The University of Technology in Liberec cooperates with the Klokner Institute on the 3D STAR project which investigates the possibilities of additive manufacturing and indicates the directions in which future construction could go. The main role is played by scientific and technical staff from the experimental department and the mechanics department.
Materials used in 3D printing
New 3D printing processes focus on innovative printing materials and ways of using them. Experience from printing on conventional 3D printers using conventional materials (plastics) is used to develop concrete printing. Employees of the experimental department are developing a mixture of cement composite (concrete) with properties ideal for the additive form of 3D printing.
The field of mechanics contributes with its experience in designing the shape of the products, the extrusion system and the control of the print. An important element is the optimization software itself, in which the desired object is “cut” into individual print layers, and the trajectory of the print head is generated so that the print is continuous. By shifting the focus of work from traditional designing to programming motion paths, the job of a civil engineer will begin to overlap with the job of a robotic systems programmer.
Any material can be used in 3D printing
Computer-controlled machines have no problem with any shape, mixture ratio or accuracy in the order of millimeters, milliliters, or grams. Exact measurement and control of outputs significantly expands the possibilities of optimizing process control within the entire print. Printing takes place on the TEST BED plotter device which was developed by the workers of the Technical University of Liberec.
In 2021, different types of print heads were tested depending on the type of print compound, the shape of the printed object, and the speed/method of printing. For a cement composite, consistency, amount of components and reinforcement with dispersed reinforcement were adjusted depending on the technological complexity and requirements for the resulting mechanical-physical parameters of the printed object.
Extensive applications for the future
Printed objects or their parts were tested in the laboratory’s loading machines, and the results served as a basis for computational models, which are continuously refined and used for static assessments. In 2022, more extensive practical applications are being prepared as part of the project. In addition to test specimens, e.g., a footbridge will be printed, which will undergo load tests in the near future.
Link to 3D star: http://3dstar.tul.cz/.