Cutting, shaping and forming of materials using appropriate tools and methods.

Materials Processing – Cutting, Shaping and Forming

Learning Objective

Develop the ability to select, apply and justify appropriate cutting, shaping and forming processes for a given material, while considering design principles, sustainability, health & safety, societal impact and the complete design‑process cycle.

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1. The Design Process (Cambridge Topic 1)

Material‑processing decisions are made primarily during the Develop & Refine Ideas and Make stages of the six‑stage design process (Empathise → Define → Develop → Refine → Make → Test). The choice of process influences cost, time, quality and the final performance of the product.

Design Stage	Processing Activity	Key Considerations
Develop & Refine Ideas	Research processes, create process‑selection tables, draft risk assessments.	Feasibility, sustainability, health & safety, cost.
Make	Set‑up machines, select tools, choose parameters, monitor quality.	Tool wear, energy use, dimensional accuracy, surface finish.
Test	Check tolerances, surface finish, functional performance.	Compliance with design brief, repeatability.

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2. Design Principles & Process Selection (Cambridge Topic 2)

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3. Communication Requirements (Cambridge Topic 3)

All processing information must be presented using the drawing conventions specified in the syllabus.

• Isometric and orthographic projections for the finished part.
• Sectional views where hidden features are shown.
• First‑angle projection (or third‑angle if explicitly stated).
• Standard symbols: BS 308 for surface finish, BS 8888 for dimensioning, welding symbols where relevant.
• Process flow diagrams and risk‑assessment tables must be clearly labelled.
• CAD screenshots are acceptable if annotated with the required symbols.

Communication Checklist (Component 2/4 portfolios)

Item	Present?
Isometric view	☐
Orthographic views (front, side, top)	☐
Section view(s)	☐
Dimensioning (BS 8888)	☐
Surface‑finish symbols (BS 308)	☐
Process flow diagram	☐
Risk‑assessment table	☐
PPE & safety symbols	☐

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4. Design & Technology in Society (Cambridge Topic 4)

Material‑processing methods shape local economies, employment patterns and cultural practices. When selecting a process, consider:

• Job creation – high‑skill CNC operation vs. low‑skill manual work.
• Supply‑chain resilience – reliance on specialised equipment or consumables.
• Regulatory compliance – laser safety standards, water‑jet discharge limits, dust‑extraction legislation.
• Community impact – noise, traffic, visual impact of workshops.

Include at least one societal factor in the justification of your process choice.

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5. Sustainable Design (Cambridge Topic 5)

5.1 Energy & Carbon Footprint

Process	Energy (kWh kg⁻¹)	Typical Waste	Recyclability of Waste	Key Sustainability Note
Sawing (hand / band)	0.02	Wood chips, metal shavings	High – can be re‑ground or composted	Low energy; waste must be collected to avoid loss.
Laser cutting	0.8 – 1.2	Fumes, minimal kerf	Fumes captured → filtered air, recyclable if metal vapour.	Precise, low scrap; high electricity demand.
Water‑jet cutting	0.5 – 0.9	Water with abrasive particles	Abrasive (e.g., garnet) can be reclaimed and reused.	No heat‑affected zone; water recycling reduces impact.
Grinding	0.1 – 0.3	Grinding dust	Dust captured → metal dust can be recycled.	Fine finish; requires dust extraction to avoid emissions.

5.2 Life‑Cycle Considerations

• Raw‑material extraction – prefer recycled aluminium, reclaimed wood, or bio‑based polymers where possible.
• Manufacturing stage – select processes with low energy intensity and minimal hazardous by‑products.
• End‑of‑life – design for disassembly; choose processes that leave the material in a recyclable form (e.g., avoid excessive contamination from lubricants).

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6. Health & Safety (Cambridge Topic 6)

6.1 General PPE & Legal References

• Safety glasses or laser‑class goggles (ISO 13485).
• Hearing protection (ear muffs or plugs) – ISO 1999.
• Protective gloves – cut‑resistant for shearing, chemical‑resistant for water‑jet abrasive.
• Lab coat or high‑visibility apron.
• Closed‑toe safety shoes.

All work must comply with ISO 12100 – Safety of machinery and relevant national regulations (e.g., Laser Safety Regulations, Control of Substances Hazardous to Health – COSHH).

6.2 Process‑Specific Hazards & Controls

Process	Key Hazards	Control Measures
Laser cutting	Eye injury from invisible IR/UV beam, skin burns, fire risk, hazardous fumes.	Class‑III laser goggles, interlocked enclosure, fire‑extinguishing blanket, exhaust extraction with HEPA filter, regular beam‑alignment checks.
Water‑jet cutting	High‑pressure jet (≥ 400 MPa), abrasive particles, noise, water contamination.	Pressure‑relief valve, protective gloves, face shield, hearing protection, abrasive‑dust extraction, water‑recycling system, proper disposal of spent abrasive.
Grinding	Flying debris, dust inhalation, wheel burst.	Safety shield, dust extraction, wheel inspection before use, hearing protection, no‑load start‑up.
Sawing / Shearing	Kick‑back, blade breakage, noise, dust.	Blade guards, push sticks, ear defenders, dust extraction, regular blade inspection.

6.3 Risk‑Assessment Template (copy‑and‑paste for coursework)

Activity	Hazard	Risk (Low/Med/High)	Control Measures	Person(s) Responsible
Laser cutting of 2 mm steel	Laser eye injury & fumes	High	Class‑III laser goggles, interlocked door, fire‑extinguisher, local exhaust with filtration.	Operator & Lab supervisor
Water‑jet cutting of composite panel	High‑pressure jet & abrasive particles	High	Pressure‑relief valve, safety shield, gloves, face shield, hearing protection, abrasive‑dust extraction.	Operator

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7. Aesthetics & Ergonomics (Cambridge Topic 7)

• Surface finish – grinding (mirror), sanding (matte), polishing (high gloss). Finish influences visual appeal and tactile comfort.
• Edge treatment – deburring, chamfering, rounding or radiusing reduces injury risk and improves handling.
• Colour & texture – anodising, powder coating, laser engraving, or wood staining can be applied after forming to meet aesthetic brief.
• Ergonomic considerations – smooth transitions, appropriate grip dimensions, and avoidance of sharp corners improve user safety and comfort.

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8. Materials & Components Reference (Cambridge Topic 8)

Material Family	Suitable Cutting Methods	Suitable Shaping Methods	Suitable Forming Methods
Soft woods (pine, plywood)	Hand/band saw, CNC router	Milling, planing, sanding	Press braking (thin sheets), steam bending
Hard woods (oak, beech)	Band saw, CNC router, low‑power laser	Milling, turning, sanding	Steam bending, press braking
Ferrous metals (steel, cast iron)	Laser, water‑jet, plasma, saw	Milling, turning, grinding	Rolling, forging, deep drawing
Non‑ferrous metals (aluminium, copper, brass)	Laser, water‑jet, CNC milling	Milling, turning, grinding	Rolling, extrusion, press braking
Polymers & composites	Laser, water‑jet, CNC router	Milling, CNC routing, sanding	Thermoforming, vacuum forming, press braking
Ceramics & glass	Water‑jet, low‑power laser	Grinding, CNC milling (diamond tools)	Pressing (tiles), thermal bending

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9. Core Stages of Materials Processing

9.1 Cutting – Removal of Material

Cutting separates a workpiece into two or more parts. Methods are classified as mechanical, thermal or chemical.

Common Cutting Methods

• Sawing – toothed blade; suitable for wood, plastics, sheet metal.
• Shearing – straight‑line shear force; ideal for thin metal sheets.
• Laser Cutting – high‑energy beam melts or vaporises material; excellent for precision and complex geometry.
• Water‑jet Cutting – high‑pressure water mixed with abrasive; no heat‑affected zone.
• Drilling – rotary bit creates circular holes; can be manual or CNC.

Tool‑Selection Table

Material	Preferred Cutting Method	Typical Tool / Machine	Key Process Parameter
Soft wood	Sawing	Hand saw / Band saw	Blade tooth pitch & speed (m/min)
Hard steel (≤ 5 mm)	Laser cutting	CO₂ or fibre laser (CNC)	Laser power (W) & focus spot size (µm)
Aluminium sheet (1–3 mm)	Shearing	Shear press or CNC turret shear	Blade clearance (µm)
Composite panels	Water‑jet	High‑pressure water‑jet with abrasive	Abrasive flow rate (kg/h) & pressure (MPa)

Process Parameters to Control

• Cutting speed (v_c) – linear speed of the cutting edge (m/min).
• Feed rate (f) – distance the workpiece advances per revolution (mm/rev) for rotary tools.
• Kerf width – width of material removed; influences dimensional accuracy.
• Power input – especially for laser and water‑jet (W or kW).

9.2 Shaping – Controlled Material Removal

Shaping refines geometry and surface finish with relatively low material loss.

Typical Shaping Operations

• Milling – rotary cutters remove material; suitable for 3‑D features.
• Turning – workpiece rotates on a lathe while a stationary tool cuts; ideal for cylindrical parts.
• Grinding – abrasive wheels produce fine finishes and tight tolerances.
• Planing & Shaping – linear motion of a single‑point tool across a flat surface.

Key Process Parameters

• Cutting speed (v_c) – m/min.
• Feed rate (f) – mm/rev (or mm/min for CNC).
• Depth of cut (a) – mm.
• Tool material & geometry – HSS, carbide, coated, number of flutes.

Material removal rate (MRR) for milling:

$$\text{MRR}=v_c \times f \times a$$

Surface‑Finish Symbols (BS 308)

Symbol	Typical Roughness (Ra, µm)
⌀ 0.8	0.8 µm (mirror finish)
⌀ 1.6	1.6 µm (very fine)
⌀ 3.2	3.2 µm (fine)
⌀ 6.3	6.3 µm (medium)
⌀ 12.5	12.5 µm (coarse)

9.3 Forming – Deformation without Material Removal

Forming changes shape by plastic deformation, compression or tension. It is often the most material‑efficient process.

Common Forming Methods

• Press Braking – bends sheet material using a V‑die.
• Rolling – reduces thickness or creates uniform cross‑sections.
• Forging – compresses metal in a die to achieve complex shapes.
• Deep Drawing – pulls a sheet into a die to form cups or shells.
• Thermoforming / Vacuum Forming – heats thermoplastic sheet and shapes it over a mould.

Key Forming Parameters

• Force (F) – required load (kN) to plastically deform the material.
• Blank holder pressure – prevents wrinkling in deep drawing.
• Temperature – for hot forming processes (e.g., forging, thermoforming).
• Die geometry & clearance – influences spring‑back and final dimensions.

Example – Press Braking of 2 mm Mild Steel

1. Calculate required bending force:
   $$F = \frac{K \times t^2 \times L}{W}$$ where K = material constant, t = thickness, L = length, W = die opening.
2. Select a brake with a rated force ≥ calculated value.
3. Set die angle (typically 90°) and perform a test bend.
4. Measure bend angle, check for spring‑back, and adjust die spacing if needed.

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10. Summary Checklist for Coursework (All Assessment Objectives)

• Identify the design brief and the relevant design principles.
• Research at least three possible processes; complete a process‑selection table.
• Justify the chosen process using functionality and sustainability (or other principles).
• Produce fully annotated drawings (isometric, orthographic, section) using BS 308 & BS 8888 symbols.
• Complete a risk‑assessment table with PPE, controls and responsible persons.
• Discuss societal impact and end‑of‑life considerations.
• Evaluate the final product against the brief (tolerances, finish, ergonomics).

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References (Cambridge International AS & A Level Design & Technology 9705)

• Cambridge International AS & A Level Design & Technology (9705) – Syllabus, 2023 edition.
• BS 308: Surface texture symbols.
• BS 8888: Technical product documentation – dimensioning and tolerancing.
• ISO 12100 – Safety of machinery.
• ISO 13485 – Medical device – PPE for laser work (applicable to laser safety).
• Relevant health & safety legislation (Laser Safety Regulations, COSHH, Control of Noise at Work).