Additive manufacturing apparatus with a chamber and a removably-mountable optical module; method of preparing a laser processing apparatus with such removably-mountable optical module

1. An additive manufacturing apparatus comprising a processing chamber and a sealed optical module, the processing chamber comprising a processing chamber window for receiving a laser beam, the processing window sealed with optically transparent material, and the sealed optical module comprising a housing containing optical components for steering and focusing the laser beam, an interface coupled with a fibre-optic cable configured to carry the laser beam and a windowed aperture through which the laser beam can pass out of the sealed optical module and into the processing chamber through the processing chamber window.

2. An additive manufacturing apparatus according to claim 1 , wherein the windowed aperture comprises an f-theta lens.

3. An apparatus according to claim 1 in which the optical components comprise a focusing element and a scanning head.

4. An apparatus according to claim 1 in which the optical components further comprise a beam expander.

5. An additive manufacturing apparatus according to claim 1 , wherein the optically transparent material seals the processing chamber to enable a pressure lower than atmospheric pressure to be maintained in the processing chamber.

6. An apparatus according to claim 1 in which the housing contains a camera.

7. An apparatus according to claim 1 comprising a radio frequency identification tag for holding information relating to the module.

8. An apparatus according to claim 1 in which the module comprises a means for monitoring laser beam parameters.

9. An apparatus according to claim 1 in which the optical components are movably mounted to a rail within the housing.

10. An apparatus according to claim 1 in which one or more optical element is movable to allow for dynamic focusing of the laser beam.

11. An apparatus according to claim 1 in which the processing chamber is adapted to operate at a pressure of 1×10 −4 Torr or less.

12. An apparatus according to claim 1 in which the optically transparent material of is at least 15 mm thickness.

13. An additive manufacturing apparatus according to claim 1 wherein, the housing of the optical module is hermetically sealable to maintain a controlled atmosphere within the housing.

14. An apparatus according to claim 13 in which the housing contains a camera.

15. An apparatus according to claim 13 wherein the controlled atmosphere within the housing is dehumidified air.

16. An apparatus according to claim 13 wherein the controlled atmosphere within the housing comprises an inert gas.

17. An additive manufacturing apparatus comprising a processing chamber, an optical module and a camera, the optical module comprising an optical train through which laser light can be passed, the optical train comprising movable optical elements that allow dynamic focusing of the laser beam to deliver a focused spot to a planar build surface within the processing chamber, wherein the camera is mounted to inspect the build surface through the optical train, including the movable optical elements.

18. An additive manufacturing apparatus according to claim 17 , wherein the optical module comprises a 45 degree mirror that allows some light to pass through to the camera.

19. An additive manufacturing apparatus comprising a processing chamber containing a planar build surface and a plurality of removably mountable optical module, each optical module arranged for steering a corresponding laser beam of a plurality of laser beams to direct a laser spot of the corresponding laser beam to the planar build surface.

20. An additive manufacturing apparatus according to claim 19 , wherein each optical module is arranged for use with a laser beam having a different wavelength.

21. A method of preparing a laser processing apparatus for operation the laser processing apparatus comprising a processing chamber, the processing chamber comprising a processing chamber window for receiving a laser beam, the processing chamber window sealed with optically transparent material, the method comprising,

providing an optical module comprising a housing containing optical components for steering and focussing the laser beam, an interface for coupling to a fibre-optic cable configured to carry the laser beam and a windowed aperture through which the laser beam can pass out of the optical module,

coupling a fibre-optic cable connected with a laser to the interface,

mounting the optical module to the laser processing apparatus such that the optical module directs the laser beam out of the windowed aperture and into the processing chamber through the processing chamber window.

22. A method according to claim 21 in which the optical module is tested and validated or certified at a location remote to the laser processing apparatus.

23. A method according to claim 21 comprising aligning optical components for focusing and steering the laser beam in a controlled environment and hermetically sealing the housing of the module.

24. A method according to claim 23 comprising the step of forming an inert gas atmosphere within the module.