The second robotic extruder developed in BioPol Track is developed for material grading. The extruder is designed to steer the mixing of two distinct composites across a continuous extrusion. In Eco-MetabolisticArchitecture the fibres and fillers are sourced from 2nd and 3rd generation feedstocks. Valorising them within 3D printed architectural elements introduces new dynamics to the sourcing and flow of resources. As new resource loops emerge within the circular bioeconomy. New use cycles introduce new value and their deployment therefore require novel modes of material specification and production that can address two criteria: material flexibility – the ability to interchange fillers and fibres in response to local material availability, and material optimization – the ability to specify the distribution of a graded material in response to design or performance criteria.
To enable material grading, the extruder is developed to include two connections to external continuous feeding systems that can be refilled without interruption to the printing process. The flow between the two materials is steered with pneumatic cylinders acting as pinch valves. The further integration of an overflow limit switch closes the valve and cuts the pressure to give the extruder time to process the material build up before restarting the material feed. Coordinated control for both pneumatic pumps is programmed into the robotic code, with Digital Outputs used to open or close the input of compressed air. Air pressure is controlled manually enabling a constant tuning during the print.
A simple test geometry is developed where the frequency of switches between two separate material feeds was incrementally increased to understand the behavior of the material before, during and after switching. The test geometry consists of a 30 centimeter by 30-centimeter panel, where lines in a five-millimeter offset were printed. Each test is run twice, producing two layers on the same geometry. Each layer switches between two material recipes.
The Eco-Metabolistic Architecture project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 101019693).
The Eco-Metabolistic Architecture project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 101019693).