Abstract: Platelet assemblies are formed from bondable platelets, such as diffusion-bondable, brazable, or adhesive-bondable platelets, with void regions in the platelets to form channels or open spaces in the finished platelet assembly. To improve the response of the platelet assembly to pressure bonding as well as to post-bonding fabrication processes such as forming, machining and welding, the void regions are filled with a sacrificial material which transmits the load of the applied pressure in the same manner as the remainder of the platelet, and yet which is removable from the finished platelet assembly by either thermal or chemical liquefaction after all potentially damaging fabrication procedures have been performed on the platelet assembly.

Abstract: A plasma torch electrode (132) comprises multiple platelets (159) oriented transverse to the electrode axis and joined together to form an electrical connection therebetween. A first group of the platelets have openings aligned to form an axial bore (164) for generating a plasma arc. A second group of the platelets define channels (172,178) aligned with each other, transverse to the electrode axis and in communication with the bore for injecting a gas, such as an inert gas, into the bore. In a specific embodiment, the plasma torch electrode comprises first and second end plates (152, 154) and a midplate (160), with the platelets stacked between and joined to the end plates and the central plate. This configuration allows precise fabrication of gas channels within the first and second sets of platelets while only requiring a small number of separate components to manufacture the plasma torch electrode.

Abstract: An electrode for a plasma torch comprises multiple platelets that are stacked together. The platelets have openings that are oriented to form a bore through the electrode adapted for generating a plasma arc. The platelets also have apertures arranged to form multiple coolant channels through the electrode. The coolant channels are immediately adjacent to the bore and extend substantially along the entire length of the bore. This increases the heat transfer area between liquid coolant flowing through the channels and the hot plasma arc within the bore to reduce the temperature of the exposed electrode surface, thereby increasing the lifetime of the electrode. A second set of passages can exist within the electrode to inject gas through the electrode wall at the surface of the bore. This secondary gas injection is directed tangential to the bore surface to create or enhanced gas swirl, thereby rotating the arc foot and eliminating or reducing arc attachment induced erosion damage.