Internal part feature cutting method and apparatus

A method for cutting a hole feature in a workpiece along at least a portion of a path including a first zone and a second zone using a plasma cutting system, the method comprising:

• initiating a plasma gas flow;
• initiating a current flow to ignite a pilot arc;
• transferring the arc to the workpiece;
• piercing the workpiece;
• cutting in the first zone using a first command speed establishing a first torch speed;
• and
• cutting in the second zone using a second command speed establishing a second torch speed, wherein the second command speed is greater than the first command speed.

A method for cutting a hole feature in a workpiece along at least a portion of a path including a first zone, a second zone, and a third zone using a plasma cutting system, the method comprising:

• initiating a plasma gas flow;
• initiating a current flow to ignite a pilot arc;
• transferring the arc to the workpiece;
• piercing the workpiece;
• cutting in a first zone and a second zone, wherein a command speed of a cut for the second zone is different than a command speed of a cut in the first zone;
• reducing a cutting current in the third zone such that the cutting current reaches substantially zero amperes at a point where an outer kerf edge of a cut in the third zone substantially meets an outer kerf edge of the cut in the first zone;
• and
• decelerating a torch speed of the plasma cutting system after the cutting current has reached substantially zero amperes.

A method for cutting a hole feature in a workpiece along at least a portion of a path including a first zone, a second zone, and a third zone and using a plasma cutting system, the method comprising:

• initiating a plasma gas flow;
• initiating a current flow to ignite a pilot arc;
• transferring the arc to the workpiece;
• piercing the workpiece;
• cutting in the second zone with a command speed different from a command speed of the first zone of the cut;
• ramping down a cutting current in the third zone to remove a diminishing material such that an outer kerf edge of a cut in the third zone substantially aligns with an outer kerf edge of a cut in the second zone;
• and
• decelerating a torch speed of the plasma cutting system after the cutting current has reached substantially zero amperes.

A method for cutting a hole feature in a workpiece using a plasma cutting system that reduces defects in the hole feature, the method comprising:

• initiating a plasma gas flow;
• initiating a current flow to ignite a pilot arc;
• transferring the arc to the workpiece;
• piercing the workpiece;
• establishing a cutting arc and a cut speed with respect to the workpiece;
• increasing the cut speed to a second cut speed after a first point in a hole cut path;
• ramping down a cutting current after a second point in the hole cut path without reducing the cut speed;
• and
• substantially maintaining the second cut speed until the cutting current reaches substantially zero amperes or increasing the second cut speed to a third cut speed before the cutting current reaches substantially zero amperes.

A method for cutting a hole feature in a workpiece using a plasma arc torch to reduce defects in the hole feature and cutting along at least a portion of a path including a first zone, a second zone and a third zone, the method comprising:

• selecting one of a plurality of cutting current ramp down operations for cutting in the third zone, wherein each of the plurality of cutting current ramp down operations is a function of a diameter of the hole feature;
• extinguishing the plasma cutting current when a torch head passes from the third zone to the second zone at a location where the first zone, second zone and third zone substantially intersect;
• and
• substantially maintaining or increasing a torch speed in the third zone until the torch head passes from the third zone into the second zone.

A method for cutting a hole feature in a workpiece using a plasma arc torch to reduce defects in the hole feature and cutting along at least a portion of a path including a first zone, a second zone and a third zone, the method comprising:

• initiating a plasma gas flow;
• initiating a current flow to ignite a pilot arc;
• transferring the arc to the workpiece;
• piercing the workpiece to begin cutting the hole feature;
• cutting along the first zone and the second zone of the path;
• initiating a ramp down of a cutting current at a first point in the third zone such that the cutting current is extinguished at a second point where the first zone, the second zone and the third zone substantially intersect, the first point in the third zone determined based on a ramp down time of the cutting current;
• and
• decelerating the plasma arc torch so that a torch speed reaches substantially zero at a predetermined distance after the second point.

A method for cutting a hole feature in a workpiece along at least a portion of a path including a first zone and a second zone using a plasma cutting system, the method comprising:

• initiating a plasma gas flow;
• initiating a current flow to ignite a pilot arc;
• transferring the arc to the workpiece;
• piercing the workpiece;
• cutting in the first zone using a first command speed establishing a first torch speed, the first command speed part of an acceleration curve;
• and
• cutting in the second zone using a second command speed establishing a second torch speed, the second command speed part of the acceleration curve and greater than the first command speed.

A method for cutting a hole feature in a workpiece along at least a portion of a path including a first zone and a second zone using a plasma cutting system, the method comprising:

• initiating a plasma gas flow;
• initiating a current flow to ignite a pilot arc;
• transferring the arc to the workpiece;
• piercing the workpiece;
• cutting where the first zone and the second zone substantially intersect at a first torch speed;
• and
• cutting at least a portion of the second zone at a second torch speed, the second torch speed greater than the first torch speed.