Method of producing a composite component
View Patent ↗A composite component ( 1 ), such as a turbine airfoil, includes a conductive portion ( 2 ), and a non-conductive portion ( 5 ), such as a thermal barrier coating or a wear protection coating, or both. In machining the component, a laser machining step is applied for machining the non-conductive portion, and an electro-machining step is applied for machining the conductive portion. The laser machining step is performed by applying preferably a high-frequency pulsed laser. The focussed laser beam working diameter (D L ) is essentially smaller than the size of the contour ( 16 ) to be machined. The contour is scanned by the laser beam ( 9 ) along a pre-defined trace ( 17 ) thus literally inscribing the desired contour into the workpiece.
1. A method of producing a composite component, said component comprising an electrically non-conductive portion and an electrically conductive portion, and the component having at least one well-defined machined geometry, wherein the electrically non-conductive portion is machined by a laser and the electrically conductive portion is machined by electro machining, said method comprising:
applying a focussed laser equipment having focus diameter (D L ) substantially smaller than the geometry to be machined;
placing the laser onto the non-conductive portion surface in such a way that the beam diameter (D L ) on the surface is substantially smaller than the geometry to be machined;
applying the laser beam of the focussed laser equipment;
leading the laser beam over the non-conductive portion surface following a defined path, thus engraving the desired geometry into the non-conductive portion;
laser machining the non-conductive portion; and
after said laser machining the non-conductive portion, joining the laser-machined non-conductive portion to the conductive portion.
2. The method as claimed in claim 1 , wherein the electro machining process and the laser machining process are carried out on different apparatuses.
3. The method as claimed in claim 2 , further comprising:
physically removing the component from a first machining apparatus; and
transferring said component to a second machining apparatus between the electro machining process and the laser machining process.
4. The method as claimed in claim 1 , further comprising:
electro machining the conductive portion prior to the joining of the conductive and the non-conductive portion.
5. A method according to claim 1 , wherein leading a movable deflection assembly comprises leading a mirror assembly.
6. A method as claimed in claim 1 , wherein leading the laser beam over the non-conductive portion surface comprises transversely and pivotally moving said deflection assembly to guide the laser beam.
7. The method as claimed in claim 1 , further comprising prior to said laser placing:
applying a conductive substrate as the conductive portion; and then
producing a non conductive coating on at least a part of a surface of the conductive substrate, to form the non-conductive portion.
8. The method as claimed in claim 7 , further comprising:
electro machining the conductive substrate prior to said producing a non conductive coating.
9. The method as claimed in claim 1 , comprising:
performing the laser machining process of the non-conductive portion;
once the laser machining process has been completely performed, thus having exposed the conductive portion, accessing the conductive portion with an electro-machining tool though the laser machined opening in the non-conductive portion; and
performing the electro-machining process of the conductive portion.
10. The method as claimed in claim 1 , wherein said electro machining comprises electro discharge machining or electro-chemical machining.
11. The method as claimed in claim 1 , comprising:
producing non-circular cross section openings in the non-conductive portion.
12. The method as claimed in claim 1 , further comprising:
swiveling at least one of the laser beam and the component into different incident angles (φ) with respect to the non-conductive portion surface.
13. The method as claimed in claim 12 , comprising:
producing a 3-dimensional freeform opening in the non-conductive portion.
14. The method as claimed in claim 1 , comprising:
performing said laser machining at an angle of incidence (φ), as measured against the non-conductive portion surface, of less than 20 degrees.
15. The method as claimed in claim 14 , wherein said angle of incidence is between 20 degrees and 12 degrees.
16. The method as claimed in claim 1 , comprising:
pulsing the laser beam.
17. The method as claimed in claim 16 , wherein pulsing comprises pulsing the laser beam at a frequency in excess of 500 Hz.
18. The method as claimed in claim 16 ,
wherein pulsing the laser beam comprises pulsing with a Q-switched laser.
19. A method according to claim 1 , wherein placing the laser onto the non-conductive portion surface comprises placing the laser focus onto the surface or inside the non-conductive portion.