Once you’ve studied form, surface, and interface, the next step is what actually holds a product together. This is where “clean design” either becomes robust or fragile. This part of the series covers mechanisms (hinges, latches, springs, sliders) and structure (ribs, bosses, fasteners, snap fits).
1. Mechanisms
Mechanisms are the parts of a product that create movement or feedback. Studying them teaches you how designers & engineers balance usability, durability, and cost.
Macbook hinges are torque-balanced. They allow smooth, one-finger opening and stays stable at any angle. In most other laptops, hinges wobble, loosen, or crack.
Cheap plastic remote controls have membrane keypads with rubber domes. They give low-cost tactile feedback but fail after repeated use. Premium remotes use mechanical switches with consistent clicks.
Car door hinges are detented to “hold” at certain angles (half-open, full-open). These detents are engineered so the door doesn’t swing freely on slopes.
Kitchen drawer slides use ball bearings or rollers for smooth motion. Premium slides soft-close; budget ones scrape or stick because they lack dampers.
2. Structure
Structure is the hidden skeleton in the body that determines strength, weight, and assembly/service speed.
Most IKEA tables have hollow honeycomb cardboard core sandwiched between fibreboard skins. Lightweight, cheap, strong enough for intended use.
Native M1/M2 purifiers have ribs under the water tray that prevent bending.
Plastic enclosures in routers, toys, appliances will have ribs, bosses for screws, and snap hooks. These small details prevent warping and reduce material use.
Dyson Vacuum cleaners have lattice structure that distributes suction evenly across chambers without adding weight.
Cheap plastic chairs have ribs on the underside to reduce flex and allow thinner walls. It makes them lighter but still strong enough to carry weight.
3. Failure and compromise
Hinges loosen when torque isn’t distributed properly (cheap laptops, doors).
Plastic surfaces crack when ribs are too thin or bosses are too tall.
Glue replaces clips in cost-cut products, making repairs harder and less durable.
Structures over-designed for strength often add unnecessary weight and cost.
Failure is where you learn most so study bad products too so you know what not to do.
Things to do
Flip any plastic part over. You’ll see ejector pin marks, ribs, bosses. Take notes of those marks as cues for manufacturing details.
For an intended motion type (spring, magnetic, bearing, friction), figure where will it wear down first?
Take clear photos of the product from all sides before opening it. Focus especially on hinges, latches, and seams.
Write down your guess about the mechanism before disassembly. Is it spring-loaded, friction-based, magnetic? Note why you think so.
Measure the motion. Use a ruler or caliper to note hinge rotation, button travel, or slider distance. Record the proxy resistance you feel.
Open the product carefully. Note if it’s held together by screws, snap fits, adhesives, or hidden clips. Document with step-by-step photos.
Sketch the mechanism. Draw the hinge, latch, or spring in simple form and label parts like pins, springs, or magnets.
Identify structural details inside the casing. Look for ribs, bosses, snap hooks, reinforcements, and ejector pin marks.
Mark failure points. Circle areas that could crack, loosen, or wear out and write why (thin walls, weak joint, material choice).
Compare with a premium alternative in the same category. Write down differences in mechanism, reinforcement, materials, and feel.
Log everything in a teardown template with photos, sketches, mechanism notes, and reflections. Keep this as part of your teardown archive.
End with redesign notes. Write 2–3 bullets on how you’d improve the mechanism or structure for cost, durability, or simplicity.