ADDITIVELY MANUFACTURED POROUS COMPONENT STRUCTURE AND MEANS FOR MANUFACTURING SAME

Abstract

A method for providing CAM manufacturing instructions for the powder-bed-based additive manufacturing of a component wherein a geometry of the component, with a solid material region, a transition region, and a porous component region, is defined on the basis of CAD data. Irradiation parameters for the manufacturing of the component, including an irradiation power, a scanning speed, a scanning pitch, and a layer thickness, are varied within the transition region in such a way as to form a porosity gradient of the structure of the component between the solid material region of the component and the porous component region.

Claims

1. A method for additive manufacturing of a component by selective laser melting or electron beam melting using manufacturing instructions (CAM) provided for the additive, powder bed-based manufacturing of a component, comprising: defining a geometry of the component, comprising a solid material area, a transition area, and a porous component area on the basis of CAD data, varying irradiation parameters for the manufacturing of the component, comprising an irradiation power, a scanning speed, a scanning distance, and a layer thickness within the transition area in such a way that a porosity gradient of the structure of the component is formed between the solid material area WO of the component and the porous component area, and reducing an irradiation power in the transition area from the solid material area to the porous component area.

2. The method as claimed in claim 1, wherein at least one irradiation parameter is selected in such a way that the structure of the component in the porous component area is between 5% and 40%.

3. The method as claimed in claim 1, wherein at least one irradiation parameter is selected in such a way that the structure of the component in the transition area has a gradually varying porosity between approximately 0 in the solid material area to a porosity value of the porous component area of approximately 20%.

4. The method as claimed in claim 3, wherein at least one irradiation parameter is selected in such a way that the porosity is formed continuously or infinitely gradually varying.

5. The method as claimed in claim 3, wherein at least one irradiation parameter is selected in such a way that the porosity is formed gradually varying in a stepped manner.

6. The method as claimed in claim 1, wherein a scanning speed is increased in the transition area from the solid material area to the porous component area.

7. The method as claimed in claim 1, wherein a scanning distance in the transition area is increased from the solid material area to the porous component area.

8. A computer program product stored on a non-transitory computer readable medium, comprising: commands which, upon execution of a corresponding program by a computer, to control irradiation in an additive manufacturing facility, cause it to implement the method as claimed in claim 1 or to manufacture the component accordingly.

9. An additively manufactured component structure, comprising: a solid material area, a transition area, and a porous component area, wherein the porous component area is a cooling body, which is configured to have a cooling fluid flow through it to cool the structure in operation, and wherein the transition area includes a porous structure, through which grating-like solid material elements extend.

10. The additively manufactured component structure as claimed in claim 9, wherein the solid material elements permeate the porous structure at least partially in a formfitting manner.

11. The additively manufactured component structure as claimed in claim 9, wherein the solid material elements extend in the transition area over a length of 0.1 mm to 0.5 mm.

12. A component, comprising: a component structure as claimed in claim 9, wherein the component is a component to be cooled of a hot gas path of a turbomachine, such as a turbine blade, a heat shield component of a combustion chamber, a resonator component, and/or an acoustic damper.

13. A method for additive manufacturing of the component structure as claimed in claim 9 by selective laser melting or electron beam melting, comprising: constructing initially the porous structure, and subsequently constructing areas of the solid material elements.

14. The method as claimed in claim 2, wherein at least one irradiation parameter is selected in such a way that the structure of the component in the porous component area is approximately 20%.

15. The additively manufactured component structure as claimed in claim 11, wherein the solid material elements extend in the transition area over a length of 0.2 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 shows a schematic sectional view of a powder bed-based, additive manufacturing process.

[0043] FIG. 2 indicates, according to the present invention, an additively manufactured structure having a continuous porosity gradient.

[0044] FIG. 3 shows a schematic top view of a hatching irradiation pattern, according to which a structure can be additively manufactured according to the invention.

[0045] FIG. 4 indicates, according to the present invention, an additively manufactured structure having a stepped porosity gradient.

[0046] FIG. 5 indicates an additively manufactured structure having a porous area and solid material elements according to an alternative embodiment of the present invention.

DETAILED DESCRIPTION OF INVENTION

[0047] In the exemplary embodiments and figures, identical or identically acting elements can each be provided with identical reference signs. The elements shown and their size relationships to one another are fundamentally not to be viewed as to scale, rather individual elements can be shown dimensioned exaggeratedly thick or large for better illustration capability and/or for better understanding.

[0048] FIG. 1 shows an additive manufacturing facility 100. The manufacturing facility 100 is preferably designed as an LPBF facility and for the additive construction of components from a powder bed. The facility 100 can also relate to a facility for electron-beam melting. Accordingly, the facility includes a construction platform 101. A component 20 to be additively manufactured is manufactured in layers from a powder bed on the construction platform 101. The powder bed is formed by a powder 6, which can be distributed in layers on the construction platform 1 by a coating device 3. After the application of each powder layer (cf. layer thickness t), according to the specified geometry of the component 20, areas of the layer are selectively melted using an energy beam, for example a laser or electron beam, by an irradiation device 2 and subsequently solidified.

[0049] After each layer, the component platform 1 is preferably lowered by an amount corresponding to the layer thickness t (cf. arrow directed downward in FIG. 1). The thickness t is typically only between 20 and 40 m, so that the entire process can easily require the irradiation of thousands to tens of thousands of layers.

[0050] In this case, high temperature gradients, for example, of 10.sup.6 K/s or more, can occur due to the energy introduction, which only acts very locally. A tension state of the component is obviously accordingly large during the construction and also after, which significantly complicates the additive manufacturing processes in general.

[0051] The geometry of the component is typically defined by a CAD file (computer aided design). After such a file is read into the manufacturing facility 100 or a corresponding control unit, the process then initially requires defining a suitable irradiation strategy, for example, by means of CAM (computer aided manufacturing), due to which the component geometry is also typically divided into the individual layers (slicing).

[0052] The component 10 is preferably a coolable component, to be cooled in operation, of the hot gas path of a turbomachine, such as a turbine blade, a heat shield component of a combustion chamber, and/or a resonator or damper component, such as a Helmholtz resonator. Alternatively, the component 10 can be a ring segment, a burner part or a burner tip, a frame, a shield, a heat shield, a nozzle, a seal, a filter, an orifice or lance, a plunger, or an agitator, or a corresponding retrofit part.

[0053] The present invention relates to a method for providing CAM manufacturing instructions (CAM method) for the additive manufacturing of a component 10, as was described on the basis of FIG. 1.

[0054] The geometry of the component 10 is partially shown in FIG. 2 and is typically defined on the basis of CAD data. The geometry of the component, to the manufacturing of which the mentioned manufacturing instructions are directed, comprises a solid material area B, a transition area T, and a porous component area T (cf. FIGS. 2 to 5 below).

[0055] In the context of the mentioned CAM method, irradiation parameters for the manufacturing of the component, at least comprising an irradiation power P, a scanning speed v, a scanning distance d, and a layer thickness t, are now furthermore varied within the transition area T in such a way that a porosity gradient of the structure of the component 10 is formed between the solid material area B of the component 10 and the porous component area H. The porous component area H is preferably provided as a cooling area or cooling structure and is accordingly configured to have a cooling fluid flow through it for cooling in operation of the component.

[0056] In particular, FIG. 2 shows a correspondingly graduated component structure or a graduated porosity of the component in the upper part. In the lower part of the illustration, in accordance with the position from left to right, an irradiation power P, for example laser power, and a scanning speed v are plotted qualitatively (can be specified in percent of a normal or standard value) over a spatial direction x, y (cf. lateral extension of the powder bed) and/or the construction direction z (latter not explicitly identified in the figures).

[0057] It can be seen that the laser power is selected relatively high in the left area of the component for solidifying a solid material structure. In the transition area T adjoining to the right on the solid material area B, the irradiation power P drops to a significantly weaker amount, in order to then assume a constant low value in the porous material area H following on the right. A reduced laser powerfor example in comparison to standard parametersadvantageously allows the reduction of the material density and thus the control of a (tailored) porosity 12 in the porous area H of the component 10.

[0058] Of course, it is known to a person skilled in the art that the selection of specific parameter values and their influence on the porosity of the component to be manufactured accordingly are furthermore dependent on the type of the powdered material.

[0059] In the middle of the porous area H, the irradiation power P and the scanning speed v extend mirror symmetrically, since a transition area T and a corresponding component area B in turn adjoin the porous area H (see farther to the right in FIG. 2).

[0060] Precisely counter to the effect of the irradiation power, a reduced scanning speed vfor example in comparison to standard parametersalso causes an increased porosity due to a spatially or temporally reduced energy introduction, which accordingly no longer contributes to the solidification of the powdered starting material. Starting from a comparatively low scanning speed in the component area B shown on the left, it is therefore increased in the left transition area T up to a (constant) maximum value in the porous component area H.

[0061] In the course of the described selective laser melting, laser sintering, or electron beam melting process, the component is thus advantageously provided according to the invention with a porosity gradient in the transition area T.

[0062] Where this is not explicitly identified, further parameters can alternatively or additionally be varied in order to generate a finished, preferably gradually varying porosity in the transition areas. In particular, a scanning distance can furthermore be varied (cf. FIG. 3 farther below). Moreover, for example, the layer thickness T can be varied; however, this is only practically usable in multiples of the solid material layer thickness t and along the construction direction z.

[0063] FIG. 3 shows a schematic top view of a hatching irradiation pattern, in which, also in a step preparing for the construction process, a scanning distance d of irradiation vectors (from left to right in the image) is varied in such a way that a density or porosity gradient is set from the solid material area B via the transition area T to the porous area H. This is possible along or with respect to each lateral direction (x/y direction) of the powder bed. In particular to manufacture a greater porosity, the scanning distance d, d1, d2 is increased in multiple steps or in a stepped manner. This takes place immediately with uniform melting track width (constant remaining irradiation parameters). In the right part of the illustration, a scanning distance d2 is shown by way of example which corresponds to double the amount of the scanning distance d1 (see area T).

[0064] According to the invention, one or more of the mentioned irradiation parameters P, v, d, t can be selected in such a way that the structure 12 of the component 10 in the porous component area H is between 5% and 40%, preferably approximately 20%.

[0065] Furthermore, one or more of the irradiation parameters can be selected in such a way that the structure 12 of the component 10 in the transition area T has a gradually varying porosity between approximately 0 in the solid material area B to a porosity value of the porous component area H of preferably approximately 20%.

[0066] Furthermore, one or more of the irradiation parameters can be selected in such a way that the porosity is formed continuously or infinitely (fluidly) varying. This is to be illustrated by the situation as shown in FIG. 2.

[0067] Furthermore, one or more of the irradiation parameters can be selected in such a way that the porosity is formed in a stepped manner (gradually). This embodiment corresponds to the situation from FIG. 4.

[0068] FIG. 4 indicates in particular from left or right on the basis of the differently hatched areas a stepped porosity or density profile of the correspondingly manufactured structure for the component 10. Gradual gradations between the solid material area B and the porous area H are shown within the area T.

[0069] FIG. 5 shows an additively manufactured component structure 10 according to an alternative embodiment of the present invention. The structure for the component can also be a component wall, for example.

[0070] The differently oriented arrows on the bottom left in the illustration of FIG. 5 are to indicate that the component can be constructed in the present case according to arbitrary construction directions and the vertical alignment shown of the component does not necessarily have to correspond to the construction direction specified by the process.

[0071] The middle area again represents the porous component area H. The arrow in the middle indicates a possible through-flow direction for a cooling fluid F, according to which the component area shown could be cooled in operation of the component (not shown in the previous figures solely for the sake of simplicity). In the present case (for example), a symmetry line, with respect to which the area shown is symmetrically formed, extends longitudinally in the middle of the porous area (approximately at the height of the arrow F).

[0072] Solely by way of example, the component area is furthermore provided with two symmetrical and identical transition areas T. According to the invention, in the transition areas T according to this embodiment, volume or solid material elements Be are provided, which preferably extend like gratings or struts from the solid material areas shown into areas of the porous structure, or permeate them. The solid material elements Be preferably permeate the porous structure 12 at least partially in a formfitting manner.

[0073] In contrast to the above-described embodiment of the component structure that is to be additively manufactured, a reinforced mechanical attachment of the porous structure to the solid material areas Be is not directly implemented here by a graduation of porous material (gradual parameter variation), but ratheras describedby the solid material elements Be extending into the porous structure.

[0074] The solid material elements Be can extend, for example, in the transition area over a length L of 0.1 mm to 0.5 mm, or more, for example, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or 10 mm, preferably 0.2 mm, into the porous structure to effectuate the strongest possible mechanical anchoring.

[0075] According to the present invention, during the powder bed-based additive manufacturing process (cf. FIG. 1 above) by means of selective laser melting or electron beam melting, preferably initially the porous structure 12 is constructed and areas of the solid material elements Be are subsequently constructed. As indicated above, this can be carried out in layers (layer sequence not explicitly identified here) according to any arbitrary construction direction Z.

[0076] A graduation of the porosity in the transition areas along a rotation angle, pivoted, can also take place, without this being explicitly identified in the figures.

[0077] According to the second alternative according to the invention to the additive component structure, the solid material elements Be can also extend different distances, for example only minimally radially inward, but instead significantly farther radially outward, into the porous structure.