Clay 3D Printer

What is Clay 3D Printing?

Clay 3D printing is an additive manufacturing technique that builds ceramic objects layer by layer from digital models. Unlike traditional sculpting, it allows you to create complex and intricate forms with exceptional precision — combining the material qualities of traditional ceramics with the design freedom of digital fabrication.

Our Machine: WASP 2040

We use the WASP 2040, an extrusion-based clay printer from Italian company WASP. It uses a screw/auger printhead to push clay through a nozzle at a controlled rate, building form layer by layer. Clay is delivered from a pressurised aluminium canister (Bolie gun) connected to a compressed air supply.

How the System Works

The machine has three key components: the rig (the WASP 2040 — a computer-controlled machine that moves the printhead in 3D space), the printhead (the auger mechanism that deposits clay), and the delivery system (pressurised aluminium container that feeds bulk clay to the printhead).

A screw/auger printhead uses the same gcode feed rate settings as plastic 3D printing — a motor turns the screw to push clay at a set rate. The settings are adjusted in PrusaSlicer for clay rather than plastic filament.

Applications

• Sculptural artworks and installations
• Functional pottery and vessels
• Prototype ceramic products
• Architectural ceramic components
• Complex geometric forms impossible with hand-throwing
• Parametric and algorithmically generated ceramics

Nozzle Size & Layer Height

The nozzle size determines the scale of detail possible and drives all other layer settings. Clay extrudes slightly wider than the nozzle itself — plan your settings accordingly:

Rule of thumb: Layer height is approximately one-third of wall width. Flatter layers (relative to wall width) give more structural stability. More rounded layers can look better aesthetically but risk delamination during drying.

Print Speed

• Small printers (WASP 2040): 25–30 mm/s print speed
• Large printers: 40–60 mm/s
• Travel speed: 30–50 mm/s — too fast can distort prints as the printhead moves between areas
• First layer: Slower than normal to ensure adhesion

Print Base

Plaster of Paris bats or unsealed wooden boards work well. Wet the board with a damp sponge just before printing so the first clay extrusion sticks. For objects requiring a base, roll out a clay slab to print onto rather than printing the base digitally — this avoids cracking from differential drying.

Material Diameter — The Critical Setting

The material diameter setting tells the slicer how much material is being fed. For clay this is set differently to plastic:

• WASP 2040: set material diameter to 1 mm
• WASP 40100: set to 2 mm

A larger number makes the software think more material is coming through — so the auger runs slower. A smaller number runs faster. If your flow rate (default 100%) seems way off, adjust the material diameter first before touching the flow percentage.

Recommended PrusaSlicer Settings (2 mm nozzle)

Saving Your Profile

Once you've configured your settings, save a named profile — e.g. Layer8_Nozzle2_Shell1. Use descriptive names that encode your key parameters so you can return to known-good settings. Do not overwrite the default Extra Coarse profile.

3D File Requirements

Wall thickness: Do not give your model a wall thickness in the 3D software. Draw just the path (a single surface). The wall thickness is defined entirely by the nozzle size and is set in the slicer. If you add thickness in your model, the slicer may try to print both an inner and outer wall.

Double/triple walls: Set Wall Line Count to 2 or 3 in the slicer — do not model this in your file.

Supported file types: STL, OBJ, 3MF, AMF, STEP/STP, SVG

Overhangs: Support structures generated by slicers don't work well in clay. Instead, model your own support — for example, a narrow 45° wedge under a chin or overhang that can be cut away once the clay stiffens.

Clay Consistency

Clay must be soft enough to feed through the system but firm enough to hold its shape as layers build up. Toothpaste consistency is the practical guide — the clay surface should look just moist, not wet or saturated.

Hard vs. Soft Clay

There's a temptation to use harder clay so the print doesn't collapse — but this creates more problems than it solves:

• Harder clay requires more pressure to push through the system
• Higher pressure squeezes water out of the mix, making the remaining clay even harder
• Very hard clay causes layers not to bond together — resulting in delamination or cracking during drying

Use soft clay at 4–5 bar pressure. If prints are collapsing, use a heat lamp or warm air to stiffen clay as you print — not harder clay.

Clay Shrinkage (Critical for Sizing)

Clay shrinks as it dries and again when fired. Shrinkage is greater in the vertical direction for 3D-printed forms (due to layer compression). As a guide when firing to 1220°C:

Account for this shrinkage when designing your model — scale up accordingly in your 3D software before printing.

Drying

As clay dries it shrinks. Uneven drying causes distortion and tension — at worst resulting in cracking. Allow objects to dry as evenly as possible:

• Most prints can be left to dry naturally in a room
• For forms with internal structures or infill, drape plastic sheeting over them to slow drying and equalise moisture
• Avoid placing in direct sun or near heat sources

Working Through the Ceramic Stages

1. Green / wet clay — just printed; very fragile, do not disturb
2. Leather hard — firm enough to handle, can be trimmed and refined; ideal point for surface work
3. Bone dry — fully air-dried; ready for bisque firing
4. Bisque firing — first kiln firing, removes remaining moisture, creates porous but stable ceramic
5. Glaze firing — optional; apply glaze and fire again for a finished surface

Recommended Software

File Formats Accepted

Export your model in any of these formats for use with PrusaSlicer:

.stl   .obj   .3mf   .amf   .step / .stp   .svg

The slicer will generate a .gcode file — the language used by the WASP 2040 to control movement, speed, and extrusion. GCode can be opened in a text editor and, at its most basic, is not too difficult to read.