Publications / 2017 Proceedings of the 34rd ISARC, Taipei, Taiwan

Optimisation of Different Concrete Mix Designs for 3D Printing by Utilizing 6DOF Industrial Robot

Pshtiwan Shakor, Jarred Renneberg, Shami Nejadi and Gavin Paul
Pages 268-275 (2017 Proceedings of the 34rd ISARC, Taipei, Taiwan, ISBN 978-80-263-1371-7, ISSN 2413-5844)

Abstract Additive Manufacturing (AM) technologies are becoming increasingly viable for commercial and research implementation into various applications. AM, such as three-dimensional printing, refers to the process of forming structures layer upon layer and finds application in prototyping and manufacturing for building construction. It has recently begun to be considered as a viable and attractive alternative in certain circumstances in the construction industry. This paper focuses on the utilisation of different concrete mixtures paired with extrusion techniques facilitated by a six Degrees of Freedom (DOF) industrial robot. Using methods of Damp Least Squares (DLS) in conjunction with Resolved Motion Rate Control (RMRC), it is possible to plan stable transitions between several waypoints representing the various print cross-sections. Calculated paths are projected via ‘spline’ interpolation into the manipulator for smooth paths and motions, controlled by customized MATLAB and C++ software. This article demonstrates the properties of different concrete mixture designs, showing their performance when used as a filament in 3D Printing and representing a comparison of the results that were found. In this study, the prepared materials consist of ordinary Portland cement, fine sand between (425~150) micron, coarse aggregate ranges (3) mm and chemical admixtures which have been used to accelerate setting times and reducing water content. Numerous tests were performed to check the buildability, flowability, extrudability and moldability of the concrete mixtures. The horizontal test was used to determine the flowability and consistency of the concrete mixture. In addition, the vertical and squeeze-flow tests were used to determine the buildability of the layers. The extrudability and moldability of the concrete mixtures were controlled by the robot and associated extruder speeds. Viable differences in the various concrete mixture designs and prints have been observed.

Keywords: 3D printing concrete, industrial robot, additive manufacturing, resolved motion rate control, squeezeflow test, speed control, moldability