EP4098766A1 - Method for coating a component of a turbomachine - Google Patents

Abstract

The present invention relates to a method for coating (21) a component (2) of a turbomachine (1) in a bath (33), in which method the component (2) is partially immersed in the bath (33) with a coating material (32). becomes; the component (2) is at least temporarily rotated (23) during the at least partial immersion about an axis of rotation (22) which lies outside the bath (33); the component (2) is at most partially immersed over the rotation (23).

Description

technical field

The present invention relates to a method for coating a component of a turbomachine.

State of the art

The turbomachine can, for example, be an aircraft engine, e.g. B. a turbofan engine. Functionally, the turbomachine is divided into compressor, combustion chamber and turbine. In the case of aircraft engines, for example, the air drawn in is compressed by the compressor and burned in the downstream combustion chamber with added kerosene. The resulting hot gas, a mixture of combustion gas and air, flows through the downstream turbine and is expanded in the process.

The procedure in question can e.g. B. relate to a component that is arranged in the fully assembled turbomachine on or in the gas channel.

Presentation of the invention

The present invention is based on the technical problem of specifying a particularly advantageous method for coating a component of a turbomachine.

According to the invention, this is achieved with the method according to claim 1 . In this case, the component is immersed in a bath with coating material, and it remains only partially immersed during the entire stay in the bath, i.e. it is never completely immersed. Furthermore, the component is rotated during the immersion process and/or in the partially immersed state, namely about an axis of rotation which lies outside the bath.

This procedure, in particular the only partial immersion and turning of the component, can lead to a good coating result overall. The rotation of the component generates centrifugal forces, for example, which at least partially counteract gravity, and can prevent the still liquid coating material from flowing or dripping, e.g. B. on a rotational position above the axis of rotation dripping radially inwards.

The surfaces to be coated can, for example, be coated more evenly and with fewer defects, but at the same time those surface areas that are not to be coated remain uncoated. This can lead to savings in operating materials, for example coating material and also cleaning materials for removing excess coating material, see below in detail. Covering devices can also be simplified or even eliminated entirely by the targeted coating. The process can allow better surface accessibility, especially for components with complex geometry. Undercuts, on the other hand, would be difficult to access, for example, for spray guns to spray on a coating, and atomization could also be costly.

Preferred configurations can be found in the dependent claims and in the entire disclosure, with the presentation of the features not always making a detailed distinction between aspects of the device and aspects of the method or use; at least implicitly, the disclosure is to be read with regard to all categories of claims. If, for example, an advantage of a device is described in a specific application, this is also to be understood as a disclosure of a corresponding use.

The fact that the component is only partially immersed "throughout the rotation" also applies to an integral consideration, i.e. integrated over a complete rotation (360°). If, for example, a segment is coated that does not extend all the way around, such as a multi-blade segment, this can be done on a rotary position be partially immersed "below" but no longer be immersed at all in an opposite rotational position "above" (e.g. after a rotation of 180° from the lower rotational position). On the other hand, the component can also extend completely around the circumference and accordingly be partially immersed over the entire circumference (thus the respective immersed area then changes over the course of the circumference). In both cases, however, a part of the component remains uncoated after complete rotation.

In a preferred embodiment, the component is a rotor blade ring or a segment of a rotor blade ring. The component can generally be, for example, a single blade, but preferably a multiple segment or a blisk. In particular, the rotor blade ring or the multiple segment can be part of the fan, the compressor or the turbine.

In a preferred embodiment of the method, the component is moved at least temporarily in addition to the rotation in a direction which is at least partially axial. The axial direction corresponds to a direction parallel to the axis of rotation; the component is particularly preferably moved parallel to the axis of rotation. The superimposition of the at least partially axial movement with the rotary movement can, for. B. prevent trapped air bubbles in the coating material due to the shape of the airfoil of a blade and consequent spatter.

According to a preferred embodiment, the angular velocity of the rotation is at least temporarily variable, ie not constant. The rotation can also take place, for example, with an angular acceleration that is also variable.

In a preferred embodiment, the angular speed of the rotation is at least temporarily constant (continuous rotary movement without changing the angular speed). In general, this can also be combined, for example, with a temporarily variable rotational speed, ie the rotational speed can be constant in one time interval and variable in another time interval. The rotational speed can be variable, for example, during the immersion process then be kept constant, or vice versa. Alternatively, however, the rotational speed can also be constant over the entire process.

According to a preferred embodiment of the method, the axis of rotation of the component is offset in the vertical direction during the rotation, ie it is moved in the vertical direction. The component is preferably at least temporarily in the immersed state during the vertical movement. As a result of the vertical offset, the distance between the axis of rotation and the surface of the bath increases or decreases, i.e. the component is immersed deeper or less deeply. The vertical movement of the axis of rotation takes place, for example, with a repeated reversal of direction, ie at least two changes between up and down movement.

According to a preferred embodiment, the component is removed from the bath for drying while continuing to rotate. It will therefore continue to be rotated during extraction and after extraction. This can, for example, facilitate the removal of excess coating material from the surface of the component. The coating material can e.g. B. also be better distributed, and it can be prevented from forming a nose.

For drying, an air flow is preferably directed onto the component, which has a velocity component which is oriented in the opposite direction to the force of gravity. The air flow can favor the drying process, e.g. through forced convection, and consequently improve the drying result. The orientation opposite to gravity can help to ensure a more even layer thickness, e.g. again prevent a formation of a nose.

According to a preferred embodiment, the rotational speed of the component is successively reduced as drying progresses after removal from the bath. The rotational speed can be adjusted, for example, as a function of the curing state of the coating material and the layer thickness. As the drying progresses, the z. B. the solvent, especially the water content in the coating, this is so viscous. through the Reducing the rotation speed can e.g. B. a consequently changed behavior of the layer into account.

In a preferred embodiment, the coating material that has dripped off the component after it has been removed from the bath is fed back into the bath, that is to say it is added to it in the liquid state. This reuse can e.g. B. be ecologically and economically advantageous.

As mentioned at the outset, the procedure according to the invention can, for example, reduce the masking effort during coating. In general, however, a certain covering can still take place; for example, the blade root can be covered by a blade, but the blade leaf can remain uncovered. A seal or sealing plane of the cover can therefore lie, for example, on a blade platform between the blade root and blade. This can e.g. B. an unintentional coating of the blade root can be prevented, even if the blade platform is inclined to the axis of rotation, so would partially immerse.

In a preferred embodiment, the axis of rotation is at least temporarily angled, ie not parallel to the surface of the bath. For example, it can be inclined throughout step (ii), preferably also during the exchange/removal. With the oblique adjustment, for example, an oblique coating edge can be realized (obliquely in relation to the longitudinal axis of the turbomachine or the engine), i.e. the coating edge can be adapted to an inclined blade platform just mentioned (so that sometimes no cover is necessary anymore).

According to a preferred procedure, the component is removed from the bath for drying after a first pass with method steps (i) to (iii) and then immersed in the bath again and rotated in a second pass according to method steps (i) to (iii). , whereby in the first and in the second run the rotation is preferably in the opposite direction. The steps described above for coating the component can be repeated until a desired layer thickness is reached. A large number of layers can be applied in succession, which can contribute to an overall more uniform overall thickness. With a lower viscosity of the coating material z. For example, for a given total thickness, more repetitions of the passes may be necessary than with a higher viscosity of the coating material. In a preferred embodiment, the number of repetitions is at least 3, and increasingly preferably at least 4, 5 or 6 in the order in which they are mentioned. Advantageous upper limits can be a maximum of 50, 40 or 30, for example.

The invention also relates to a method for producing a component of a turbomachine, the component being coated according to method steps (i) to (iii). The coating preferably serves as a mask during subsequent processing of the component and is removed again after this subsequent processing. The coating can therefore be a lacquer, for example, which can serve as a covering agent.

According to a preferred embodiment, the subsequent processing is an electrochemical method, for example with material removal. For example, an area of the component surface, e.g. B. can be provided with armor.

Brief description of the drawings

The invention is explained in more detail below using an exemplary embodiment, with the individual features within the framework of the independent claims also being able to be essential to the invention in a different combination and no distinction being made in detail between the different claim categories.

Figur 1

eine Strömungsmaschine, konkret ein Mantelstromtriebwerk in einem Längsschnitt;

Figur 2a,b

ein erfindungsgemäßes Beschichten eines Bauteils für eine Strömungs-maschine gemäß Figur 1.

In detail shows

figure 1

a turbomachine, specifically a turbofan engine, in a longitudinal section;

Figure 2a,b

according to an inventive coating of a component for a turbomachine figure 1 .

Preferred embodiment of the invention

figure 1 shows a turbomachine 1, specifically a turbofan engine, in a longitudinal or axial section. The turbomachine 1 is functionally divided into a compressor 1a, a combustion chamber 1b and a turbine 1c. Both the compressor 1a and the turbine 1c are each made up of several stages, each stage is composed of a guide blade ring and a moving blade ring. During operation, the rotating blade rings rotate about the longitudinal axis 2 of the turbomachine 1. The intake air is compressed in the compressor 1a and then burned in the downstream combustion chamber 1b with added kerosene. The hot gas is expanded in the turbine 1c and drives the rotor blade rings. The reference number 2 references, by way of example, a compressor rotor blade ring in a blisk design.

Figure 2a and 2b show a schematic representation of the coating according to the invention of a component 2, which in this example is a compressor blade ring in a blisk design. During the coating, the component 2 is immersed in a bath 33 with liquid paint as the coating material 32 .

During the immersion, the component 2 is rotated about an axis of rotation 22 which lies outside of the bath 33 . The reference number 23 references the direction of rotation of the component 2, with the component 2 being able to be rotated constantly or temporarily also undergoing an angular acceleration. In the partially immersed state, the component is rotated further, optionally it can also be moved up and down vertically, referenced by reference number 24.

However, the component 2 is not completely immersed over the entire circulation, nor is it integrated over the circulation. The resultant only partial coverage of the component 2 with the coating material 32 is made recognizable by the hatched area 21, a central area of the component 2 remains uncoated. Furthermore, the component 2 can optionally also be moved axially in the immersed state (not shown), ie in the present case perpendicular to the plane of the drawing.

According to Figure 2b the component 2 was removed from the bath 33 for drying, and it is then rotated further, cf. the direction of rotation 23. From the fans shown, a respective air flow 34 with a speed component opposite to gravity is directed onto the component 2. Coating material 35 drained from component 2 is collected in a drip container 37, it is returned to bath 33 and thus reused. As the drying progresses, the rotational speed of the component 2 can be successively reduced until it comes to a standstill. <b>REFERENCE LIST</b> flow machine 1 compressor 1a combustion chamber 1b turbine 1c Compressor blade ring in blisk design 2 longitudinal axis 3 Coated area of the component 21 axis of rotation 22 direction of rotation 23 Vertical movement of the component when immersed 24 coating material 32 bath 33 airflow 34 Dripped coating material 35 Return of the coating material to the bath 36 drainer 37

Claims (14)

Method for coating (21) a component (2) of a turbomachine (1) in a bath (33), in which method i) the component (2) is partially immersed in the bath (33) with a coating material (32); ii) the component (2) is at least temporarily rotated (23) during the at least partial immersion about an axis of rotation (22) which lies outside the bath (33); iii) the component (2) is at most partially immersed over the rotation (23). Method according to Claim 1, in which the component (2) is a rotor blade ring or a segment of a rotor blade ring. Method according to one of the preceding claims, in which during step (ii) the component (2) is at least temporarily additionally moved in a direction which is at least partially axial. A method according to any one of the preceding claims, in which the angular velocity of the rotation (23) is at least temporarily variable. Method according to one of the preceding claims, in which the angular velocity of the rotation (23) is at least temporarily constant. Method according to one of the preceding claims, in which the axis of rotation (22) can be changed in the vertical direction (24) during the at least temporary rotation (23), i.e. it is moved in the vertical direction (24), the component (2) during the vertical Movement (24) is at least temporarily in the immersed state. A method according to any one of the preceding claims, wherein the axis of rotation (22) is at least temporarily oriented at an angle to a surface of the bath (33). A method according to any one of the preceding claims, in which the component (2) is removed from the bath (33) for drying and is further rotated during removal and after removal. Method according to Claim 8, in which, in order to dry the component (2), an air flow (34) is directed onto the component (2), which air flow (34) has a velocity component which is directed in the opposite direction to the force of gravity. Method according to Claim 8 or 9, in which the rotational speed of the component (2) is successively reduced after removal from the bath as drying progresses. A method according to any one of claims 8 to 10, wherein the coating material (35) dripped from the component (2) after removal from the bath (33) is added to the bath (33) in the liquid state. Method according to one of the preceding claims, in which the component (2) is removed from the bath (33) for drying after a first pass with method steps i) to iii), the component (2) thereafter in a second pass after Process steps i) to iii) again immersed in the bath (33) and rotated (23), wherein in the first and in the second pass rotated in opposite directions (23). Method for producing a component (2) of a turbomachine (1), the component (2) being coated (21) according to method steps i) to iii), the coating (21) serving as a mask in a subsequent processing of the component and is removed again after the subsequent processing. A method according to claim 13, wherein the subsequent processing is an electrochemical method.

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