Method for operating a machine for laser machining of tubes and profiled sections with an automatic system for the application of threaded inserts integrated in the machine

1 . A method for operating a machine for laser cutting of tubes and profiled sections comprising:

a working head provided with a focusing device adapted to emit a focused laser beam onto a surface of a tube or profiled section to be worked, and

a carriage on which the working head is mounted, said carriage being mounted so as to translate relative to the tube or profiled section to be worked both in a first transverse direction and in a second transverse direction orthogonal to the first transverse direction, said first and second transverse directions being orthogonal to a longitudinal axis of the tube or profiled section to be worked, and

an automatic insert application system for placing a threaded insert into a housing formed in a wall of the tube or profiled section by said laser beam, said automatic insert application system being integrated into the machine and being configured to operate in a coordinated manner with said working head,

wherein said automatic insert application system comprises a riveter provided with a threaded rotating pin configured to engage a threaded hole of the threaded insert for gripping and placing the threaded insert,

wherein the working head and the riveter are mounted on said carriage so as to be translationally integral therewith in both said first transverse direction and in said second transverse direction,

wherein said automatic insert application system further comprises an insert supply assembly and an insert picking seat configured to receive threaded inserts individually from said insert supply assembly, said insert supply assembly and said insert picking seat being arranged adjacent to the carriage,

wherein the automatic insert application system further comprises a proximity sensor configured to detect a presence of the threaded insert in the insert picking seat,

wherein the method comprises the following steps:

a) forming a housing in the tube or profiled section by said working head,

b) moving said carriage from the tube or profiled section to the insert picking seat,

c) gripping a threaded insert from the insert picking seat by said riveter,

d) moving said carriage from the insert picking seat to the tube or profiled section,

e) placing the threaded insert into the housing of the tube or profiled section by said riveter, and

f) carrying out a cutting operation by said working head,

wherein the proximity sensor is configured to change its state due to picking of the threaded insert from the insert picking seat and consequently provide a detection signal, and wherein step c) comprises the following steps:

c1) gripping the threaded insert by the riveter and lifting the threaded insert from the insert picking seat,

c2) determining, based on said detection signal, a detected picking height reached by the threaded insert during the picking, at which the proximity sensor has changed its state,

c3) comparing said detected picking height with an expected picking height depending on geometric parameters of the threaded insert,

c4) if the detected picking height is different from the expected picking height, repositioning the threaded insert into the insert picking seat, releasing the threaded insert, and repeating steps c1-c3,

c5) if the detected picking height is still different from the expected picking height, discarding the threaded insert.

2 . The method of claim 1 , wherein the automatic insert application system further comprises a linear actuator mounted on said carriage, and wherein the riveter is mounted on the linear actuator, said linear actuator being configured for translationally moving the riveter relative to said carriage in said second transverse direction, between a rest position and a working position.

3 . The method of claim 1 , wherein said carriage is configured to shuttle between the tube or profiled section and the insert picking seat to enable the riveter to grip the threaded insert from the insert picking seat and enable the riveter to place the threaded insert onto the tube or profiled section, between a hole cutting operation and a subsequent cutting operation carried out on the tube or profiled section by said working head.

4 . The method of claim 1 , wherein the proximity sensor is further configured to change its state due to reception, in the insert picking seat, of the threaded insert supplied by the insert supply assembly, and consequently to provide a detection signal, and wherein step c) comprises, in case of failed reception of the threaded insert in the insert picking seat,

repeating a supply of the threaded insert by the insert supply assembly.

5 . The method of claim 1 , wherein step e) comprises the following steps:

e1) lowering the riveter with the threaded insert until the housing of the tube or profiled section is engaged,

e2) determining a detected working height reached by the riveter,

e3) comparing said detected working height with an expected working height depending on dimensions of the tube or profiled section,

e4) if the detected working height is different from the expected working height, discarding the threaded insert.

6 . The method of claim 1 , wherein step a) is carried out based on input data comprising an instructed position of a centroid of the housing in the tube or profiled section, and geometric parameters of the threaded insert to be applied.