A method of cleaning a workpiece after a welding process is provided, wherein the cleaning is conducted by removing oxide from the surface of the workpiece which is formed on the weld and the heat-affected zone of the workpiece during the previous welding process, wherein an electric arc is generated between the workpiece and a non-consumable electrode to remove the oxide on the workpiece, wherein a power source is provided to electrically communicate the workpiece and the non-consumable electrode and wherein the non-consumable electrode is anodic connected and the workpiece is cathodic connected.

The present disclosure provides a welding electrode and methods of manufacturing the same. The welding electrode can include a composite body having a tip portion and an end portion. The composite body can include a shell defining a cavity through the end portion, the shell comprising a first metal that includes one or more of the following: a precipitation hardened copper alloy, copper alloy, and carbon steel. The composite body can also include a core within the shell, the core extending through the shell from the tip portion to the cavity, the core comprising a second metal that includes dispersion strengthened copper. The core and the shell have a metallurgical bond formed from co-extrusion.

An apparatus for making three-dimensional physical objects of a predetermined shape includes a printing header having a least one arc welding torch. The arc welding torch includes an axially extending first nozzle and an axially extending non-consumable electrode, which is disposed substantially coaxially within the first nozzle and having a tip disposed at a distal end thereof and/or outside the first nozzle; means for supplying electricity to the electrode; means for supplying a protecting gas to the first nozzle for shielding the electrode from oxidising conditions; an axially extending through-hole formed through the electrode; an elongated non-electrified guide portion disposed within the through-hole terminating inwardly of the tip; and a consumable material wire that is fed through the guide portion relatively to the electrode so that the material wire is not electrified by the guide portion or by the electrode.

A holding apparatus (100) for electrostatically holding a component (1), in particular a silicon wafer, includes at least one base body (10, 10A, 10B) which is composed of a first plate (11A) and a second plate (12), the first plate (11A) being arranged on an upper side (10A) of the base body (10, 10A, 10B) and the second plate are made of an electrically insulating material, a plurality of projecting, upper burls (13A) which are arranged on the upper side (10A) of the base body (10, 10A, 10B) and form a support surface for the component (1), and a first electrode which is arranged to receive a clamping voltage, wherein the first plate (11A) is made of an electrically conductive, silicon-including ceramic and forms the first electrode. A method for producing the holding apparatus (100) is also described.