learndesign.tech Search

Reverse engineering a product

Design Project 2 weeks Medium build

Take a product apart down to its base components, mount every part on a display board (knolled, grouped and hand-labelled), then explain how it works in a group presentation where each member presents three slides.

The parts of a disassembled cordless drill laid out at right angles on a white sheet, grouped by type, photographed from directly above.

Overview

Everything manufactured was designed by someone who made decisions: what to mould, what to stamp, where the screws go, how the case snaps together, how the thing is meant to be assembled in a factory and never taken apart again. Reverse engineering is reading those decisions back out of the object.

You take a product apart until nothing can be separated further without breaking it. Every screw, spring, gear, board and moulding then goes onto a display board: laid out at right angles, grouped, evenly spaced, and mounted tightly enough that the whole thing can be picked up, tilted and hung on a wall without a part shifting. That layout is knolling, and the discipline of it is the point: you cannot organise parts you have not looked at. Categories and part names are written on the board by hand.

The board has to explain the product to someone who has never seen inside one. The presentation does the same out loud: every group member presents three slides, with the board up front to point at.

Good candidates: a cordless drill, an electric toothbrush, a computer mouse, a hard drive, an inkjet printer, a toaster, a mechanical toy, a bike derailleur, a stapler. Bring something you are curious about. It does not need to work.

Skills needed

  • KnollingEvery part at right angles, grouped by function or type, with even space between groups.
  • Mounting parts to a boardMatching the fixing to the part so nothing shifts when the board is lifted, tilted or hung.
  • Hand lettering for labelsConsistent size, placement and baseline. Pencil first, then ink.
  • Identifying materials and processesInjection moulding, die casting, stamping, machining, extrusion. Reading part lines, ejector marks and draft angles.
  • Measuring with calipersOutside, inside and depth measurements, and recording them in a table.
  • Modelling a part in FusionRecreate one part from your measurements. Pick something small — a bolt, a spacer, a clip.
  • Presenting with slidesThree slides each. One idea per slide, photos over text, and point at the real part on the board while you talk.

Assessment

Criterion Developing Proficient Exemplary
Disassembly Stopped at sub-assemblies; parts broken Fully separated to base components, fasteners bagged Separated cleanly and could be reassembled from your documentation
Knolling Parts scattered or overlapping Square to the board edges, grouped, evenly spaced The grouping is an argument about how the product works
Mounting Parts fall off or swing when the board moves Every part tight; the board can be lifted and tilted Fixings suit each part and stay out of the way visually
Labels Some parts named Every part and group hand-labelled, legible from a metre Consistent size, placement and baseline across the whole board
Inventory Parts listed Every part with material, process and function Processes identified from physical evidence and explained
Function description Names what it does Explains each subsystem and how they connect Explains why it was designed that way and what it cost
Presentation Slides read aloud, board unused, or some members present fewer than three slides Every member presents three clear slides and points at parts on the board Someone who has never seen the product understands it afterwards

Deliverables

  • The display board, every component mounted tightly and knolled into neatly labelled groups; category headings and part labels on the board
  • A presentation about how the product works (3x slides per group member)
  • One part replicated in Fusion from your caliper measurements

Materials

  • One product per group
  • Screwdriver set including Torx and security bits, spudger, pliers, hex keys
  • Zip bags and a marker for fasteners
  • A display board, plywood or stiff card, sized to the part count
  • Fixings to suit: wire ties, small screws, hot glue, clear elastic, pins
  • Fine black pen or marker for the hand-written labels
  • Calipers

Steps

Week 1: Take it apart

  1. Photograph the product whole, from several sides. Note anything on the labels: model, ratings, where it was made.
  2. Batteries out. Then find the fasteners. Some hide under labels and rubber feet. Bag and label the screws from each stage so you know what came from where.
  3. Work from the outside in. Snap-fit cases open with a spudger at the seam, not a screwdriver. If something will not come apart, look for a screw you missed before you force it.
  4. As each sub-assembly comes out, keep its parts together until you have understood it. Then separate it fully.
  5. Keep a running list: what you removed, in what order, and anything that surprised you.

Week 2: Organise, mount, present

  1. Fill in the inventory table. For material and process, look at the evidence: parting lines and ejector pin marks mean injection moulding; a rough textured side and smooth machined faces mean die casting; sheared edges mean stamping. The names you choose here are the names that end up on the board.
  2. Measure five parts with calipers and add the dimensions to the table.
  3. Decide your categories. Structure, mechanism, electronics, fasteners, seals and springs is a reasonable default, but the best boards group by what the product actually does. Within a group, sort by size.
  4. Dry layout. Arrange everything on the board before anything is fixed, and leave room for the labels — they are part of the composition, not squeezed into gaps afterwards. Photograph the layout before you commit.
  5. Knoll it: every part parallel or perpendicular to the board edges, consistent gaps, nothing touching or overlapping.
  6. Mount every part. Match the fixing to the part — wire ties or small screws for heavy housings, hot glue for light mouldings, clear elastic or pins for springs and small hardware. Then pick the board up and tilt it. Anything that moves is not mounted.
  7. Hand-write the category headings and part labels. Legible from a metre, consistent size and placement throughout. Pencil first, then ink.
  8. Write the function description, one paragraph per subsystem: what it does, what it connects to, what would fail if it were missing.
  9. Photograph the finished board square-on in even light, plus a close-up where the labels are readable.
  10. Build and give the presentation on how the product works. Each group member makes and presents three slides. Split the product between you, by subsystem for example, so nobody repeats anyone else. Across the group, cover what the product was, how it comes apart, how the parts work together, and one thing that surprised you. Use your photos and inventory, keep the text short, and point at parts on the board while you talk.
  11. Replicate one part in Fusion from your own caliper measurements. Pick something small — a bolt, a spacer, a spring clip, a knob. Sketch it, constrain it, and drive repeated features with parameters. Check a measurement on the real part against the same dimension in your model before you call it done, then put a render beside a photo of the original.

Stretch options

  • Reassemble the product from your own documentation and see if it works.
  • Design the board so parts can be taken off and put back, and use it to teach the teardown to someone else.
  • Estimate the part count and the number of assembly operations, and guess at the factory cost.
  • Redesign one part so the product would be easier to repair.