Abstract: An additive manufacturing system includes an electrode head comprising an array of electrodes for depositing material to form a three-dimensional part. The array includes a first plurality of electrodes formed from a first metallic material having a first ductility and a first hardness, and a second plurality of electrodes formed from a second metallic material having a second ductility and a second hardness, wherein the first ductility is greater than the second ductility and the second hardness is greater than the first hardness. A power source provides electrical power for establishing a welding arc for each electrode. A drive roll system drives each electrode.

Abstract: Erasable coatings for xerography paper comprise a pigment such as calcium carbonate in a binder such as an aqueous emulsion of an acrylic polymer. The erasability of the coating is improved by replacing at least 15 wt % of the binder with a polyalkane or (preferably) polyalkene wax, such as an aqueous emulsion of a polyolefin.