| 摘要 |
In general, the present invention provides a method of piercing a workpiece with a plasma arc torch of the type having a plasma gas flow path for directing a plasma gas through the torch and a secondary gas flow path for directing a secondary gas through the torch. The method comprises directing a flow of shield gas along a distal end portion of the plasma arc torch to deflect metal spatter generated from the piercing, and ramping a current provided to the plasma arc torch along a profile during piercing and controlling current ramp parameters as a function of a thickness of the workpiece and an operating current level, wherein the current ramp parameters comprise a length of time, a ramp rate, a shape factor, and a modulation. |
