LAYER CONSTRUCTION METHOD AND LAYER CONSTRUCTION DEVICE FOR ADDITIVELY MANUFACTURING AT LEAST ONE COMPONENT REGION OF A COMPONENT, AND COMPUTER PROGRAM PRODUCT AND STORAGE MEDIUM

Abstract

The layer construction method comprises at least the following steps: a) applying at least one powder layer of a material to at least one construction and joining zone of at least one movable construction platform; b) locally solidifying the material to form a component layer, wherein the material is selectively scanned along scan lines by at least one energy beam and fused; c) lowering the construction platform layer by layer by a predefined layer thickness; and d) repeating the steps a) to c) until the component region is complete.

In step b), a distance h.sub.s between at least two central lines of neighboring scan lines in at least one component layer is adjusted in accordance with Formula I

0.85≤b.sub.smin/h.sub.s≤1.00  (I)

wherein b.sub.smin represents a minimum melt pool width of the scan lines.

Claims

1. A layer construction method for the additive manufacturing of at least one component region of a component, comprising at least the following steps: a) applying at least one powder layer of a material to at least one construction and joining zone of at least one movable construction platform; b) locally solidifying the material to form a component layer, wherein the material is selectively scanned along scan lines by at least one energy beam and fused; c) lowering the construction platform layer by layer by a predefined layer thickness; and d) repeating the steps a) to c) until the component region is complete, wherein, in step b), a distance h.sub.s between at least two central lines of neighboring scan lines in at least one component layer is adjusted in accordance with Formula I
0.85≤b.sub.smin/h.sub.s≤1.00  (I) wherein b.sub.smin represents a minimum melt pool width of the scan lines.

2. The layer construction method according to claim 1, wherein, in step b), a laser beam with a power of between 200 W and 300 W is used as the energy beam.

3. The layer construction method according to claim 1, wherein, in step b), a mean scan speed of the at least one energy beam is adjusted to a value of between 800 mm/s and 1100 mm/s.

4. The layer construction method according to claim 1, wherein the construction platform in step c) is lowered by a layer thickness of between 30 μm and 50 μm.

5. The layer construction method according to claim 1, wherein, in step b), the distance h.sub.s between at least two central lines of neighboring scan lines is adjusted to a value of between 130 μm and 150 μm.

6. The layer construction method according to claim 1, wherein the hatch distance h.sub.s of the majority of the central lines of neighboring scan lines or the distance h.sub.s of all central lines of neighboring scan lines in at least one component layer is adjusted in accordance with Formula I.

7. The layer construction method according to claim 1, wherein a material taken from the group composed of steel, aluminum alloys, titanium alloys, cobalt-based alloys, chromium-based alloy, nickel-based alloy, copper alloys, intermetallic alloys, or any mixtures thereof is used.

8. The layer construction method according to claim 1, wherein at least the component region is subjected after its production to a hot isostatic pressing process.

9. A layer construction device for the additive manufacturing of at least one component region of a component by an additive layer construction method, comprising: at least one powder feed for applying at least one of powder layer of a material to at least one construction and joining zone of at least one movable construction platform; at least one radiation source for producing at least one energy beam for the layer-by-layer and local solidification of the material by selective scanning and fusing of the material along scan lines; and a control device, which is configured and arranged to: control the powder feed in such a way that it applies at least one powder layer of the material to the construction and joining zone of the construction platform; and control the construction platform in such a way that it is lowered layer by layer by a predefined layer thickness, wherein the control device is configured and arranged to adjust, in at least one component layer, a distance h.sub.s between at least two central lines of neighboring scan lines in accordance with Formula I
0.85≤b.sub.smin/h.sub.s≤1.00  (I) wherein b.sub.smin represents a minimum melt pool width of the scan lines.

10. The layer construction device according to claim 9, wherein it is configured and arranged as a selective laser-sintering and/or laser-melting device.

11. (canceled)

12. (canceled)

13. (canceled)

14. The layer construction method of claim 1, wherein a computer program product, including commands, is configured and arranged to execute the layer construction method.

15. The layer construction device of claim 9, further comprising: a computer program product, including commands, is configured and arranged to be executed by the control device.

16. The layer construction method of claim 1, wherein a computer-readable storage medium, including commands, is configured and arranged to execute the layer construction method.

17. The layer construction device of claim 9, further comprising: a computer-readable storage medium, including commands, is configured and arranged to be executed by the control device.

18. The layer construction method of claim 1, wherein the component is a turbomachine component.

19. The layer construction device of claim 9, wherein the component is a turbomachine component.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0020] Further features of the invention ensue from the claims, the figures, and the description of the figures. The features and combinations of features mentioned in the above description as well the features and combinations of features mentioned below in the description of the figures and/or solely in the figures can be used not only in the respectively presented combination, but also in other combinations, without departing from the scope of the invention. Hence, the invention is also regarded as comprising and disclosing embodiments that are not shown and explained explicitly in the figures, but ensue and can be produced by separated combinations of features taken from the explained embodiments. Also regarded as being disclosed are embodiments and combinations of features that, accordingly, do not have all features of an independent claim as originally formulated. Moreover, embodiments and combinations of features are regarded as being disclosed, in particular by way of the embodiments explained above, that go beyond or depart from the combinations of features presented in reference to the claims. Herein:

[0021] FIG. 1 shows a schematic sectional view of a layer construction device according to the invention;

[0022] FIG. 2 shows a schematic illustration of a scan line;

[0023] FIG. 3 a schematic illustration of three scan lines that are spaced apart from one another in accordance with the invention;

[0024] FIG. 4 shows a schematic illustration of three scan lines that are arranged at a hatch distance that is not in accordance with the invention;

[0025] FIG. 5 shows a diagram in which, on the abscissa axis, an input volume energy is plotted and, on the ordinate axis, a resulting mean grain size of an additively manufactured component is plotted;

[0026] FIG. 6 shows a diagram in which, on the abscissa axis, an input volume energy is plotted and, on the ordinate axis, a resulting maximum grain size of an additively manufactured component is plotted;

[0027] FIG. 7 shows a microstructure slice image of a microstructure in the regions Va and VIa shown in FIG. 5 and FIG. 6; and

[0028] FIG. 8 shows a microstructure slice image of a microstructure in the region Vb and VIb shown in FIG. 5 and FIG. 6.

DESCRIPTION OF THE INVENTION

[0029] FIG. 1 shows a schematic sectional view of a layer construction device 10 according to the invention. The layer construction device 10 serves for the additive manufacture of at least one component region 12 of a component 14 by an additive layer construction method. The layer construction device 10 comprises at least one powder feed 16 with a powder tank 18 and a coater 20. The powder feed 16 serves for applying at least one layer of powder of a material 22 to a construction and joining zone II of a construction platform 24 that is movable in accordance with arrow B. To this end, the coater 20 is moved in accordance with arrow III in order to transport the material 22 from the powder tank 18 to the construction and joining zone II. The layer construction device 10 further comprises at least one radiation source 26 for producing at least one energy beam 28 for layer-by-layer and local solidification of the material 22 by selective scanning and melting of the material 22 by the energy beam 28 along scan lines 40 (see FIG. 2). In addition, a control device 30 is provided, which is designed to control the powder feed 16 in such a way that it applies at least one layer of powder of the material 22 to the construction and joining zone II of the construction platform 24, and the construction platform 24 is lowered layer by layer by a predefined layer thickness in accordance with arrow B. In addition, the control device 30 is configured in such a way that, in at least one component layer, a hatch distance h.sub.s between at least two central lines M of neighboring scan lines 40 is adjusted in accordance with Formula I

0.85≤b.sub.smin/h.sub.s≤1.00  (I)

wherein b.sub.smin designates a minimum melt pool width of the scan lines 40. Furthermore, the layer construction device 10 comprises an optical device 32, by which the energy beam 28 can be moved over the construction and joining zone II. The radiation source 26 and the device 32 are coupled to the control device 30 for data exchange. Furthermore, the layer construction device 10 comprises a fundamentally optional heating device 34, by which the powder bed can be thermally adjusted to a desired base temperature. The heating device 34 can comprise, for example, one induction coil or a plurality of induction coils. Alternatively or additionally, it is also possible to provide other heating elements, such as, for example, IR radiators or the like.

[0030] FIG. 2 shows a schematic illustration of a scan line 40 that has a length l.sub.s and, in this instance, is linearly executed. The scan line 40 has a central line M, along which the laser beam 28 has been guided and has melted the material 22. As process parameters by way of example, a laser power of 250 W, a scan speed of 960 mm/s, and a layer thickness of 40 μm are set. The scan line 40 further has a region with a minimum melt pool width b.sub.smin and a region with a maximum melt pool width b.sub.smax. The hatch distance between the central line and one edge of the melt pool is formally ½ b.sub.s, where the value b.sub.s varies along the scan line 40 between b.sub.smin and b.sub.smax.

[0031] FIG. 3 shows a schematic illustration of three scan lines 40, which are spaced apart from one another in accordance with the invention and are produced using the aforementioned process parameters. This means that the hatch distance h.sub.s between neighboring central lines M of the scan lines 40 corresponds to the formula 0.85≤b.sub.smin/h.sub.s≤1.00 and, in the present example, is about 140 μm. Thereby ensured is the deliberate creation of an at least largely isotropic or quasi-isotropic microstructure that, at least for the most part, is free of defects. It can be seen that the scan lines 40 are arranged at least mostly edge to edge and neither substantially overlap nor exhibit appreciable gaps. In addition, the value b.sub.s varies only slightly along the individual scan lines 40.

[0032] FIG. 4 shows a schematic illustration of three scan lines 40, which are arranged from one another at a hatch distance of h.sub.s that is not in accordance with the invention. It can be seen that the scan lines 40 overlap, in part to a great extent, and exhibit substantially more greatly varying widths (b.sub.s) in the direction of extension. Nonetheless, at the same time, isolated gaps appear between adjacent scan lines 40. This leads to locally greatly varying energy inputs and, accordingly, to greatly varying grain sizes and a corresponding anisotropic microstructure.

[0033] FIG. 5 shows a diagram of an additively manufactured component 14 (not shown), in which, on the abscissa axis, an input volume energy VE in J/mm.sup.3 is plotted and, on the ordinate axis, a resulting mean grain size KG in μm is plotted. FIG. 6 shows a diagram of the additively manufactured component 14, in which, on the abscissa axis, the input volume energy VE [J/mm.sup.3] is plotted and, on the ordinate axis, a resulting maximum grain size KG.sub.max [μm] is plotted. The diagrams illustrate the relationship between the mean and maximum grain size KG, KG.sub.max and the input volume energy VE, which also is determined essentially by the hatch distance h.sub.s. The regions Va, VIa mark an at least nearly isotropic material state without noteworthy preferred orientation in the microstructure, while the regions Vb, VIb mark strongly anisotropic states or microstructures. Whereas differences transverse to the construction direction can be neglected at least in a first approximation, great differences in the mechanical properties are revealed in the construction direction and are associated with the degree of isotropy or anisotropy of the microstructure.

[0034] FIG. 7 shows for further clarification a microstructure slice image of a microstructure in the regions Va and VIa shown in FIG. 5 and FIG. 6, while FIG. 8 shows a microstructure slice image of a microstructure in the regions Vb and VIb shown in FIG. 5 and FIG. 6.

[0035] The parameter values given in the documentation for definition of the process and measurement conditions for the characterization of specific properties of the subject of the invention are also to be regarded in the scope of deviations—for example, due to measurement errors, system errors, DIN tolerances, and the like—as being comprised in the scope of the invention.