Clay and porcelain for 3d printing

Our printers are capable of printing a wide variety of materials, including standard clay, technical ceramics, porcelain, cement, and biomaterials. Printed objects from clay can be processed using standard ceramic techniques: dried, fired in a ceramic kiln, glazed if necessary, and fired again. Freshly printed pieces that have not yet dried can be smoothed, sculpted, cut, and joined - just like regular wet clay. It is recommended to perform these operations when the clay reaches a leather-hard stage, that happens few hours or one day after printing.

General Requirements for Materials

During the printing process, the material is pressurized to approximately 2–4 atm inside the syringe. From there, it is pushed through a hose into the print head and then extruded through the nozzle. Therefore, the primary requirement for any material is good extrudability—even if the hose is short and has a relatively large diameter.

Clay and porcelain are easy to extrude and can be used without special additives. Using clays specifically formulated for 3D printing generally does not offer significant advantages. Moreover, clay manufacturers currently have limited experience with 3D printing, and the formulations of such clays are often based on the subjective experience of a few enthusiasts. These specialized clays are not necessarily better than standard sculpting or pottery clays.

In general, the following recommendations can be made regarding clay. Good extrudability is achieved with a high content of fine clay particles. However, high particle dispersion also increases stickiness (high elasticity), which can cause the material to adhere to the nozzle. This may result in the nozzle dragging the printed layer, bending or tearing the walls of the object. This issue is more common when printing with porcelain and less so with clay. The effect is especially detrimental when printing with retraction, where the nozzle prints several closed contours per layer and moves between them.

To mitigate these effects, it is recommended to avoid additives with anisometric (elongated) particles, such as paper or synthetic fibers, bentonite, etc. Instead, clays containing grog (larger particles of pre-fired clay) are preferable. Typical recommended grog particle sizes are 0.25 or 0.5 mm. The maximum particle size should not exceed one-quarter of the nozzle diameter being used. If natural clay is used, it should be sieved before printing to prevent nozzle clogging. In such cases, using a smaller nozzle diameter can help reduce material adhesion to the nozzle.

Concrete is a more complex material and is generally prone to separation under pressure. Standard concrete mixes used for casting walls or foundations are unsuitable for 3D printing. Special concrete formulations designed for 3D printing must be used, or high-dispersion components (such as fly ash or bentonite) must be added manually to prevent separation into heavy particles and water. On the other hand, aggregates larger than sand should be avoided (this does not apply to specialized concrete 3D printers). Due to its relatively low viscosity, concrete typically has good extrudability and can be printed through large nozzles (≥4 mm), provided the separation issue is resolved.

New materials: If you're unsure whether your experimental material has sufficient extrudability, we recommend testing it by extruding it through a 50 ml medical syringe with an outlet diameter of 1–2 mm. This is usually a reliable indicator.

Viscosity and Plasticity

Material Mixing

Material Loading

Material Examples

Nozzles, Substrate, Printing Conditions

Pottery equipment