Image: Research Associates Rosy Heywood and Sonny Lightfoot using the extruder
Written by Rosy Heywood, Research Associate, Centre for Print Research
The production and prototyping of ceramic media has been predominantly based at the Centre for Print Research labs. The centre has expansive facilities with an array of technical equipment. Specialist machinery used in this project includes a hydraulic piston extruder and 3D printer. Other workshop equipment was utilised including an industrial dough mixer, ball mill and laser cutter.
During the design phase of creating the ceramic media it was considered a requirement that the production methods are able to produce 160 pieces of each type of media efficiently and consistently in size and also, the production method should be scalable and easily repeatable for future experimentation.
In our research, the importance of the porosity of the ceramic media was being analysed. And three production methods were established for the creation of three sets of media of varying porosities. Low porosity media was produced through extruding standard terracotta clay, medium porosity was produced by extruding a clay and sawdust composite and high porosity media was produced using an organic foam impregnation method. The specialist technical equipment used for low and medium porosity media is detailed below.
With its origins in the production of bricks, extruders are now used in many different industries. According to Frank Handle in Extrusion in Ceramics, notable applications are in the production of foodstuffs such as pasta, shaping of aluminium profiles, wrought copper alloys and steel and for the extrusion of hard metal, graphite, coal and plastics.
The extruder housed at The Centre for Print Research was built by the technical team for the specific use with clay and clay composites. The clay is pushed through a die by the manually operated hydraulic ram. The die determines the extruded profile shape and size which can be extruded to different lengths.
To create the desired extrusions, we designed dies and 3D printed them to fit the ram cylinder. The benefits of using a piston extruder for this research is; it is easy to clean so small chance of contamination, little material is wasted and bespoke extrusion profiles can be produced with ease and precision using desktop 3D printers.
3D printing technology was utilised in this research to create bespoke manufacturing tools. Additive manufacturing is the production of 3D objects printed from a CAD (Computer Aided Design) model.
Filament is fed through the printer and the model is printed layer by layer. In prototyping we used a recycled Polylactic Acid (PLA) filament for the tools. PLA is a bio-plastic made from fermented plant starch and is commonly used in 3D printing due to versatility and ease of printing.
The advantage of using this technology is that we could create bespoke tools for specific processes during manufacturing the media. For example, a die was printed to extrude cylinders 20mm in diameter and a cutting jig was printed to cut them into exactly 20mm individual lengths.