Abstract: Laser cutting processes are provided which are controlled using as a reference signal one or more emission lines which are characteristic of the radiation emitted by a gas or, more generally, by an emitting element present in the volume irradiated by the laser beam focussed by a laser head and adjusting, on the basis of this reference signal, at least one of the following process control parameters: the power of the laser, the frequency and the duty cycle of the laser pulse, the pressure of an assisting gas emitted by a nozzle forming part of the laser head, the relative speed of the laser head with respect to the workpiece, the distance between the laser head and the surface of the workpiece, and the distance between the focal point of the laser beam and the surface of the workpiece. Laser cutting devices are also provided.

Abstract: Laser cutting processes are provided which are controlled using as a reference signal one or more emission lines which are characteristic of the radiation emitted by a gas or, more generally, by an emitting element present in the volume irradiated by the laser beam focussed by a laser head and adjusting, on the basis of this reference signal, at least one of the following process control parameters: the power of the laser, the frequency and the duty cycle of the laser pulse, the pressure of an assisting gas emitted by a nozzle forming part of the laser head, the relative speed of the laser head with respect to the workpiece, the distance between the laser head and the surface of the workpiece, and the distance between the focal point of the laser beam and the surface of the workpiece. Laser cutting devices are also provided.

Abstract: Filter plugs for cigarettes are supplied to a filter tip attachment machine by a feed unit comprising a hopper into which filter plugs of at least one type are directed in succession from a filter maker. The hopper is positioned above a row of rotating drums, each furnished peripherally with a plurality of aspirating axial flutes by which the filters are taken up singly from the hopper and directed to a transfer station; here, the flutes are aligned axially one by one with the inlet of a pneumatic feed duct connecting with the filter tip attachment machine. The hopper is equipped with sliding baffles by which it can be partitioned to create at least two sectors, each serving at least one drum, so that filters of different length can be handled simultaneously, and the unit is able to operate in conjunction with filter makers and filter tip attachment machines of more than one type upstream and downstream.