The Esab Group Inc.

Barry Gaskins Turner

Thomas Franklin Oakley

Joseph Valerious Warren

A method of cutting a workpiece along a cutting path that is arcuate or that has one or more arcuate portions includes the step of determining a control parameter that is proportional to the angular velocity of the torch. The arc current supplied to the torch is regulated based on the control parameter and the linear advance rate of the torch, which in turn is a function of the material type and thickness of the workpiece. In one embodiment of the invention suitable for the cutting of holes, the control parameter is the diameter of the hole to be cut, which for a specified linear advance rate is inversely proportional to the angular velocity of the torch. The current is increased above a nominal current when the hole diameter is less than or equal to a predetermined limiting diameter, and otherwise is set at the nominal current. In other embodiments of the invention suitable for cutting holes or other shapes, the control parameter is the radius of curvature of the cutting path. Alternatively, the angular velocity can be used as the control parameter. Increasing the current at higher angular velocities and/or when cutting holes of small diameter tends to reduce the problem of the arc not following the desired cutting path and creating cut surfaces that do not conform to the desired cut surfaces.

Method of cutting a workpiece along an arcuate path with a plasma arc torch

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.

Growing community of inventors

Pamplico, SC, United States of America

Barry Gaskins Turner