WO2023280716A1

WO2023280716A1 - Building platform for the additive repair of components

Info

Publication number: WO2023280716A1
Application number: PCT/EP2022/068291
Authority: WO
Inventors: Simon Steven; Clemens MIASKOWSKI; Collin THEISS
Original assignee: Lufthansa Technik Ag
Priority date: 2021-07-06
Filing date: 2022-07-01
Publication date: 2023-01-12
Also published as: DE102021117360A1

Abstract

The invention relates to a building platform (1) for the additive repair of components (50) and to the use thereof. The building platform (1) comprises a plurality of repair positions that are arranged in the plane (91) of the building platform (1) and each have component receptacles (2) for fastening a component (50) to be repaired thereto in a precise position and orientation. At least one component receptacle (2) is individually displaceable in a direction (90) perpendicular to the plane (91) of the building platform (1) and optionally fixable. When this building platform (1) is used, the displaceable component receptacles (2) are fixed in a position along their displaceability such that those faces of the components (50) fastened thereto that are intended for material deposition lie in a common plane (94).

Description

Construction platform for additive repair of components

The invention relates to a construction platform for the additive repair of components and their use.

Methods and systems for additive manufacturing are known in the prior art, in which successively applied layers of metal powder are selectively remelted by a controlled laser beam according to a specified CAD model to form a solid material after solidification ("selective laser melting"; SLM After all layers have been processed accordingly, the non-remelted powder can be removed and a metal component remains, which must be reworked as required or can be used directly.

The technology of the additive manufacturing process with selective laser melting is also used for the additive repair of components. For this purpose, additional material is applied to existing components using the method described, for example to compensate for missing or worn areas on a component.

In order to be able to carry out appropriate repairs, the exact positioning or at least exact determination of the position of the component to be repaired on the construction platform of the production system is essential. This is the only way to ensure that the material powder lying directly on the component to be repaired is actually remelted by a laser beam and thus firmly connected to the component to be repaired.

Furthermore, it is imperative that when repairing several components in one production system at the same time, those surfaces on which material is to be applied, in a common building level. This is the only way to apply and remelt the material powder, which is to be selectively melted, in layers with the necessary precision in order to ensure a firm connection between the component and the new material to be repaired for each component to be repaired.

In order to achieve a common level for the material application, in the prior art, identical components, such as engine blades of gas turbines or aircraft engines, which are to be repaired at the same time in an additive manufacturing system by material application, are prepared identically. For this purpose, for example, so much material is removed from all components to be repaired, regardless of their actual damage, that the damage to be repaired is removed from all components to be repaired at the same time, before all components are then restored to their original or another predetermined form Material order completed. This equal treatment of all components means that more material is regularly removed from some of the components than would actually be necessary to damage these components. With these components, more material then has to be applied by the additive manufacturing system than with material removal that is individually tailored to the actual damage to the individual components.

The alternative, which is also fundamentally known from the prior art, of preparing each component individually and individually and reassembling it in an additive manufacturing system, is not sufficiently efficient, especially for smaller components, and is therefore regularly not economically viable. The invention is based on the object of creating a device and a method for its use with which the disadvantages known from the prior art no longer occur or only occur to a reduced extent.

This object is achieved by a construction platform according to the main claim and a method for its use according to the independent claim 12. Advantageous developments are the subject matter of the dependent claims.

Accordingly, the invention relates to a construction platform for additive repair of components with a plurality of repair positions arranged in the plane of the construction platform, each of which has component receptacles for fastening a component to be repaired to it in a precise position and position, with at least one component receptacle in the direction perpendicular to the plane of the The construction platform can be individually moved and optionally fixed.

Furthermore, the invention relates to the use of a construction platform according to the invention according to one of the preceding claims, with the displaceable component holders being fixed in a position along their displaceability such that those surfaces of the components attached thereto which are intended for the additive application of material lie in a common plane .

The invention has recognized that with a common arrangement of components to be repaired on a construction platform, for which a plurality of repair positions are provided with corresponding component holders for fastening the individual components in the correct position and location, an advantageous additive repair of the components can be achieved. if at least part of the component recordings, preferably all Component holders, move in a direction perpendicular to the level of the construction platform and can be optionally fixed in any position along this mobility. This makes it possible to align the surfaces of the individual components on which the material application required for the repair is to take place by moving the component holders in a common plane, without having to remove identical material from the individual components, as is the case here is the case in the prior art.

The construction platform according to the invention is sufficiently flexible to also be used in other process steps of the additive repair apart from the actual application of material, such as evaluating the damage to the individual components and/or removing material from the individual components, up to the damaged areas to be repaired are removed. If machines and devices known from the prior art are used for this, the component recordings of the construction platform according to the invention can be moved to a common height in relation to the construction platform or in a common plane parallel to the construction platform and fixed there, which results in a known construction platform comparable bare arrangement of the component recordings or of components attached thereto results. The machines and devices used must therefore for the use of the Vorrich device according to the invention in principle not or only slightly changed or is adjusted, with the adjustment - if at all he required - operating parameters of the machines and devices regularly limited to the readjustment of individual loading For example, due to a possibly greater height of the construction platform according to the invention compared to those from the prior art. The displaceability of at least one component holder is in the direction away from the construction platform or the plane defined by the arrangement of the component holders and their direction of displacement, which is, for example, at the height of the underside of the construction platform or at the height of the component holders in the fully retracted state can lead, limited by a stop. If several or all of the displaceable construction part shots have a corresponding stop, the proposals or the component shots are located if they are adjacent to these shots, preferably in a common plane parallel to the building platform level. The displaceability of the component holder is limited in a defined manner or the fully extended state of a component holder is defined by the respective stop, with suitable design of the stops being able to ensure that all component holders resting against their corresponding stops lie in one plane, what can be advantageous or necessary for individual processing steps during the repair of components.

It is preferred if an actuating element is provided on at least one component holder, which selectively or permanently urges the component holder in the direction of the stop. In other words, if it is not fixed, an appropriately equipped component recording should be moved by the actuating element to the previously described stop and kept there. The actuating element can apply the corresponding force to the component receptacle permanently or only selectively as required.

The actuating element can be, for example, a spring element, a hydraulic or pneumatic cylinder or an electric drive. While a spring element actuation element as a component recording basically permanently pushes in the direction of its stop, the other alternatives mentioned can be deactivated if necessary. In particular, if the actuating element is designed as an electric drive, it is also possible, with appropriate control, to move the component holder exactly to a desired position using the electric drive alone.

The optional fixing of the at least one component holder can preferably be achieved by a fixing device which interacts with the at least one component holder in a non-positive manner. The force-locking fixation can regularly be designed in such a way that the shifting position of a component holder does not unintentionally change when it is selectively fixed. One possibility for this is the be preferred embodiment of a fixation device as a clamping system, in which the fixation device by pressing we least one clamping jaw on a surface of the Befestigungsvor device parallel to the direction of their displacement.

An individual fixing device can be provided for each displaceable component holder. However, it is also possible for a fixing device to be designed for the simultaneous fixing of groups of displaceable component receptacles or all component receptacles.

The construction platform can have at least three stop columns with contact surfaces on their free ends on the construction platform on the side of the component receptacles, with the contact surfaces defining a stop plane parallel to the plane of the construction platform. With the help of the stop pillars or the stop level defined by them, the movable component holders can be easily aligned in such a way that those surfaces of the components attached to them on which the material al order is to take place, is aligned in a common plane. For this purpose, the construction platform with the contact surfaces of the contact columns can be brought into contact with a planar contact surface, which then lies in the contact plane, e.g. by placing a planar contact plate, which can be part of the construction platform according to the invention, on the contact surfaces or the construction platform is brought with the bearing surfaces in contact with egg ner suitable flat surface. The individual construction part shots to which components are attached can then be moved so that the respective surfaces of the components provided for the material order rest against the stop surface before the component shots are fixed. If all component holders are aligned and fixed accordingly, the contact between the construction platform and the stop surface can be eliminated again, whereby the surfaces of the components provided for the application of material remain aligned in the stop plane defined by the stop columns.

The construction platform can also have a support plate for optional attachment to the stop pillars, which is designed to provide additional support for construction parts attached in the component receptacles. With a corresponding support plate, which can only be attached as an option, the components attached to the building platform can be used for individual processing steps, such as e.g. B. the removal of material by milling, are additionally secured in order to avoid or at least reduce unnecessary stress and / or unwanted deformation of the components that could negatively affect the processing result. The support plate can, for example, have lead-through openings through which the individual components can be passed. It is also possible to additionally secure the components, for example by means of clamping devices in the individual lead-through openings. The construction platform preferably has clamping modules or clamping bolts of a zero-point clamping system on the side facing away from the component receptacles. The construction platform can be repeatedly attached in a defined position to a mount with suitable counterparts via the components in question of a zero-point clamping system. It is thus possible to fix the construction platform variably in different machines for the individual processing steps without the need for time-consuming alignment of the construction platform and/or calibration of the machine.

The construction platform according to the invention is particularly suitable for the simultaneous additive repair of smaller components. In particular, the construction platform or its component receptacles can be designed for attaching engine blades of a gas turbine or an aircraft engine to it. The engine blades can be fastened to the component mounts with their respective feet and, if the turbine tips have been worn down differently to eliminate damaged areas, the component mounts can be moved, as described, so they can be aligned so that the material intended for protruding is positioned Surfaces of the individual engine blades are in a common plane.

To explain the use according to the invention, reference is made to the above statements.

In order to easily align the surfaces of the components attached to the component receptacles, which are provided for material application, in a common plane, a flat stop plate can be arranged along this plane at times. The surfaces of the components in question can then be brought into contact with the stop plate by moving the construction part of the shots. If the component mounts are then fixed, the for The surfaces of the components intended for the application of material remain in the desired level even after the stop plate has been removed.

The invention will now be described by way of example with reference to an advantageous embodiment with reference to the accompanying drawings. Show it:

FIG. 1: an exemplary embodiment of a construction platform according to the invention;

FIG. 2: a sectional view through the construction platform according to FIG. 1;

FIG. 3: a bottom view of the construction platform according to FIG. 1;

FIG. 4: the construction platform according to FIG. 1 with a support plate attached thereto;

FIG. 5 shows a schematic representation of the connection of a construction platform according to FIG. 1 with a machine-side receptacle;

FIG. 6: a detailed illustration of the component holder of the construction platform according to FIG. 1; and

Figure 7a-g: a schematic representation of the inventive Shen use of the construction platform according to Figure 1.

FIG. 1 shows an exemplary embodiment of a construction platform 1 according to the invention. The construction platform 1 comprises a large number of repair positions arranged in a grid pattern, each with a component receptacle 2. Components 50 to be repaired—in this case engine blades of a gas turbine engine—are positioned on the component receptacles 2. and fixed in place. In other words, the fastening takes place in such a way that no relative movement occurs between a construction part receptacle 2 and a component 50 to be repaired fastened thereto.

All of the component holders 2 can be displaced individually in a direction 90 perpendicular to the plane 91 of the construction platform 1 . The level 91 results from the direction of displacement 90 of the individual component receptacles 2 and the component receptacles 2 in the fully retracted position, ie. H. least on the construction sub-platform 1 protruding state.

As shown in the sectional view according to FIG. The displaceability is limited by a stop 5 in the direction away from the plane 91 of the construction platform 1 .

Furthermore, a spring element 6 is provided as an actuating element 7 for each component receptacle 2 , which permanently urges the piston 3 assigned to a component receptacle 2 in the direction of the stop 5 .

In order to nevertheless fix the component receptacles 2 in any position along their respective displaceability, clamping systems 8 are provided, with which in the illustrated embodiment two component receptacles 2 can always be secured non-positively in their respective position along the displacement direction 90 . The clamping systems 8 can be operated through openings 9 in the bottom of the construction platform 1, it can be reached with screws 10. By tightening the screws 10, the component holders 2 are in their current position fixed without changing the position due to the fixation.

The component platform 1 has four stop columns 11 on the side of the component receptacles 2 . At their free ends remote from the construction platform 1 , the contact columns 11 each have bearing surfaces 12 which lie in a common contact plane parallel to the plane 91 of the construction platform 1 . A flat stop plate 17 (not shown here, but cf. FIGS. 7c and 7d) can be brought into contact with the contact surfaces 12, which then extends in the stop plane.

The stop columns 11 are also designed so that a support plate 13, as shown in FIG. 4, can be fastened thereto. The support plate 13 has one of the number of component mounts 2 corresponding to number of passage openings 14 through which - the tips of the engine blades 50 can be passed - in the exemplary embodiment before lying. The lead-through openings 14 each have clamping devices 15 with which the engine blades 50 can also be secured in their position.

On the side of the construction platform 1 facing away from the component holders 2, compressed-air operated clamping modules 15 of a zero-point clamping system, as is fundamentally known from the prior art, are provided (cf. FIG. 3). These clamping modules 15 can, as indicated in FIG Repairing components 50 can be arranged, who brought the and align the construction platform 1 exactly to a predetermined zero position by the clamping plate 60.

The component receptacles 2 of the construction platform 1 are shown in greater detail in FIG. The component mounts 2 are designed in such a way that the engine blades 50 are inserted with their blade root in the direction indicated by the arrow 92 into the component mounts 2 and are then clamped in a fixed position and position by appropriately tightening the screws 16 . In that regard, the component mounts correspond to those of the prior art.

A use according to the invention of the construction platform 1 described above for the additive repair of engine blades 50 is described below with reference to FIGS. 7a-g. In FIGS. 7a-g, the representation of the construction platform 1 is greatly simplified from green for the sake of clarity. The machines etc. used in the individual process steps were also not shown, since these are basically machines known from the prior art.

The machines in question will be described below as machines designed separately from each other. However, it is of course also possible for several functions required for the repair of the engine blades 50 to be integrated together in one machine.

In the additive repair of engine blades 50 using the construction platform 1 according to FIG. At the beginning of the repair process, the engine blades 50 to be repaired are therefore, as in connection with FIG Described in FIG. 6, each individually fastened in a component receptacle 2 of the construction platform 1.

After the attachment of the engine blades 50 in the building part shots 2, engine blades 50 are first measured ver and examined for damage in the blade tips out. For this purpose, the component holders 2 are moved into the position specified by the stops 5, for example with the aid of the respective actuating elements 7 or spring elements 6 (cf. FIG. 2). In this position they are fixed and secured by the clamping systems 8 (see FIG. 7a).

The construction platform 1 is then arranged together with the engine blades 50 fastened to it on a clamping plate 60 in a device suitable for measuring and defect detection, as is known from the prior art, and centered in a zero position via the clamping modules 15 . The engine blades 50, particularly in the area of the blade tips, are then measured and examined for damage, with the surfaces of the individual engine blades 50 being recorded three-dimensionally, e.g. by laser, and transferred to a digital data model, which is then used to determine Deviations that could represent damage are compared with a target model. In addition or as an alternative to this, the blade surfaces can also be recorded optically, with suitable automated image analyzes being able to detect possible defects in the engine blades 50 .

If the damage in the area of the blade tips is recorded for each of the engine blades 50, it can then be determined up to which height the tips of the individual engine blades 50 must be removed and then rebuilt using additive methods. Also this is basically known from the prior art. In FIG. 7b, the individually determined heights up to which the individual engine blades 50 are to be removed are indicated by dashed lines.

While the component holders 2 are still fixed in the positions defined by the stops 5, the support plate 13 is then fastened to the stop columns 11 according to Figure 4, so that the engine blades 50 are passed through the respective feed-through openings 14 and secured there with the clamping devices 15 secured (see FIG. 7b). The construction platform 1 together with the engine blades 50 and the support plate 13 can then be arranged and centered on the clamping plate 60 in the working area of a machine for machining, e.g. a CNC milling machine, which then cuts the individual engine blades 50 to the individually determined dimension shortens and creates an end face parallel to the level 91 of the construction platform 1 on the engine blades 50 (cf. FIG. 7c).

In the next step, the clamping elements 8 and thus the fixation of the component receptacles 2 are released. A flat stop plate 17 is then lowered in the direction indicated by the arrow 92 perpendicular to the plane 91 of the construction platform 1, so that the flat stop plate 17 gradually comes into contact with the respective previously created end faces of the engine blades 50. The flat stop plate 17 then pushes the component receptacles 2 against the urging of the spring elements 6 until the flat stop plate 17 rests on the bearing surfaces 12 of the stop columns 11 (cf. FIG. 7d).

In this position, the component recordings 2 are again fixed by the clamping elements 8, so that the end faces of After removal of the planar stop plate 17, engine blades 50 lie in a common plane 94, which in the example shown corresponds to the stop plane defined by the bearing surfaces 12 (cf. FIG. 7e).

Since the end faces of all engine blades 50, on which the engine blades are to be rebuilt by adding material, lie in a common plane, known additive manufacturing processes based on 3D printing, e.g. selective laser melting, can be used to form the engine blades 50 to their original or any tweaked form. For this purpose, the free spaces between the component holders 2 and the engine blades 50 are first filled with a suitable powdery material up to level 94, before the same or another material is then applied in layers and selectively remelted to form a solid material after solidification, so that according to the known principle of selective laser melting the desired shape for the individual engine blades 50 results. Since the end faces of the engine blades 50 are aligned exactly in a common plane, it is ensured that the newly applied remelted material is firmly connected to the remaining parts of the engine blades 50.

The end of the 3D printing process is shown in FIG. 7f, the separation between the original engine blade 50 and the material added by the 3D printing being indicated by dashed lines only for clarification.

By turning the construction platform 1 over, the material that has not been remelted during the 3D printing can be easily removed by utilizing the force of gravity (FIG. 7g). Alternatively or in addition In addition, remaining non-remelted material can also be sucked off. The engine blades 50 can then be detached from the component mounts 2 . It is of course also possible to carry out further (post) processing steps on the engine blades 50 while the engine blades 50 are still attached to the component mounts 2 .

The component holders 2 can, of course, also be moved again into suitable positions for corresponding processing steps, if necessary.

Claims

patent claims

1. Construction platform (1) for additive repair of components (50) with a plurality of in the plane (91) of the construction platform

(1) arranged repair positions, each of which has component receptacles (2) for fastening a component (50) to be repaired to it in the correct position and position, characterized in that at least one component receptacle (2) extends in direction (90) perpendicularly to the plane (91 ) of the construction platform (1) can be individually slid and optionally fixed.

2. Construction platform according to claim 1, characterized in that all the component holders (2) can be displaced individually in the direction (90) perpendicular to the plane (91) of the construction platform (1) and can be selectively fixed.

3. Construction platform according to claim 1 or 2, characterized in that the displaceability of at least one component holder (2) in the direction away from the plane (91) of the construction platform (1) is limited by a stop (5).

4. Construction platform according to claim 3, characterized in that an actuation element (7) is provided on at least one component holder (2), which pushes the component holder (2) selectively or permanently in the direction of the stop (5).

5. Construction platform according to claim 4, characterized in that the actuating element (7) comprises a spring element (6), a hydraulic or pneumatic cylinder or an electrical drive.

6. Construction platform according to one of the preceding claims, characterized in that for the selective fixing of the at least one component receptacle (2) there is provided a non-positively locking device which interacts with the at least one component receptacle (2).

7. Construction platform according to claim 5, characterized in that the fixing device comprises a clamping system (8).

8. Construction platform according to one of the preceding claims, characterized in that on the construction platform (1) on the side of the component receptacles (2) at least three stop columns (11) with bearing surfaces

(12) are provided at their free ends, wherein the bearing surfaces (12) define a stop plane parallel to the plane (91) of the construction platform (1).

9. Construction platform according to claim 7, characterized in that a support plate (13) for optional attachment to the stop columns (11) is provided, the support plate

(13) for additional support of the components (2) fastened in the component holders (50) is formed.

10. Construction platform according to one of the preceding claims, characterized in that clamping modules (15) or clamping bolts of a zero-point clamping system are provided on the side of the construction platform (1) facing away from the component receptacles (2).

11. Construction platform according to one of the preceding claims, characterized in that at least one component receptacle (2) for fastening an engine blade (50) of a gas turbine, preferably an aircraft engine, is designed thereon.

12. Use of a construction platform (1) according to one of the preceding claims for the additive repair of components (50), characterized in that the displaceable component receptacles (2) are fixed in a position along their displaceability, that the surfaces of the components (50) attached thereto lie in a common plane (94). 13. Use according to claim 12, characterized in that for aligning the surfaces provided for material application of the components (50) fastened to the component holders (2) in a common plane (94), there is at times a flat stop plate (17) along this plane (94 ) are arranged, with which the surfaces in question of the components (50) are brought into contact by moving the component receptacles (2).