Method for Removing, by means of a Laser Beam, a Bulge deposited on the Surface of a Workpiece when a Through Hole is formed

A laser processing machine comprising:

• a laser beam generator;
• a traversable laser machining head with a gas nozzle, from which the laser beam together with the process gas emerges;
• and
• a control system which is programmed to control the movement of the laser machining head and to adjust the pressure of the process gas to:
• form a hole in the workpiece using the laser beam and a process gas emerging from a gas nozzle, such that the formed hole extends only partially through the workpiece,
• remove a bulge deposited on a surface of the workpiece around the hole during forming the hole partially through the workpiece, by directing a flow of gas through the nozzle toward the workpiece surface as the nozzle is moved with the laser beam switched off, the flow of gas being delivered to the nozzle at a higher pressure than the process gas is delivered to the nozzle during forming the hole partially through the workpiece;
• and then
• fully pierce the hole through the workpiece by the laser beam, using the process gas.

A computer program product for use on a control system of a laser processing machine, the computer program product comprising a computer useable medium having computer readable program code stored on the computer useable medium, the computer readable program code comprising:

• program code for causing the control system to activate a laser beam and a gas nozzle to form a hole in the workpiece using the laser beam and a process gas emerging from a gas nozzle, such that the formed hole extends only partially through the workpiece;
• program code for causing the control system to remove a bulge deposited by the forming on a surface of the workpiece around the hole, by directing a flow of gas through the nozzle toward the workpiece surface as the nozzle is moved with the laser beam switched off, the flow of gas being delivered to the nozzle at a higher pressure than the process gas is delivered to the nozzle during forming the hole partially through the workpiece;
• and then remove a bulge deposited on a surface of the workpiece around the piercing whole as the gas nozzle is moving past the hole and/or beyond the hole while the laser beam is switched off;
• and
• program code for causing the control system to activate the laser beam to fully pierce the hole through the workpiece by the laser beam, using the process gas.