Portable device for laser marking

11) A method to safely make a laser marking, said method comprising:

• having a portable device, wherein the portable device comprising:
• at least one marking head provided with at least one gripping element graspable by a user,
• at least one marking chamber associated with said marking head positionable between a laser light generator configured to generate a laser light beam and a surface to be marked, said marking chamber comprising at least one head end having a marking opening for the passage of said laser light beam, wherein said head end is intended, in use, to contact said surface to be marked so that said surface closes said marking opening,
• at least one inlet line in fluidic communication with said marking chamber and configured to feed, into said marking chamber, a substantially constant flow of air,
• at least one air outlet opening formed on said marking chamber and configured to allow air to escape from said marking chamber and fumes generated by the laser light beam during the marking of the surface to be marked, and
• at least one measurement assembly arranged at least partly inside said marking head, operationally associated with said marking chamber and configured to verify whether the value of the internal pressure in said marking chamber and/or said flow of air fed from said inlet line falls within a predetermined range of values in order to determine the possible presence of defects in said surface to be marked;
• positioning said marking chamber between said laser light generator and said surface to be marked;
• closing said marking opening with said surface to be marked;
• feeding a flow of air into said marking chamber by means of said inlet line;
• making, by means of one of said measurement devices, a first measurement of said internal pressure of said marking chamber at a first time to obtain a first value of said internal pressure;
• making, by means of the other of said measurement devices, a second measurement of said internal pressure of said marking chamber at a second time to obtain a second value of said internal pressure;
• assessing whether said first value and said second value fall within said predetermined range of values;
• and
• blocking the emission of the laser light beam towards said surface to be marked.