The Esab Group Inc.

Esab Welding Products, Inc.

Thomas Franklin Oakley

Barry Gaskins Turner

Joseph Valerious Warren

A plasma arc torch system having automatic purge and fill capability includes a plasma arc torch which has a supply line coupled with a passage in the torch for supplying a process fluid through the torch to a nozzle of the torch. The system further includes a process fluid supply system including at least first and second supplies containing first and second process fluids, respectively, and a purge gas supply containing an inert purge gas. A valve system is coupled between the process fluid supply system and the supply line and between the purge gas supply and the supply line, the valve system including at least one valve operable to selectively couple the supply line to one of the first, second, and purge supplies. An actuator system is connected to the valve system, the actuator system being electrically activatable to cause the valve system to couple the supply line to one of the supplies. To enable automatic purge and fill operations, the system includes a control system including a programmable controller electrically connected to the actuator system, and an electronic data storage device in data communication with the controller, the data storage device containing at least one set of process requirements including a process fluid requirement. The controller is programmed to read the set of process requirements from the data storage device and to control operation of the actuator system so as to automatically couple the supply line with the first or second supply in accordance with the process fluid requirement.

Apparatus and method for supplying fluids to a plasma arc torch

A process and apparatus for stopping a cutting operation of a plasma arc torch is disclosed which minimizes the oxidation of the electrode to thereby extend life of the electrode. A flow of oxidizing gas is directed through a plasma chamber and nozzle. An electrical current is then conducted through the electrode to form a plasma arc. The electrical current is cut no later than a time F for extinguishing the plasma arc. The flow of oxidizing gas is switched off a determinable time interval before time F, and a flow of non-oxidizing gas is switched on no later than time F, whereby the non-oxidizing gas substantially completely purges the oxidizing gas from the torch creating an inert environment, whereby the plasma arc extinguishes in the inert environment.

Method and apparatus for improving plasma ARC consumable life

A digitizing probe and method is disclosed for accurately locating the edges and determining the orientation of a generally planar, metal workpiece relative to the orthogonal axes of a computer numerical control ('CNC') cutting machine. The CNC cutting machine includes a microcomputer controller for moving a transverse gantry in the longitudinal and lateral directions which define the orthogonal axes of the cutting machine. The digitizing probe and the cutter of the cutting machine are mounted on separate vertically movable support arms secured to support brackets provided on the transverse gantry. Thus, the digitizing probe and the cutter may be independently positioned at predetermined heights above the top surface of the workpiece. The digitizing probe includes a plurality of analog inductive proximity sensors arranged in a fixed, predetermined array. The digitizing probe is positioned above the workpiece and moved by the controller incrementally in the longitudinal and lateral directions around the perimeter of the workpiece. The electrical signals from the sensors are continuously monitored by the controller such that the edges of the workpiece are located and the orientation of the workpiece relative to the orthogonal axes is determined. The digitizing probe maps the footprint of a workpiece, or a remnant workpiece, to select a particular machined part to be produced from the workpiece with a minimum amount of scrap.

Digitizing probe

An electrode and a plasma arc torch are provided wherein the useful service life of the electrode is extended and the starting ability of the torch is improved because the arc is transferred from an initiation point to a final attaching point which is centered on the electrode. The electrode includes a generally cylindrical body defining a longitudinal axis and having a substantially planar front face that is perpendicular to the longitudinal axis. The front face has a central region at which the arc is to be supported after initiation of the arc. The front face further defines at least one groove extending radially inward for guiding the arc from the point of initiation along the front face toward the central region. Because the arc easily and quickly moves from its initiation point to the central region of the electrode along the groove, starting ability of the plasma arc torch is improved and service life of the electrode is lengthened. Moreover, because the arc is directed to an optimal steady state attaching point in the central region of the electrode, electrode wear due to non-optimum attaching position is reduced, thereby further extending the useful electrode service life.

Plasma electrode with arc-starting grooves

A method of controlling a plasma are torch in cutting or marking a workpiece along a path of travel having a starting point and stopping point in accordance with a predetermined program and in which an arc extinguish order in issued at a predetermined point or location on the path of travel spaced upstream of the stopping point a distance determined by the speed or velocity of the torch and the arc extinguish delay time between issuance of the arc extinguish order and actual extinguishment of the arc so that the arc is extinguished at the precise instant the torch arrives at the stopping point.

Method of controlling a plasma arc cutting torch

A system and method for detecting nozzle and electrode wear of plasma arc torches in which the average change in the stand-off between the electrode or the nozzle assembly of the plasma arc torch and a workpiece is monitored, and corrective measures are taken once the average change in the stand-off of the electrode and nozzle assembly exceeds a predetermined value. The corrective measures may include changing the arc voltage of the plasma arc torch, modifying the speed at which the plasma arc torch travels, modifying the average current of the power supply of the plasma arc torch, or the flow rate of the plasma supply gases or cut water of the plasma arc torch. The number of corrections is monitored so that after a predetermined number of such corrections, the system and method notifies an operator or the plasma arc torch itself that the electrode or surrounding nozzle requires replacement.

System and method for detecting nozzle and electrode wear

An apparatus for mounting a cutting torch to a shape cutting machine is disclosed, and which incorporates a control system for signaling the machine in the event the torch contacts an obstruction during either vertical or lateral movement of the torch by the machine. The control system includes a pair of plates mounted to the torch so that the plates are displaced relative to each other when the torch contacts an obstruction, and a number of gas release valves are mounted to the plates and which are connected to a gas line so that a signal is generated upon a relative displacement of the plates. The signal is directed to the control logic of the shape cutting machine so that it may take corrective action.

Growing community of inventors

Florence, SC, United States of America

Thomas Franklin Oakley