An apparatus for the removal of waste heat and material during laser
cutting of a hollow workpiece by a laser beam includes a duct with
external dimensions that permit insertion of at least a portion of the
duct within the hollow workpiece, a chamber within the duct for receiving
the laser beam, and an opening in an outer surface of the duct for
admitting the laser beam into the chamber. The apparatus further includes
a first inlet in the duct for supplying a liquid to the chamber, a second
inlet in the duct for supplying a gas to the chamber, and a nozzle
adapted for supplying a mixture of the liquid and the gas to the chamber.