Configurable Mold System for 3D Tiles — Open Source Digital Fabrication

What it is

A modular matrix of 16×16 ratchet cells that can be digitally configured to cast an almost unlimited number of unique tile geometries, all with a single reusable infrastructure. Instead of making a new mold for every shape, you reconfigure this one.

This system uses a repurposed FDM 3D printer as the actuator, which moves over each cell sequentially and sets its height position via G-code. No custom electronics, no individual actuators per cell , just a mechanical ratchet system and a printer you might already have lying around.

Why it exists

Traditional mold-making for unique architectural geometries is expensive, wasteful, and inaccessible at small scale. This project explores whether digital fabrication, specifically configurable casting, can offer a sustainable, low-cost alternative that anyone can replicate.

This system is rooted in maker culture and frugal engineering and open source principles: open, replicable, low-cost, and designed to give a second life to "obsolete" hardware.

How it works

The mold is a 16×16 matrix of ratchet cells (14×14mm each), each with 25 possible height positions (0–50mm, 2mm steps). A repurposed 3D printer moves over the matrix and pushes each cell to its target height using a wooden dowel attached to the print head. The G-code generation is implemented in Grasshopper, although the same process could be easily achieved using other scripting or computational design workflows.

While this prototype uses a repurposed 3D printer, any programmable positioning system (e.g., a robotic arm or CNC machine) could perform the same task.

Once configured, cell extenders and side walls form a cavity for casting. To ensure a watertight system, uniform pressure must be applied along the entire perimeter, compressing the sealing surfaces and preventing leakage. The system has been tested with white cement and marble powder.

What you can make

The system is designed for generating 3D tile-based surfaces. It can translate images into height fields by extracting grayscale values (e.g. portraits or patterns), generate data-driven reliefs from inputs such as temperature maps or other datasets, and produce fully custom architectural tile geometries. These can be assembled into larger compositions for facades, interior wall cladding, ceilings, or other surface systems, where each tile contributes to a continuous or patterned 3D relief surface.

Materials & printing notes

Print the ratchets and base in PETG. This is important, PLA may seem like the obvious choice, but its flexibility under repeated mechanical stress causes the ratchet teeth to deform over time, losing position accuracy. PETG holds up significantly better for anything that takes repeated load or pressure.

For the cell extenders, the pieces that sit on top of the ratchets and form the casting surface, I recommend experimenting with TPU. Depending on the geometry you're casting, demoulding can be tricky: undercuts and complex shapes tend to grip the set cement. TPU's flexibility makes extraction much easier and reduces the risk of breaking the tile during demoulding. It's worth the extra print time.

The side walls and separator can be printed in PLA without issues, as they don't take mechanical stress in the same way.