Laser cutting head for a machine tool

A laser cutting head associable to a machine tool, comprising:

• a collimating group to collimate a laser beam coming from a laser emitting apparatus;
• a focusing group to focus in a focal point said laser beam exiting collimated from said collimating group;
• supporting and moving assembly to support and move along an adjustment direction at least one between said collimating group and focusing group;
• at least one optical element to receive said laser beam exiting focused from said focusing group and reflect a focused first portion of the received laser beam;
• an electronic processor adapted to operate said supporting and moving assembly to move at least one between said collimating group and focusing group along said adjustment direction;
• at least one wavefront sensor adapted to receive said focused first portion of the laser beam, perform a phase measurement of a wavefront of said focused first portion, obtain a reconstructed wavefront on the basis of said phase measurement and send said reconstructed wavefront to said electronic processor, the electronic processor being configured to perform a comparison between said reconstructed wavefront and a reference wavefront, determine on the basis of said comparison one or more optical aberrations to which the laser beam is subjected and operate said supporting and moving assembly to reduce said one or more optical aberrations and change said focal point.

A laser cutting head associable to a machine tool, comprising:

• a collimating group to collimate a laser beam coming from a laser emitting apparatus;
• a focusing group to focus in a focal point said laser beam exiting collimated from said collimating group;
• at least one adaptive optical device having adjustable shape;
• at least one optical element to receive said laser beam exiting focused from said focusing group and reflect a focused first portion of the received laser beam;
• an electronic processor adapted to adjust the shape of said adaptive optical device;
• characterized in that it comprises at least one wavefront sensor adapted to receive said focused first portion of the laser beam, perform a phase measurement of a wavefront of said focused first portion, obtain a reconstructed wavefront on the basis of said phase measurement and send said reconstructed wavefront to said electronic processor, said electronic processor being configured to perform a comparison between said reconstructed wavefront and a reference wavefront, determine on the basis of said comparison one or more optical aberrations to which the laser beam is subjected and adjust the shape of said adaptive optical device to reduce said one or more optical aberrations and change said focal point.

A method for controlling the laser cutting of a workpiece, comprising the steps of:

• performing the laser cutting of said workpiece by means of a laser cutting head associated to a machine tool;
• powering said laser cutting head with a laser beam;
• collimating and focusing in a focal point said laser beam;
• reflecting at least one focused first portion of said focused laser beam;
• performing a phase measurement of a wavefront of said at least one focused first portion;
• obtaining a reconstructed wavefront on the basis of said phase measurement;
• performing a comparison between said reconstructed wavefront and a reference wavefront;
• determining on the basis of said comparison one or more optical aberrations to which said laser beam is subjected;
• reducing said one or more optical aberrations to which said laser beam is subjected in order to change said focal point of the laser beam.