Reverse Engineering with CAD: Rebuilding Broken Parts at Home
Have you ever had a tool, appliance, or piece of equipment fail because of a small broken part? Most of the time, replacements are expensive, hard to find, or no longer manufactured. That’s where reverse engineering with CAD and 3D printing comes in—allowing you to recreate broken components at home and bring items back to life.
What is Reverse Engineering?
Reverse engineering is the process of reconstructing an existing part into a digital model so that it can be repaired, improved, or reproduced. In a home or small-lab setting, this usually involves:
Measuring the broken part (with calipers, micrometers, or even 3D scanning).
Modeling the geometry in CAD software such as SolidWorks or Fusion 360.
Prototyping a new version with 3D printing, CNC machining, or another fabrication method.
Tools You’ll Need
Measuring equipment: Digital calipers, ruler, or micrometer.
CAD software: SolidWorks, Fusion 360, or FreeCAD (open source).
Fabrication tool: FDM 3D printer for plastics, or CNC if the part needs to be in metal.
Optional: A 3D scanner for complex geometries.
Step-by-Step Example
Imagine a plastic gear in a coffee grinder has cracked:
Disassemble carefully to remove the broken gear.
Take measurements of diameter, number of teeth, and shaft bore using calipers.
Model in CAD by sketching the gear profile and extruding it to the correct thickness.
Choose material: PLA might work for testing, but PETG or nylon is better for long-term durability.
Print and test fit the replacement gear.
Refine as needed—small tweaks to tolerances can make a big difference.
Benefits of Reverse Engineering at Home
Cost savings: Printing a $1 replacement part vs. buying a $50+ assembly.
Sustainability: Keeps equipment out of landfills.
Customization: Improve weak spots in the original design.
Skill building: Enhances your CAD, measurement, and fabrication abilities.
Tips for Success
Overbuild slightly: Add extra thickness or fillets to reduce stress points.
Use stronger filaments (nylon, PETG, or carbon-fiber filled) for mechanical parts.
Iterate quickly: Expect to make 2–3 prototypes before the part works perfectly.
Document your process: Take notes and save CAD files for future use.
Closing Thoughts
Reverse engineering isn’t just for big engineering firms—it’s a powerful way for makers, students, and engineers to extend the life of everyday equipment. With a simple set of tools and some creativity, you can transform broken parts into an opportunity to learn, save money, and practice real-world engineering skills.