Curriculum/DP Design/B4.1 Production Systems

Production Systems | B4.1

Guiding questionHow is the ideal production system determined for a product?

Scale changes everything. A product made once, a product made ten thousand times and a product made ten million times are not the same design problem, even when the object looks identical. The production system decides what tooling can be justified, what tolerances are achievable, what a single change costs once the line is running, and how many people are involved in making the thing at all.

B4.1 maps the whole spectrum, from craft production through mechanisation and assembly line methods to computer-integrated manufacturing (CIM). Before the Industrial Revolution everything sat at one end of it, shaped from start to finish by a single skilled artisan. A modern smartphone sits at the other, with over a thousand components made across dozens of countries on systems that run around the clock.

No single system is the right answer for every product. Scale, cost, customisation and material each constrain the choice. Understanding how they do is what lets you design something that can actually be made, and what lets you predict how a production decision will show up in the finished object's appearance, function and price.

This is also the topic where the course gets political, whether it says so or not. Choosing between craft production, an assembly line and computer-integrated manufacturing is a choice about labour, about where a product is made, and about who benefits from making it. The efficiency arguments are real and you should learn them properly, because Paper 2 will ask for them. It is worth also noticing what those arguments leave out, a habit that will serve you well in C1.1 and C2.1.

Students must be able toIdentify the most effective type of production system (craft, mechanised, automated, assembly line, hybrid production systems and computer integrated manufacturing (CIM)) used in the manufacture of a given product.

Six main production systems exist on a continuum from human-centred to machine-centred:

SystemHuman vs. machine balanceTypical volumeTypical products
Craft productionAlmost entirely human; hand tools or simple machinesOne-off to very small batchesCustom furniture, jewellery, haute couture, artisan ceramics
Mechanised productionMachines operated by humans; workers still guide each stepSmall to medium batchesSmall-run textiles, workshop metalwork
Assembly line productionStandardised tasks; workers perform single repeated operationsHigh volume, identical productsFord automobiles, consumer appliances
Automated production (CAD/CAM, CNC)Machines operate autonomously; minimal human interventionHigh to very high volumePrecision machined parts, circuit boards
Computer-Integrated Manufacturing (CIM)Entire enterprise automated: design, production, QC, logisticsVery high; mass customisation possibleModern automotive plants, electronics factories
Hybrid productionStrategic combination of the aboveVariableLuxury cars (hand-stitched interior + robot-welded body)

Before the Industrial Revolution, craft production was the only method. Apprentices spent up to seven years learning multiple skills. Henry Ford's introduction of the moving assembly line ("Fordism") and its standardised part system marked a turning point, and his famous remark that customers could have "any colour as long as it's black" illustrates the trade-off between efficiency and customisation.

Regulatory Papers, Please preview
Interactive Tool
Regulatory Papers, Please

Develop a product from concept to market and watch a corner cut early resurface as a failed safety test, a certification refusal or a recall.

Students must be able toDiscuss the advantages and disadvantages of each production system, including craft production, mechanisation, automation, assembly line, hybrid production systems and CIM.

SystemAdvantagesDisadvantages
Craft productionHigh customisation; direct client communication; each piece unique; skilled craftsmanship valuedVery slow; labour-intensive; high cost per unit; low volume; inconsistency between pieces
Mechanised productionFaster than craft; moderate consistency; lower skill threshold than fully manualHigher capital cost than craft; still requires significant human oversight
Assembly line productionHigh efficiency; consistent output; economies of scale (lower unit cost at volume); reduced need for skilled labourHigh capital investment; inflexible (design changes are costly); monotonous work → worker dissatisfaction; single breakdown halts the whole line
Automated production (CNC/CAM)24/7 operation; reduced human error; consistent quality; lower long-term labour costs; reduced workplace injuriesHigh capital investment; requires specialised technical staff; inflexible if product changes
CIMIntegrates entire enterprise; enables mass customisation; data accessible globally; near-perfect repeatabilityVery high initial setup cost; staff restructuring required; complex interdependencies: software failure can halt production
Hybrid productionBalances customisation and efficiency; flexible; suits premium productsComplex to manage; higher cost than pure automation; requires skilled workers alongside machines

CIM and mass customisation: CIM can produce customised products at near mass-production efficiency. Consumers may follow their order in real time via online interfaces. Distributors worldwide can access production data, enabling just-in-time supply chains.

Students must be able toDetermine appropriate manufacturing techniques for each scale of production, including one-off production, batch production, mass production, mass customisation and continuous production.

Scale of production is the primary driver of system choice. As volume increases, fixed costs are spread over more units, reducing the cost-per-unit. However, higher-volume systems require greater capital investment and offer less flexibility.

ScaleVolumeSystem matchExamples
One-off (jobbing)1 unitCraft / manualBespoke suit, custom trophy, one-off concept car
Batch productionTens to thousandsMechanised / semi-automatedSeasonal clothing range, limited-edition sneakers, artisan bread
Mass productionThousands to millionsAssembly line / automatedStandard Ford models, IKEA furniture, PET bottles
Mass customisationMillions of individually configured variantsCIM with flexible automationBuild-to-order laptops (Dell), personalised trainers (Nike By You), Invisalign aligners
Continuous (process) productionNon-stop, 24/7Fully automated processSteel mills, petroleum refineries, paper mills, bottling plants

Key principle: "low-volume work would most likely be produced by craftsmen, whereas high-volume work would be more suited to mechanical and/or automated processes." As volume increases, fixed costs (tooling, equipment) become less significant per unit, while variable costs (labour) dominate less.

Interactive
Production-System Matcher

Select a product below, then select the production system and scale it actually calls for.

Discussion
Is mass customisation actually customisation?

Nike By You lets you pick colours and materials for a shoe built on an existing last, the mould that defines its actual shape and fit. Dell lets you configure a laptop's RAM, storage and colour, but not redesign its hinge or port layout. Invisalign generates a unique aligner for each patient's teeth, but only within a treatment plan built from the company's own software and material set.

In each case, is the customer really designing anything, or just selecting from a large but fixed menu of options that a CIM system can produce without retooling? Where would you draw the line between genuine "mass customisation" and simply offering a lot of variants of a mass-produced product?

Students must be able toDiscuss factors that influence choices of manufacturing techniques, including type of product, material(s) used, scale of production, production system, cost constraints and environmental considerations; and justify the selection of appropriate manufacturing techniques for a product.

Manufacturing technique selection is never made in isolation; multiple factors interact:

FactorHow it influences technique selectionExample
Type of productGeometry, function, and required precision constrain optionsA turbine blade requires CNC + investment casting; a water bottle uses blow moulding
Material(s)Formability, machinability, meltability, and compatibility with tooling limit choicesTitanium requires EDM or 5-axis CNC; thermoplastics suit injection moulding
Scale of productionHigh volumes justify tooling investment; low volumes require flexible processes1 unit → 3D print; 1 million units → injection mould
Production systemAvailable equipment and workforce skills constrain technique optionsA factory with only CNC machines cannot use injection moulding without new investment
Cost constraintsTooling amortisation, material cost, labour cost, and energy cost all factor inDie casting tooling costs $20,000–$200,000 but per-part cost at volume is very low
Environmental considerationsMaterial waste, energy consumption, emissions, and end-of-life recyclability are increasingly mandatoryWaterjet cutting produces no heat-affected zone and less waste; powder coating has no VOC solvents

Patent mining (searching databases such as Google Patents, WIPO, and USPTO) helps manufacturers analyse competitor innovations, identify trends, and plan development strategies while avoiding intellectual property infringement.

Students must be able toDeconstruct and analyse multi-component products to determine how they were made and their relevance within the assembly and function of a product.

Reverse engineering (also called teardown or disassembly analysis) is the systematic process of deconstructing an existing product to understand its design, materials, manufacturing methods, and assembly sequence. It is used to reduce development time, identify opportunities for improvement, and benchmark against competitors.

Six-step reverse engineering process:

  1. External visual examination: Identify materials, joining methods, seams, hidden fasteners, and possible disassembly points. Plan the disassembly sequence. Record by photo/video.
  2. Disassembly: Carefully remove components using appropriate tools. Label and number every part. Record the entire process to enable reassembly.
  3. Component analysis: For each part, determine: Is it functional, aesthetic, or safety-related? How does it contribute to overall function? What wear considerations exist? Could it be made redundant?
  4. Manufacturing analysis: Identify the manufacturing process used for each component. Recognise how processes enhance material properties (work hardening, annealing). Confirm materials by mass, colour, magnetism, and surface finish.
  5. Assembly analysis: Record the assembly sequence. Determine whether assembly was manual or automated. Assess whether the product is designed for disassembly or is single-use.
  6. Redundancy assessment: Identify unnecessary parts or overdesigned components that could be eliminated to reduce cost and material.

Useful tools for disassembly: tweezers, magnifying glass, magnet (to identify ferrous metals), screwdrivers of various types, voltmeter (for electronic components).

Students must be able toDiscuss how production methods can influence the function and aesthetics of a product.

Production methods directly shape both the function (how the product works) and the aesthetics (how it looks and feels) of a product. A designer who understands production constraints can design with them, not against them.

ProductProduction methodEffect on functionEffect on aesthetics
Phone caseInjection moulded polymerLightweight, durable, consistent wall thickness, snap-fit geometry possibleSmooth uniform surface; wide colour range via pigmented resin; fine moulded textures
Phone case (premium)CNC-machined aluminium + anodisingHigher structural rigidity; scratch resistance; heat dissipation; precise tolerances for camera cutoutsMetallic lustre; jewel-like edges from CNC chamfering; vibrant anodised colours
Wooden chairCNC machiningPrecise mortise-and-tenon joints improve structural rigidity; consistent replicationSmooth, clean lines; identical reproductions; intricate carved patterns possible
Wooden chairHand-carving (craft)Each piece tailor-made; potential variation in joint qualityVisible craftsmanship; unique grain and ornamental detail in each piece
Car body panelSheet metal stamping (cold forming)Work-hardened surface is impact-resistant; aerodynamic curves reduce dragSmooth consistent curves; pressing dictates the form language of the vehicle
Cooking panCast iron (sand casting)Excellent, even heat retention; robust; develops seasoned non-stick surface over timeTraditional rustic appearance; visible texture; patina develops with age

Key relationships:

  • Forging creates directional grain structure → directional strength (unlike casting, which can be isotropic).
  • Annealing (controlled heating and cooling of glass or metal) reduces internal stresses → less likely to crack under load.
  • 3D printing (FDM) leaves visible layer lines → distinctive aesthetic that can be hidden by post-processing or embraced as a design feature.
  • Cold rolling creates smooth, work-hardened sheet → flat reflective surface finish.
Key concept
Work Hardening

Work hardening (also called strain hardening) is the increase in a metal's strength and hardness that happens when it is repeatedly bent, rolled, hammered or stamped at room temperature. The mechanical deformation creates and tangles dislocations inside the metal's crystal structure; the more tangled these dislocations become, the more the material resists further deformation, so it becomes harder and stronger but also less ductile.

This is why cold rolling, sheet metal stamping and forging all leave a part stronger than the unworked material it started as: the table above shows a car body panel gaining impact resistance from stamping and a cold-rolled sheet gaining a flat, reflective finish, both as direct side effects of work hardening. If a part needs to be reshaped further after this point, it is often softened first using a heat treatment such as annealing (see the forging/annealing row above), which reverses the effect by letting the dislocations relax.

Work hardening in practice
  • Sheet metal stamping: a car body panel becomes stiffer and more impact-resistant than the flat sheet it was pressed from
  • Cold rolling: repeated rolling produces a harder, smoother, more reflective sheet surface
  • Repeated bending of wire: a paperclip becomes stiff and brittle at the bend point, and eventually snaps

Ten questions covering the learning objectives for this topic. Select one answer per question, then click "Check all answers" to see your score and the explanations.

Q1 · 4.1.1 Production system types
Before the Industrial Revolution, manufacturing was characterised by:
A single artisan, often after an apprenticeship of up to seven years, made each item complete. Output was low, cost per unit high and no two pieces identical. The moving assembly line was the turning point away from this, trading variety for volume and consistency.
Q2 · 4.1.1 Production system types
A luxury car manufacturer robot-welds the body shell but hand-stitches the interior trim. This is best described as:
Hybrid production deliberately combines systems, using automation where repeatability and speed matter and skilled hand work where the customer is paying for craft. It balances customisation against efficiency, at the cost of being more complex to manage and needing both skilled workers and machinery.
Q3 · 4.1.2 Advantages & disadvantages
Which is a genuine disadvantage of assembly line production?
The line is optimised around one product, so design changes are slow and costly, and because stations run in series a stoppage anywhere halts everything downstream. Its strengths are the opposite of the distractors: strong economies of scale, consistent output and a reduced need for skilled labour, though the repetitive work carries its own cost in worker dissatisfaction.
Q4 · 4.1.2 Advantages & disadvantages
The distinguishing feature of computer-integrated manufacturing (CIM) is that it:
Because the whole enterprise shares one data model, a change in CAD can flow straight into manufacturing instructions, variants can be produced without retooling, and distributors can see production data globally. The costs are a very high setup investment, staff restructuring, and the risk that a software fault stops everything at once.
Q5 · 4.1.3 Scale of production
Steel mills, petroleum refineries and paper mills run without stopping. This scale of production is:
Continuous, or process, production runs around the clock on fully automated plant, because stopping and restarting the process is either impossible or extremely expensive. Batch production makes tens to thousands of units at a time, such as a seasonal clothing range, and one-off production makes a single unit.
Q6 · 4.1.3 Scale of production
Build-to-order laptops and made-to-measure dental aligners are examples of:
Mass customisation uses CIM and flexible automation to produce individually configured units at close to mass-production efficiency. It is worth asking how much real design freedom the customer has: the configuration is usually a wide but fixed menu of options the system can build without retooling.
Q7 · 4.1.4 Factors influencing choice
A team needs one polymer bracket for testing next week, and later expects to produce a million of them. The appropriate techniques are:
Scale is the factor that decides here. A single part cannot justify tooling that costs tens or hundreds of thousands, so a flexible tool-free process wins. At a million units the tooling is spread across every part made and the per-unit cost falls far below any additive process. Material, geometry, available equipment and environmental impact then refine the choice.
Q8 · 4.1.5 Reverse engineering
In a reverse engineering teardown, redundancy assessment means:
It is the last of the six steps, after visual examination, disassembly, component analysis, manufacturing analysis and assembly analysis. Removing or combining parts that do no essential work cuts cost, material and assembly time, which is exactly the reasoning design for manufacture builds on.
Q9 · 4.1.6 Production & design aesthetics
A stamped car body panel is stiffer and more impact resistant than the flat sheet it was pressed from. This is because stamping:
Deforming metal cold creates and tangles dislocations, so it resists further deformation: harder and stronger, but less ductile. Cold rolling produces the same effect along with a flat reflective finish, and a paperclip bent repeatedly eventually snaps for the same reason. Annealing reverses it by letting the dislocations relax.
Q10 · 4.1.6 Production & design aesthetics
Compared with a hand-carved chair, a CNC machined chair typically shows:
Machining produces consistent mortise-and-tenon joints and identical copies, which improves rigidity and gives a clean, uniform look. Hand carving offers visible craftsmanship and a unique piece each time, with more variation in joint quality. Layer lines belong to fused deposition printing, not machining.
Every Paper 2 question is attached to a product. Nothing here can be answered from memory alone: read the case study first, then answer the parts in order. The tariff tells you how many creditable points to make, and the command term tells you what kind of point counts. Write your answer before you open either panel, then mark yourself against the markscheme rather than against the example. This topic is HL only, so these questions appear on HL Paper 2 and never on SL.
Question 1 · B4.1 · HL only6 marks
Case study

A tailoring house on Savile Row makes suits to individual measure. A cutter takes some thirty measurements, drafts a paper pattern for that customer alone, and the suit is hand sewn over fifty or more hours across three fittings.

A high-street retailer sells suits in fixed sizes, cut in stacks of forty layers and sewn on a line where each operator performs one operation.

Table 1: The two production systems compared

Savile RowHigh street
Production systemCraftAssembly line
Labour per suit50–80 hours2 hours
Units per year~200 per house~400 000
PatternOne per customer8 sizes, 2 fits
Price£4500£180
Operator skillFive year apprenticeshipDays per operation
Alteration after saleIncluded, indefinitelyLimited

(a) State the scale of production used by the high-street retailer, see Table 1. [1]

(b) Outline why the assembly line requires far less operator skill per person, see Table 1. [2]

(c) Explain why craft production remains viable for suits despite costing twenty-five times as much, see Table 1. [3]

Example answer

(a) Mass production.

(b) The work is divided so that each operator performs one operation repeatedly rather than making a whole suit, so the skill each person needs is the skill for that operation alone and can be learned in days. The knowledge that used to sit in the tailor's head has been moved into the pattern, the jig and the sequence of the line, so it no longer has to be held by the person doing the work.

(c) The two systems are not selling the same thing, so the price comparison is not the whole picture. Craft production is the only system that can produce a pattern for one body, and a customer whose proportions fall outside eight standard sizes cannot be fitted by the high-street system at any price, so for that customer the alternatives are a bespoke suit or a poor fit. The system also delivers what a small number of buyers value beyond fit: individual cloth selection, the involvement of the three fittings, and a garment made by a named person, none of which mass production can offer because they depend on the customer and the maker meeting. Indefinite alteration extends the suit's life far beyond a high-street one, which changes the cost per year of wear even though it does not close a gap of that size. What makes it viable commercially is that the market it serves is small and does not overlap with the other, so the two systems compete for different customers, and at 200 suits a year a house has no need to reach the volume that would justify a line.

Markscheme

(a) Production systems are selected according to the required scale of production.
• Mass production ✓

Award [1] for the correct scale up to [1 max]. Do not credit one-off or batch.

(b) Production systems can be categorised based on the balance between the manufacturer and the tools and machinery they use.
• Work is divided so each operator performs one operation repeatedly ✓
• The operator does not make a whole suit ✓
• The skill required is that of one operation and can be learned in days ✓
• Knowledge is moved from the tailor into the pattern, the jig and the line sequence ✓
• It no longer has to be held by the person doing the work ✓
• Repetition builds speed at a single task quickly ✓
• Lower skill means a larger available workforce and lower wage cost ✓

Award [1] for each relevant brief point on the lower skill requirement up to [2 max]. Credit the division of labour for full marks.

(c) Production systems can be unique and specific to the type of product being manufactured.
• The two systems are not selling the same product, so price alone does not decide ✓
• Craft is the only system that can produce a pattern for one body ✓
• A customer outside eight standard sizes cannot be fitted by the line at any price ✓
• For that customer the alternatives are bespoke or a poor fit ✓
• Individual cloth selection is available only where each suit is made separately ✓
• The three fittings are part of what is bought, not merely a process step ✓
• A garment made by a named person cannot be produced by a line ✓
• Indefinite alteration extends service life and changes cost per year of wear ✓
• The market is small and does not overlap with the mass market ✓
• At 200 suits a year a house has no volume that would justify a line ✓
• Scarcity and provenance are themselves part of the product's value ✓

Award [1] for each relevant reason / cause explaining the viability of craft production up to [3 max]. Award a maximum of [2] where the response argues only from quality without identifying what the system uniquely provides.

Question 2 · B4.1 · HL only6 marks
Case study

A factory makes glazed ceramic floor tiles. Clay powder is pressed into a tile, dried, printed with a pattern, glazed and fired in a kiln 90 m long through which tiles move continuously on rollers. The kiln cannot be stopped and restarted quickly, because heating and cooling it takes three days.

Table 2: Tile plant

QuantityValue
Output14 000 m² per day
Kiln operationContinuous, 24 hours
Kiln heat-up from cold3 days
Pattern changeover20 minutes at the printer
Body changeover, different clay6 hours
Staff on shift11

(a) State the production system used in this factory, see Table 2. [1]

(b) Describe why the kiln is run continuously rather than switched off overnight, see Table 2. [2]

(c) Analyse how the changeover times in Table 2 shape the way the factory schedules its production. [3]

Example answer

(a) Continuous flow production.

(b) Heating the kiln from cold takes three days, so switching it off overnight would cost three days of output to save eight hours of firing, which is a net loss on any accounting. The energy saved is also smaller than it appears, because most of the fuel goes into heating the kiln's own mass and structure rather than the tiles, and that heat would have to be put in again. Repeated heating and cooling would additionally crack the refractory lining and the rollers, shortening the life of the most expensive asset in the plant.

(c) The two changeover times differ by a factor of eighteen, and that difference determines the shape of the schedule. A 20 minute pattern change is cheap enough to make several times a shift, so the factory can run short batches of different patterns and respond to what customers order without holding stock of everything. A 6 hour body change costs most of a shift's output, so it cannot be treated the same way, and the factory must group every product sharing a clay body together and run them before changing. In practice this means the schedule is organised in two levels: long campaigns defined by the body, with pattern changes sequenced freely inside them. That has consequences beyond the factory, because a customer ordering a tile whose body is not currently running waits until the next campaign, so lead times depend on which body a product uses rather than on how much of it is wanted. The result is a strong pressure back onto the design department to use as few different bodies as possible, since every additional body multiplies the number of campaigns and cuts the plant's effective capacity.

Markscheme

(a) Production systems are selected according to the required scale of production.
• Continuous flow production ✓

Award [1] for the correct production system up to [1 max]. Accept mass production if the response refers to continuous operation.

(b) The design of a production system requires an understanding of a product's components and the manufacturing techniques used.
• Heating from cold takes three days ✓
• Shutting down overnight costs three days of output to save eight hours of firing ✓
• That is a net loss on any accounting ✓
• Most fuel heats the kiln's own mass and structure rather than the tiles ✓
• That heat must be put in again on restart, so the energy saving is small ✓
• Repeated heating and cooling cracks the refractory lining and the rollers ✓
• It shortens the life of the plant's most expensive asset ✓
• Continuous running also gives consistent firing conditions and product quality ✓

Award [1] for each detail, leading to an account of why the kiln runs continuously, up to [2 max].

(c) Various factors influence the choice of manufacturing techniques, and the design of a production system constrains what it can make.
• The two changeover times differ by a factor of eighteen ✓
• A 20 minute pattern change is cheap enough to make several times a shift ✓
• Short batches of different patterns can be run to order ✓
• The factory need not hold stock of every pattern ✓
• A 6 hour body change costs most of a shift's output ✓
• Products sharing a clay body must be grouped and run together ✓
• The schedule is organised in two levels: campaigns by body, patterns sequenced within ✓
• A customer ordering a tile whose body is not running waits for the next campaign ✓
• Lead time depends on which body a product uses, not on quantity ordered ✓
• This pressures the design department to use as few bodies as possible ✓
• Every additional body multiplies campaigns and cuts effective capacity ✓

Award [1] for each distinct guiding element / structure identified in how changeover times shape scheduling up to [3 max]. Award a maximum of [2] where the response does not distinguish the two changeover types.

Question 3 · B4.1 · HL only10 marks
Case study · part 1

A start-up has designed an electric cargo scooter for urban deliveries. It has a welded steel frame, a moulded polymer load box, a proprietary battery pack and bought-in motor, controller and wheels.

The company expects to sell 800 units in the first year and hopes for 20 000 by year four.

(a) Identify two factors that determine which production system the start-up should use in year one. [2]

Case study · part 2

Table 3: Load box, two production routes

Vacuum formingInjection moulding
Tooling cost£3000£90 000
Tooling lead time2 weeks16 weeks
Cycle time4 minutes90 seconds
Cost per part at 800/yr£38£131
Cost per part at 20 000/yr£31£12
Design changesCheap, new mouldExpensive, tool modification

(b) Outline why the cost per part falls so much more steeply for injection moulding, see Table 3. [2]

Case study · part 3

The steel frame is welded in a jig. In year one it is welded by hand; at higher volume a robot cell could do it.

(c) Describe why hand welding suits year one production, see Table 3. [2]

Case study · part 4

An investor argues the company should commit to injection moulding and robot welding now, so that it is ready for 20 000 units and has the lowest possible unit cost from the start.

(d) Evaluate the investor's proposal, see Table 3. [4]

Example answer

(a) The scale of production, at 800 units, and the capital available to invest in tooling.

(b) Almost all of injection moulding's cost at low volume is the £90 000 tool, and that figure does not change with the number of parts made, so it is divided across every unit produced. At 800 units it adds £112 to each part; at 20 000 it adds £4.50. Vacuum forming starts with a tool costing only £3000, so it has very little fixed cost to spread and its price per part is mostly material and labour, which volume barely reduces.

(c) At 800 units a year the company needs about three frames a day, and hand welding meets that without any capital outlay, so money stays available for tooling and stock. It also suits a design that will change, because a welder works from a jig and a drawing and can be told to move a bracket, whereas a robot cell has to be reprogrammed and its fixtures rebuilt.

(d) The investor's reasoning is correct about the destination and wrong about when to leave.

The proposal has a real case. Unit cost at volume is dramatically lower, £12 against £31 for the load box, and the sixteen-week tool lead time means that ordering late would leave the company unable to supply if demand arrived faster than expected. Committing now also avoids paying twice for tooling.

The objection is that it spends the company's money on a volume it does not have. Injection moulding costs £131 per box at 800 units against £38 for vacuum forming, so the proposal makes each of year one's scooters more expensive by £93, not less, and it does so while consuming £90 000 of capital before the product has proved it sells. For a start-up the risk is not that unit cost is too high, it is running out of money, and a hard tool converts cash into an asset that is worthless if the design changes or the product fails.

The design change point in Table 3 is the strongest objection. A first-year product is not finished: 800 units in real delivery use will find problems the company has not anticipated, and vacuum forming lets the box be changed for the cost of a new £3000 mould, while an injection tool must be modified expensively or scrapped. Committing the design at the moment least is known about it is the wrong order.

The same argument applies to welding. A robot cell needs volume to justify itself and locks in a frame geometry the company may want to alter.

The proposal should be rejected as stated, but its timing concern should be acted on. The company should run vacuum forming and hand welding through year one, and start the sixteen-week injection tool when orders show volume is arriving, not when the business plan hopes it will. The right decision is to define the trigger for switching rather than to switch now or later on faith.

Markscheme

(a) Production systems are selected according to the required scale of production, and various factors influence the choice of manufacturing techniques.
• Scale of production, 800 units ✓
• Capital available for tooling ✓
• Tooling lead time ✓
• Likelihood of design changes ✓
• Skills and workforce available ✓
• Factory space ✓
• Uncertainty in the demand forecast ✓

Award [1] for each relevant factor identified up to [2 max].

(b) Production systems are selected according to the required scale of production.
• Almost all of injection moulding's low-volume cost is the £90 000 tool ✓
• That cost is fixed and does not change with the number of parts ✓
• It is divided across every unit produced ✓
• At 800 units it adds £112 per part; at 20 000 it adds £4.50 ✓
• Vacuum forming's tool costs only £3000, so there is little fixed cost to spread ✓
• Its per-part price is mostly material and labour, which volume barely reduces ✓
• The shorter 90 second cycle also reduces labour per part at volume ✓

Award [1] for each relevant brief point on why the cost falls more steeply up to [2 max]. Credit responses that distinguish fixed from variable cost.

(c) The design of a product is influenced by the limitations of a production system and manufacturing techniques.
• 800 units a year is about three frames a day ✓
• Hand welding meets that rate without capital outlay ✓
• Capital stays available for tooling and stock ✓
• It suits a design that will change ✓
• A welder works from a jig and a drawing and can be told to move a bracket ✓
• A robot cell must be reprogrammed and its fixtures rebuilt ✓
• A robot cell at this volume would stand idle most of the time ✓
• A skilled welder can also handle rework and one-off variants ✓

Award [1] for each detail, leading to an account of why hand welding suits year one, up to [2 max].

(d) Production systems are selected according to the required scale of production, and the choice must match actual rather than hoped-for volume.
Strengths of the proposal:
• Unit cost at volume is far lower, £12 against £31 for the load box ✓
• The 16 week tool lead time means a late order leaves the company unable to supply ✓
• Committing now avoids paying for tooling twice ✓
• A single production route simplifies the supply chain ✓
Limitations:
• It spends the company's money on a volume it does not have ✓
• At 800 units injection moulding costs £131 per box against £38 ✓
• It makes each year one scooter £93 more expensive, not less ✓
• £90 000 of capital is consumed before the product has proved it sells ✓
• For a start-up the risk is running out of money, not high unit cost ✓
• A hard tool converts cash into an asset worthless if the design changes or the product fails ✓
• 800 units in real delivery use will find unanticipated problems ✓
• Vacuum forming allows a change for a new £3000 mould ✓
• An injection tool must be modified expensively or scrapped ✓
• Committing the design when least is known about it is the wrong order ✓
• A robot cell similarly locks in a frame geometry the company may want to alter ✓
Judgment:
• The proposal should be rejected as stated ✓
• Its timing concern is legitimate and should be acted on ✓
• Run vacuum forming and hand welding through year one ✓
• Start the 16 week tool when orders show volume arriving, not when the plan hopes it will ✓
• Define the trigger for switching rather than switching on faith ✓

Award [1] for each distinct strength / limitation, leading to an appraisal of the investor's proposal, up to [4 max]. Award a maximum of [3] where only strengths or only limitations are given. Credit responses that identify design change risk or that propose a trigger for switching.

Assembly line, Wikipedia
en.wikipedia.org/wiki/Assembly_line
How the moving assembly line worked at Ford, what it did to build time and cost, and what it did to the people working on it. Background for the mass production section of 4.1.2.
Ford Model T, Wikipedia
en.wikipedia.org/wiki/Ford_Model_T
The product the assembly line was built around, including where any colour so long as it is black actually came from. A production system shaping the design of the product, which is 4.1.6 in one example.
Injection moulding, Wikipedia
en.wikipedia.org/wiki/Injection_moulding
Tooling cost, cycle time and the design rules that come with the process. The clearest illustration of why production volume decides which process makes sense.
Computer-integrated manufacturing, Wikipedia
en.wikipedia.org/wiki/Computer-integrated_manufactu…
How CIM ties CAD, CAM, robotics and business systems into one system, and what breaks when the links between them fail.
Google Patents
patents.google.com
Free full text patent search by company, inventor or keyword. Use it for patent mining, and to see how much manufacturing detail companies disclose in public.
Reverse engineering, Wikipedia
en.wikipedia.org/wiki/Reverse_engineering
The systematic teardown process and the legal limits on it. Read this before disassembling a product for analysis so your method has a structure.

Linking Questions

  • To what extent are prototyping techniques becoming production systems? (A2.2)
  • Which aspects of structural, mechanical and electronic systems impact on the availability of certain production systems? (A3.2) (A3.3) (A3.4)
  • How does the design of a product for specific manufacturing techniques limit the choice of production system? (A4.1)
  • How does material selection in a commercially viable product impact the cost of using different production systems? (B3.1)
  • Why is a deep understanding of how components are manufactured and assembled vital for effective product analysis and evaluation? (C3.1)
  • To what extent does the selection of a production system affect the outcome of a product's life-cycle analysis? (C3.2)