The Esab Group Inc.

Joseph Valerious Warren

Barry Gaskins Turner

Thomas Franklin Oakley

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

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

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.

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Florence, SC, United States of America

Joseph Valerious Warren