The Design and Development of an Extrusion System for 3D Printing Cementitious Materials

Additive manufacturing (AM), popularly known as `3D printing', is a manufacturing technique that builds physical 3D objects layer by layer using materials such as polymers, metals, and cementitious composites. The widespread popularity of additive manufacturing in most industries ranging from biomedical to aerospace suggests a revolution in manufacturing which has recently emerged to the construction sector. Considered as the future of construction, AM is used in 3D concrete printing due to its benefits in reducing the waste and contributing towards circular economy goals through the use of recovered waste materials from demolition sites. This paper presents an active extrusion system for the 3D printing of cementitious materials for the construction industry. The system has been designed from first principles and therefore can be extended to other materials and scaled up with slight hardware modifications. A robust design has been realized using an unconventional yet simplistic approach. The extrusion system uses some additions to the design to generate a consistent output of material throughout a print. The effectiveness of the extruder is demonstrated through an extensive printing and testing of various printed objects.