Robotic additive manufacturing along curved surface — A step towards free-form fabrication

This paper presents a method and process to fabricate parts or structures by printing along curved surfaces with use of industrial robots. Software is developed to generate the fabrication path program that can take advantage of the 6-DOF articulated industrial robotics. Unlike the traditional vertically layer-by-layer 3D printing scheme, with the angled printing capability, a robotic fabrication path can be designed along the direction of curved surfaces or the direction of physical property requirements such as higher mechanical strength, specific thermal, electrical and even biomedical characteristics. The fabricating path program such as G-code will be then converted to a robot program such as RAPID. The part building process will be simulated and optimized for given robot specification, mounting configuration and building plate location. Robot dispensing software and hardware interface are employed to coordinate the motion speed and material extrusion rate. Robotic Additive Manufacturing (RAM) testing cells have been built to carry out and verify the printing scheme along curved surface, which is one step further towards free-form fabrication.