Flat-Pack Plywood Lamp: Design for Manufacture and Mock-Up Fidelity
A Year 11 class is designing a flat-pack desk lamp to sell at a weekend market. The brief: laser-cut from 3 mm plywood, every part must fit inside a 300 × 300 mm sheet, no glue or screws, flat-packs into a 320 × 320 × 40 mm box, holds a 5 W LED strip with a 6 mm cable, and sells for under $18. The laser bed is 600 × 400 mm, so two lamps can nest per sheet. One student's final idea uses seven parts and three different slot widths; another uses four parts and one slot width of exactly 3.0 mm. The class must present one A3 sheet that lets a buyer see what the lamp looks like lit, and lets the laser operator cut it without asking questions. A student has built a 1:1 model from 0.6 mm card and it fits together beautifully.
1. Judge which of the two ideas is the better design for manufacture and justify your judgement against the brief.
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The four-part idea wins on most counts, but not on all of them.
Where it wins: four parts means fewer cuts, less assembly time, fewer chances of an error in a market-stall batch. One slot width means one laser setting and one measurement to check. Fewer, larger parts also nest better on a 300 × 300 sheet, which directly serves the under-$18 target because material waste and machine time are the main costs.
Where it is a risk: a slot of exactly 3.0 mm assumes the ply is exactly 3.0 mm. Real 3 mm ply varies by roughly ±0.2 mm, and the laser kerf removes another 0.1–0.2 mm, so a 3.0 mm slot can be loose enough to wobble or tight enough to split the ply on assembly. The single slot should be drawn at about 3.1 mm and a test joint cut before the batch.
Where the seven-part idea has merit: more parts can create better light diffusion or a shade that angles without a hinge, which is a performance gain, not just complexity. But it has to earn that complexity against the brief's constraints, and nothing in the setup shows it does.
2. The card mock-up fits perfectly. Explain what it does and does not prove, and what you would do next.
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The card model proves the geometry of the assembly sequence: the parts go together in the intended order, nothing clashes, the proportions look right at 1:1 and the shade reads as a shade.
It does not prove the things the brief actually depends on:
- Thickness and fit – 0.6 mm card cannot represent a 3 mm slot with a friction fit. The whole joinery concept is untested.
- Laser kerf – card cut by hand has no kerf; the laser will remove material and change the fit.
- Strength and stiffness – card is not a proxy for ply in bending; the shade may sag or the base may flex.
- Loading and cable – the 5 W strip, the driver and the 6 mm cable add weight and a route that the card model does not test.
- Flat-pack size – whether the parts nest inside 320 × 320 × 40 mm is a drawing question, not a card question.
Next: cut one test joint at 1:1 from an offcut of the actual ply at the actual laser setting, then a full 1:1 ply prototype and a timed assembly. Only after that revise the slot dimension.
3. Recommend what goes on the A3 presentation sheet and how the lamp should be rendered, so the sheet serves both the buyer and the laser operator.
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The sheet needs two audiences, so split it by purpose rather than decorating one drawing.
For the buyer (presentation side): one large three-quarter view with the lamp lit. Render with a clear single light source: warm light escaping under the shade, a cool ambient fill on the outside faces, and a cast shadow to sit the object on a surface. Show the plywood as a material, not a flat colour – a light base tone with a slightly darker edge band to indicate the laminated edge grain. Keep the background minimal so the contrast does the work. Do not render over the joinery; leave the slot visible.
For the laser operator (technical side): an exploded isometric with numbered callouts and a parts list (part number, material, thickness, quantity), a 1:1 section detail through the slot showing its true width and depth, the nesting layout on the 300 × 300 sheet, and overall dimensions only where they matter.
Label the scale and projection on every technical view; the presentation view can be marked 'not to scale'.