Plasma arc torch and cutting system

A plasma cutting system, comprising:

• a plasma arc torch;
• a plasma cutting power supply that supplies a plasma cutting current to the plasma arc torch;
• a torch actuator that moves the plasma arc torch during a cutting operation;
• a motion controller operatively connected to the torch actuator to control movements of the plasma arc torch during the cutting operation;
• and
• a gas controller configured to control a flow of plasma gas and a flow molten metal clearing gas to the plasma arc torch,
• wherein the flow of molten metal clearing gas is active during a piercing operation of the plasma arc torch, and the gas controller is configured to automatically determine a completion of the piercing operation and stop the flow of molten metal clearing gas upon determining the completion of the piercing operation.

An attachment for a plasma arc torch, comprising:

• an outer retaining cap that is attachable to the plasma arc torch and that is configured to secure a shield cap to the plasma arc torch;
• a sleeve located radially outward from the outer retaining cap and configured to receive a flow of pressurized gas;
• an insulator located between the outer retaining cap and the sleeve;
• and
• a gas flow channel configured to direct a gas flow from the sleeve to a distal portion of the outer retaining cap.

A plasma cutting method, comprising the steps of:

• providing an open air plasma cutting system for cutting a workpiece in open air, wherein the open air plasma cutting system includes a plasma arc torch;
• initiating a flow of plasma gas to the plasma arc torch;
• initiating a flow of molten metal clearing gas to the plasma arc torch;
• and
• automatically stopping the flow of molten metal clearing gas to the plasma arc torch upon determining a completion of a piercing operation while controlling the flow of plasma gas to the plasma arc torch.