METHOD FOR PRODUCING A COMPONENT HAVING A CAVITY

Abstract

A method for producing an electrically conductive component having a cavity is described. An efficient production method for such a component, which allows a high variability of the wall thickness of the component, is implemented by applying a load-bearing layer consisting of an electrically conductive material to a soluble substrate and then dissolving and at least partially removing the substrate.

Claims

1-17. (canceled)

18. A method for producing an electrically conductive component having a cavity, comprising: applying a load-carrying, fluid-tight layer made of an electrically conductive material onto a soluble substrate, wherein said application of said layer is a thickness of more than 3 micrometers, including more than 20 micrometers, in such a way that the substrate is covered by the layer in a fluid-tight manner, and that thereafter the substrate is dissolved and at least partially removed.

19. The method according to claim 18, further comprising forming the load-carrying, fluid-tight layer in a layer thickness of less than 20 mm, including less than 5 mm.

20. The method according to claim 18, further comprising providing the substrate with a strand-shaped design, and applying the layer to the lateral surface(s) of the substrate on all sides, such that the lateral surface(s) of the substrate is or are covered in a fluid-tight manner.

21. The method according to claim 18, further comprising applying the load-carrying layer to the substrate by applying particles.

22. The method according to claim 18, further comprising at least partially making the substrate of an electrically conductive material, including a metal or an electrically conductive plastic material, or of an electrically insulating material filled with conductive particles.

23. The method according to claim 18, further comprising at least partially making the substrate of an electrically insulating material, including a plastic material, a wax, a ceramic material or a thermoplastic material.

24. The method according to claim 18, further comprising pre-coating the substrate with an electrically conductive pre-coating substance, including a metal, including a metal in the form of microparticles or nanoparticles or a conductive plastic material or carbon, including carbon in the form of graphite or carbon nanotubes, before the load-carrying layer is applied.

25. The method according to claim 18, further comprising applying the load-carrying layer to the substrate by way of a galvanic, including an electrochemical or electroless galvanic method, a PVD coating method, or a CVD coating method.

26. The method according to claim 18, further comprising applying the load-carrying layer to the substrate by way of a plasma spraying process or by immersing the substrate in molten metal.

27. The method according to claim 18, further comprising applying the load-carrying layer to the substrate so as to surround the substrate in a fluid-tight manner on all sides.

28. The method according to claim 18, further comprising detaching the substrate from the load-carrying layer by burning out, dissolution in a solvent, mechanical crushing, chemical decomposition, melting, evaporation or sublimation, and is at least partially removed.

29. The method according to claim 18, further comprising deforming the substrate together with the load-carrying layer after the same has been applied, and including being bent, and thereafter the substrate is at least partially removed.

30. The method according to claim 18, further comprising creating a helical substrate and extending the helical substrate in the longitudinal direction of the helices before the coating is applied, and thereupon is provided with the coating.

31. The method according to claim 18, further comprising deforming, or processed by way of forming, the semi-finished product comprising the substrate and the coating after the coating has been applied to the substrate.

32. The method according to claim 18, further comprising that after the coating has been applied, the semi-finished product comprising the substrate and the coating is deformed into a coil geometry, and is subsequently pressed, so as to calibrate a coil body for an available installation space, and achieve a planar abutment of one turn to the next of the coil body.

33. The method according to claim 18, further comprising twisting or transposing multiple electrically conductive components, which are designed as strand-shaped conductors, with one another, together with the substrate, so as to achieve a reduction in the skin effect, including an insulation of the conductors/electrically conducting components with respect to one another being carried out prior to or after twisting.

34. The method for according to claim 18, further comprising pouring the substrate into a mold coated with a material that adheres to the surface of the substrate and that has such properties that it enables or facilitates the deposition and/or the adhesion of the load-carrying layer on the substrate.

Description

[0057] The invention will be shown and described hereafter based on figures of a drawing. In the drawings:

[0058] FIG. 1 shows a strand-shaped substrate in a perspective view,

[0059] FIG. 2 schematically shows the process of coating,

[0060] FIG. 3 shows a perspective view of a coated substrate,

[0061] FIG. 4 shows the produced component after the substrate has been removed, in a perspective view,

[0062] FIG. 5 shows a winding of a tubular component produced according to the invention,

[0063] FIG. 6 shows a component that was bent prior to the removal of the substrate, and

[0064] FIGS. 7 and 8 show a helical substrate in the extended and compressed states.

[0065] FIG. 1 shows a cylindrical, strand-shaped substrate 1, which is coated within the scope of the method according to the invention. The substrate 1 is a simple example, which can be used for the production of a hollow wound wire having a hollow-cylindrical cross-section.

[0066] The substrate 1 is shown in FIG. 2, wherein arrows 2, 3, 4 indicate that particles, for example atoms, microparticles or nanoparticles or droplets, are applied from the outside onto the surface of the substrate 1. For this purpose, the substrate can optionally have a pre-coating, which can be electrically conducting, for example, so as to be able to use coating methods that require the application of a voltage, or that function, for example, as an electroless galvanic deposition.

[0067] FIG. 3 shows the substrate 1 comprising an applied load-carrying layer 5. The illustration is shown schematically, and the thickness of the layer 5 as well as the ratio of the layer thickness to the diameter of the substrate are only shown by way of example. In many cases, the thickness of the layer/coating 5 will be lower in relation to the diameter of the substrate 1.

[0068] FIG. 4 shows the end product in the form of a hollow tube 5, wherein the substrate 1 is separated from the layer/coating 5 by liquefaction, burning out or removal otherwise.

[0069] FIG. 5 shows a helical coil 6, which is composed of a bent tube 7. This can be produced in the bent shape, as shown in FIG. 5, by way of a similarly shaped substrate having a metal layer applied thereon. However, it is also possible to initially use an extended straight strand-shaped substrate, to coat it, and produce a straight tube thereby. As is shown in FIG. 6, for example, this can be bent together with the coated substrate. After the substrate, together with the coating, has been brought into the desired shape, the substrate can be removed. Such a deformation of the produced tubular component, together with the substrate still present therein, has the advantage that, during the deformation, the cross-section is preserved as a result of being supported by the substrate therein, and bending of the tubular component can be avoided. FIG. 6 optionally, in dotted form, also shows an insulating coating 8 of the electrically conducting layer 5.

[0070] However, it is also conceivable to first remove the substrate from the component, and thereafter deform the hollow component.

[0071] FIG. 7 shows a substrate in the form of a helix shown schematically in a side view, in which, in the relaxed state, the individual turns 9, 10 are located closely together. FIG. 7 shows that the substrate is being extended along the longitudinal axis 11 of the helix by tensile forces 12, 13 prior to the coating process. The substrate may consist of an elastic material, for example an elastic polymer.

[0072] FIG. 8 shows the helix after the coating process, wherein the coating is schematically indicated by the dotted lines 14. The coating can be made of the electrically conductive, load-carrying metal layer, which later forms the conducting component. However, the coating may also comprise an electrically insulating cover layer made of a plastic material or an oxide or another material. FIG. 8 shows a compressed state in the longitudinal direction of the helix, which arises either after the tensile forces 12, 13 have been eliminated, as a result of relaxation of the substrate material, or is actively achieved by the application of compression forces 15, 16 in the longitudinal direction of the helix.

[0073] Two exemplary embodiments will be described hereafter based on specific materials.

Exemplary Embodiment 1

[0074] A wax that is suitable for producing complex structures by way of molding is mixed with a graphite. As a result, electrical conductivity is achieved in the mixture which can be controlled by the proportion of admixed graphite (for example, 1/1000 1/Ohm*cm). The resistance is selected so as to be sufficiently small for the galvanic deposition of a copper sheath on the substrate. The surface structure of the wax-like substrate can also be influenced by the manner in which graphite is admixed. By configuring the surface structure of the substrate, for example setting a particular roughness or unevenness, this shape is transferred to the inner surface of the component formed by the applied layer, so that the flow behavior of a fluid through the hollow component can also be determined.

[0075] A copper sulfate solution can be used for the galvanic deposition, and the component is cathodically polarized. By way of the deposition parameters, the layer thickness of the copper sheath can be varied in a wide range between a few micrometers up to several millimeters.

[0076] After the copper has been deposited, the wax of the substrate is melted out at 120 C. and thus removed.

Exemplary Embodiment 2

[0077] A complex geometric shape of a substrate can initially be produced in a wax injection molding process or by way of a forming process from a tool. In addition to the use of injection molding processes, cutting processes are also conceivable, alternatively and/or additionally.

[0078] The substrate created in this way can be provided with a thin layer of platinum or palladium in a sputtering process so as to create electrical conductivity of the surface of the substrate. Thereupon, the substrate can be galvanically coated with copper. In a subsequent step, the wax/substrate can be melted out of the component by heating.

[0079] The invention makes it possible to produce metallic components that have complex shapes and an inner hollow space, for example in the form of a longitudinal channel, and a variably settable wall thickness. The metallic coating can be carried out using pure metals, such as highest-purity copper or aluminum, so that the best electrical conductivity levels can be achieved. Such materials cannot be easily processed in casting processes or forming processes, without risking damage to the structure, which, among other things, can also result in leakage.

[0080] By way of the method, it is possible to produce tools that are coated with metal from profiled wires, which are cut to the proper dimension in a subsequent process step, and brought by way of forming into the desired geometry, such as a coil.

[0081] It is possible to produce coils or windings, in particular during the production of internally cooled electrical conductors, which enable a considerably increased current density compared to coils/windings of the prior art. In this way, mechanical drives having increased torque density, for example, can be made possible.