METHOD FOR PRODUCING A THREE-DIMENSIONAL OBJECT

Abstract

A method for producing a three-dimensional object by successive solidification of layers of a powder-type construction material that can be solidified using radiation. The method includes providing a laser system with a housing, a construction chamber, a coating device for applying construction material in layers, a radiation device for applying the applied layers of construction material with radiation, and a group structure on which the object and/or a support structure for the object is additively constructed; forming the support structure for supporting the three-dimensional object, by successive solidification of layers of the construction material; forming individual sub-objects that form a determined section of the three-dimensional object, by successive solidification of layers of the construction material, wherein one sub-object is formed on the support structure; forming joining regions between the sub-objects for joining the sub-objects by forming the three-dimensional object; removing the three-dimensional object from the support structure.

Claims

1. A method for producing a three-dimensional object (1) by successive solidification of layers of a powder-type construction material that can be solidified using radiation, said method comprising the following steps: providing a laser sintering system or a laser melting system with a housing, a construction chamber arranged therein, a coating device for applying construction material in layers, a radiation device for radiating the applied layers of construction material, and a group structure on which the object and/or a support structure for the object is additively constructed; characterized by the following steps forming the support structure (2) for at least partially supporting the three-dimensional object (1) to be produced, by successive solidification of layers of the construction material; forming a number of individual sub-objects (6) that form a determined section of the three dimensional object (1) to be produced, by successive solidification of layers of the construction material, wherein at least one sub-object (6) is formed at least partially on the support structure (2); forming joining regions (7) between the sub-objects (6) for at least partially joining the sub-objects (6) by forming the three-dimensional object; removing the three-dimensional object (1) from the support structure (2).

2. A method according to claim 1, characterized in that at least a part of the support structure (2) and at least a part of at least one sub-object (6) are formed simultaneously.

3. A method according to claim 1, characterized in that forming the joining regions (7) is performed outside or within the SLS or SLM system.

4. A method according to claim 1, characterized in that the joining regions (7) are formed such that they join together sub-objects (6) that are, at least partially, arranged or to be arranged next to each other and/or on top of each other.

5. A method according to claim 1, characterized in that the joining regions (7) are designed geometrically different depending on the position of the sub-objects (6) to be joined using these joining regions related to the three-dimensional object (1) to be produced.

6. A method according to claim 1, characterized in that at first at least a part of the sub-objects (6) is joined using joining regions (7) of a first, especially point-type, geometric design, in order to convert the sub-objects (6) joined in this manner into a manageable state, and successively joining regions (7) of a second, especially linear, geometric design are formed and/or joining regions (7) of the first geometric design already formed are successively completed by forming, especially linear, joining regions (7) of the second geometric design.

7. A method according to claim 1, characterized in that at least a part of the joining regions (7) is at least partially formed elastically such that deformation-related mechanical stresses of the sub-objects (6) and/or of the object (1) are reduced.

8. A method according to claim 1, characterized in that sub-objects (6) arranged next to each other and/or on top of each other are joined such that a slot-type gap space (8) is formed between them.

9. A method according to claim 1, characterized in that forming appropriate joining regions (7) is performed by solidification of powder-type construction material and/or by melting on already solidified sub-object portions of already produced sub-objects (6).

10. A method according to claim 1, characterized in that appropriate sub-objects (6) to be joined are joined together by forming appropriate joining regions (7) by substance bonding.

11. A method according to claim 10, characterized in that the appropriate sub-objects (6) to be joined are welded together.

12. A method according to claim 1, characterized in that forming the support structure (2) and/or forming the sub-objects (6) is interrupted temporarily, to perform at least one measure affecting the properties of the support structure (2) formed by then and/or the properties of the sub-objects (6) formed by then, for example, heat treatment.

13. A method according to claim 1, characterized in that at least two of the appropriate sub-objects (6) are formed with equal or different geometric design.

14. A method according to claim 1, characterized in that at least one sub-object (6) is formed with at least one reception room limiting the, especially closed, reception volume for reception of at least one third item.

15. A three-dimensional object (1) produced according to a method of claim 1.

Description

[0042] The invention is explained in more detail by means of exemplary embodiments in the drawings. In which:

[0043] FIG. 1, 2 are each a schematic diagram to illustrate the performance of a method according to an exemplary embodiment of the invention; and

[0044] FIG. 3 is an enlarged illustration of the individual unit III shown in FIG. 2.

[0045] FIG. 1, 2 are each a schematic diagram to illustrate the performance of a method according to an exemplary embodiment of the invention.

[0046] FIG. 1 shows a perspective view of the method at a certain point in time at which a certain layer of a powder-type construction material is solidified. At this point in time, the three-dimensional object 1 is not completely produced yet. FIG. 2 is a side or cross-sectional view of the method at a certain point in time.

[0047] Using the method, three-dimensional, especially large-size, objects 1, especially technical components such as car wing elements, turbine bucket elements, airfoil elements, can be produced by successive solidification of layers of a powder-type construction material that can be solidified using radiation. Specifically, the method is a laser sintering process, SLS process in short, or a laser melting process, SLM in short.

[0048] According to the method, a support structure 2 is formed to at least partially support the three-dimensional object 1 to be produced by successive solidification of layers of a powder-type construction material that can be solidified using radiation. Then, in addition to additive forming of the three-dimensional object 1 actually to be produced, additive forming of a support structure 2 is also carried out. Therefore, the support structure 2 is also formed by successive solidification of the construction material in the same process in which the three-dimensional object 1 actually to be produced is formed.

[0049] Forming the support structure is carried out on a construction platform 3 of a construction chamber 4 of a device for carrying out the method, not shown in detail, i.e., especially a device for carrying out a laser sintering process or a laser melting process.

[0050] The support structure 2 serves for fixing or support of the three-dimensional object to be produced. The three-dimensional object 1 to be produced is successively constructed onto the support structure 2. Accordingly, the support structure 2 in its geometric design, especially in its cross-section, is adapted to the geometric design, especially the cross-section, of the three-dimensional object 1 to be produced (cf. FIG. 2). The support structure 2 fully represents the cross-section of the three-dimensional object 1 to be produced in the exemplary embodiments shown in the figures.

[0051] As can be seen in FIG. 1, support structure 2 comprises several support elements 5.

[0052] The support elements 5 can be of equal or unequal geometric design, i.e., equal or unequal shape or equal or unequal dimensions, and can be arranged in regular or irregular manner. The support elements 5 shown in the figures are formed strut-like or pillar-like.

[0053] The three-dimensional object 1 that is typically formed simultaneously with the support structure 2 is formed in segments. Thus, several individual or separate sub-objects 6 are formed, each forming a certain cross-sectional portion of the three-dimensional object 1 to be produced. As results from FIG. 2, each sub-object 6 forms a certain portion of the overall cross-section of three-dimensional object 1. Thus, the three-dimensional object to be produced is not constructed over its entire cross-section, but individual sub-objects 6 are constructed successively. Regarding position, the sub-objects 6 are formed related to each other such that the arrangement thereof makes the overall cross-section of the three-dimensional object 1.

[0054] With the, especially cross-sectional, division or subdivision of the three-dimensional object 1 to be produced into individual sub-objects 6, deformation effects related to material or production are reduced, since particular deformation effects in the sub-objects, which are considerably smaller in area or volume compared to the finished three-dimensional object, are, if at all, definitely smaller.

[0055] The support structure 2 and the sub-objects 6 can, as mentioned, be formed at the same time or simultaneously and thus together. From FIG. 2 it can be seen that one sub-object 6 is already to be formed over a layer of powder-type construction material to be solidified in a certain portion of the construction chamber 4, here outer regions, according to the dimensions of the three-dimensional object 1 to be produced, and in another portion of the construction chamber 4, here inner regions, no sub-object 6 is to be formed (yet), but a portion of the support structure 2, i.e., support elements 5, is to be formed.

[0056] The support structure 2 ensures that the sub-objects 6 are or will be safely arranged in their relative position to each other. Thus, the support structure 2 can be moved to each other or handled together with the sub-objects 6 fixed or supported by this without changing the relative position of the individual sub-objects 6. Of course, the construction platform 3 together with the support structure 2 formed thereon and the sub-objects 6 formed thereon can also be moved to each other without changing the relative position of the individual sub-objects 6.

[0057] For joining the sub-objects 6, joining regions 7 between the sub-objects 6 for at least partially joining the sub-objects 6 are formed during forming of the three-dimensional object 1. During forming of the joining regions 7 shown in the figures as a bold line, the sub-objects 6 are generally supported or fixed by the support structure 2. Forming particular joining regions 7 can be carried out by solidification of powder-type construction material and/or by melting on already solidified sub-object portions of particular produced sub-objects 6.

[0058] The joining regions 7 join the sub-objects 6 typically by substance bonding. The substance-by-substance bond is typically carried out using welding joints; thus sub-objects 6 are typically welded together.

[0059] Appropriate joining regions 7 can basically be formed in any geometric design. In FIG. 1, both point-type and linear joining regions 7 are exemplarily shown.

[0060] Appropriate joining regions 7 can be designed geometrically different depending on the position of the sub-objects 6 to be joined by using them related to the three-dimensional object 1 to be produced. The geometric design, i.e., especially dimensions and shape, of appropriate joining regions 7 can thus depend on the position at which they are located related to the three-dimensional object 1 to be produced. In FIG. 1, merely exemplary joining regions 7 that join together sub-objects arranged in outer regions of the three-dimensional object 1 mainly have a point-type form, whereas joining regions 7 that join together sub-objects 6 that are, in comparison, arranged in inner regions of the three-dimensional object 1 mainly have a linear form.

[0061] It is also imaginable to first join a part of the sub-objects 6 using joining regions 7 of a first geometric design only, e.g., point-type joining regions 7, to implement a pre-fixing, to convert sub-objects 6, e.g., into a manageable state, and to form the actual joining of the sub-objects 6 by using successively formed joining regions 7 of a second geometric design, e.g., linear joining regions 7, or by successively complementing the joining regions 7 of the first geometric design, e.g., to linear joining regions. Appropriate joining regions 7 of the first geometric design can be formed mechanically less stable than respective joining regions 7 of the second geometric design.

[0062] Forming appropriate joining regions 7 can be performed outside or within the device implementing the method. Consequently, the joining regions 7 can also be formed in the same process in which also the support structure 2 and the sub-objects 6 are formed.

[0063] In terms of the (further) reduction or compensation of mechanical stresses occurring related to material or process within the sub-objects or within the three-dimensional object, individual or several joining regions 7 can be formed at least partially elastically such that deformation-related mechanical stresses, i.e., tensile stresses and/or compressive, of the sub-objects 6 or the entire three-dimensional object 1 can at least be partially reduced. The joining regions 7 can thus, for example, be formed through the respective geometric design thereof, having elastical properties due to which mechanical stresses within the or between the sub-objects 6 can be reduced or compensated.

[0064] Appropriately, sub-objects 6 arranged next to each other and/or on top of each other are joined together using appropriate joining regions 7 such that a slot-type gap space 8, i.e., a slot, is formed or remains between them. Such a slot-type gap space 8 is shown in FIG. 3. Forming slot-type gap spaces 8 between sub-objects 6 arranged next to each other is also an opportunity to reduce or compensate mechanical stresses related to material or production. Mechanical joining of particular sub-objects is not affected by forming appropriate slot-type gap spaces. The slot-type gap spaces 8 are typically dimensioned so small, i.e., so narrow, that they are not or hardly to be seen on the finished object 1. Typically, the slot-type gap spaces 8 have a width in a range from 1 to 100 μm, especially in a range from 10 to 30 μm.

[0065] In a last step of the method, the three-dimensional object 1 completely formed is taken off, e.g., manually or (semi-)automatically, the support structure 2.

[0066] Prior to taking the three-dimensional object 1 off the support structure 2 or the construction platform, the three-dimensional object 1 can, however, be processed or treated. Thus, it is possible, for example, to subject the three-dimensional object 1 arranged on the support structure 2 to suitable post processing procedures to increase the surface quality. It is also possible to subject the three-dimensional object 1 continuously arranged on the support structure 2 to heat treatment to relieve inner mechanical stresses that may be present. It is further possible to clean the three-dimensional object 1 continuously arranged on the support structure 2, i.e., especially to remove construction material clinging to the surface.

[0067] In order to perform at least one measure affecting the properties of the support structure 2 formed by then and/or the properties of the sub-objects 6 formed by then, i.e., for example, heat treatment, forming the support structure 2 and/or forming the sub-objects 6 can also be interrupted temporarily, i.e., fora certain period of time.

[0068] One or more sub-objects 6 can be formed with a reception room that is limiting the, especially closed, reception volume to receive at least one third item. Such a third item can, for example, be a lightweight element of a lightweight structure, e.g., constructed like a sandwich. This is particularly purposeful when the three-dimensional object 1 is an airfoil or a portion of an airfoil element forming an airfoil.

LIST OF REFERENCE NUMBERS

[0069] 1 Object

[0070] 2 Support structure

[0071] 3 Construction platform

[0072] 4 Construction chamber

[0073] 5 Support element

[0074] 6 Sub-object

[0075] 7 Joining region

[0076] 8 Gap space