Underside comparison of an original piston, a casting with runners, and a trimmed casting

Project / 09 · Applied Research

Piston Reverse Engineering

From a vintage car part to a reconstructed model and a newly cast piston.

Piston Reverse Engineering

Developing a 3D repair cycle for old or broken vintage car parts: scanning the original, repairing it digitally, producing moulds through 3D printing, and casting and post-processing the replacement.

Year
2020
Role
Researcher, Designer
Original piston, mould patterns, sand moulds, casting, and trimmed replacement arranged as a production sequence
Section through the scanned piston in yellow beside the reconstructed CAD geometry in grey
Overlaid piston cross-sections and a red-and-white surface comparison highlighting geometric deviations

Reverse engineering

Reconstructing a design from a 3D scan is not only about replicating its design features. The complex geometry of a piston required a multi-step fabrication strategy combining positive and negative moulds. Functional requirements such as weight, centre of mass, and production limitations made this case study particularly complex.

The project followed seven steps:

  1. 3D scanning
  2. Reverse engineering
  3. Mould design
  4. 3D printing plastic patterns for the outer sand mould
  5. 3D printing the sand core for the internal cavity
  6. Metal casting
  7. Post-processing

To record and compare design versions, a Grasshopper script was developed to track deviations from the original geometry and visualise problematic areas.

Original piston, its scanned surface, and a transparent reconstructed CAD model
Two sand mould halves, a top plate, and a core used to form the piston
Original piston beside a fresh casting with runners and a trimmed casting
Four cast pistons viewed from beneath to show their internal cavities and pin bosses
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