Method for laser drilling a component made of a ceramic matrix composite, the method including a step of trepanning and a step of removing slag by enlarging the laser beam, hold obtained by this method, component made of a ceramic matrix composite containing it, and turbojet comprising such a component
View Patent ↗A method of drilling holes in a component made of a ceramic matrix composite with a laser beam. The method includes: a percussion first step during which an initial hole having an initial diameter and a hole axis is drilled; a trepanning second step during which an intermediate hole, coaxial with the initial hole and having a larger diameter than that of the initial hole, is drilled by shifting the laser beam and then making it rotate about the hole axis; and a third step during which the focal point of the laser beam is moved along the hole axis and then pulses are triggered, to obtain a final hole.
1. A method of drilling holes in a component made of a ceramic matrix composite with a laser beam, wherein said method comprises:
a percussion first step during which an initial hole, having an initial diameter and a hole axis, is drilled by focusing the laser beam in the thickness of the component to be drilled;
a trepanning second step during which an intermediate hole, coaxial with the initial hole and having a larger diameter than that of the initial hole, is drilled by shifting the laser beam and then making the laser beam rotate about the hole axis; and
a third step during which the laser beam is centered on the initial hole axis and enlarged within said intermediate hole from a first diameter smaller than said intermediate hole to a second diameter reaching slag present on an inside of the intermediate hole and wherein pulses of the enlarged laser beam are triggered during said third step so as to destroy said slag with said pulses to obtain a final hole.
2. The method as claimed in claim 1 , wherein the number of pulses during said third step is between 1 and 5.
3. The method as claimed in claim 1 , wherein during said third step the focal point of the laser beam is moved, by moving the focal point away from the position that the focal point occupies during the first and second steps.
4. The method as claimed in claim 1 , wherein the focal point of the laser beam is moved during the third step by bringing the focal point closer to the position that the focal point occupies during the first and second steps.
5. The method as claimed in claim 1 , wherein the hole is oriented along an axis perpendicular to the surface of said component.
6. The method as claimed in claim 1 , wherein the hole is oriented along an axis inclined to the surface of said component.
7. The method as claimed in claim 6 , wherein the hole is inclined at an angle (α) of between 20° and 40° to the surface of said component.
8. The method as claimed in claim 7 , wherein the hole is inclined by an angle (α) of approximately 30° to the surface of said component.
9. The method as claimed in claim 1 , applied to a CMC component of a turbojet.
10. The method as claimed in claim 1 , wherein said laser beam has a pulse power during said third step when destroying said slag that is substantially equal to a pulse power used to drill said component during said percussion first step.