Method and apparatus for producing a three-dimensional object

• US 5,658,412 A
• Filed: 08/08/1994
• Issued: 08/19/1997
• Est. Priority Date: 01/11/1993
• Status: Expired due to Fees

• Current Assignee: EOS GmbH Electro Optical Systems
• Original Assignee: EOS GmbH Electro Optical Systems
• Inventors: Retallick, Dave, Reichle, Johannes, Langer, Hans J.
• Primary Examiner(s): SELLS, JAMES D
• Application Number:
  US08/284,511
• Time in Patent Office: 1,107 Days
• Field of Search: 156/272.2, 156/273.3, 156/273.5, 156/275.5, 156/290, 156/307.1, 156/359, 156/379.6, 156/379.8, 156/381, 156/382, 156/272.8, 264/22, 264/308, 264/DIG. 59, 264/405, 264/497, 264/85, 264/125, 425/174.4
• US Class Current: 156/272.8
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/32 of the atmosphere, e.g. composition or pressure in a building chamber
• CPC Class Codes: B22F 12/10 Auxiliary heating means
• CPC Class Codes: B22F 12/44 characterised by the configuration of the radiation means
• CPC Class Codes: B22F 3/005 Loading or unloading powder metal objects transport in general B65G
• CPC Class Codes: B29C 2791/005 Using a particular environment, e.g. sterile fluids other than air
• CPC Class Codes: B29C 41/50 Shaping under special conditions, e.g. vacuum
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

In a method for producing a three-dimensional object wherein the object is produced layer by layer by applying a layer of a material which can be solidified by irradiation with electromagnetic radiation and subsequently solidifying the layer at the points corresponding to the object by irradiation the problem is encountered that the production process is considerably delayed by long heating and cooldown times within the apparatus used for the production. According to the invention this problem is solved by irradiating and thereby solidifying in each layer a region of the material surrounding the object so as to produce a container wall (26) for the material (21).

Claims

1. A method for producing a three-dimensional object by layerwise solidifying a powdered material which can be solidified by irradiation with an electromagnetic radiation, the method comprising the steps of:

a) moving an elevation adjustable base at least partly into a cutout of a work table, said cutout having an inner defining surface closely surrounding said base;

b) charging an amount of said powdered material corresponding to a predetermined thickness of a first layer into said cutout onto said base;

c) irradiating a contour region of said first layer adjacent to said inner defining surface of said cutout;

d) lowering said base by an amount corresponding to a layer thickness of a next layer;

e) charging an amount of said powdered material corresponding to said layer thickness of said next layer into said first layer;

f) irradiating regions of said next layer which correspond to said object to be formed and to said contour region adjacent to said inner surface of said cutout to form said object and a container having a wall surrounding said object; and

g) repeating said steps d) to f) for a predetermined number of layers to form said object within said container made from said powdered material;

wherein, before producing said object, solidifying a material layer over the entire area enclosed by the container wall so as to produce a closed bottom layer for said container.

2. The method of claim 1 further comprising producing said object in an inert gas atmosphere.

3. The method of claim 1, further comprising providing a controlled laser beam for irradiation.

4. The method of claim 1, further comprising irradiating said powdered material to sinter said material together at said irradiated regions.

5. The method of claim 1, wherein forming a container wall around the object further comprises solidifying a corresponding annular region in each layer so as to generate a cylindrical container wall.

6. The method of claim 1, further comprising, after producing said container and said object, solidifying a material layer over the entire area which is enclosed by the container wall to produce closed cover for said container.

7. The method of claim 1, further comprising moving the container together with said object, after completion thereof, into a removal container for cool-down under controlled conditions.

8. Apparatus for producing a three-dimensional object by layerwise solidifying a powdered material which can be solidified by irradiation, the apparatus comprising:

a work table having a cutout with an inner defining surface;

an elevation adjustable base having an external contour corresponding substantially to said inner defining surface of said cutout;

level adjustment means for displacing said base in a vertical direction between an uppermost position in which an upper surface of said base is within said cutout and substantially at the same level as an upper side of said work table and a lowermost position below said work table in which a distance between said work table and an upper side of said base is greater than a maximum height of said object;

means for applying a layer of said powdered material onto said base;

irradiation means disposed above said work table in a fixed positional relationship to said work table for irradiating selected portions of said layer; and

control means connected to said irradiation means for controlling said irradiation means to irradiate portions of said layer corresponding to said object and an additional region adjacent to said inner surface of said cutout and surrounding said object region so as to form a container having a wall around said object region, said container having integrally formed bottom and side walls.

9. The apparatus of claim 8, wherein said base is formed as a table which is guided laterally or from below and comprises a laterally arranged elevation adjustment means for said table.

10. The apparatus of claim 8, further comprising means for lowering said base into a position level with a laterally adjacent receiving plate.

11. The apparatus of claim 10, further comprising a container having a wall surrounding said object and discharge means adapted to engage said container wall for displacing said container from said base onto said receiving plate.

12. The apparatus of claim 10, further comprising a closeable opening for discharging said container surrounding said object.

13. The apparatus of claim 12, further comprising a removal container and means for sealingly attaching said removal container to said closeable opening.

14. The apparatus of claim 13, further comprising inert gas supply means and an adjustable heating means for said removal container.

15. The apparatus of claim 14, wherein the inert gas supply means consists of a nitrogen supply means.

16. The apparatus of claim 8, wherein the irradiation means comprises a laser beam.