Electron Beam Free Form Fabrication (EBF3)

EBF3 works in a vacuum chamber, where an electron beam is focused on a constantly feeding source of metal wire, which is melted and applied by drawing one layer at a time on a computer-controlled positioning table until the part is complete. By controlling the raster pattern, the e-beam selectively heats the outer edges of the wire if it strays from the melt zone. With such selective heating, the wire automatically curls away from the high heat outer edge and back into the region of the molten pool. Thus, with a fixed raster pattern, the process becomes self-correcting without any sensing or external control of process parameters. EBF3 can handle two different sources of metal feedstock at the same time, which can be controlled independently to allow precise control of mixing of materials during deposition. EBF3 incorporates the following technologies, which can also be licensed individually: (1) a vapor-barrier vacuum isolation system that maintains a vacuum in the electron beam column adjoined to another chamber at higher pressure without loss of vacuum; (2) a system that controls and measures the height of an additive layer of metal using an electron beam in combination with a sensor and image processor; (3) a gas phase alloying system for wire fed joining & deposition, which is being developed for the controlled introduction of gases into molten metals in order to selectively impart beneficial properties to the final product (e.g. strength, corrosion resistance, etc.); and (4) a closed-loop system that is being developed to detect various fabrication anomalies and automatically send feedback to the fabrication system to modify the input parameters to maintain process consistency.