1. An additive manufacturing apparatus, comprising:
a build module comprising a build chamber, and a least one of but less than all of the following elements:
(a) a directed energy source;
(b) a powder supply;
(c) a powder recovery container; and
(d) a powder applicator; and
a workstation comprising the remainder of elements (a)-(d) not included in the build module.
2. The apparatus as claimed in claim 1 further comprising a transport mechanism configured to move the build module in to and out of the workstation.
3. The apparatus as claimed in claim 2 wherein the transport mechanism is a conveyor.
4. The apparatus as claimed in claim 2 wherein:
the workstation comprises an enclosure sized to enclose one or more build modules; and
the transport mechanism comprises a turntable disposed partially within the enclosure and defining a worksurface configured to receive the build module therein.
5. The apparatus as claimed in claim 1 wherein either the build module or the workstation includes a planar worksurface including a build chamber opening communicating with the build chamber.
6. The apparatus as claimed in claim 1 wherein the build module includes:

a planar worksurface having a build chamber opening communicating with the build chamber;
a peripheral wall extending past the worksurface opposite the build chamber to define a workspace; and
a window transparent to radiant energy that spans across the peripheral wall to close off the workspace.
7. The apparatus as claimed in claim 6 wherein the workstation comprises an enclosure sized to enclose one of the build modules, the enclosure including one or more seals configured to allow a build module to pass therethrough.
8. An additive manufacturing apparatus, comprising:
a plurality of workstations and build modules as claimed in claim 1; and an electronic central controller operably connected to each of the workstations.
9. An additive manufacturing apparatus, comprising:
a plurality of workstations and build modules as claimed in claim 1; and a central shielding gas supply coupled to each of the workstations.
10. An additive manufacturing apparatus, comprising:
a plurality of workstations and build modules as claimed in claim 1; and a central cooling fluid supply coupled to each of the workstations.
11. An additive manufacturing apparatus, comprising:
a plurality of workstations and build modules as claimed in claim 1; and a central ventilation system coupled to each of the workstations.

12. An additive manufacturing apparatus, comprising:
a workstation including a directed energy source;
a build module, comprising: a first build chamber; and
a peripheral wall extending past the worksurface opposite the first build chamber to define a workspace; and
a transport mechanism operable to move the build module into and out of the workstation.
13. The apparatus as claimed in claim 12 wherein the build module includes a planar worksurface with a first build chamber opening communicating with the first build chamber.
14. The apparatus as claimed in claim 12 wherein each module includes a window transparent to radiant energy that spans across the peripheral wall to close off the workspace.
15. The apparatus as claimed in claim 12 wherein the workstation comprises an enclosure sized to enclose one of the build modules, the enclosure including one or more seals configured to allow a build module to pass therethrough.
16. The apparatus as claimed in claim 12 wherein the transport mechanism is a conveyor.
17. The apparatus as claimed in claim 12 wherein:
the workstation comprises an enclosure sized to enclose one or more of the build modules; and
the transport mechanism comprises a turntable disposed partially within the enclosure and defining a worksurface configured to receive the build module therein.

18. The apparatus as claimed in claim 17 wherein the enclosure contains a powder supply configured to drop powder onto the worksurface.
19. The build module as claimed in claim 17 further comprising a moveable powder applicator disposed in the workspace and contacting the worksurface.
20. An additive manufacturing method, comprising:
moving a build module having a build chamber into a workstation;
depositing powder onto a build platform which is disposed in the build chamber;
directing a beam from a directed energy source to fuse the powder;
moving the platform vertically downward within the build chamber by a layer increment of powder; and
repeating in a cycle the steps of depositing, directing, and moving to build up the part in a layer-by-layer fashion until the part is complete
21. The method as claimed in claim 20 further comprising:
moving the build module out of the workstation;
moving another build module having a build chamber into the workstation; performing in a cycle the steps of depositing, directing, and moving to build up a subsequent part in a layer-by-layer fashion until the subsequent part is complete
22. The method as claimed in claim 21 wherein the build modules are moved in to and out of the workstation using a conveyor.
23. The method as claimed in claim 21 wherein the build modules are moved in to and out of the workstation using a turntable.

24. The method as claimed in claim 20 further comprising:
providing a plurality of workstations; and
controlling the operation of the plurality of workstations using an electronic central controller.
25. The method as claimed in claim 20 further comprising:
providing a plurality of workstations; and
cooling a directed energy source of each workstation using a central cooling system.
26. The method as claimed in claim 20 further comprising:
providing a plurality of workstations; and
providing shielding gas to the plurality of workstations using a central gas supply system.
27. The method as claimed in claim 20 further comprising:
providing a plurality of workstations; and
providing ventilation to the plurality of workstations using a central ventilation system.