Device for shaping temperature-resistant components by means of selective laser melting

Abstract

The invention relates to a device (10) for selective laser melting of a near-α Ti alloy (34). The device (10) has a layer arrangement (16) with layers (14a, 14b, 18) applied on top of one another, wherein at least one of the layers (14a) has the near-α Ti alloy (34). The layer arrangement (16) is arranged on a substrate panel (12) of the device (10). A laser beam source (24) is designed to selectively melt the layers (14a, 14b, 18) using a laser beam (26). A heating unit (20) of the device (10) can introduce heat energy into an uppermost layer (18) of the layer arrangement in the direction (SR) from the substrate panel (12) to the layer arrangement (16), in order to heat the uppermost layer (18) to a temperature between 250°C and 600°C. The uppermost layer (18) is, in particular, the layer of the layer arrangement (16) at the greatest distance from the substrate panel (12).

Description

[0001] Device for forming temperature-resistant components by selective laser melting

[0002] Background of the invention

[0003] The invention relates to a device for selective laser melting. The invention further relates to a method for selective laser melting.

[0004] EP 1 355 760 B1 discloses a device for selective laser melting, in which a heating plate is integrated into a build platform that can reach heating temperatures of more than 500°C. The heating plate can heat layers of metallic materials located on the build platform during component formation by selective laser melting of the layers. This serves to reduce stresses in the respective component during selective laser melting.

[0005] The disadvantage is that components manufactured using state-of-the-art devices often have comparatively low temperature resistance. Furthermore, the components manufactured in this way continue to exhibit elevated residual stresses, which lead to an increased tendency to crack in many materials.

[0006] Object of the invention

[0007] The object of the invention is to provide a device for selective laser melting with which components can be produced that are mechanically stable over a wide temperature range. It is also an object of the invention to provide a method for selective laser melting with which such components can be produced. Description of the invention

[0008] This object is achieved according to the invention by a device according to claim 1. A method according to the invention has the features according to claim 6. Advantageous embodiments emerge from the dependent claims.

[0009] The device according to the invention is designed for selective laser melting of a Ti-Near-g alloy and has the following features:

[0010] - a substrate plate;

[0011] - a coating device for applying layers of the Ti-Near-o alloy on the substrate plate in a layer arrangement, wherein the layers are arranged on top of one another;

[0012] - at least one layer of the layer arrangement with the Ti-Near-o alloy;

[0013] - a laser beam source for fusing at least parts of the layers with a laser beam;

[0014] - a heating device which is arranged to heat an uppermost layer of the layer arrangement in the direction from the substrate plate to the layer arrangement after the application of the uppermost layer and before the irradiation of the uppermost layer with the laser beam to a temperature in a temperature range of 250°C to 600°C.

[0015] The at least one layer containing the Ti-near-o alloy in the layered arrangement ensures that components formed from the layered arrangement by selective laser melting exhibit comparatively high fracture strength and creep resistance at room temperature as well as at temperatures of several hundred degrees Celsius. Furthermore, the Ti-near-o alloy imparts such components high corrosion resistance.

[0016] The device is designed to heat the respective topmost layer of the layer arrangement after application before irradiation with the laser beam in order to avoid stresses in the component during the forming of the component, which could, for example, lead to cracks in the component. Avoiding such stresses increases the fracture strength and dimensional stability of the components produced by the method according to the invention. Comparatively high growth rates / build rates and large layer thicknesses / layer thicknesses are also possible during selective laser melting. Preferably, build rates greater than or equal to 20 cm are used. 3 / h and layer thicknesses greater than or equal to 40 pm.

[0017] Ti-near-o alloys consist predominantly of a hexagonal alpha phase and, to a lesser extent, a body-centered cubic beta phase. In addition to titanium, Ti-near-o alloys preferably also contain 1% to 2% of the beta-stabilizing alloying elements vanadium, molybdenum, niobium, tantalum, iron, manganese, chromium, nickel, copper, silicon, and / or hydrogen. Examples of Ti-near-o alloys are Ti-6AI-4V, Ti-6AI-4V-ELI, Ti-6AI-6V-2Sn, and / or Ti-6AI-7Nb.

[0018] In a preferred embodiment of the device, the heating device is configured to heat the layer arrangement in a temperature range of 250°C to 600°C. This reduces stresses between the layers of the layer arrangement, thus increasing the mechanical stability of the components formed in the method according to the invention.

[0019] In an advantageous variant of the device, the heating device is designed to heat the uppermost layer to a temperature in a temperature range of 300°C to 500°C, in particular 350°C to 475°C. Heating the respective uppermost layer of the layer arrangement to a temperature in this temperature range results in particularly low stresses in the respective uppermost layer during selective laser melting. The scope of the device according to the invention also includes an embodiment designed to heat the entire layer arrangement to a temperature in this temperature range. In a further embodiment of the device, the heating device is designed in the form of an electrical heater of the substrate plate, in particular in the form of a resistance heater. Integrating the heating device into the substrate plate results in a compact design of the device.An electric heater can be quickly and precisely adjusted to a desired heating temperature.

[0020] The invention also encompasses an embodiment of the device in which the Ti-near-0 alloy is present in the form of Ti6242. Ti6242, with a comparatively simple composition, is characterized by relatively good weldability and comparatively high ductility after preheating in the temperature range according to the invention.

[0021] A method according to the invention for the selective laser melting of a Ti-near-o alloy comprises the following steps: a) coating a substrate plate with a layer arrangement, wherein the layers of the layer arrangement comprise a Ti-near-o alloy as material and are arranged one on top of the other, and the layer arrangement has an uppermost layer in the direction from the substrate plate to the layer arrangement; b) heating the uppermost layer of the layer arrangement to a temperature in a temperature range of 250°C to 600°C; c) fusing at least parts of the uppermost layer with a laser beam.

[0022] Components manufactured using such a process are characterized by high fracture strength and creep resistance, even at temperatures of several hundred degrees Celsius. These properties are achieved by the at least one layer comprising a Ti near-o alloy as its material and by avoiding mechanical stresses in the respective uppermost layer of the layer arrangement before irradiation with the laser beam. Preferably, the entire layer arrangement is heated to a temperature between 250°C and 600°C before each irradiation with the laser beam. In an advantageous embodiment of the process, the uppermost layer of the layer arrangement is heated to a temperature in a temperature range of 300°C to 500°C, in particular 350°C to 475°C. As a result, the stresses in the uppermost layer are kept at a particularly low level during selective laser melting.The method according to the invention also includes a variant in which the entire layer arrangement is heated to a temperature in this temperature range during the method according to the invention.

[0023] Further advantages of the invention will become apparent from the description and the drawings. Likewise, the above-mentioned and further-described features can be used individually or in combination in any desired manner. The embodiments shown and described are not intended to be exhaustive, but rather are exemplary in nature for describing the invention.

[0024] Detailed description of the invention and drawing

[0025] Fig. 1 shows a schematic diagram of a device for selective laser melting.

[0026] Fig. 1 shows a schematic sectional view of a device 10 for selective laser melting. The device 10 has a substrate plate 12, on which layers 14a, 14b of material powder (not shown) are applied to one another in a layer arrangement 16. After application, a topmost layer 18 of the layer arrangement 16 in the direction SR from the substrate plate 12 to the layer arrangement 16 is heated by a heating device 20 to a temperature in a temperature range between 250°C and 600°C. The heating device 20 is designed as an electric heater 22 that is integrated into the substrate plate 12, thereby achieving a compact design of the device 10 and precise control of the heating temperature by a controller 36 of the electric heater 22.The electric heater 22 heats, in addition to the uppermost layer 18, also the other layers 14a, 14b of the layer arrangement 16, thereby reducing stresses between the layers 14a, 14b, 18 of the layer arrangement 16.

[0027] In order to at least partially melt the uppermost layer 18 after heating, possibly fusing it with the other layers 14a, 14b of the layer arrangement 16, the device 10 has a laser beam source 24 from which a laser beam 26 is emitted, which irradiates the uppermost layer 18. As a result, a component 28 (here, for example, frustoconical) is formed from the layer arrangement 16. By heating the uppermost layer 18 before irradiation, stresses in the component 28 are relieved during forming by the selective laser melting of the respective uppermost layer 18. After the selective laser melting of the respective uppermost layer 18, the substrate plate 12 is lowered by a lifting device 30 of the device 10 in order to apply a new layer of material powder to the layer arrangement 16 by a coater 32 in a known manner (not shown).

[0028] At least one of the layers, here layer 14a by way of example, comprises a Ti near-o alloy 34 as its material (symbolically represented by a black box) in order to impart greater dimensional stability to the component 28 at temperatures of several hundred degrees Celsius. In particular, all layers 14a, 14b, 18 of the layer arrangement 16 comprise the Ti near-o alloy 34 as its material. Preferably, at least one of the layers 14a, 14b, 18, in particular all layers 14a, 14b, 18, is formed from a Ti near-o alloy 34.

[0029] Fig. 1 also shows a method 50 according to the invention, in which the component 28 is manufactured by laser melting the Ti near-o alloy 34, wherein the uppermost layer 18 is heated to more than 250°C but less than 600°C prior to laser melting. With reference to the figure of the drawing, the invention relates to a device 10 for the selective laser melting of a Ti near-o alloy 34. The device 10 has a layer arrangement 16 with layers 14a, 14b, 18 applied to one another, wherein at least one of the layers 14a comprises the Ti near-o alloy 34. The layer arrangement 16 is arranged on a substrate plate 12 of the device 10. A laser beam source 24 is designed to selectively melt the layers 14a, 14b, 18 with a laser beam 26.A heating device 20 of the device 10 can introduce thermal energy into a topmost layer 18 of the layer arrangement 16 in the direction SR from the substrate plate 12 to the layer arrangement 16 in order to heat the topmost layer 18 to a temperature between 250°C and 600°C before the topmost layer is irradiated with the laser beam 26. The topmost layer 18 is, in particular, the layer of the layer arrangement 16 with the greatest distance from the substrate plate 12.

[0030] List of reference symbols

[0031] 10 Device

[0032] 12 substrate plate

[0033] 14a, 14b Layers of the layer arrangement 16 16 Layer arrangement

[0034] 18 top layer

[0035] 20 Heating device

[0036] 22 electric heaters

[0037] 24 Laser beam source 26 Laser beam

[0038] 28 component

[0039] 30 lifting device

[0040] 32 coaters

[0041] 34 Ti-Near-o- Alloy 36 Electric Heating Control

[0042] 50 procedures

[0043] SR direction from the substrate plate to the layer arrangement

Claims

Patent claims 1. Device (10) for selective laser melting of a Ti-near-o alloy (34), comprising: - a substrate plate (12); - a coating device (32) for applying layers (14a, 14b, 18) of the Ti-Near-o alloy (34) on the substrate plate (12) in a layer arrangement (16), wherein the layers (14a, 14b, 18) are arranged on top of one another; - at least one layer (14a) of the layer arrangement with the Ti-Near-o alloy (34); - a laser beam source (24) for fusing at least parts of the layers (14a, 14b, 18) with a laser beam (26); - a heating device (20) which is designed to heat an uppermost layer (18) of the layer arrangement (16) in the direction (SR) from the substrate plate (12) to the layer arrangement (16) after the application of the uppermost layer (18) and before the irradiation of the uppermost layer (18) with the laser beam (26) to a temperature in a temperature range of 250°C to 600°C.

2. Device according to claim 1, wherein the heating device (20) is configured to heat the layer arrangement (16) in a temperature range of 250°C to 600°C.

3. Device according to claim 1 or 2, wherein the heating device (20) is configured to heat the uppermost layer (18) to a temperature in a temperature range of 300°C to 500°C, in particular 350°C to 475°C.

4. Device according to one of the preceding claims, wherein the heating device (20) is designed in the form of an electric heater (22) of the substrate plate (12). Device according to one of the preceding claims, wherein the Ti-near-o alloy (34) is in the form of Ti6242. Experience (50) for selective laser melting of a Ti-near-o alloy (34), comprising the steps of: a) coating a substrate plate (12) with a layer arrangement (16), wherein the layers (14a, 14b, 18) of the layer arrangement (16) comprise a Ti-near-o alloy (34) as material and are arranged one on top of the other, and the layer arrangement (16) has an uppermost layer (18) in the direction (SR) from the substrate plate (12) to the layer arrangement (16); b) heating the uppermost layer (18) of the layer arrangement (16) to a temperature in a temperature range of 250°C to 600°C; c) fusing at least parts of the uppermost layer (18) with a laser beam (26). Experience according to claim 6, wherein the uppermost layer (18) of the layer arrangement (16) is heated to a temperature in a temperature range of 300°C to 500°C, in particular 350°C to 475°C.

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