HOMOGENEOUS COOLING FOR WELDING PROCESSES, IN PARTICULAR WAAM

Abstract

The invention relates to a welding process for producing a component (10) by depositing multiple layers (100) of a metal material in layers, said layers lying one on top of the other. In said process, the base (10a) of the component (10) is placed in a liquid coolant (6) such that the coolant contacts the base (6), and a surface (10b) of the base (6) lies above the coolant level (3). A first layer (100) of the material is deposited onto the surface (10b) by welding the material to the surface (10b), and each subsequent layer (100) is deposited onto a temporary component surface (10bb) formed by the previously deposited layer (100) by welding the material to the temporary component surface (10bb), wherein the heat resulting from welding the material is absorbed by the coolant (6). The invention additionally relates to a device (1) for carrying out the method.

Claims

1. Welding method for producing a component (10) by layer-by-layer deposition of multiple layers (100) of a metal material, said layers lying one on top of the other, wherein a base (10a) of the component (10) is placed in a liquid coolant (6) so that the coolant contacts the base (6) and a surface (10b) of the base (6) is arranged above the coolant level (3), wherein a first layer (100) of the material is deposited on the surface (10b) by welding the material to the surface (10b), and wherein each subsequent layer (100) is deposited on a current component surface (10bb) formed by the previously deposited layer (100) by welding the material to the current component surface (10bb), wherein the heat respectively resulting from welding the material is absorbed by the coolant (6).

2. The welding method according to claim 1, wherein the coolant level (3) is varied in relation to the component (10) and/or in that the component (10) is lowered in the coolant (6) so that a distance (A) between the coolant level (3) and the respective current component surface (10bb) lies within a predefined range.

3. The welding method according to claim 2, wherein the distance lies within the range of 0.1 mm to 50 mm.

4. The welding method according to claim 1, wherein the coolant (6) is arranged in a container (11).

5. The welding method according to claim 1, wherein heat is extracted from the coolant (6).

6. The welding method according to claim 1, wherein the coolant (6) is circulated.

7. The welding method according to claim 1, wherein a flow (S) is generated in the coolant (6) and directed to a current welding position (P) where material is being deposited on the current component surface (10bb).

8. The welding method according to claim 1, wherein an actual temperature of a currently deposited layer of the component (10) is measured, wherein the distance between the coolant level (A) and the current component surface (10bb) is regulated such that the actual temperature approaches a predefined target temperature.

9. The welding method according to claim 1, wherein the coolant (6) is kept at a constant temperature.

10. The welding method according to claim 1, wherein the base (10a) rests on a positioning device (2), wherein in particular the positioning device is configured for lowering the component (10) in the coolant (6) and/or for spatially aligning the base (10a).

11. The welding method according to claim 1, wherein the positioning device (2) comprises a hexapod (40).

12. The welding method according to claim 1, wherein the material is welded to the surface (10b) of the base (10a) or to the current component surface (10bb) by means of one of the following methods (V): gas metal arc welding welding, tungsten inert gas welding, plasma welding, laser welding, hybrid welding, tandem welding.

13. The welding method according to claim 1, wherein a current height (A) of the component (10) above the coolant level (3) is measured and the coolant level (3) is regulated such that the height (A) is approximated to a predefined target value.

14. The welding method according to claim 1, wherein an energy dissipated into the coolant (6) during the welding of a layer is measured and compared to an energy introduced into the layer, wherein, in the event of a deviation, one or more, in particular all, of the following parameters are changed in order to equalize the two energies: a volume flow of a flow (S) of the coolant (6), an inlet temperature of the coolant (6) during introduction into the container (11), a distance (A) between the current component surface (10bb) and the coolant level (3).

15. Device (1) for carrying out a welding method (V), in particular according to any one of the preceding claims, comprising: a container (11) for receiving a liquid coolant (6), a platform (2) for carrying the component (10) to be produced, a welding device (12) for welding a material to a component surface (10bb) of the component (10) to be produced, a device (40) for adjusting a distance (A) between a component surface (10bb) of the component and a coolant level (3) of the coolant (6) arranged in the container (11).

Description

[0054] Further features and advantages of the present invention shall be described in the following figure descriptions of exemplary embodiments of the invention, with reference to the figures. Shown are:

[0055] FIG. 1 a schematic representation of a device according to the invention or of a method according to the invention; and

[0056] FIG. 2 a schematic representation of a hexapod which in the method according to the invention can be used for carrying the component.

[0057] According to FIG. 1, the invention relates to a welding method or to a device 1 for carrying out a welding method. In this respect, the device 1 has a container 11 into which a liquid coolant 6 can be filled so that the coolant 6 forms a coolant level 3.

[0058] A supporting structure, e.g., in the form of a platform 2, for carrying the component 10 to be produced, is also arranged in the container 11. The device 1 furthermore comprises a welding device 12 which is designed to weld a material to a component surface 10bb of the component 10 to be produced or to a surface 10b of a base 10a (e.g., metal plate) of the component 10 or which, in the following layers, welds the weld material to the previous layer (this deposition of layers is also referred to as build-up welding). The base 10a thus represents the initial state of the component 10 to be produced, onto which additional layers 100 of the material are welded in the course of the method. The uppermost layer 100 or component surface 10bb to which the current layer 100 is welded is also referred to as the current component surface 10bb. Lastly, the device 1 preferably also comprises a device 40 or positioning device 40 (e.g., hexapod 40) for adjusting a distance A between a or the current component surface 10bb of the component 10 and the coolant level 3 of the coolant 6 arranged in the container 11. Alternatively or additionally, the coolant level 3 may also be adjusted by introducing additional coolant 6 into the container 11 and the coolant level 3 thus following the current component surface 10bb (the component 10 grows in height or vertically layer by layer).

[0059] According to one embodiment of the device 1 for cooling the coolant 6, there is also the possibility of drawing coolant 6 from the container 11 (e.g., via a line 7), cooling it in a cooling device 9 of the device 1 and reintroducing it into the container (e.g., via a line 8). Alternatively or additionally, the device 1 according to the invention for cooling the coolant 6 may comprise a heat exchanger arranged in the container 11.

[0060] In order to carry out the welding method, the base 10a of the component 10 is arranged and possibly fixed on the platform 2, which is movable in the vertical z and also tiltable, wherein the platform 2 is arranged with the base 10a in the liquid coolant 6 so that the coolant contacts the base 10a and a surface 10b of the base 6 is arranged above the coolant level 3, wherein a first layer 100 of the material is deposited on the surface 10b by welding the material to the surface 10b, and wherein each subsequent layer 100 is deposited on a current component surface 10bb formed by the previously deposited layer 100 by welding the material to the current component surface 10bb, wherein the heat respectively resulting from welding the material is absorbed by the coolant 6. The coolant level 3 is adjusted with respect to the current component surface 10b such that a distance between the level 3 and the current component surface 10b is constant or lies within a prespecified range. For this purpose, the component 10 is correspondingly lowered in the coolant (e.g., in each case after completion of a layer 100) and/or the level 3 is correspondingly raised, e.g., by introducing additional coolant 6 into the container 11.

[0061] According to one embodiment of the invention or device 1, it is also conceivable for a welding torch to perform necessary movements (x, y, z). The component 10 can remain completely immobile in this case. However, in order to also be able to weld overhangs, it is provided in this case that the component 10 be mounted at least tiltably.

[0062] So that the component 10 can be aligned as well as possible with respect to the level 3 or so that even complex geometries can be welded in a simple manner (in particular overhangs), the platform 2 is preferably mounted on a hexapod 40 which may, for example, be formed according to FIG. 2 (the platform 2 may also be spatially positionable in some other way). In this case, the hexapod 40 has six arms 4 which can be adjusted in length and may be formed, for example, by linear motors. Each arm 4 is articulated at one end at an underside 2a of the platform 2 by means of a joint 41 and at the other end at a base plate 43 of the hexapod 40 by means of a joint 42 or alternatively directly at a bottom of the container 11.

[0063] The device 1 according to the invention for improving the cooling of the component 10 may furthermore have heat-conducting plates 20 on an underside 2a of the platform, wherein the heat-conducting plates 20 project from the underside 2a and are contacted by the coolant 6.

[0064] In addition, the device 1 may furthermore comprise a screw 5 or a comparable device for circulating the coolant 6 in the container 11. A flow S directed onto the component 10 may also be generated by means of the screw 5, said flow improving convection in the region of the component 10 and thus its cooling.

[0065] Furthermore, alternatively or additionally, it is also possible to move the entire container 11 vertically in order to change the coolant level 3 with respect to the component 10. The component 10 is then held with a suitable device.

TABLE-US-00001 List of reference signs  1 Device  2 Platform  2a Underside of the platform  3 Coolant level  4 Arm of the hexapod  5 Screw  6 Coolant  7 Line  8 Line  9 Cooling device 10 Component to be produced 10a Base of the component 10b Surface of the base 10bb Current component surface 11 Container 12 Welding device 20 Heat-conducting plate 40 Hexapod 41 Joint 42 Joint 43 Base plate of the hexapod (or bottom of the container 11) S Flow P Welding position V Welding method Z Vertical