Controlling heat input, spatter and weld penetration in GMA welding for solid freeform fabrication

Two new approaches for metal transfer control during the GMA welding process, one based on a laser beam placed through the are and the other based on real-time image processing, allow lower heat input, reducing spatter and weld penetration. The controlled welding process and CNC milling operation are combined together to form a hybrid rapid prototyping process. Test parts obtained in this procedure show better surface quality, dimensional accuracy and high density, while demonstrating new technological opportunities in rapid prototyping of real metallic parts.