WE CLAIM
1. A method of forming a build in a powder bed, comprising:
emitting a plurality of laser beams from selected fibers of a diode laser fiber array onto the powder bed, the selected fibers of the array corresponding to a pattern of a layer of the build; and
simultaneously melting powder in the powder bed corresponding to the pattern of the layer of the build.
2. A method according to claim 1, further comprising:
controlling at least one of a duration of each laser beam, a pulse energy of each diode laser, a pulse width of each diode laser, an average output power of each diode laser, an energy distribution of each laser beam, power density of each laser beam, a rate of reduction of the power of each laser beam, and/or a distance of ends of the fibers from the powder bed.
3. A method according to claim 2, wherein the average output power of each diode laser is up to about 60 W.
4. A method according to claim 2, wherein the average output power of each diode laser is between about 2 W to about 60 W.
5. A method according to claim 2, wherein the power density of each laser beam is about 1,000,000 W/cm2.

6. A method according to claim 2, wherein the distance of ends of the fibers from the powder bed is between about 5 mm to about 150 mm.
7. A method according to claim 2, wherein the energy distribution of each laser beam is Gaussian or a top hat.
8. A method according to claim 1, wherein the powder is metal, ceramic, glass or plastic.
9. A method according to claim 1, further comprising:
emitting laser beams from fibers at least adjacent to the pattern of the layer; and
heating the powder adjacent to the powder of the layer of the build to control a cooling rate of the melted powder.
10. A method according to claim 9, wherein heating the powder adjacent to
the powder of the layer comprises heating the powder at least one of prior to
and/or during and/or after simultaneous melting of the powder of the pattern of the
layer.

11. A method according to claim 9, wherein a power density of the laser beams heating the powder adjacent the pattern is in a range of from about 100 W/cm2 to about 100,000 W/cm2.
12. A method according to claim 1, wherein a thickness of each layer is between about 1 µm to about 1 mm.
13. A method according to claim 12, wherein a thickness of each layer is about 100 µm.
14. A method according to claim 1, wherein the build is a repair of a component.
15. A method according to claim 14, wherein the component is a turbine component.
16. A method according to claim 15, wherein the turbine component is an airfoil.
17. A method according to claim 1, wherein the build is a component of a turbine.
18. A method according to claim 17, wherein the component is an airfoil.

19. A method according to claim 1, further comprising:
repeating the emitting and simultaneous melting to form a plurality of layers of the build.
20. A method according to claim 1, further comprising: allowing the melted powder to cool and solidify.
21. A method according to claim 1, further comprising:
moving the selected fibers and the powder bed relative to each other; and
simultaneously controlling the diode lasers of the selected fibers during relative movement.
22. An apparatus for forming a build in a powder bed, comprising:
a diode laser fiber array comprising a plurality of diode lasers and a plurality of optical fibers corresponding to the plurality of diode lasers, each optical fiber configured to receive a laser beam from a respective diode laser and configured to emit the laser beam;
a support configured to support a powder bed or a component configured to support the powder bed at a distance from ends of the optical fibers; and
a controller configured to control the diode laser fiber array to emit a plurality of laser beams from selected fibers of the diode laser fiber array onto the powder bed, the selected fibers of the array corresponding to a pattern of a layer

of the build and simultaneously melt the powder in the powder bed corresponding to the pattern of the layer of the build.
23. An apparatus according to claim 22, wherein the controller is further configured to control at least one of a duration of each laser beam, a pulse energy of each diode laser, a pulse width of each diode laser, an average output power of each diode laser, an energy distribution of each laser beam, power density of each laser beam, a rate of reduction of the power of each laser beam, and/or a distance of ends of the fibers from the powder bed.
24. An apparatus according to claim 22, wherein the controller is further to control the diode laser fiber array to emit laser beams from fibers adjacent to the pattern of the layer and heat the powder adjacent to the powder of the layer of the build to control a cooling rate of the melted powder.
25. An apparatus according to claim 24, wherein the controller is configured to control the diode laser fiber array to heat the powder adjacent to the powder of the layer at least one of prior to and/or during simultaneous melting of the powder of the pattern of the layer.
26. An apparatus according to claim 22, wherein the optical fibers are provided in a plurality of linear arrays.
27. An apparatus according to claim 26, wherein the plurality of linear arrays are arranged in closed packed configuration.

28. An apparatus according to claim 22, wherein each optical fiber comprises a core, a cladding surrounding the core, and a buffer surrounding the cladding.
29. An apparatus according to claim 28, wherein the core and the cladding are formed of silica, and a refractive index of the core is larger than a refractive index of the cladding.
30. An apparatus according to claim 29, wherein a diameter of the core is from about 60 µm to about 105 µm.
31. An apparatus according to claim 30, wherein a thickness of the cladding is about 10 µm
32. An apparatus according to claim 31, wherein the buffer is formed of acrylate or polyimide.
33. An apparatus according to claim 32, wherein a thickness of the buffer is about 62 µm.
34. An apparatus according to claim 28, wherein a diameter of each optical fiber is about 250 µm.

35. An apparatus according to claim 22, wherein the fibers have circular cross sections.
36. An apparatus according to claim 22, further comprising:
at least one lens, the at least one lens being configured to collimate the laser beams.
37. An apparatus according to claim 22, further comprising:
at least one lens, the at least one lens being configured to provide a predetermined divergence to each of the laser beams.
38. An apparatus according to claim 22, further comprising:
an actuator configured to move the support, wherein the controller is configured to control the actuator to adjust the distance between the powder bed and the ends of the optical fibers.