Robotic arm printing

Robotic arm printing is 3D concrete printing in which the nozzle is carried by a multi-axis industrial robot arm rather than by a frame. Because a six-axis arm controls orientation as well as position, the nozzle can be tilted to follow a curved surface, print inclined or non-planar layers, and approach a part from directions a gantry cannot reach. The trade-off is reach: a standard arm works within a radius of a few metres, so the element, not the building, is normally the unit of production.

In practice

Arms are most often used in a plant for precast components, façade panels, formwork and connection nodes, where the same cell can also handle finishing and handling operations. Reach is extended by mounting the arm on a linear rail, a rotating table or a mobile platform, at the cost of added calibration. Toolpaths are usually generated in a parametric environment and posted to the robot's own controller, so the workflow involves robot programming rather than conventional slicing alone. Payload, hose management and the torque of the extruder on the wrist are the practical constraints, along with the safety enclosure an industrial arm requires.

Related terms

• Gantry printer — a frame-based printer with a larger envelope but a fixed nozzle orientation.
• Toolpath — the programmed path the nozzle follows, which an arm can define in six axes.
• Precast — factory production of elements, the setting in which arms are used most.