Device and method for electrochemical machining

Abstract

The present invention relates to a device (1) for machining a component (2) by means of electrochemical machining, the device comprising a machining cathode (11) for electrochemically removing material from the component (2), a component holder (6) for holding the component (2) during the machining, and a positioning unit (12) for moving the machining cathode (11) relative to the component holder (6). The component holder (6) and the positioning unit (12) are movable relative to each other in a penetration direction (19) of the machining cathode (11), the machining cathode (11) is additionally laterally movable by means of the positioning unit (12), i.e. at an angle to the penetration direction (19), and the positioning device (12) has a linear drive (13) by means of which the lateral movability is implemented.

Description

[0001] DEVICE AND METHOD FOR ELECTROCHEMICAL MACHINERY

[0002] DESCRIPTION

[0003] Technical area

[0004] The present invention relates to a device for machining a component by electrochemical removal.

[0005] State of the art

[0006] During electrochemical machining, a working gap is created between the component and the tool, with the component typically polarized as the anode and the tool as the cathode. Due to the non-contact nature of the machining, even relatively hard materials can be machined using material removal techniques, which is why the process can be advantageously used in the manufacture of components for axial flow machines, particularly aircraft engines. Against this background, special requirements may arise regarding the accuracy and reproducibility of component machining. This is intended to illustrate a preferred application environment, but does not initially limit the present subject matter in its generality.

[0007] Description of the invention

[0008] The present invention is based on the technical problem of providing an advantageous device for machining a component by electrochemical removal.

[0009] This is achieved according to the invention with the device according to claim 1. In this device, a component holder, in which the component is arranged for processing, and a positioning unit with the processing cathode are initially displaceable relative to one another in an immersion direction. In this immersion direction, the processing cathode is successively moved into the component during removal, i.e. the component holder and processing cathode are moved towards one another. The processing cathode can also be displaced laterally with the positioning unit, i.e. at an angle to the immersion direction. This lateral displaceability is achieved via a linear drive of the positioning unit, with which the processing cathode can be displaced laterally with a translational movement during component processing.

[0010] Compared to an alternative conceivable approach in which a rotary movement would be converted into a lateral offset via an eccentric and a corresponding suspension, the linear drive can be advantageous in that the lateral offset can be decoupled from other movement components. This can simplify the design of process-related equipment (e.g., free-form surface design) because no linked path movements need to be taken into account. The decoupling from the plunging movement can also be advantageous during operation, for example, if the processing cathode has to be retracted in the event of a malfunction, which can be simplified if no multi-axis linked path movement needs to be taken into account. In addition, the relative offset in the plunging direction and the lateral offset additionally realized via the linear drive can also be easier to implement on the control side.

[0011] Preferred embodiments can be found in the dependent claims and the entire disclosure, whereby the presentation of the features does not always distinguish in detail between device and method or use aspects; in any case, the disclosure is implicitly to be read with regard to all claim categories. For example, if a processing device suitable for a specific operation is described, this is to be understood simultaneously as a disclosure of a corresponding operating method, and vice versa.

[0012] The lateral offset is angled relative to the immersion direction, meaning the movement path realized with the linear drive can generally be inclined or, preferably, perpendicular to the immersion direction. The relative displaceability of the component holder and positioning unit in the immersion direction can be realized with a corresponding displacement unit, with which, viewed in a fixed coordinate system, the positioning unit can be displaced in the immersion direction towards the component holder during removal, or the component holder can be displaced relative to the positioning unit with the processing cathode (and in the opposite direction when the processing cathode is retracted). Preferably, the positioning unit is at rest in the fixed coordinate system relative to the immersion direction, meaning the component holder / component is moved, preferably lowered vertically downwards towards the processing cathode during removal.

[0013] As explained at the beginning, the processing cathode is preferably polarized. The component processing itself can be carried out, for example, using a so-called ECM (electrochemical machining, ECM) process, but especially also a PEM (precise electrochemical machining) or PECM (pulsed electrochemical machining) process. One advantage of the linear drive can be, for example, that it allows for different oscillation shapes to be easily adjusted or superimposed on the lateral offset, e.g., a trapezoidal or sinusoidal shape as required.

[0014] In general, the linear drive can be implemented mechanically or piezoelectrically, for example, but in a preferred embodiment it is provided as a linear motor. This has a stator and a rotor which can be moved along the stator according to the magnetic field principle (is pushed or pulled along the travel path by repeated polarity reversals). The linear motor, also referred to as a “linear direct drive”, can be easily integrated due to its compact design, for example. In addition, it can be used to implement force detection with relative sensitivity, which can reduce the risk of collisions. Compared to a hydraulic drive, for example, energy consumption can be reduced. Furthermore, in the event of a leak, the hydraulic fluid could also contaminate the electrolyte (downtime / costs). Compared to a linear motor, a hydraulic drive can also place increased demands on the control system and / orelectrical control, which in turn means expenditure (area, costs and energy).

[0015] In general, the lateral offset of the processing cathode could also be coupled to the rotor via a gear or deflection rod, for example. However, in a preferred embodiment, the processing cathode is arranged on the rotor, i.e., mounted directly to it. This can, for example, reduce the number of components and thus result in an overall simpler and thus, for example, less prone to failure design.

[0016] In general, the path along which the slider is movable on the stator is preferably straight over the entire travel path. Irrespective of this, in a preferred embodiment, the slider is held positively to the stator along the travel path, preferably over the entire travel path. This positive engagement exists in directions perpendicular to the travel path, meaning that the slider is held at a defined distance from the stator perpendicular to the travel path, which can allow for high precision, for example.

[0017] In a preferred embodiment, the guide comprises a rod that extends through the slider in a direction parallel to the movement path. The slider can slide along the movement path on the rod, which is preferably linear (straight) over at least this length. Preferably, the guide additionally comprises a second rod, which the slider also encloses and which is parallel to the first rod.

[0018] According to a preferred embodiment, the machining cathode is mounted on the positioning unit via a quick-action chuck, preferably on the slider. This can allow for quick changeover, for example, if a machining cathode with a different contour is required or if the machining cathode has reached its service life and needs to be replaced. The quick-action chuck can, for example, comprise one or more centering pins on which the mounted machining cathode sits in alignment.

[0019] According to a preferred embodiment, in addition to the (first) processing cathode, the device comprises a second processing cathode, which is laterally displaceable (angled to a second immersion direction) by means of a second positioning unit. The second positioning unit also comprises a (second) linear drive, preferably again a linear motor. All statements made above generically for the "processing cathode" and "positioning unit" initially relate to the first processing cathode and positioning unit, but are expressly intended to be disclosed with regard to the design of the second processing cathode and positioning unit. The first and second positioning units are preferably structurally identical to one another.

[0020] In general, the first immersion direction of the first processing cathode could also be angled to the second immersion direction of the second processing cathode, meaning the cathodes could be immersed into the component at an angle to each other during removal. In a preferred embodiment, however, this immersion occurs in parallel, meaning the first and second immersion directions coincide.

[0021] According to a preferred embodiment, the first and second positioning units are provided such that the movement path of the first linear drive lies on a common straight line and / or on two collinear paths with the movement path of the second linear drive. With respect to the recess created by the immersion of the electrodes into the component, the first electrode can then be displaced with the first positioning unit during removal (in addition to the immersion) toward a first flank delimiting the recess, while the second processing cathode is displaced with the second positioning unit toward a second flank, which also delimits the recess and is opposite the first flank.

[0022] The invention also relates to a method for machining a component by electrochemical removal, wherein material is electrochemically removed using a machining cathode, and the component and the machining cathode are displaced relative to one another in an immersion direction. Furthermore, the machining cathode is laterally displaced (angled, in particular perpendicular to the immersion direction) using a positioning unit on which the machining cathode is arranged. This lateral offset is adjusted using a linear drive of the positioning unit, preferably a linear motor. This method is preferably carried out on a device disclosed herein; for possible details, reference is made to the above explanations.

[0023] In a preferred embodiment, the component that is subjected to material removal is a component for a turbomachine, in particular for an aircraft engine. Particularly preferably, the component can be a so-called blisk (blade-integrated disk), i.e., a disk with blades integrally (monolithically) formed therewith. Material removal allows the spaces between the blades or airfoils to be exposed (and the blades remain intact).

[0024] Short description of the drawings

[0025] In the following, the invention is explained in more detail using exemplary embodiments, whereby the individual features within the scope of the independent claims can also be essential to the invention in other combinations and no distinction is made in detail between the different claim categories.

[0026] In detail,

[0027] Figure 1 shows a device for machining a component by electrochemical removal;

[0028] Figure 2a, b a detailed view of a positioning unit of the device according to Figure 1;

[0029] Figure 3 shows an aircraft engine in a schematic longitudinal section.

[0030] Preferred embodiment of the invention

[0031] Figure 1 shows a device 1 for processing a component 2 by electrochemical removal, for which the device 1 has a (first) processing cathode 11 arranged on a (first) positioning unit 12. This has a (first) linear drive 13 designed as a linear motor 14. With the positioning unit 12, the processing cathode 11 can be displaced laterally along a movement path 15, specifically perpendicular to a (first) immersion direction 19. A relative displacement between the component 2 and the processing cathode 11 is realized by lowering the component 2 with a displacement unit 5 (shown only schematically), with which the component holder 6 and thus the component 2 can be lowered and thus the processing cathode 11 can be immersed in the immersion direction 19.As explained in detail in the introduction to the description, the lateral offset, which is realized via the linear drive 13, is decoupled from this, so that no complex deflection gear etc. is required.

[0032] The device 1 further comprises a second processing cathode 21, which is mounted on a second positioning unit 22 with a second linear drive 23, namely a linear motor 24. The second movement path 25 lies on a straight line with the first movement path 15. Both linear motors 14, 24 each have a stator 14.1, 24.1 and a rotor 14.2, 24.2, which is movable on the stator 14.1, 24.1 according to the magnetic field principle. The processing cathodes 11, 21 are each mounted on the rotor 14.2, 24.2 via a respective quick-action chuck 16, 26.

[0033] Figures 2a and b show the (first) positioning unit 22 in detail (the second positioning unit is constructed analogously), in a top view and a side view. The rotor 14.2 is held in a form-fitting manner on a guide 30, which has a first and a second linear rod 30.1, 30.2. The rods 30.1, 30.2 extend through the rotor 14.1, which can slide along the movement path 15 on the rods 30.1, 30.2. Magnets 31 are arranged on the underside of the rotor 14.1, with which the rotor can be moved by appropriate polarity reversal along the magnets 32 of the stator 14.2 (shown only schematically).

[0034] Figure 3 shows a turbomachine 40, in this case an aircraft engine 41. This is functionally divided into a compressor 42, a combustion chamber 43, and a turbine 44. During operation, intake air is compressed in the compressor 42 and combusted with added kerosene in the downstream combustion chamber 43, with the resulting hot gas being expanded in the turbine 44. Both the compressor 42 and the turbine 44 each have several stages with guide vanes and rotor blade rings. For example, a rotor blade ring of the turbine 44, referenced here by way of example with the reference numeral 45, can be designed as a blisk.

[0035] LIST OF REFERENCE SYMBOLS

[0036] Device 1

[0037] Component 2

[0038] Transfer unit 5

[0039] Component holder 6

[0040] First processing cathode 11

[0041] First positioning unit 12

[0042] First linear actuator 13

[0043] First linear motor 14

[0044] Stator 14.1, 24.1

[0045] Runners 14.2, 24.2

[0046] Keyless chuck 16, 26

[0047] First movement section 15

[0048] First immersion direction 19

[0049] Second processing cathode 21

[0050] Second positioning unit 22

[0051] Second linear drive 23

[0052] Second linear motor 24

[0053] Second movement distance 25

[0054] First positioning unit 22

[0055] Guided tour 30

[0056] Bars 30.1, 30.2

[0057] Magnets 31

[0058] Magnets 32

[0059] Turbomachine 40

[0060] Aircraft engine 41

[0061] Compressor 42

[0062] Combustion chamber 43

[0063] Turbine 44

[0064] Blade ring / / z 45

Claims

CLAIMS Device (1) for machining a component (2) by electrochemical removal, with a machining cathode (11) for electrochemically removing material from the component (2), a component holder (6) for holding the component (2) during removal, and a positioning unit (12) for displacing the machining cathode (11) relative to the component holder (6), wherein the component holder (6) and the positioning unit (12) are displaceable relative to one another in an immersion direction (19) of the machining cathode (11), wherein the machining cathode (11) is additionally displaceable laterally with the positioning unit (12), i.e. at an angle to the immersion direction (19), and wherein the positioning unit (12) has a linear drive (13) with which the lateral displaceability is realized. Device (1) according to claim 1, wherein the linear drive (13) is a linear motor (14), i.e. a linear motor which is arranged along a stator (14) according to the magnetic field principle.1) has a movable rotor (14.2). Device (1) according to claim 2, wherein the processing cathode (11) is arranged on the rotor (14.2). Device (1) according to claim 2 or 3, which is configured to measure a force applied with the displacement of the rotor (14.2) via an electrical power applied to move the rotor (14.2). Device (1) according to one of claims 2 to 4, wherein the rotor (14.2) is held positively on a guide (30) on its movement path (15) along the stator (14.1) in directions perpendicular to the movement path (15). Device (1) according to claim 5, wherein the guide (30) has a rod (30.1, 30.2) which the rotor (14.2) encloses. Device (1) according to one of the preceding claims, wherein the processing cathode (11) is removably mounted on the positioning unit (12) via a quick-action chuck (16).Device (1) according to one of the preceding claims, comprising a second processing cathode (21) and a second positioning unit (22) for displacing the second processing cathode (21) relative to the component holder (6), wherein the component holder (6) and the second positioning unit (22) are displaceable relative to one another in a second immersion direction of the second processing cathode (21), wherein the second processing cathode (21) is laterally displaceable with the second positioning unit (22), i.e., at an angle to the second immersion direction, and wherein the second positioning unit (22) has a second linear drive (23) with which the lateral displaceability is realized. Device (1) according to claim 8, wherein the first and second positioning units (12, 22) are jointly displaceable relative to the component holder (6), and the first and second immersion directions (19) coincide.Device (1) according to claim 8 or 9, wherein a movement path (25) of the second linear drive (23) lies on a straight line with a movement path (15) of the first linear drive (13). Method for machining a component (2) by electrochemical removal, in which material is electrochemically removed from the component (2) using a machining cathode (11), the component (2) and the machining cathode (11) are displaced relative to one another in an immersion direction (19) of the machining cathode (11), and with a positioning unit (12) on which the machining cathode (11) is arranged, the machining cathode (11) is displaced laterally, i.e. at an angle to the immersion direction (19), using a linear drive (13) of the positioning unit (12). Method according to claim 11, in which a device (1) according to one of claims 1 to 10 is used. Method according to claim 11 or 12, in which the component (2) is a component for a turbomachine (40), in particular for an aircraft engine. Method according to claim 13, in which the component (2) is a blisk (45).Method for producing a component (2), in which the component (2) is processed in a method according to one of claims 11 to 14.

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