Plasma electrode (1) for a plasma arc torch consisting of an electrode body, at least one electrode core (4) disposed on the electrode tip, wherein the plasma electrode (1) is constructed in at least two parts and consists of the electrode tip (2) and an electrode part (3), and out of the electrode tip (2) and a electrode part (3) consists, and that the electrode tip (2) is held replaceably on the electrode part (3).

A plasma torch includes an electrode, a center pipe, and a coolant passage. The electrode includes an internal passage, a tip portion, a convex portion, and an electrode insert. The center pipe is at least partially arranged in the internal passage of the electrode. The center pipe includes first and second pipe ends. The coolant passage first, second, third, and fourth passages. A coolant flows from the first passage through the second passage and the third passage to the fourth passage. At least a part of the convex portion is arranged in the center pipe. The inner surface of the center pipe includes a first inclined surface having a diameter that decreases toward a distal direction. The distal direction is a direction extending from the second pipe end to the first pipe end. The first inclined surface extends toward the root portion of the convex portion.

Embodiments of the present invention include a plasma cutting torch and plasma cutting torch components, such as electrodes, cathodes, retainer caps, etc. having a unique physical features, including threads relationships. Embodiments include torch components having modified square thread with a specialized thread configuration including a particular relationship between thread crest and root, and included angles of thread sidewalls.

A liquid cooled electrode for a contact start plasma arc cutting torch is provided. The electrode includes an elongated body defining a longitudinal axis. The elongated body includes a proximal end shaped to matingly engage a torch body of the plasma arc cutting torch and a distal end located substantially opposite of the proximal end along the longitudinal axis. The electrode also includes one or more contact surfaces disposed on an external surface of the distal end of the electrode body between the proximal and distal ends. The one or more contact surfaces are shaped to physically contact a nozzle disposed within the plasma arc cutting torch during a portion of a pilot arc initiation process. The physical contact is configured to support transmission of a pilot arc current between the electrode and the nozzle with a density of at least about 3000 amps per square inch.

A consumable assembly for a plasma arc torch is provided, the consumable assembly including an electrode provided within an interior of a nozzle. The electrode may include a sidewall having one or more fluid passageways formed therethrough, an end wall extending from a distal end of the sidewall, and a central cavity defined by an inner surface of the sidewall and the end wall, the central cavity extending between distal and proximal ends of the electrode. The electrode may further include a heat removal element extending into the central cavity from the inner surface of the sidewall. In one embodiment, the consumable assembly includes a current and gas conduit at the proximal end of the electrode, the current and gas conduit including an interior bore radially aligned with the electrode for collectively delivering a plasma gas, a shield gas, and a vent gas into the central cavity of the electrode.

A liquid coolant tube for a plasma arc cutting torch including a hollow elongated inner body shaped to translate within a hollow elongated outer body. The hollow elongated outer body of the liquid coolant tube is shaped to fixedly connect to the plasma arc cutting torch and includes a set of electrode guides. An external surface of the hollow elongated outer body and the set of electrode guides partially define a set of coolant flow channels between the set of electrode guides. The set of electrode guides are shaped to facilitate alignment of an electrode within the plasma arc cutting torch.

A center pipe is used in a plasma torch including a base portion and an electrode to supply cooling water into the electrode. The center pipe includes a pipe body and a contact piece. The pipe body has a tube-like shape with a cooling water channel therein. The pipe body is electrically conductive and configured to be electrically connected to an external power source via the base portion. The contact piece is arranged radially outside the pipe body at an intermediate position between a base end surface and a tip end surface of the pipe body. The contact piece is electrically conductive and energizes the electrode through contact with an internal circumferential surface of the electrode. The base end surface is disposed outside the electrode when the center pipe is inserted into the electrode. The pipe body is configured to be electrically connected to the electrode via the contact piece.

A contact start liquid-cooled plasma arc cutting torch is provided that includes a translatable liquid-cooled electrode, a nozzle, and a multi-piece cathode. The electrode comprises an electrode body defining a proximal end and a distal end along a longitudinal axis of the electrode body. The electrode body includes a coolant cavity configured to receive at least a portion of a coolant tube of the torch for directing a liquid coolant flow distally through the coolant tube within the coolant cavity. The cathode is disposed about the proximal end of the electrode body and includes a first body shaped to matingly engage the electrode and a second body shaped to matingly engage the torch. The first body slidingly engages the second body such that the first body and the electrode are axially translatable relative to the second body along the longitudinal axis.

A liquid cooled electrode for a contact start plasma arc cutting torch is provided. The electrode includes an elongated body defining a longitudinal axis. The elongated body includes a proximal end shaped to matingly engage a torch body of the plasma arc cutting torch and a distal end located substantially opposite of the proximal end along the longitudinal axis. The electrode also includes one or more contact surfaces disposed on an external surface of the distal end of the electrode body between the proximal and distal ends. The one or more contact surfaces are shaped to physically contact a nozzle disposed within the plasma arc cutting torch during a portion of a pilot arc initiation process. The physical contact is configured to support transmission of a pilot arc current between the electrode and the nozzle with a density of at least about 3000 amps per square inch.

A replacement part unit for a plasma torch includes an electrode, an insulation guide, and a nozzle. The insulation guide includes a hole into which the electrode is inserted. The insulation guide is coupled to the electrode by press-fitting or adhesion. The nozzle includes a hole into which the insulation guide is inserted. The nozzle is coupled to the insulation guide by press-fitting or adhesion.