How do CAD, CAM and CNC link design to manufacture, and what does automation add?
Digital design and manufacture: CAD, CAM and CNC machining, additive manufacture (3D printing), the role of automation, robotics and flexible manufacturing systems, and the benefits and drawbacks of computer-integrated manufacture.
A focused answer to Eduqas A-Level Product Design on digital design and manufacture: CAD, CAM and CNC machining, additive manufacture by 3D printing, automation, robotics and flexible manufacturing systems, and the benefits and drawbacks of computer-integrated manufacture.
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What this dot point is asking
Eduqas wants you to explain how CAD, CAM and CNC link design to manufacture, what additive manufacture and automation add, and the benefits and drawbacks of computer-integrated manufacture. Digital manufacture is how modern products are designed and made accurately and at scale, and it is examined as definitions, as the CAD-to-CNC workflow, and as a balanced discussion of automation.
CAD, CAM and CNC
Additive manufacture and digital tools
Automation, robotics and flexible manufacturing
Benefits and drawbacks
Digital and automated manufacture must be weighed up. The benefits are high and consistent quality and repeatability (machines do not tire or vary), speed and high output, lower long-term labour cost, the ability to make complex shapes (additive) and to run dangerous or repetitive tasks safely, and easy design changes through CAD. The drawbacks are the very high initial cost of equipment and integration, inflexibility (reprogramming and retooling take time and money to change product), the need for skilled technicians to set up and maintain the systems, vulnerability to breakdown, and the impact on employment (fewer manual jobs, but new technical roles). The balanced conclusion is that digital and automated manufacture suit high-volume production where the setup cost is justified by low unit cost and consistent quality.
Exam-style practice questions
Practice questions written in the style of WJEC Eduqas exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Eduqas 20204 marksExplain the difference between CAD and CAM, and explain how a CAD file is used to drive a CNC machine.Show worked answer →
A Component 1 short-answer question. Marks for the definitions and the link between them.
CAD (computer-aided design) is the use of software to create an accurate 2D or 3D virtual model of a product. CAM (computer-aided manufacture) is the use of computer-controlled machines to make the product. The CAD model is converted into machine instructions (a tool path, often G-code), which are sent to a CNC (computer numerical control) machine; the CNC machine then follows those coordinates automatically to cut, mill, turn, route or print the part accurately and repeatably.
Award marks for the CAD-then-CAM link: design the model, generate the tool path, run it on the CNC machine. A common dropped mark is treating CAD and CAM as the same thing.
Eduqas 20226 marksDiscuss the benefits and drawbacks of using automation and robotics in the manufacture of a mass-produced product. Refer to cost, quality and employment in your answer.Show worked answer →
A Component 1 extended question marked by levels of response. Reward a balanced view across cost, quality and employment.
Benefits: automation and robots work continuously without breaks, fast and accurately, giving high, consistent quality and repeatability, lower long-term labour cost, and the ability to do dangerous or repetitive tasks safely. Drawbacks: very high initial cost of equipment and integration, inflexibility (reprogramming and retooling to change product), the need for skilled maintenance, and job losses or changed roles for workers.
A top answer weighs the gains (consistent quality, speed, lower running cost, safety) against the costs (capital outlay, inflexibility, employment impact), and reaches a clear conclusion that automation suits high-volume production where its high setup cost is justified by consistent quality and low unit cost, while acknowledging the social impact.
Related dot points
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A focused answer to Eduqas A-Level Product Design on shaping and forming processes: injection moulding, blow moulding, vacuum forming, extrusion and rotational moulding for polymers, casting and forging for metals, and laminating and steam bending for timber, with the material and scale each suits.
- Wasting processes (sawing, drilling, milling, turning, laser and water-jet cutting) that remove material, and addition and joining processes (welding, brazing, soldering, adhesives, mechanical fixings, 3D printing) that join or build up material, with their uses and trade-offs.
A focused answer to Eduqas A-Level Product Design on wasting and addition processes: sawing, drilling, milling, turning and laser and water-jet cutting that remove material, and welding, brazing, soldering, adhesives, mechanical fixings and 3D printing that join or build up material, with their uses and trade-offs.
- The scales of production (one-off or bespoke, batch, mass and continuous), just-in-time and lean manufacturing, the relationship between volume, tooling cost and unit cost, and how the chosen scale shapes the manufacturing method.
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- Quality control and quality assurance, tolerances and upper and lower limits, the use of gauges, jigs, fixtures and templates, statistical process control and Six Sigma, and how tolerances enable interchangeable parts and consistent quality.
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- Modelling and prototyping: physical models, prototypes and mock-ups, the role of CAD and CAM, rapid prototyping (3D printing and laser cutting), virtual modelling and simulation, and how iterative testing of models refines a design.
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Sources & how we know this
- Eduqas A Level Design and Technology specification (Product Design) — Eduqas (2017)