and rechecked until the DTI reading stays constant through a full rotation, confirming it is running true.

[1] correctly explains that the DTI plunger contacts the workpiece and the chuck is rotated by hand to observe the dial. [1] correctly explains that dial variation indicates the workpiece is off-centre, and that the workpiece is adjusted until the reading is constant. Max [2].

Upper tolerance limit = nominal dimension + tolerance = 20 mm + 0.05 mm = 20.05 mm. Lower tolerance limit = nominal dimension − tolerance = 20 mm − 0.05 mm = 19.95 mm. Any manufactured shaft measuring between 19.95 mm and 20.05 mm inclusive would be accepted as within tolerance.

[1] correct upper limit (20.05 mm). [1] correct lower limit (19.95 mm). Max [2].

Quality control (QC) is reactive: it involves inspecting, measuring or testing components — either during production or once finished — against a specification, and rejecting, reworking or scrapping any that fall outside tolerance. Quality assurance (QA) is proactive: it involves setting up and monitoring the systems, standards, procedures and staff training used throughout the whole production process, with the aim of preventing defects from being produced in the first place, rather than simply catching them afterwards.

[1] correctly explains quality control (inspecting/testing to catch faulty parts). [1] correctly explains quality assurance (process-wide systems/procedures to prevent faults), with a clear point of contrast between the two. Max [2].

Radius = diameter ÷ 2 = 20 ÷ 2 = 10 mm. Cross-sectional area A = πr² = 3.14 × 10² = 314 mm². Volume V = A × L = 314 × 300 = 94,200 mm³. Converting to cm³ (1 cm³ = 1,000 mm³): 94,200 ÷ 1,000 = 94.2 cm³.

[1] correct method shown (area = πr², volume = area × length). [1] correct final answer of 94.2 cm³ (accept 94,200 mm³, or 94.25 cm³/94,247.8 mm³ if the more precise value of π is used). Max [2].

Density = mass ÷ volume = 156 g ÷ 20 cm³ = 7.8 g/cm³. This value falls exactly within the typical published density range for steel (approximately 7.8–7.9 g/cm³), so the result is physically consistent with the block being made of steel.

[1] correct calculation (density = 7.8 g/cm³, formula shown). [1] correctly identifies this as consistent with steel's typical density. Max [2].

Sheet area = 500 × 500 = 250,000 mm². Area of one circular blank = πr² = 3.14 × 50² = 3.14 × 2,500 = 7,850 mm². Total area of 20 blanks = 20 × 7,850 = 157,000 mm². Waste area = sheet area − total blank area = 250,000 − 157,000 = 93,000 mm². Percentage waste = (waste area ÷ sheet area) × 100 = (93,000 ÷ 250,000) × 100 = 37.2%.

[1] correct calculation of total blank area (157,000 mm² using π = 3.14, or 157,079.6 mm² using a more precise π). [1] correct final percentage waste of 37.2% (allow 37.17–37.2% depending on the value of π used), with method clearly shown. Max [2].

(a) Length per component = component length + cutting waste allowance = 80 mm + 5 mm = 85 mm. (b) Total length for 150 components = 85 mm × 150 = 12,750 mm = 12,750 ÷ 1,000 = 12.75 m. (c) Total cost = total length in metres × cost per metre = 12.75 × £3.20 = £40.80.

(a) [1] correct answer of 85 mm. (b) [1] correct conversion method (mm to m). [1] correct answer of 12.75 m. (c) [1] correct final cost of £40.80. Max [3] overall may be awarded as: [1] part (a); [1] part (b); [1] part (c), each requiring correct working shown; the own-figure rule applies if an earlier part is carried forward correctly.

CAD software allows a design to be created, dimensioned and modified with high precision, and changes can be made quickly by editing the digital model rather than redrawing it entirely by hand. CAD files can also be shared instantly with others, used directly to drive CAM manufacturing equipment, and analysed using simulation tools (e.g. checking how a part will behave under load) before any physical prototype is made, saving time and material cost.

[2] one genuine, clearly explained benefit of CAD (e.g. fast/accurate editing, simulation/testing before manufacture, direct link to CAM, easy sharing/storage). [1] if the benefit is stated but not explained. Max [2].

CAM uses a CAD model to generate a program that automatically controls a machine (such as a CNC milling machine or lathe) to cut a part. Because the machine follows the exact same programmed toolpath every time, it produces components with much greater precision and consistency between parts than manual machining, where accuracy depends on the individual operator's skill and can vary due to fatigue or human error; CAM can also run unattended for long periods, increasing production speed for large batches.

[1] identifies a genuine CAM improvement (e.g. precision/consistency, speed, reduced reliance on operator skill). [1] explains the mechanism by which it improves on manual methods. Max [2].

Additive manufacturing (3D printing) builds a part layer by layer directly from a CAD model, rather than removing material from a solid block (as in traditional machining) or requiring a mould tool (as in injection moulding). This has had a major impact on manufacturing by making it economical to produce complex shapes — including internal features that would be impossible to machine conventionally — in low volumes or as one-off prototypes, without the high upfront tooling cost of processes such as injection moulding, significantly speeding up product development and design iteration.

[1] a genuine, relevant emerging technology named (e.g. additive manufacturing/3D printing, robotics/automation, the Internet of Things (IoT) in manufacturing). [1] a specific, accurately explained impact on manufacturing. Max [2].