Centre for Fine Print Research University of the West of England Centre for Fine Print Research
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Case Studies

Solid free-form fabrication in fired ceramic as a design aid for concept modelling in the ceramic industry


Design case study: Denby sugar bowl (Download the PDF)

The UWE Centre for Fine Print Research (CFPR) collaborated with Denby Pottery in a project which set out to investigate the practical implications of recent research into the development of a novel 3D printable ceramic material for rapid prototyping in the ceramic industry. Denby is one of the UKs longest-established ceramic manufacturers and is well known throughout the world for the quality of its stoneware, china tableware and glaze finishes. The design team at Denby already make extensive use of 3D computer aided design and rapid prototyping within their new product development process. Currently the Denby design studio has a Z-corp 3D printer which is used to fabricate concept models in a plaster-based composite material.

The aim of the project, which was funded by UK AHRC follow-on funding scheme, was to explore and demonstrate the application of rapid prototyping in a ceramic material which could be fired and glazed, in order to better represent the visual and tactile qualities of a manufactured ceramic item. Ceramic powder-binder 3D printing is a layer-by-layer fabrication process in which a specially-prepared ceramic powder is bound together by a liquid binder which is selectively deposited by an inkjet print head. Following 3D printing, the “green” ceramic object is removed from the 3D printer and placed in an oven to dry. Any unbound (loose) powder surrounding the object is removed and then the object is placed in a kiln and fired at typically 1200oC.

One of the first items that the Denby designers invited the CFPR team to make by ceramic 3D printing was a sugar bowl. The shape of sugar bowl was based on an existing Denby production item. Denby designers added a flower pattern in low relief on the lid and sides of the sugar bowl. The relief pattern would be challenging to make using conventional ceramic forming techniques such as slip casting because of the difficulty of releasing the item from a mould. However it could potentially be made by ceramic 3D printing. The Denby production sugar bowl is shown in figure 1 and the 3D CAD model of the sugar bowl with flower relief pattern is shown in figure 2.


Figure 1 Denby production sugar bowl


Figure 2 Sugar bowl with flower relief pattern, 3D CAD model

The sugar bowl and lid were 3D printed in ceramic and then depowdered and dried in an oven. The sugar bowl and lid were then placed in the kiln to be fired. The results of the first attempts at firing the ceramic sugar bowl are shown in figure 4. The first attempt at firing the sugar bowl and lid was unsuccessful because the items were unsupported during the firing process. The 3D printed ceramic powder is held together by an organic binder. As the 3D printed items are heated in the kiln the organic binder burns out before the sintering temperature for the ceramic powder is reached. This means that the 3D printed ceramic items pass through a vulnerable stage when there is no binder present to hold the powder together. At that stage any unsupported shapes are likely to collapse before the sintering temperature is reached.

Figure 3. Sugar bowl in the kiln

 

Figure 4. The first attempts at firing the 3D printed ceramic sugar bowl and lid were unsuccessful

In order to support the 3D printed items during the firing process, it is necessary to design and make purpose built setters. Setters are support structures that help maintain the shape of the ceramic item during the firing process. Setters are commonly used in conventional ceramics to maintain the shape of vulnerable items as they are fired, for example, vitreous ceramics with thin sections.
When using 3D CAD software, it is a relatively quick and easy process to generate a setter simply by offsetting the external or internal surfaces of the shapes that require support. The design of the setters for the sugar bowl and lid are shown in figure 5.

The 3D printed ceramic sugar bowl, together with support structures (setters) are shown in the kiln in figure 6. The fired ceramic sugar bowl and lid are shown in figure 7. Following the first firing, the sugar bowl and lid are dipped in a porcelain slip, as shown in figure 8. This increases the density of the 3D printed ceramic and improves the surface finish. Following dipping, the sugar bowl and lid are fired for a second time. The results of the second firing are shown in figure 9.

Figure 5. Setters for the sugar bowl and lid, 3D CAD models

Figure 6. Sugar bowl and lid on setters in the kiln

Figure 7. Fired ceramic sugar bowl and lid

 

Figure 8. Dipping the sugar bowl in porcelain slip

Figure 9. Sugar bowl and lid following second firing

 

Figure 10. 3D printed ceramic sugar bowls, fired and glazed

This case study demonstrates that ceramic 3D printing may be exploited to create a concept model in fired ceramic with low relief surface patterning which would be difficult to make by conventional ceramic forming techniques. The ceramic concept model was successfully fired and then glazed in the conventional manner, as shown in figure 10. In collaboration with Denby, work is ongoing to develop a range of glazed finishes which are compatible with the UWE ceramic powder-binder 3D printing process, enabling finished items to take on the appearance of a conventionally-formed ceramic piece.