Fibre optic laser machining equipment for etching grooves forming incipient cracks

A method of etching at least one groove in a lateral wall or surface of a mechanical part by laser pulses supplied by a fiber optic laser device, the groove defining an incipient crack for subsequent facturing of the mechanical part into at least two pieces, the method comprising:

• controlling the fiber optic laser device so that the laser pulses have a peak power of more than 400 W and at least two times greater than the mean maximum power of the laser device, and
• wherein a duration of the laser pulses is below or within the nanosecond range of 1 ns to 1000 ns.

A laser machining equipment provided for machining at least one rectilinear groove, defining an incipient crack, in a wall of an aperture of a mechanical part, comprising:

• a machining head including an end slot, a height of which is at least equal to a length of the machined grooves,
• the machining head comprising a removable mirror and a focusing means integral with the mirror that moves linearly so that the laser beam exits through the end slot by gradually moving along the end slot,
• the machining head being held in a fixed position during the laser machining of the rectilinear groove in the mechanical part.

A laser machining equipment provided for successive machining of two grooves, defining two diametrically opposite incipient cracks, in a wall of an aperture in a connecting rod, wherein a bottom part of the machining head has a larger width than a diameter of the aperture of the connecting rod, the bottom part of the machining head remaining entirely above the connecting rod during the machining of the two grooves.