Patent Description:
Using additive or generative manufacturing methods, such as for example 3D printing methods, in which a component is constructed in layers from a loose material on the basis of a digitized geometric model of the component, components with complex geometries such as internal hollow spaces or cavities can be manufactured efficiently. In the case of complex components that are manufactured in an additive method from a metal material, a post-treatment of the component is typically carried out to improve the surface quality of an inner and/or outer surface of the component.

The process known as electro-polishing is one possibility for post-treatment of the surface of interior surfaces that define cavities of a complex component, in particular for smoothing the interior surfaces. An electrode is here inserted into the cavity, and the component is immersed, with the electrode, in an electrolyte bath.

For smoothing the interior surface, the component and the electrode are connected to an electric voltage source in such a way that the electrode forms a cathode and the component forms an anode. The material is this way anodically removed from the interior surface, and the interior surface thereby smoothed. An electro-polishing method for additively manufactured components is described in, for example, <CIT>.

<CIT> discloses additive manufacturing of a hollow metal component and a coaxial electrode within the hollow component. This coaxial electrode is used as a cathode in a subsequent electro-polishing process for polishing the hollow metal component.

<CIT> discloses additive manufacturing of a component and an electrode at the same time and using this electrode in a subsequent electro-polishing process for polishing the hollow metal component, wherein insulating spacers are provided that hold the electrode in a desired distance to a surface of the component.

<CIT> discloses generating support structures in a 3D-printing process.

<CIT> discloses providing an electrode within a cavity of a component during an electro-polishing process, wherein the electrode comprises a plurality of insulating spacers that hold the electrode in a predefined distance to the inner surface of the cavity.

<CIT> describes a system configured for machining a workpiece that includes an interior surface defining an internal passage. The system includes an electrode located within the internal passage and electrically isolated from the workpiece, an electrolyte supply, a power supply, and a remover. The electrolyte supply is configured for circulating an electrolyte in a gap between the electrode and the workpiece. The power supply is configured for applying a voltage between the electrode and the workpiece to facilitate smoothing the interior surface. The remover is configured for completely removing the electrode from within the internal passage after smoothing the interior surface.

The object of the present invention is to provide improved solutions for the manufacture of a complex component.

This object is achieved both by a method with the features of claim <NUM>.

Advantageous embodiments are subject to the dependent claims in connection with the description.

According to the invention, a method is provided for the manufacture of a complex component. The method comprises a construction of the component from a metal material in an additive manufacturing method with at least one cavity segment that has a cavity open on at least one side and defined by an interior surface of the component, a formation of an auxiliary electrode during the construction of the component, for example of the same metal material as the component or of another conductive material, in general of an electrode metal material, a formation of one or a plurality of supporting structures that connect the auxiliary electrode to the interior surface of the component during the construction of the component, for example of the same metal material as the component or of another material, in general of a supporting structure material, an electrical insulation of the auxiliary electrode from the interior surface by separating the supporting structures from the interior surface or from the auxiliary electrode, and a performance of an electro-polishing of the interior surface in an electrolyte bath by connecting the component and the auxiliary electrode to different poles of an electric voltage source in such a way that the auxiliary electrode forms a cathode and the component forms an anode.

According to this aspect of the invention, a complex component is first constructed in layers from a metal material in an additive manufacturing method, for example in a 3D printing method, where said component comprises at least one cavity defined by an interior surface, wherein the interior surface further defines at least one opening through which the cavity is accessible. The component can, for example, be a hydraulic assembly, wherein the cavity segment that comprises the cavity can be formed for example by a tube segment.

During the construction of walls that define the component, an auxiliary electrode, e.g. in the form of an elongated, cylindrical segment, is formed in the cavity segment by the additive manufacturing method. Put simply, the auxiliary electrode is printed at the same time. In order to maintain the auxiliary electrode at a predetermined distance from the interior surface of the component, at least one supporting element or a supporting structure, e.g. in the form of a bar or a bridge that extends between the interior surface and the auxiliary electrode, is also formed during the additive manufacture of the component. A plurality of supporting structures, spaced apart from one another along a circumference of the auxiliary electrode, can also be provided. The auxiliary electrode, the supporting structure and the component are thus manufactured as a single piece or single part. The at least one supporting structure is advantageously arranged in the region of the opening of the hollow space, whereby it is easily accessible.

After the construction of the component with the auxiliary electrode and the at least one supporting structure, the at least one supporting structure is mechanically separated, for example being cut through or broken through. The auxiliary electrode is in this way electrically insulated from the interior surface and thus from the component. An electro-polishing of the interior surface is carried out in a further step. The auxiliary electrode and the component are arranged for this purpose in an electrolytic fluid and connected to an electric voltage source, preferably a DC voltage source, wherein the auxiliary electrode serves as a cathode and the component as the anode. Metal material, in particular projections, are removed from the anode as a result, and the surface roughness of the interior surface is thus reduced. The electro-polishing can, for example, also be carried out in combination with plasma-electrolytic or electrochemical surface treatment.

One idea on which the invention is based is that an auxiliary electrode that is used for electro-polishing during the manufacture of the component in an additive manufacturing method is formed at the same time. The auxiliary electrode can thus be arranged without difficulty in complicated, undercut hollow spaces that otherwise would only be accessible from outside with difficulty if at all. A further advantage is that the electrode is easily positioned by means of the supporting structures that are provided at a desired distance from the interior surface, whereby the electro-polishing can be carried out with improved efficiency and quality. A further advantage is that the geometry of the auxiliary electrode (such as the diameter, cross-section area or material thickness), can be varied and printed at a desired distance from the interior surface, whereby the electro-polishing can be carried out with improved efficiency and quality.

According to that the invention, the electrical insulation comprises an insertion of a separating head of a separating tool into an opening, defined by the interior surface, of the cavity along the auxiliary electrode, wherein the separating head has an interior circumferential surface that defines and encloses a longitudinal axis and, oriented opposite to this, an exterior circumferential surface, and a cutting through of the one or plurality of supporting structures with a separating segment of the separating head which, with reference to the longitudinal axis, forms a front end of the separating head, wherein the separating head is inserted into the opening sufficiently far that the supporting structures lie against an electrically insulating material forming, at least in segments, the interior circumferential surface and/or the exterior circumferential surface with reference to the longitudinal axis, wherein the separating head remains arranged in the cavity during the electro-polishing. Accordingly, a separating head, in particular in the form of a hollow cylinder, for example in the form of a circular hollow cylinder, is inserted into the opening and moved against the supporting structures in order to cut through them. This offers the advantage that in some cases all the supporting structures can be cut through together in a single working step. The separating head further comprises an electrically insulating region at an interior circumferential surface that defines the hollow cylindrical form and that faces toward the auxiliary electrode when the separating head is in the state that is inserted into the opening, and/or at an exterior circumferential surface that faces the interior surface of the component when the separating head is in the state that is inserted into the opening, wherein said region preferably extends around the full circumference of the separating head and at least with a certain length along the longitudinal axis of the separating head. When cutting through the at least one supporting structure, the separating head is inserted into the opening sufficiently far that the supporting structure lies within the electrically insulating region with reference to the longitudinal axis. The at least one supporting structure is thus mechanically cut through by the separating head, and the separating head simultaneously forms an electrical insulation.

According to one further embodiment, the component is designed with at least two supporting structures spaced apart along a circumference of the auxiliary electrode, and wherein the exterior circumferential surface of the separating head lies against the interior surface of the component when separating the supporting structures, and the separating head remains arranged in the cavity during the electro-polishing. At least two supporting rods or supporting bridges that extend between the interior surface and the circumferential surface of the auxiliary electrode are accordingly formed during the construction of the component. The exterior circumferential surface of the separating head is designed with a diameter that corresponds to the diameter of the opening of the cavity, and is pushed into the cavity through the opening, whereby the supporting bridges in the region of the interior surface are separated therefrom, and lie against the interior circumferential surface of the separating head. Since a plurality of supporting structures are provided spaced along the circumference of the electrode, the supporting structures continue to reliably hold the auxiliary electrode at a predetermined distance from the interior surface of the component for as long as the separating head is inserted in the opening. The separating head can thus, for example, remain in the opening during the electro-polishing, and hereby advantageously holds the auxiliary electrode in position.

According to a further embodiment, it is provided that the interior circumferential surface of the separating head lies against a circumferential surface of the auxiliary electrode when separating the supporting structures, and the separating head remains arranged in the cavity during the electro-polishing. In the region of the auxiliary electrode, the at least one supporting structure is accordingly separated therefrom when the separating head is inserted into the cavity through the opening. In particular, the auxiliary electrode is accommodated in an accommodating space defined by the interior circumferential surface of the separating head through the insertion of the separating head into the opening. The auxiliary electrode can, for example, come into contact with the interior circumferential surface of the separating head. Through the accommodation of the auxiliary electrode in the accommodating space defined by the interior circumferential surface of the separating head, it can continue to be held reliably at a predetermined distance from the interior surface of the component by the separating head, as long as the separating head is inserted in the opening or the cavity. The separating head can thus, for example, remain in the opening during the electro-polishing, and hereby advantageously holds the auxiliary electrode in position.

According to one embodiment, the separating head can be rotated about the longitudinal axis during separation of the supporting structures. The separating head can, in particular, be inserted into the opening in a combined translation and rotation movement. As a result, shear forces are applied by the separating head to the at least one supporting structure or the at least one supporting element, whereby this is easier to cut through.

According to a further embodiment, the supporting structures are formed in a first end segment that is connected to the interior surface of the component with local predetermined breaking points for separating the supporting structures from the interior surface such as, for example, notches. At least one taper or narrowing of the diameter can accordingly be formed at a respective supporting element in the region of the interior surface of the component. This advantageously simplifies the separation of the respective supporting structure from the interior surface.

According to a further embodiment, the supporting structures are formed in a second end segment that is connected to the auxiliary electrode with local predetermined breaking points such as, for example, notches, for separating the supporting structures from the auxiliary electrode. At least one taper or narrowing of the diameter can accordingly be formed at a respective supporting element in the region of the circumferential surface of the auxiliary electrode. This advantageously simplifies the separation of the respective supporting structure from the interior surface.

According to a further embodiment of the method, a removal of the auxiliary electrode from the cavity of the cavity segment is also provided. The removal is carried out after the electro-polishing. It can, for example, be provided that the auxiliary electrode is withdrawn through the opening of the cavity after the electro-polishing of the interior surface. In appropriate cases, the separating head is first removed from the opening. Optionally, the supporting elements are also removed from the cavity. If the supporting elements are separated in the region of the interior surface of the component, for example by means of the separating head which lies with the exterior circumferential surface against the interior surface, the auxiliary electrode and supporting structures can advantageously be removed from the cavity together, or as one piece.

According to a further embodiment, the component is constructed with a first cavity segment and a second cavity segment connected to this, wherein the auxiliary electrodes of the first and of the cavity segment are designed as one piece and with a predetermined breaking point in a connecting region of the auxiliary electrodes, and wherein the auxiliary electrodes are separated from one another on removal from the cavities of the cavity segments at the predetermined breaking point which can, for example, be implemented in the form of a notch of the electrode. The first cavity segment can, for example, comprise a cavity extending in a first direction, and the second cavity section can comprise a cavity extending in a second direction that is connected to the first cavity. Auxiliary electrodes are accordingly provided in both cavities, wherein the auxiliary electrode of the first cavity segment extends in the first direction and the auxiliary electrode of the second cavity segment in the second direction. In order to simplify a withdrawal of the auxiliary electrodes from both the first and the second direction, a constriction or a notch can be provided as a predetermined breaking point at a crossing point at which the electrodes are connected.

According to an aspect of the disclosure, a separating tool, which does not form part of the present invention, is provided. The separating tool can, in particular, be used in a method according to the first aspect of the invention for separating the at least one supporting structure during the step of the electrical insulation. The features and advantages disclosed in connection with the first aspect of the invention thus apply also to the separating tool according to the second aspect of the invention, and vice versa.

The separating tool comprises a separating head with an interior circumferential surface that defines and encloses a longitudinal axis, and an exterior circumferential surface that is oriented in opposition to this. The separating head has a separating segment which forms a front end of the separating head with reference to the longitudinal axis, wherein the interior circumferential surface and/or the exterior circumferential surface of the separating head is formed, at least in segments with reference to the longitudinal axis, of an electrically insulating material.

The separating head thus has the form of a sleeve or of a hollow cylinder that defines a longitudinal axis. A separating segment that is configured to cut through the metal supporting structures is formed at a first, front end of the separating head. The separating head is, further, designed to be electrically insulating at least in regions. The separating head can accordingly be formed to be electrically insulating along the whole of the longitudinal axis or only in a discrete region. Preferably the electrically insulating region includes the whole of the longitudinal axis. In particular, at least the exterior circumferential surface or at least the interior circumference surface or both surfaces can have electrically insulating properties in regions.

The separating tool is, thus, formed with a separating head that has electrically insulating properties in regions. This can, for example, as described above, be used for cutting through supporting elements that are manufactured as one piece with a complex component and an auxiliary electrode. This design simplifies an electrical insulation of the auxiliary electrode from the component. At the same time, the separating head can advantageously be used for fixing the auxiliary electrode relative to the component.

It may be provided that the separating head is itself, at least in segments with reference to the longitudinal axis, formed of the electrically insulating material. The separating head can, for example, be formed entirely or at least partially of a plastic material, e.g. a polymer. In particular, a cross-section between the interior circumferential surface and the exterior circumferential surface of the separating head can be formed of an electrically insulating material.

It may be provided that the interior circumferential surface and/or the exterior circumferential surface is coated with the electrically insulating material at least in segments with reference to the longitudinal axis. The carrier head can accordingly itself be formed of an insulating or of a non-insulating material, for example a metal material, and only the interior circumferential surface and/or the exterior circumferential surface are at least partially provided with a layer of electrically insulating material, for example a plastic material. This offers the advantage that the carrier head can be formed of a mechanically robust material, while the insulation layer provides the electrical insulation.

The separating segment may comprise a separating structure, in particular in the form of sawteeth, cutting burrs or the like. This advantageously simplifies cutting through the supporting structures.

It may be provided that the separating head comprises at least one passage opening for passing through electrolytic fluid in the region of a rear end which, with reference to the longitudinal axis, is located in opposition to the front end. A flow of fluid from the interior circumferential surface to the exterior circumferential surface is thereby enabled. This is in particular advantageous if the separating head remains in the opening of the cavity of the component during the electro-polishing, since in this way the electrolytic fluid can be circulated better, which has a positive effect on the surface quality of the component. The larger is the flow surface defined by the passage openings, the more effectively the circulation of the electrolytic fluid is improved, and the efficiency of the electro-polishing is accordingly better.

The at least one passage opening can, for example, extend along the longitudinal axis. The passage opening is accordingly designed as a longitudinal recess, extending along the longitudinal axis, between the interior circumferential surface and the exterior circumferential surface of the separating head.

As a further option, the at least one passage opening extends into an end plate forming the rear end of the separating head. The separating head accordingly comprises an end plate which is located, with reference to the longitudinal axis, in opposition to the separating segment. The end plate comprises at least one passage opening. This passage opening can preferably merge into a longitudinal passage opening.

The separating tool additionally may comprise a coupling for mechanically connecting the separating tool to a drive apparatus, wherein the coupling is connected to a rear end of the separating head which, with reference to the longitudinal axis, is located opposite to the front end. The coupling can, for example, be realized in the form of a shaft or a spigot that stands up from the end plate concentrically with the longitudinal axis.

With reference to direction statements and axes, in particular to direction statements and axes that relate to the route of physical structures, a route of an axis, a direction or a structure "along" another axis, direction or structure here means that these, in particular the tangents arising at a respective location of the structures, each extend at an angle of less than or equal to <NUM> degrees, preferably less than or equal to <NUM> degrees, and particularly preferably parallel to one another.

With reference to direction statements and axes, in particular to direction statements and axes that relate to the route of physical structures, a route of an axis, a direction or a structure "across" another axis, direction or structure here means that these, in particular the tangents arising at a respective location of the structures, each extend at an angle of more than <NUM> degrees, preferably more than <NUM> degrees, and particularly preferably perpendicular to one another.

The invention is explained below with reference to the figures of the drawings. In the figures:.

The same reference signs in the figures identify components that are identical or identical in function, unless otherwise stated.

<FIG> shows, by way of example, a complex component <NUM> in the form of a hydraulic assembly that is assembled from a plurality of pipe segments <NUM>. The pipe segments <NUM> each form, speaking generally, cavity segments <NUM>, wherein each cavity segment <NUM> has an open cavity <NUM>. As can be seen in <FIG>, each pipe segment <NUM>, or each cavity segment <NUM>, has at least one opening <NUM> that forms of opening of the cavity <NUM>. The hydraulic assembly illustrated in <FIG> with cavity segments <NUM> formed by pipe segments <NUM> is purely exemplary. A cavity <NUM> of a cavity segment <NUM> can, for example, also be designed as a drop-shaped cavity or as a blind-hole cavity or in general as a hollow space. An interior surface 1a of the component <NUM> thus in general defines a cavity <NUM> open on at least one side.

<FIG> shows by way of example that auxiliary electrodes <NUM> are arranged in the cavities <NUM>. The auxiliary electrodes <NUM> are used to carry out an electro-polishing of an interior surface 1a of the component <NUM>, and can subsequently be removed. In <FIG> the component <NUM> is thus shown before finishing, i.e. during a manufacturing method that is explained below in detail.

<FIG> shows by way of example a step of the method in which the component <NUM>, the auxiliary electrode <NUM> and a supporting structure or supporting elements <NUM> are constructed in an additive manufacturing method. The component <NUM>, the auxiliary electrode <NUM> and the at least one supporting structure or the at least one supporting element <NUM> can, for example, be constructed of a metal material <NUM>, for example of the same metal material <NUM>. It is also conceivable that only the component <NUM> and the auxiliary electrode <NUM> are constructed of a metal material <NUM>, for example the same or different, in general electrically conductive metal materials. The supporting element <NUM> can also be constructed from a nonconductive material.

For the additive construction of the component <NUM>, the auxiliary electrode <NUM> and the supporting elements <NUM>, the modelling material <NUM>, for example the metal material or different metal or plastic materials, is supplied to a 3D printing apparatus <NUM>, as is shown in <FIG>. The modelling material <NUM> can, for example, be present in powder form for this purpose. In principle, the present invention allows for a wide range of possibilities for liquefaction of the modelling material <NUM> in which heat can be introduced at specific localities in the deposited modelling material <NUM>. The use of lasers and/or particle beams, e.g. electron beams, is in particular advantageous, since in this way heat can be generated in a highly targeted and controlled manner. The additive construction or production can thus, for example, be chosen from the group of selective laser sintering, selective laser melting, selective electron-beam sintering and selective electron-beam melting or the like. Fundamentally, however, any desired additive method can be used, for example a directed energy deposition (DED) method. Additive construction is explained below by way of example in connection with selective laser melting (SLM), wherein the modelling material <NUM> is applied in powder form to a working platform <NUM> and is liquefied in specific locations through laser irradiation with a laser beam <NUM>, whereby, after cooling the cohering component <NUM> results, including the auxiliary electrode <NUM> and supporting elements <NUM>.

An energy source in the form of a laser to <NUM>, for example an Nd:YAG laser, transmits a laser beam <NUM> to a selected location on a specific part of a powder surface of the powdery modelling material <NUM> which lies on the working platform <NUM> in a working chamber <NUM>. An optical deflection apparatus or a scanner module such as, perhaps, a movable or tilting mirror <NUM> that deflects the laser beam <NUM> to a specific part of the powder surface of the modelling material <NUM> in accordance with its tilted position, can be provided for this purpose. The modelling material <NUM>, here in the form of a metal powder, is heated at the point where the laser beam <NUM> impinges, so that the powder particles are locally fused together, forming an agglomerate when cooled. The laser been <NUM> scans the powder surface depending on a digital model of the component <NUM> that is provided, for example, by a computer <NUM>, with the auxiliary electrode <NUM> and the supporting structure <NUM>. After the selective melting and local agglomeration of the powder particles in the surface layer of the modelling material <NUM>, excess modelling material <NUM> that has not been agglomerated can be discarded. The working platform <NUM> is then lowered by means of a lowering piston <NUM> (see arrow in <FIG>), and new modelling material <NUM> is transferred from a reservoir into the working chamber <NUM> with the aid of a powder feed <NUM> or other suitable apparatus. In this way a three-dimensionally sintered or "printed" component <NUM> made of agglomerated metal material <NUM> emerges in an iterative, generative construction process. The surrounding powdery modelling material <NUM> can here serve to support the part of the component <NUM> constructed so far. Through the continuous downward movement of the working platform <NUM>, the component, together with the auxiliary electrode <NUM> and the supporting elements <NUM>, emerge in a layered model generation process.

<FIG> shows schematically, and purely by way of example, a sectional view of a cavity segment <NUM> of the component <NUM> that is constructed in the additive manufacturing method. <FIG> shows a sectional view of the component <NUM> illustrated in <FIG> resulting from a cut along the line A-A illustrated in <FIG>. The cavity segment <NUM> comprises a cavity <NUM> that is defined by an interior surface 1a of walls <NUM> of the component <NUM> formed from the metal material <NUM>. In <FIG>, the cavity segment <NUM> is designed, by way of example, as a pipe segment <NUM>. The interior surface 1a thus defines a cavity <NUM> extending longitudinally that has openings <NUM> at opposing sides. As is illustrated purely by way of example in <FIG>, the interior surface 1a can define a circular cross-section. Other forms of the cavity <NUM> are, of course, also conceivable, for example having a curved longitudinal extension, with rectangular or polygonal cross-sections or the like. In general, a construction of the component <NUM> takes place with at least one cavity segment <NUM> that comprises a cavity <NUM> that is open at at least one opening <NUM> and is defined by the interior surface 1a of the component <NUM>.

As is further illustrated in <FIG> and already referred to above, in the additive construction of the component <NUM>, an auxiliary electrode <NUM> of an electrically conductive electrode material, for example of the metal material <NUM> and that extends in the cavity <NUM>, is constructed or printed at the same time. The auxiliary electrode <NUM> can, for example, be designed as a rod-like, elongated element which extends from the at least one opening <NUM> of the cavity <NUM> into the cavity <NUM>. <FIG> shows by way of example that the auxiliary electrode <NUM> extends between the opposing openings <NUM> of the cavity <NUM>. As can be seen in <FIG>, the auxiliary electrode <NUM> can, for example, be designed in such a way that it runs along a longitudinal extension of the cavity <NUM>. The auxiliary electrode <NUM> can, for example, be formed with a predetermined distance a4 from the interior surface 1a of the component <NUM>, as is shown schematically in <FIG>. The auxiliary electrode <NUM> can, for example, have a circular cross-section, as is illustrated by way of example in <FIG>. Other cross-sectional forms are, of course, also conceivable. A diameter d4 of the auxiliary electrode <NUM> can, for example, lie in a range between <NUM> and <NUM>.

<FIG> illustrates by way of example a plan view of a component <NUM> that has a first cavity segment 3A, a second cavity segment 3B and a third cavity segment 3C. The component <NUM> can, in general, have at least one cavity segment <NUM>. As is illustrated by way of example in <FIG>, the second and the third cavity segments 3B, 3C can each be designed as tubes and are each connected to the first cavity segment 3A, wherein the cavities <NUM> of the individual cavity segments 3A, 3B, 3C merge into one another. An auxiliary electrode <NUM> is constructed here in each of the cavity segments 3A, 3B, 3C, independently of their number. The auxiliary electrodes <NUM> of the individual cavity segments 3A, 3B, 3C are connected to one another, or are designed as one piece during the additive construction of the component <NUM>. <FIG> shows schematically a connecting region <NUM> in which the auxiliary electrodes <NUM> of different cavity segments 3A, 3B, 3C are joined to one another or branch off one another. As is shown by way of example in <FIG>, the auxiliary electrodes can be designed in the connecting region <NUM> with one or a plurality of notches <NUM> that serve as predetermined breaking points of the electrode <NUM>.

To position the auxiliary electrode <NUM> in a fixed location relative to the interior surface 1a of the component <NUM>, one or a plurality of supporting structures or supporting elements <NUM> are created additively from a supporting structure material, e.g. from the metal material <NUM>, during the additive construction of the component <NUM>. At least one supporting element <NUM> is, in general, generated, wherein, for reasons of clarity, reference will be made below to "the supporting elements <NUM>". The supporting elements <NUM> are designed as rod-shaped structures which extend between the auxiliary electrode <NUM>, in particular a circumferential surface 4a of the auxiliary electrode <NUM> that defines the cross-section of the auxiliary electrode <NUM> and the interior surface 1a of the component <NUM>, as is illustrated in <FIG>, schematically in each case. The supporting elements <NUM> thus connect the interior surface 1a and the auxiliary electrode <NUM>. The component <NUM>, the auxiliary electrode <NUM> and the supporting elements <NUM> are thus manufactured as one piece. A diameter d5 of the supporting elements <NUM> can, for example, lie in a range between <NUM> and <NUM>.

As illustrated schematically in <FIG>, the supporting elements or supporting structures <NUM> can be designed with notches <NUM> in a first end segment <NUM> connected to the interior surface 1a of the component <NUM>. The diameter d5 of the respective supporting structure <NUM> is locally reduced by the notches <NUM>. These notches <NUM> serve as predetermined breaking points of the supporting structure <NUM>. Alternatively or in addition, notches <NUM>, which also serve as predetermined breaking points, can also be designed in a second end segment <NUM> of the supporting structures <NUM> that is in contact with the auxiliary electrode <NUM>.

As is illustrated by way of example in <FIG>, a plurality of supporting elements spaced along the circumference of the auxiliary electrode <NUM> can be designed at one location with reference to the longitudinal extension of the auxiliary electrode <NUM>. <FIG> illustrates by way of example that a total of four supporting elements <NUM> are provided, which are arranged, spaced apart from one another, at an angle α of <NUM> degrees to one another. More or fewer than four supporting elements <NUM> can, of course, also be provided. As can be seen in <FIG>, the supporting elements <NUM> are preferably arranged in the region of the opening <NUM> of the cavity <NUM>, for example at a predetermined distance a31. The predetermined distance a31 can, for example, lie in a range between <NUM> percent and <NUM> percent of a diameter d31 of the opening.

After the construction of the component <NUM>, the auxiliary electrode <NUM> and the supporting structures <NUM>, an electrical insulation of the auxiliary electrode <NUM> from the interior surface 1a is created through mechanically cutting through the supporting structures <NUM>. The supporting structures <NUM> can, in particular, be separated from the interior surface 1a of the component <NUM> or the circumferential surface 4a of the auxiliary electrode <NUM>. The separation is carried out by a separating tool <NUM>, as is illustrated by way of example in <FIG> and <FIG>. The separating tool <NUM> is illustrated by way of example in <FIG>, <FIG>, and is explained below in detail.

The separating tool <NUM> illustrated by way of example in <FIG>, <FIG> comprises a separating head <NUM> and an optional coupling <NUM> mechanically connecting the separating tool <NUM> to a drive apparatus (not illustrated).

As can be seen in <FIG>, <FIG>, the separating head <NUM> is realized as a sleeve-shaped or cylindrical body which has an interior circumferential surface 110a and, oriented opposite to this, an exterior circumferential surface 110b. The interior circumferential surface 110a defines and encloses a longitudinal axis L100. The cutting head <NUM> extends along the longitudinal axis L100 between a first, front end <NUM> and a second, rear end <NUM> located opposite this. An end plate <NUM> can, in particular, be provided at the rear end <NUM>. At the front end <NUM>, the cutting head <NUM> has an opening <NUM> defined by the interior circumferential surface 110a, as can in particular be seen in <FIG>. A separating segment <NUM> is, further, formed at the front end <NUM> of the separating head <NUM>, and is configured to cut through the supporting elements <NUM>. The separating segment <NUM> can, optionally, be formed of a metal material, for example of a steel or a titanium alloy. The separating segment <NUM> can, optionally, comprise a separating structure <NUM>, for example in the form of sawteeth, as is illustrated schematically in <FIG>. Cutting burrs or the like are also conceivable as separating structures <NUM>. In <FIG> and <FIG> the separating segment <NUM> is symbolically set apart visually from a main segment <NUM>, adjacent to it with reference to the longitudinal axis L100, by a dashed line. In general, the separating segment <NUM> forms a front end <NUM> of the separating head <NUM>.

As is illustrated in <FIG> by way of example, the separating head <NUM> can comprise one or a plurality of passage openings <NUM>. A separating head <NUM> with four passage openings <NUM> is illustrated by way of example in <FIG>. More or fewer than four passage openings <NUM> can, of course, also be provided. The passage openings <NUM> are formed in the region of the rear end <NUM> of the separating head <NUM>, and can in particular extend along the longitudinal axis L100 in the form of longitudinal elongated recesses, as is illustrated in <FIG>. As is further shown in <FIG>, it can optionally be provided that the passage openings <NUM> extend into the end plate <NUM>.

The optional coupling <NUM> can, in particular, be designed as a shaft or spigot, which is connected to the rear end <NUM> of the separating head <NUM>, for example with the end plate <NUM>. A coupling <NUM> in the form of a shaft with a circular cross-section is illustrated by way of example in <FIG>, and is arranged coaxially with the longitudinal axis L100 and protrudes from the end plate <NUM>. In <FIG> the coupling is arranged in the same way as in <FIG>, but is designed with a rectangular cross-section.

The separating head <NUM> comprises an electrically insulating material <NUM>, for example a plastic material such as a polymer, at the interior circumferential surface 110a and/or at the exterior circumferential surface 110b. The interior circumferential surface 110a and/or the exterior circumferential surface 110b can in particular be formed entirely or partially of an electrically insulating material <NUM>. In <FIG> it can, for example, be provided that the interior circumferential surface 110a and/or the exterior circumferential surface 110b around the entire circumference and, with reference to the longitudinal axis L100, over the entire main segment <NUM>, i.e. between the rear end <NUM> and the beginning of the separating section <NUM> that is symbolized by the dashed line, is formed of an electrically insulating material <NUM>. This is illustrated symbolically in the sectional view of <FIG>. It is also conceivable that the interior circumferential surface 110a and/or the exterior circumferential surface 110b is only formed of an electrically insulating material <NUM> in the region of the front end <NUM> with reference to the longitudinal axis L100, for example in the separating segment <NUM>, and in an end region of the main segment <NUM> that is adjacent to that, as is illustrated schematically in the sectional views of <FIG>. In general, the interior circumferential surface 110a and/or the exterior circumferential surface 110b of the separating head <NUM> is, with reference to the longitudinal axis L100, at least in segments formed of an electrically insulating material <NUM>.

In <FIG> and <FIG>, each of which represents a sectional view of the separating head <NUM> illustrated in <FIG> or <FIG> in use for separating the supporting elements <NUM>, the hatching of the separating head <NUM> in the main segment <NUM> illustrates by way of example that the separating head <NUM> can be itself at least in segments with reference to the longitudinal axis L100 formed of the electrically insulating material <NUM>. The separating head <NUM> can, for example, be formed of a moulded plastic part. The interior circumferential surface 110a and/or the exterior circumferential surface 110b of the separating head <NUM> are thus formed of an electrically insulating material <NUM>. <FIG> shows schematically, and purely by way of example, a further possibility for designing the interior circumferential surface 110a and/or the exterior circumferential surface 110b to be electrically insulating. <FIG> shows schematically that the exterior circumferential surface 110b in the end region of the main segment <NUM> that is adjacent to the separating segment <NUM> is provided with a coating of an electrically insulating material <NUM>. The interior circumferential surface 110a can of course, alternatively or in addition, also be provided with such a coating.

<FIG> and <FIG> show, by way of example, a separation of the supporting structures or supporting elements <NUM> for electrically insulating the auxiliary electrode <NUM> from the interior surface 1a of the component <NUM> with the aid of the separating tool <NUM> described above. As is suggested in <FIG> and <FIG> by the arrow P1, the separating head <NUM> with the separating segment <NUM> is inserted in advance into the opening <NUM> of the cavity <NUM>, and moved along the auxiliary electrode <NUM> into the interior of the cavity <NUM>, or in the direction of the supporting elements <NUM>. As a result the separating segment <NUM>, or the front end <NUM> of the separating head <NUM>, comes to lie against the supporting elements <NUM>. Through further movement of the separating head <NUM> along the auxiliary electrode <NUM> against the supporting elements <NUM>, optionally combined with a rotation of the separating head <NUM> about the longitudinal axis L100, the supporting elements <NUM> are mechanically cut through by the separating head <NUM>, in particular by means of the separating segment <NUM>. It can, for example, be provided that the separating segment <NUM> cuts through the supporting elements <NUM> by means of the optional separating structure <NUM>. It can also be provided that the separating segment <NUM> exerts a mechanical stress on the supporting elements <NUM> that is large enough for the supporting elements <NUM> to break, e.g. at one of the predetermined breaking points formed by the optional notches <NUM> (<FIG>).

As is further illustrated schematically in <FIG> and <FIG>, the separating head <NUM> is inserted into the opening <NUM> or moved into the cavity <NUM> after the cutting through of the supporting elements <NUM> further along the auxiliary electrode <NUM> sufficiently far that the supporting elements <NUM> are adjacent to the electrically insulating material <NUM> of the interior circumferential surface 110a or of the exterior circumferential surface 110b. The supporting elements <NUM> are thereby separated physically from the interior surface 1a of the component <NUM> or of the auxiliary electrode <NUM>, and the electrical insulation is improved through the electrical insulation material <NUM> of the separating head <NUM>.

<FIG> illustrates by way of example that an exterior diameter of the separating head <NUM> defined by the exterior circumferential surface 110b corresponds to the diameter d31 of the opening <NUM> of the cavity <NUM> defined by the interior surface 1a. To separate the supporting structures <NUM> from the interior surface 1a the separating head <NUM> is moved into the cavity <NUM> with the exterior circumferential surface 110b adjacent to the interior surface 1a of the component <NUM>. The supporting structures <NUM> at the interior surface 1a of the component <NUM> are thereby cut through, e.g. broken through at the optional notches <NUM> at the first end segment <NUM> of the supporting structures <NUM>. To ensure that the supporting structures <NUM> are cut through at the interior surface 1a of the component <NUM> and not at the auxiliary electrode <NUM>, it can, for example, be provided that notches <NUM> are only provided in the first end segment <NUM> of the supporting structures <NUM>, or that the supporting structures <NUM> in the first end segment <NUM> are notched more deeply or, in general, more markedly weakened, than in the second end segment <NUM>.

Through the movement of the separating head <NUM> further into the cavity <NUM>, the supporting elements <NUM> are placed against the interior circumferential surface 110a of the separating head <NUM>. The separating head <NUM> is moved on until the supporting elements <NUM> lie with their second end segment <NUM> at the electrically insulating material <NUM> of the interior circumferential surface 110a. When the supporting elements <NUM> are broken through, as described above, they are bent in the movement direction P1 of the separating head <NUM>, and are thereby tensioned against the interior circumferential surface 110a as a result of their elasticity. As can clearly be seen in <FIG>, the supporting structures <NUM>, assuming they are provided with at least two supporting structures <NUM> spaced along a circumference of the auxiliary electrode <NUM>, can support the auxiliary electrode <NUM> against the separating head <NUM>, so that the auxiliary electrode <NUM> can be held at a predetermined distance a4 from the interior surface 1a of the component <NUM> after the separation of the supporting structures <NUM> by the separating head <NUM>.

<FIG> illustrates by way of example that an interior diameter of the separating head <NUM> defined by the interior circumferential surface 110a corresponds to the diameter d4 of the auxiliary electrode <NUM> defined by the circumferential surface 4a. To separate the supporting elements <NUM> from the auxiliary electrode <NUM>, the separating head <NUM> is moved into the opening <NUM> of the cavity <NUM>, and the auxiliary electrode <NUM> is inserted into the separating head <NUM>, so that the interior circumferential surface 110a of the separating head <NUM> lies against the circumferential surface 4a of the auxiliary electrode <NUM>. By moving the separating head <NUM> along the auxiliary electrode <NUM> into the cavity <NUM>, the supporting structures <NUM> are cut through at the circumferential surface 4a of the auxiliary electrode <NUM>, for example at the optional notches <NUM> in the second end segment <NUM> of the supporting structures <NUM>. To ensure that the supporting structures <NUM> are cut through at the circumferential surface 4a of the auxiliary electrode <NUM> and not at the interior surface 1a of the component <NUM>, it can, for example, be provided that notches <NUM> are only provided in the second end segment <NUM> of the supporting structures <NUM>, or that the supporting structures <NUM> in the second end segment <NUM> are notched more deeply or, in general, more markedly weakened, than in the first end segment <NUM>.

Through the movement of the separating head <NUM> further into the cavity <NUM>, the supporting elements <NUM> are placed against the exterior circumferential surface 110b of the separating head <NUM>. The separating head <NUM> is moved on until the supporting elements <NUM> lie with their second end segment <NUM> at the electrically insulating material <NUM> of the exterior circumferential surface 110b. When the supporting elements <NUM> are broken through, as described above, they are bent in the movement direction P1 of the separating head <NUM>, and are thereby tensioned against the exterior circumferential surface 110b as a result of their elasticity. As can clearly be seen in <FIG>, the supporting structures <NUM>, assuming they are provided with at least two supporting structures <NUM> spaced along a circumference of the auxiliary electrode <NUM>, can support the auxiliary electrode <NUM> against the separating head <NUM>, so that the auxiliary electrode <NUM> can be held at a predetermined distance a4 from the interior surface 1a of the component <NUM> after the separation of the supporting structures <NUM> by the separating head <NUM>.

<FIG> schematically shows an electro-polishing of the interior surface 1a of the component <NUM>. After the additive manufacture of the component <NUM>, the auxiliary electrode <NUM> and the supporting elements <NUM>, and the cutting through of the supporting elements <NUM>, the auxiliary electrode <NUM> can be used as the cathode for the electro-polishing. The component <NUM>, with the auxiliary electrode <NUM> arranged therein, is arranged for this purpose in an electrolyte bath <NUM>, i.e. in a container <NUM> filled with electrolytic liquid <NUM>, as is illustrated schematically in <FIG>. The auxiliary electrode <NUM> can here for example be held, as shown in <FIG>, by the separating head <NUM> which is in turn supported by the supporting elements <NUM>. <FIG> shows by way of example that the separating head <NUM>, as shown in <FIG>, lies with the interior circumferential surface 110a against the circumferential surface 4a of the auxiliary electrode <NUM>. It is, of course, also conceivable that the separating head <NUM>, as shown in <FIG>, lies with the exterior circumferential surface 110b against the interior surface 1a of the component. In this case, the optional passage openings <NUM> are advantageous, since they assist the flow of electrolytic fluid <NUM> in the cavity <NUM> through the opening <NUM>.

To perform the electro-polishing, the auxiliary electrode <NUM> is connected to different poles (+, -) of an electric voltage source U in such a way that the auxiliary electrode <NUM> forms a cathode and the component <NUM> forms an anode. The electric voltage source U can, in particular, be a direct voltage source. During the electro-polishing, an anodic removal of metal material <NUM> takes place at the interior surface 1a of the component <NUM>, whereby this is smoothed. Through the formation of the auxiliary electrode <NUM> during the additive manufacture of the component <NUM>, the auxiliary electrode <NUM> can be placed in cavities <NUM> of the component <NUM> in a simple manner. The auxiliary electrode <NUM> can in particular be positioned very precisely at a predetermined distance a4 from the interior surface 1a which simplifies the electro-polishing and improves the surface quality of the interior surface 1a that is achieved. Through the separation of the supporting elements <NUM> by means of the separating head <NUM>, the precise positioning of the auxiliary electrode <NUM> can be maintained for the electro-polishing in a simple manner.

After the electro-polishing, the auxiliary electrode <NUM> can be removed from the cavity <NUM> of the cavity segment <NUM>, for example by withdrawing using a suitable tool, e.g. with tongs (not illustrated). If the component <NUM> is designed with a plurality of mutually connected cavity segments <NUM>, e.g. as this is illustrated in <FIG> and <FIG>, the auxiliary electrodes <NUM> can be separated from one another at the optional notch <NUM> in a simple manner when removing from the cavities <NUM>. For example, a torsional or bending stress can be applied to the individual electrodes <NUM> in order to achieve a fracture at the respective notch <NUM>. The electrode <NUM>, separated from the remaining auxiliary electrodes <NUM>, can then be withdrawn through the opening <NUM> out of the respective cavity <NUM>.

Claim 1:
Method for the manufacture of a complex component (<NUM>) with following method steps:
constructing the component (<NUM>) from a metal material (<NUM>) in an additive manufacturing method with at least one cavity segment (<NUM>) that has a cavity (<NUM>) open on at least one side and defined by an interior surface (1a) of the component (<NUM>);
forming an auxiliary electrode (<NUM>) during the construction of the component (<NUM>);
forming at least two supporting structures (<NUM>) that connect the auxiliary electrode (<NUM>) to the interior surface (1a) of the component (<NUM>) during the construction of the component (<NUM>);
electrically insulating the auxiliary electrode (<NUM>) from the interior surface (1a) by mechanically separating the at least two supporting structures (<NUM>) from the interior surface (1a) or from the auxiliary electrode (<NUM>), wherein electrically insulating includes:
inserting a separating head (<NUM>) of a separating tool (<NUM>) into an opening (<NUM>), defined by the interior surface (1a), of the cavity (<NUM>) along the auxiliary electrode (<NUM>), wherein the separating head (<NUM>) has an interior circumferential surface (110a) that defines and encloses a longitudinal axis (L100) and, oriented opposite to this, an exterior circumferential surface (110b), and
cutting through the at least two supporting structures (<NUM>) with a separating segment (<NUM>) of the separating head (<NUM>) which, with reference to the longitudinal axis (L100), forms a front end (<NUM>) of the separating head (<NUM>), wherein the separating head (<NUM>) is inserted into the opening (<NUM>) sufficiently far that the at least two supporting structures (<NUM>) lie against an electrically insulating material (<NUM>) forming, at least in segments, the interior circumferential surface (110a) and/or the exterior circumferential surface (110b) with reference to the longitudinal axis (L100); and performing an electro-polishing of the interior surface (1a) in an electrolyte bath (<NUM>) by connecting the component (<NUM>) and the auxiliary electrode (<NUM>) to different poles of an electric voltage source (U) in such a way that the auxiliary electrode (<NUM>) forms a cathode and the component (<NUM>) forms an anode, wherein the separating head (<NUM>) remains arranged in the cavity (<NUM>) during the electro-polishing.