Computer-Aided Manufacture (CAM)

This lesson examines Computer-Aided Manufacture (CAM) — the use of computer-controlled machines to make products. CAM is a core topic in AQA GCSE Design and Technology (8552), Section 3.1.1, and links closely with CAD, CNC, 3D printing and laser cutting.

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What Is CAM?

Computer-Aided Manufacture (CAM) is the use of computer software and CNC machines to automate the manufacturing process. The designer creates a file in CAD, which is then converted into machine instructions (typically G-code) that tell the machine exactly how to cut, shape or build the product.

The CAD/CAM Workflow

The diagram below shows the complete CAD/CAM workflow from initial design through to finished product:

graph LR
    A["1. Design\nin CAD"] --> B["2. Export file\n(.STL / .DXF / G-code)"]
    B --> C["3. Set up CAM\n(tool paths, speeds)"]
    C --> D["4. Simulate\non screen"]
    D --> E["5. CNC Machine\nmanufactures part"]
    E --> F["6. Inspect\nfinished product"]

1. Design the product in CAD software (e.g. Fusion 360, SolidWorks).
2. Export the file in a format the machine understands (.STL, .DXF, G-code).
3. Set up the CAM software — define tool paths, cutting speeds, depths of cut.
4. Simulate the machining operation on screen to check for errors.
5. Manufacture — the CNC machine follows the instructions to produce the part.
6. Inspect the finished product for accuracy.

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CNC Machines Used in CAM

Machine	Process	Materials	Typical Use
CNC milling machine	Rotating cutter removes material from a workpiece	Metals, plastics, timber	Precision components, moulds
CNC lathe	Workpiece rotates; cutting tool removes material	Metals, plastics, timber	Cylindrical parts (bolts, legs, spindles)
CNC router	Rotating cutter moves across sheet material	MDF, plywood, acrylic, foam	Signs, furniture parts, packaging
CNC laser cutter	High-energy laser beam cuts or engraves material	Acrylic, plywood, card, fabric	Intricate shapes, engraving, prototypes
CNC plasma cutter	Ionised gas jet cuts through thick metal	Mild steel, stainless steel, aluminium	Metal fabrication, structural components
CNC waterjet cutter	High-pressure water (with abrasive) cuts material	Almost any material including glass, stone, composites	Precision cutting without heat distortion

Key CNC Terminology

Term	Meaning
G-code	The programming language that tells CNC machines where to move, how fast and what operations to perform
Tool path	The route the cutting tool follows across the workpiece
Feed rate	The speed at which the workpiece or tool moves during cutting
Spindle speed	The rotational speed of the cutting tool (measured in RPM)
Depth of cut	How deep the tool cuts into the material per pass
Work offset	The reference point (origin) from which all coordinates are measured

AQA Exam Tip: A common exam question asks you to explain the process of using CAD/CAM to manufacture a product. Walk through the steps: design in CAD → export file → set up CAM tool paths → simulate → machine the part → inspect. Using correct terminology like "G-code" and "tool path" gains marks.

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3D Printing (Additive Manufacturing)

3D printing (also called additive manufacturing) builds objects layer by layer from a digital model, rather than removing material (subtractive manufacturing). It is a form of CAM.

Common 3D Printing Technologies

Technology	Process	Materials	Typical Use
FDM (Fused Deposition Modelling)	Melts and extrudes thermoplastic filament layer by layer	PLA, ABS, PETG, nylon	Prototyping, functional parts, school projects
SLA (Stereolithography)	UV laser cures liquid resin layer by layer	Photopolymer resin	High-detail models, dental moulds, jewellery
SLS (Selective Laser Sintering)	Laser fuses powdered material layer by layer	Nylon, metal powders	Functional prototypes, end-use parts

Advantages of 3D Printing

Advantage	Explanation
No tooling required	No moulds, jigs or fixtures needed — the printer builds directly from the CAD file
Complex geometries	Hollow structures, interlocking parts and organic shapes that would be impossible with traditional methods
Rapid prototyping	A prototype can be printed in hours rather than weeks
Customisation	Every print can be different at no extra cost (e.g. custom-fit hearing aids)
Reduced waste	Material is added, not removed — less scrap than CNC machining

Limitations of 3D Printing

Limitation	Explanation
Slow for mass production	Printing one item takes minutes to hours; injection moulding takes seconds
Limited materials	Fewer material options than traditional manufacturing
Surface finish	Layer lines are visible; post-processing (sanding, painting) may be needed
Size constraints	Build volume is limited by the size of the printer
Strength	FDM parts can be weaker along layer boundaries than solid machined parts

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Laser Cutting

Laser cutting uses a focused beam of light to cut or engrave materials. It is fast, precise and widely used in schools, makerspaces and industry.

How Laser Cutting Works

1. The design is created in CAD (usually a 2D vector drawing).
2. The file is sent to the laser cutter (typically as a .DXF or .SVG file).
3. The laser beam is focused on the material surface.
4. For cutting, the laser passes through the full thickness of the material.
5. For engraving, the laser removes a shallow layer from the surface.

Materials Suitable for Laser Cutting

Material	Notes
Acrylic (PMMA)	Cuts cleanly with polished edges
Plywood	Cuts well; charring on edges adds character
MDF	Cuts cleanly but produces more smoke
Card and paper	Very fast; ideal for packaging prototypes
Fabric	Clean cuts that seal edges (preventing fraying)

Materials NOT Suitable for Laser Cutting

• PVC — releases toxic chlorine gas when heated
• Polycarbonate — discolours and produces harmful fumes
• Metals (on school-grade CO₂ lasers) — require industrial fibre lasers