Product Design: CAD, Ergonomics and IP

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1Summary 重點摘要

From CAD models and ergonomics and industry standards, through the four manufacturing processes, maintenance and cost-effectiveness, to copyright, trademark, patent and registered design, Secondary 3 teaches you to evaluate a product from every angle.

2Vocabulary cards Vocabulary

3Step by step Steps

1. Expressing ideas with CAD and 3D modelsSecondary 2 covered freehand sketches and isometric drawing; Secondary 3 adds computer-aided design. In CAD software you build a 3D model, view it from any angle, dimension it precisely, change parameters quickly, and pass the geometry straight to a laser cutter or 3D printer; computer animation and short video can even show how the product opens and assembles, so clients understand the design before seeing the object. For example, model a folding table in CAD, simulate the folding action to check the legs never clash, edit by dragging a few dimensions, then send the board layout straight to the laser — every measurement exact.
2. Critique, appreciation and contemporary designLearn to appreciate and to criticise: ask what problem a design solves, what materials and processes it uses, and where its beauty comes from. Contemporary design movements give you reference points: green design stresses recyclability and low energy, inclusive design insists everyone can use it, and minimal design achieves function with the fewest lines and parts. For example, judging a household kettle, you might note its steel-and-plastic build, its large clear buttons suited to elders and its legible scale marks — inclusive and minimal at once — while reduced packaging and recyclable parts invite the green design test.
3. Ergonomics and industry standardsErgonomics puts human size, strength and habit into design: handle thickness fits the palm, buttons sit where thumbs reach, screens rise to the eyes — a product that feels natural prevents mistakes. Industry standards are the safety floor: appliances must meet electrical safety rules, food containers food-contact rules, and toys must pass safety tests and state the suitable age; these are not options but the legal threshold for sale. For example, a schoolbag must fit a child's shoulders and spine — wide padded straps, weight close to the back — that is ergonomics, while materials free of harmful substances and buckles that pass pull tests are what standards demand.
4. The roles of designers and engineersA product is usually born from two pairs of hands. Designers look after user needs, appearance and experience, proposing what the product should be; engineers look after structure, materials and manufacturability, ensuring the idea can be produced safely in quantity. The two go back and forth through research, sketches, models and tests, coordinating resources and processes with marketing and production. For example, for a new water bottle the designer proposes a waisted body and one-handed cap while the engineer calculates thread strength and seal dimensions; several prototypes later they settle a mass-production scheme balancing looks, feel and cost.
5. Four manufacturing processes: remove, form, join, finishTurning material into product falls into four basic classes. Removing cuts excess away — sawing, drilling, turning, laser cutting. Forming changes shape — injection moulding, vacuum forming, bending, forging. Joining assembles parts — screws, gluing, welding, mortise and tenon. Surface treatment protects and beautifies — sanding, painting, plating, anodising — fighting corrosion and extending service life. For example, making a tin-plate pen pot: shear the sheet to its developed shape, bend it into a tube and weld the seam, then grind the weld and spray primer and colour — all four processes appear on one small product.
6. Maintenance, disposal and safety standardsGood design leaves room for maintenance: parts can be replaced, seals are available to buy, manuals explain cleaning — and the product lives longer. Design must also plan for disposal, marking recyclable parts and how to remove batteries. Manufacture needs safety measures too: machine guards, protective equipment for workers, and safety tests before products leave the factory — precautions written into standards that protect workers and users alike. For example, a fan with a removable front grille cleans easily, its blade screws use common sizes so parts can be replaced, the base carries ratings and recycling labels, and drop and heat-rise tests are passed before sale — maintenance, disposal and safety decided on the drawing board.
7. Intellectual property: the legal net around creativityIntellectual property protects creative work, and four kinds divide the job. Copyright protects original expression the moment a work exists — manuals, illustrations, software. Trademarks identify the source of goods; once registered, others may not use the same mark. Patents protect new technical solutions; they need application and examination, and once granted others may not copy for a fixed term. Registered designs protect a product's shape, pattern and colour. Faster technology makes copying easier and infringement trickier, so designers must know how to protect their own work and respect others'. For example, a new bicycle frame can be a registered design, its suspension a patent, the brand logo a trademark, and the poster automatically copyrighted — four protections each in place.
8. Cost-effectiveness and key evaluationEvaluating products and production systems means weighing several factors at once: is quality stable, is cost reasonable, is timing on schedule, how great the environmental impact. Cost-effectiveness compares what you put in with what you get: doubling cost for double the life is worth it; ten times the cost for a one-per-cent better experience deserves doubt. The same comparison applies when choosing processes, tools and materials, so that a sensible manufacturing plan can be arranged. For example, an injection-moulded plastic screwdriver handle is cheaper than metal, insulating, fast to make and consistent in quality; a metal handle feels premium, but its cost and weight do not suit the home market — evaluation is always a balance, never a single champion.

4Diagrams Diagrams

5Worked example Example

6Common mistakes Mistakes

7Quick check Quick check

8Recap Recap

• CAD models make ideas precise, editable and machine-ready
• Ergonomics fits the product to people; standards are the safety floor
• Four processes: removing, forming, joining, surface treatment
• IP has four kinds: copyright is automatic; trademark, patent and registered design need registration
• Evaluate products against quality, cost, lifespan, safety and environment together