Construction 3D printing, also known as concrete 3D printing, is the process of printing structures with concrete materials. Even though these printers use the additive manufacturing principle, they face different challenges, and the 3D printing process is therefore slightly different in terms of the equipment used, the parameters to be controlled and the systems for printing a structure.

We take a quick look at the stages of 3D printing, the factors influencing print quality, and the process involved in construction 3D printing.

Concrete 3D printing steps

A typical concrete 3D printing process follows three steps: data preparation, concrete material preparation, and 3D printing.

Data preparation

The data preparation step involves the generation of trajectories for the robotic arms. The nozzle is attached to the robotic arm and moves using massive guide rails. These also form the boundaries of the print area. The robotic arm with its nozzle moves within the boundaries of the area in the same way as an extruder in an FDM 3D printer.

The advanced software creates individual slices of the model to be 3D printed. The path is then drawn and the movement of the arm is optimized to 3D print the concrete structure.

Concrete preparation

The concrete material preparation step prepares the material for use in the 3D printer. Concrete is more difficult to work with than other traditional 3D printing materials. Preparing, mixing and loading the concrete 3D printing material into a container is all part of the material preparation step. This freshly prepared material is then pumped into the nozzle as needed during printing. Mainly, four factors influence the print quality during this step.

1. Pumpability: The ease with which material is moved through the pump delivery system.
2. Printability: The ease and reliability with which material can be deposited using a deposit device.
3. Buildability: Resistance of a wet material deposited to deformation under load.
4. Open time: The period of time during which the other three properties are consistent within acceptable tolerances.

The behavior of fresh concrete, in particular its pumpability and constructability, deteriorates over time in 3D concrete printing processes, and it is essential to balance it in order to obtain satisfactory results. Fluidity also decreases over time, which can lead to intermittent deviations in material deposition. These properties, however, are difficult to control and vary widely depending on the manufacturer’s concrete mix, the delivery systems used, and the deposition device used. A slight variation in any of these items can have a significant impact on print quality.

Concrete 3D printing Treat

There are several 3D printing construction technologies but the printing process is usually carried out by gantry systems or robotic arm systems.

In the gantry system, the manipulator, a device for handling concrete material eliminating the need for physical contact by an operator, is mounted on the ceiling to locate the printing nozzle in XYZ coordinates. But it also limits the amount of freedom of the 3D printer.

In robotic arm systems, because it eliminates the use of a manipulator, the system provides additional degrees of freedom to the nozzle, allowing more precise printing workflows such as printing with the tangential continuity method.

But, regardless of the system used for construction 3D printing, the coordination between the speed of movement of the nozzle and the material flow rate is crucial for the result of the printed filament. If required, multiple robotic arms can be programmed to operate simultaneously to reduce overall print time.

After 3D printing, post-processing procedures can be applied to remove excess parts created as support structures or any surface finishing is required. It can also be automated in some cases.

To learn more about the construction 3D printing industry in India and get in touch with relevant stakeholders, please contact us at [email protected]

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