At first glance, 3D printing might seem like a fully digital manufacturing process: prepare the data, send it to the printer and wait for the finished product. But according to Jan Vítek, a designer and lecturer at the Faculty of Mechanical Engineering at Brno University of Technology, ceramic 3D printing is far from that simple. Clay remains soft during printing, reacts to moisture, dries and shrinks. This means that makers need not only digital design skills but also an understanding of the material – and sometimes they literally have to lend the print a helping hand. At Maker Faire Brno, taking place at the Brno Exhibition Centre on 17–18 October, Jan Vítek will introduce participants to the world of ceramics and 3D printing in his workshop.

What first drew you to ceramic 3D printing?

I first encountered it while working on my bachelor's thesis. I was mainly interested in parametric and generative design methods, and an opportunity came up to explore porcelain 3D printing in collaboration with a porcelain studio in Brno. At the time, I was actually more interested in the design methods than in porcelain itself.

I was experimenting with SLA printing and even tried developing my own porcelain-based material. The result was a small collection of porcelain cups. I became so fascinated by the subject that it has stayed with me ever since. I later returned to it in depth during my doctoral research at BUT's Faculty of Fine Arts.

So it wasn't your experience in a pottery class that led you to it?

I did attend pottery classes, and I really enjoyed them. I also worked with ceramics because of my hobby of growing bonsai trees – I needed to make my own pots. So I came to the subject from several directions, but the collaboration with the porcelain studio was particularly important. It was an incredibly enriching experience and motivated me to continue working in this field.

How would you explain the basic principle of ceramic 3D printing?

Surprisingly, it's similar to one of the oldest pottery techniques – building vessels from coils of clay. A potter rolls out a coil of clay and gradually builds up the shape. A printer essentially does the same thing: it extrudes material through a nozzle and deposits it in layers along predefined toolpaths.

Some international practitioners therefore use the term Computer Assisted Coil Building. In a way, modern technology builds on a traditional ceramic technique.

Do you need a special ceramic mixture for printing?

You can use ordinary pottery clay. However, you need to adjust its consistency with water so that it passes smoothly through the extruder and nozzle. Both smooth clay and clay containing grog can be used. Grog can help the print retain its shape and reduce deformation, but the particles must not be too large, as they could wear down the extruder. Ultimately, it's still ceramic clay.

What do you see as the main advantage of additive manufacturing over conventional ceramic production methods?

Primarily in one-off and small-batch production. Conventional manufacturing often relies on plaster moulds, which are relatively expensive to make. They therefore only become economically viable when producing larger quantities.

With 3D printing, I can modify a digital design almost instantly. If I want to create another version of a product, I simply change the input data and print it. With conventional manufacturing, every significant change would often require a new mould. For designers, this opens up much greater possibilities for variation and customisation.

You also built your own printer during your doctoral studies. How difficult was that?

Commercial ceramic 3D printing systems are available, but they're quite expensive. I had a general understanding of how they worked: you have a reservoir that feeds material into a screw extruder, which then pushes it through a nozzle.

So I decided to try building my own system. That was followed by a long process of development and gradual fine-tuning. It took about two years before the printer worked the way I wanted it to. I think its results are now comparable to those of some commercial machines.

What's the hardest part of ceramic 3D printing?

The main difference compared with printing plastic is how the material behaves. Plastic solidifies relatively quickly after being deposited. Clay hardens as it dries, which is much slower, so the entire print remains soft throughout the printing process.

This means it can collapse or deform, and creating features such as overhangs is more difficult. Sometimes you need to dry the print as you go, perhaps using warm air. But clay also has one advantage: it isn't hot. If I need to hold an overhang in place with my finger for a moment or support it with a piece of clay, I can do that. Once the object has dried, these interventions can be touched up fairly easily.

Does that mean ceramic 3D printing isn't as automated as people might expect from digital manufacturing?

Exactly. We often imagine 3D printing as a process where you send data to a machine and don't have to worry about anything else. With clay, it's still very much a craft. You need to understand the material and how it behaves, monitor the process during printing and intervene when necessary. It's precisely this combination of traditional craftsmanship and digital skills.

What has surprised you most about the possibilities of ceramic 3D printing?

Above all, how much clay can actually handle. I was surprised by how thin the walls could be and how much detail you could achieve. Initially, I also thought the softness of the material would severely limit the complexity of the shapes.

But it turned out that if you find the right approach, you can create objects that would be practically impossible to manufacture using conventional methods. The technology really opens the door to entirely new forms.

Why would some shapes be impossible to produce using conventional methods?

Moulds are one of the main challenges. You have to be able to remove the finished product from them. If an object has undercuts facing in awkward directions, internal recesses or very complex geometry, you need an extremely complicated mould – and sometimes it's not even possible to divide the mould in a way that allows the product to be removed. Of course, the more complicated the mould, the more expensive it becomes. With 3D printing, this problem disappears in many cases.

Ceramic 3D printing doesn't have to be limited to design objects. Where else do you see potential applications?

A lot depends on the specific technology. For example, there are powder-based ceramic printing methods that are also used for more precise technical applications and high-temperature components. Extrusion printing, which is what I focus on, is less precise because of the layer height and the width of the extruded material, so it isn't suitable for some highly specialised technical applications.

However, I see great potential in large-format printing and architecture. Clay is an interesting material in this respect, partly because it can be sourced locally. In the past, clay for construction was also obtained locally, much like the material used by local brickworks. Today, people are experimenting with small-scale architectural structures and additives that can improve clay's resistance to moisture.

Compared with concrete, clay has interesting properties in terms of sustainability and indoor climate. Of course, many challenges remain: drying large prints, cracking, structural failures and water resistance. But I believe further development will help overcome some of these obstacles.

You also presented your printer and ceramic 3D printing at the international FabX gathering. How did visitors respond?

I was delighted by the unexpectedly high level of interest. The workshop was originally planned for ten people, but more than thirty turned up. Afterwards, people from different parts of the world contacted me, even from New Zealand, asking for details and sending me the results of their own experiments. I also discussed the subject with colleagues from the University of Porto.

I think people are attracted partly by the fact that ceramic 3D printing is still a relatively new and unexplored field, and partly by the material itself. Ceramics have a completely different character from plastic. The combination of a beautiful traditional material with digital technology is what makes it so interesting to me as well.

Thank you for the interview. Finally, I'd like to add that anyone interested will soon have another opportunity to attend your workshop, this time at Maker Faire Brno. The festival takes place at the Brno Exhibition Centre on the weekend of 17–18 October. Jan Vítek will be running his workshop on Saturday morning. Tickets can be purchased online via the Maker Faire website.