DEVICE AND METHOD FOR ELECTROPOLISHING BY MEANS OF A CONDUCTIVE SURFACE

Abstract

The invention describes a device for electropolishing by means of a conductive surface (1) which contacts a metal part (2) to be polished, with a relative movement being caused between the conductive surface (1) and the metal part (2) to be polished, and wherein the part (2) is connected to the power source (3) and the conductive surface (1) is connected to an electrode (4). The invention also describes a method for electropolishing which comprises: a step of polishing, wherein a conductive surface (1) contacts a metal part (2) to be polished, with a relative movement being caused between both, and wherein the part (2) is connected to the power source (3) and the conductive surface (1) is connected to an electrode (4); and a step of regenerating the conductive surface (1), wherein the conductive surface (1) which has been in contact with the part in the step of polishing is regenerated or replaced.

Claims

1. A device for electropolishing by means of a conductive surface which, applicable for polishing the surface of a metal part (2), comprises: a power source (3); an electrode (4); a conductive surface (1); a system that provides electrical connectivity to the metal part (2) to be polished at a pole of the power source (3); a system that provides electrical connectivity to the conductive surface (1) at the opposite pole of the power source (3); and a system that provides relative movement of the conductive surface (1) with respect to the metal part (2) to be polished, wherein the electrode (4) contacts one side of the conductive surface (1) and the part (2) to be polished can be brought into contact with the conductive surface (1) on the other side, such that a polishing effect occurs when the power source (3) applies a potential difference between the part (2) to be polished and the electrode (4), characterized in that the conductive surface (1) is manufactured with a non-conductive material that retains a conductive liquid solution, such that the conductive surface has an electrical conductivity that can be measured between the two sides of the material.

2. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that the conductive surface (1) adopts a rolling conveyor belt-type configuration and the system that provides relative movement of the conductive surface (1) with respect to the part (2) to be polished comprises two or more drums on which the conductive surface (1) is mounted, with a motor (M) that provides rotational movement to the belt.

3. The device for electropolishing by means of a conductive surface according to claim 2, characterized in that the conductive surface (1) adopts a continuous belt configuration.

4. The device for electropolishing by means of a conductive surface according to claim 2, characterized in that the conductive surface (1) adopts a configuration in which it is initially wound in a drum, arranged so that it can be wound in a second drum.

5. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that the system that provides relative movement of the conductive surface (1) with respect to the part (2) to be polished is a system that provides a circular, orbital, circular translational, rotating, or linear oscillating movement of a flat conductive surface (1).

6. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that the conductive surface (1) is made of a solid electrolyte-type material, such that the conductive surface has an electrical conductivity that can be measured between the two sides of the material.

7. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that the conductive liquid solution contains at least one strong acid.

8. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that the conductive liquid solution contains sulfuric acid, methanesulfonic acid, phosphoric acid, citric acid, EDTA, polyethers, or polyethylene glycol.

9. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that the conductive liquid solution is an emulsion.

10. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that the conductive liquid solution contains complexing agents.

11. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that the conductive surface (1) is made of a porous polymer material with functional groups capable of retaining and transporting metal ions, said groups consisting of sulfonic acid/sulfonate, carboxylic acid/carboxylate, or chelating functional groups.

12. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that it comprises a system for partially or completely regenerating or exchanging the conductive liquid solution retained on the conductive surface (1) which includes a pressure system between two drums, the application of temperature, or the application of dry air.

13. The device for electropolishing by means of a conductive surface according to claim 1, characterized in that the system that provides relative movement of the conductive surface (1) with respect to the metal part (2) to be polished comprises means for moving the conductive surface (1) with respect to the metal part (2).

14. A method for electropolishing by means of a conductive surface which comprises the following steps: a step of polishing, in which a conductive surface (1) contacts a metal part (2) to be polished, with a relative movement being caused between the conductive surface (1) and the metal part (2) to be polished, and wherein the part (2) is connected to the power source (3) and the conductive surface (1) is connected to an electrode (4) a step of regenerating or replacing the conductive surface (1), in which the conductive surface (1) which has been in contact with the part in the preceding step of polishing is regenerated or replaced so that the conductive surface maintains sufficient conductivity during the step of polishing, characterized in that it further comprises a step of impregnating the conductive surface (1) with a liquid electrolyte that is retained on said conductive surface (1).

15. The method for electropolishing by means of a conductive surface according to claim 14, characterized in that the step of regenerating or replacing the conductive surface comprises the following sub-steps completely or partially eliminating the liquid electrolyte used adding new liquid electrolyte.

Description

DESCRIPTION OF THE DRAWINGS

[0050] To complement the description that is being made and for the purpose of aiding to better understand the features of the invention, a drawing is attached to the present specification as an integral part thereof, in which the following is depicted in an illustrative and non-limiting manner:

[0051] FIG. 1, which is the only FIGURE, shows a schematic depiction of an embodiment of the device for electropolishing by means of a conductive surface object of the invention, where the main parts and elements which it comprises can be seen.

PREFERRED EMBODIMENT OF THE INVENTION

[0052] In view of the described FIGURE and according to the numbering used therein, a non-limiting embodiment of the device for electropolishing by means of a conductive surface of the invention, which comprises what is described in detail below, can be seen.

[0053] In that sense, as can be seen in said FIGURES, the device (10) of the invention basically comprises: [0054] a power source (3); [0055] an electrode (4); [0056] a conductive surface (1) [0057] a system that provides electrical connectivity to the metal part (2) to be polished at a pole of the power source (3); [0058] a system that provides electrical connectivity to the conductive surface (1) at the opposite pole of the power source (3); and [0059] a system that provides relative movement of the conductive surface (1) with respect to the metal part (2) to be polished, [0060] wherein the electrode (4) contacts one side of the conductive surface (1) and the part (2) to be polished can be brought into contact with the conductive surface (1) on the other side, such that a polishing effect occurs when the power source (3) applies a potential difference between the part (2) to be polished and the electrode (4).

[0061] The system that provides relative movement of the conductive surface (1) with respect to the metal part (2) to be polished can be, for example, by means of a rolling conveyor, as described below, or consist of a circular, orbital, circular translational, rotating, or linear oscillating movement of a flat conductive surface (1).

[0062] FIG. 1 shows a schematic depiction of a preferred embodiment option of the device (10) of the invention, wherein the conductive surface (1) adopts a rolling conveyor belt-type configuration which comprises two or more drums on which the conductive surface (1) is mounted in the form of a continuous belt, with a motor (M) that provides rotational movement to the belt.

[0063] Alternatively, the conductive surface (1) adopts a configuration that can be compared to a VHS or a cassette. Initially, the conductive surface (1) is wound in a drum, arranged so that it can be wound in a second drum. The segment of the conductive surface (1) stretched between both drums is used for the polishing process. A motor (M) provides movement for the belt. This device successively winds and unwinds a certain length of the belt, causing the belt to move back and forth. When the conductive surface (1) of this certain length of the belt is saturated, working with the subsequent segment occurs. In this way, working with a conductive surface (1) is always performed in optimal conditions.

[0064] In turn, the part to be polished (2) is connected to the power source (3) and arranged such that it contacts the conductive surface (1).

[0065] The opposite pole of the power source (3) is connected to an electrode (4). In an embodiment option, the electrode (4) can be a flat element which is arranged in contact with the belt which constitutes the conductive surface (1) as shown in FIG. 1, although, alternatively, it can be a conductive drum that acts as an electrode (4).

[0066] In one embodiment of the invention, the conductive surface (1) is made of a solid electrolyte-type material. For example, conductive surfaces based on ionomeric polymers, Nafion, Hycar, ion exchange membranes, polystyrene sulfonate, sulfonated styrene and divinylbenzene copolymer, gel-type structures including polyether chains, among others.

[0067] In another embodiment variant of the invention, the conductive surface (1) is a fabric, sheet, membrane, paper, polymer, cloth, cardboard, bundle of fibers, or other material with comparable characteristics that retains a conductive liquid solution, such that the conductive surface has an electrical conductivity that can be measured between the two sides of the material.

[0068] Said conductive liquid solution preferably contains at least one strong acid, and it is preferably an aqueous solution. Strong acids improve the elimination of the metal oxides formed on the surface. Strong acids of preferred use are sulfuric acid or a sulfonic acid such as, for example, methanesulfonic acid or toluenesulfonic acid.

[0069] The conductive solution can contain phosphoric acid since it produces passive phosphate layers on the treated surfaces, which improves anti-corrosion resistance.

[0070] The conductive solution can be an emulsion of an organic phase in a polar phase or vice versa. The advantages of using emulsions as a conductive phase is the formation of structured layers on the metal surface to be polished, which allows obtaining very low final roughness.

[0071] The conductive solution can include one or more complexing agents or chelating agents. These compounds favor the dissolution of metal ions, so they contribute to a more effective dissolution of the oxides formed on the metal surface. Among chelating agents of preferred use are citric acid, EDTA, polyethers such as, for example, polyethylene glycol, among others.

[0072] Furthermore, in this second embodiment, although not depicted, the device comprises a system for partially or completely regenerating or exchanging the conductive liquid solution retained on the conductive surface (1).

[0073] In the preferred embodiment, the conductive surface (1) is made of a porous polymer material with functional groups capable of retaining and transporting metal ions. Preferably, these functional groups are sulfonic acid/sulfonate, carboxylic acid/carboxylate groups, or chelating functional groups. The presence of these groups facilitates ion retention, such that the concentration of metal ions in the retained liquid electrolyte is kept relatively low and the quality of the polishing process is maintained over time.

[0074] Preferably, the described device (10) is a portable device, such that it is movable, and the part (2) to be polished is static. In this embodiment, the system that provides relative movement of the conductive surface (1) with respect to the metal part (2) to be polished comprises means for moving the conductive surface (1) with respect to the metal part (2) that remains stationary.

[0075] However, in an alternative embodiment, it also can be a fixed device (10), i.e., it does not move, with the part (2) to be polished being that which moves closer to the moving belt constituting the conductive surface (1). In this embodiment, the system that provides relative movement of the conductive surface (1) with respect to the metal part (2) to be polished comprises means for moving the metal part (2) with respect to the conductive surface (1) which is stationary.

[0076] It is also envisaged for the relative movement of the part (2) with respect to the conductive surface (1) to occur by means of the use of a robotic arm, which would allow the automatic application of complex shapes in the process.

[0077] Having sufficiently described the nature of the present invention, as well as the way of putting it into practice, it is not considered necessary to further expand on its explanation so that any expert in the field can understand its scope and the advantages derived from it.