Tool electrode for improving electrolytic machining stray corrosion and method of use thereof

Abstract

The application discloses a tool electrode for improving electrolytic machining stray corrosion and a use method thereof, and the tool electrode comprises a metal shaft, an insulating layer and an outer metal sleeve. The method is to synchronously perform an electrochemical reaction by adopting an electrodepositing and electrolytic composite method, and the principle is to utilize trace additive of the electrodepositing to inhibit material removal of a non-machining area of electrolytic machining. When being connected, the electrodepositing and electrolysis form two independent units by connecting different power modules, namely, an electrolytic machining closed loop circuit formed by the metal shaft, a machined part and a pulse power source, and an electrodepositing closed loop circuit formed by the outer metal sleeve, the machined part and a direct current power source. The two units are blocked by the insulating layer. When the pulse power source and the direct current power source are synchronously connected, an anodic corrosion removal occurs in a region corresponding to an end portion of the metal shaft connected to a negative pole of the pulse power source, and the electrodepositing occurs in a region corresponding to an end portion of the outer metal sleeve connected to a positive pole of the direct current power source, so that the stray corrosion of the non-machining area of the machined part is inhibited.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemical machining, in particular to a tool electrode for improving stray corrosion of electrolytic machining and a method of using the same. BACKGROUND

[0002] Stray corrosion is a common phenomenon in electrolytic machining. Due to the influence of the side wall electric field of electrolytic machining, electrochemical corrosion occurs in the non-machining area of the workpiece. Stray corrosion has a great impact on the surface quality of the workpiece. Therefore, it is urgent to study the method of inhibiting stray corrosion, which is also one of the problems to be solved to promote the development of electrolytic machining.

[0003] Electrolytic machining is a non-contact subtractive manufacturing technology based on anode dissolution, which has the characteristics of no machining stress, no metamorphic layer, no tool wear and high machining efficiency. It has been widely used in the field of aerospace, especially in some complex structural parts such as engine disk, casing, etc., which has irreplaceable advantages and application prospects.

[0004] At present, the common method to improve stray corrosion is to directly insulate the side wall of the tool electrode, but stray corrosion still exists. Electrodeposition can protect the surface of the workpiece at the source and further inhibit the occurrence of stray corrosion in the non-machining area.

[0005] Chinese patent CN201610539143.9 discloses a follow-up type auxiliary anode electrolytic wire cutting machining system and method, which belongs to the technical field of electrolytic machining. It comprises a workpiece anode (6), an auxiliary anode (5), an electronic load (8), a tool electrode wire (3), and a machining power supply (7). The auxiliary anode (5) is fixed in position relative to the tool electrode wire (3) and moves with it. The positive electrode of the machining power supply (7) is connected to the auxiliary anode (5) and one end of the electronic load (8), and the negative electrode is connected to the electrode wire (3). The other end of the electronic load (8) is connected to the workpiece anode (6). During the machining process, the potential of the auxiliary anode is higher than that of the workpiece. On the upper and lower surfaces of the workpiece, the potential of the tool electrode is mostly attracted by the auxiliary anode. Therefore, stray corrosion in the non-machining area of the upper and lower surfaces of the workpiece anode is inhibited. However, this patent only insulates the cathode side wall of electrolytic machining. The existing side wall insulation can only improve the machining quality of electrolytic machining, but cannot eliminate the existence of pitting defects from the root. SUMMARY

[0006] The purpose of the present application is to overcome the defects of the prior art and provide a tool electrode for improving electrolytic machining stray corrosion and a method thereof, which mainly integrates the electrodeposition technology on the tool electrode of electrolytic machining to realize material removal and protection of non-machining surface simultaneously, and in order to realize continuous protection of the non-machining area, a continuous discharge DC power source can be used as the energy source of electrodeposition, and in terms of improving the surface quality of the machining area, the electrolytic machining can use a pulse power source to realize material removal; so as to solve the defect of stray corrosion existing on the non-machining surface of electrolytic machining, and the related additive manufacturing technology is used for electrochemical deposition to react in the form of ions, and material accumulation is realized on the non-machining surface to achieve the purpose of protecting the non-machining surface.

[0007] The purpose of the present application can be achieved by the following technical solutions:

[0008] A tool electrode for improving electrolytic machining stray corrosion, comprising a metal shaft, an insulating layer and an outer metal sleeve, the metal shaft and the outer metal sleeve are provided with an insulating layer, the metal shaft is connected with the negative electrode of a pulse power source during use, the outer metal sleeve is connected with the positive electrode of a DC power source during use, and the positive electrode of the pulse power source and the negative electrode of the DC power source are used to connect a workpiece.

[0009] Further, the metal shaft and the negative electrode of the pulse power source are connected through a wire, the outer metal sleeve and the positive electrode of the DC power source are connected through a wire, the positive electrode of the pulse power source and the workpiece are connected through a wire, and the negative electrode of the DC power source and the workpiece are connected through a wire.

[0010] Further, the tool electrode and the workpiece are connected by an electrolytic machining salt solution.

[0011] Further, the metal ions in the electrolytic machining salt solution are selected from copper, nickel, zinc, chromium or tin.

[0012] Further, the metal shaft material is an electrolytic machining cathode material.

[0013] Further, the metal shaft material is selected from copper, tungsten or stainless steel.

[0014] Further, the insulating layer material is a non-metallic material.

[0015] Further, the insulating layer material is selected from organic glass, silica gel or epoxy resin.

[0016] Further, the outer metal sleeve material is a metal corresponding to the metal ions in the electrolytic machining salt solution.

[0017] Further, the outer metal sleeve material is selected from a copper, nickel, zinc, chromium or tin layer.

[0018] Further, the thickness of the insulation layer is 0.05-0.15 mm.

[0019] Further, the thickness of the insulation layer is 0.05-0.15 mm.

[0020] Further, the metal shaft is a cylindrical metal shaft, and the insulation layer uniformly covers the surface of the cylindrical metal shaft.

[0021] Further, the metal shaft is a cylindrical metal shaft, and the insulation layer uniformly covers the surface of the cylindrical metal shaft.

[0022] Further, the metal shaft is a cylindrical metal shaft, and the insulation layer uniformly covers the surface of the cylindrical metal shaft.

[0023] Further, the metal shaft is a cylindrical metal shaft, and the insulation layer uniformly covers the surface of the cylindrical metal shaft.

[0024] S1, the positive electrode of the direct current power supply is connected to the outer metal sleeve, and the negative electrode of the direct current power supply is connected to the workpiece, forming a closed loop circuit of electrodeposition;

[0025] S2, the positive electrode of the pulse power supply is connected to the workpiece, and the negative electrode of the pulse power supply is connected to the metal shaft, forming a closed loop circuit of electrochemical machining;

[0026] S3, the pulse power supply and the direct current power supply are turned on at the same time, and the electrodeposition and the electrochemical machining are reacted in the electrochemical machining salt solution;

[0027] S4, the area corresponding to the end of the metal shaft connected to the negative electrode of the pulse power supply is anodically etched, and the area corresponding to the end of the outer metal sleeve connected to the positive electrode of the direct current power supply is electrodeposited, thereby inhibiting the stray corrosion of the non-machining area of the workpiece.

[0028] A tool electrode for improving the stray corrosion of difficult-to-machine materials in electrochemical machining has the following principle:

[0029] The electrodeposition and the electrochemical machining are simultaneously carried out by using the method of electrodeposition and electrochemical deposition, and the trace additive of the electrodeposition is used to inhibit the material removal of the non-machining area of the electrochemical machining; when the wires are connected, the electrodeposition and the electrochemical machining form two independent units by connecting different power supply modules, i.e., the electrochemical machining closed loop circuit formed by the metal shaft, the workpiece and the pulse power supply, and the electrodeposition closed loop circuit formed by the outer metal sleeve, the workpiece and the direct current power supply, and the two units are blocked by the insulation layer; when the pulse power supply and the direct current power supply are turned on at the same time, the electrochemical machining and the electrodeposition share a set of electrochemical solution system, the area corresponding to the end of the metal shaft connected to the negative electrode of the pulse power supply is anodically etched, and the area corresponding to the end of the outer metal sleeve connected to the positive electrode of the direct current power supply is electrodeposited, thereby blocking the material dissolution of the non-machining area of the electrochemical machining, and effectively inhibiting the stray corrosion of the non-machining area of the workpiece.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] (1) The tool electrode provided by the present application is integrated by an electrodeposited tool and an anode metal shaft of electrolytic machining through an intermediate insulating layer, and the method provided integrates electrodeposition and electrolytic machining by using different power sources to perform electrochemical reactions synchronously, so as to not only realize material removal of a machining area, but also inhibit the occurrence of stray corrosion of a non-machining area from the source;

[0032] (2) The present application first proposes to directly act on the non-machining area by using electrodeposition to perform protection, and the existing side wall insulation can only improve the machining quality of electrolytic machining, and cannot eliminate the existence of pitting defects from the root;

[0033] (3) The device has simple structure and is convenient to implement, and is suitable for improving the surface quality of electrolytic machining and will not cause pitting to reduce the surface quality of a workpiece;

[0034] (4) The present application has universal applicability for electrolytic machining of metal parts and is suitable for machining of various surface structures. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The present application is a structural schematic diagram and a machining principle diagram.

[0036] The reference signs are explained as follows: 1, a workpiece, 2, an outer metal sleeve, 3, a pulse power source, 4, an insulating layer, 5, a metal shaft, 6, a direct current power source, and 7, an electrolytic machining salt solution. DETAILED DESCRIPTION

[0037] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0038] A tool electrode for improving stray corrosion of electrolytic machining includes a metal shaft 5, an insulating layer 4 and an outer metal sleeve 2, the metal shaft 5 and the outer metal sleeve 2 are provided with the insulating layer 4, the metal shaft 5 is connected with a negative electrode of a pulse power source 3 in use, the outer metal sleeve 2 is connected with a positive electrode of a direct current power source 6 in use, and a positive electrode of the pulse power source 3 and a negative electrode of the direct current power source 6 are connected with a workpiece 1.

[0039] Further, the metal shaft 5 is connected with the negative electrode of the pulse power source 3 through a wire, the outer metal sleeve 2 is connected with the positive electrode of the direct current power source 6 through a wire, the positive electrode of the pulse power source 3 is connected with the workpiece 1 through a wire, and the negative electrode of the direct current power source 6 is connected with the workpiece 1 through a wire.

[0040] Further, the tool electrode and the workpiece 1 are connected with an electrolytic machining salt solution 7. Further, the tool electrode and the workpiece 1 are connected with an electrolytic machining salt solution 7.

[0041] Furthermore, the metal ions in the electrolytic processing salt solution 7 are selected from copper, nickel, zinc, chromium, or tin.

[0042] Furthermore, the metal shaft 5 is made of an electrolytic machining cathode material.

[0043] Furthermore, the metal shaft 5 is made of copper, tungsten, or stainless steel.

[0044] Furthermore, the insulating layer 4 is made of a non-metallic material.

[0045] Furthermore, the insulating layer 4 is made of acrylic glass, silicone, or epoxy resin.

[0046] Furthermore, the outer metal sleeve 2 is made of the metal corresponding to the metal ions in the electrolytic processing salt solution 7.

[0047] Furthermore, the outer metal sleeve 2 is made of copper, nickel, zinc, chromium, or tin.

[0048] Furthermore, the thickness of the insulating layer 4 is 0.05 to 0.15 mm.

[0049] Furthermore, the thickness of the insulating layer 4 is 0.1 mm.

[0050] Furthermore, the metal shaft 5 is a cylindrical metal shaft, and the insulating layer 4 is uniformly wrapped around the surface of the cylindrical metal shaft.

[0051] Furthermore, the insulating layer 4 is wrapped around the metal shaft 5 at a height that is higher than the height of the outer metal sleeve 2.

[0052] Furthermore, the outer metal sleeve 2 and the maximum outer diameter of the insulating layer 4 form a minimum interference fit.

[0053] Furthermore, the present invention also provides a method for using a tool electrode to improve stray corrosion in electrolytic machining, the specific steps of which are as follows:

[0054] S1. Connect the positive terminal of DC power supply 6 to the outer metal sleeve 2 and the negative terminal of DC power supply 6 to the workpiece 1 to form a closed loop of electrodeposition.

[0055] S2. Connect the positive terminal of the pulse power supply 3 to the workpiece 1 and the negative terminal of the pulse power supply 3 to the metal shaft 5 to form a closed-loop circuit for electrolytic machining.

[0056] S3. Simultaneously turn on the pulse power supply 3 and the DC power supply 6. Both electrodeposition and electrolytic processing are carried out in the electrolytic processing salt solution 7.

[0057] S4, the region corresponding to the end of the metal shaft 5 connected to the negative pole of the pulse power source 3 is anode-etched, the region corresponding to the end of the outer metal sleeve 2 connected to the positive pole of the direct current power source 6 is electrodeposited, and the stray corrosion of the non-processed region of the processed piece 1 is inhibited.

[0058] The application will be described in detail below with reference to the drawings and specific embodiments.

[0059] Embodiment 1

[0060] Referring to Figure 1 , the embodiment provides a tool electrode for improving stray corrosion in electrolytic processing, which comprises a metal shaft 5, an insulating layer 4 and an outer metal sleeve 2, the metal shaft 5 and the outer metal sleeve 2 are provided with the insulating layer 4, the metal shaft 5 is connected to the negative pole of the pulse power source 3 in use, the outer metal sleeve 2 is connected to the positive pole of the direct current power source 6 in use, and the positive pole of the pulse power source 3 and the negative pole of the direct current power source 6 are connected to the processed piece 1.

[0061] In the embodiment, the metal shaft 5 is connected to the negative pole of the pulse power source 3 through a wire, the outer metal sleeve 2 is connected to the positive pole of the direct current power source 6 through a wire, the positive pole of the pulse power source 3 is connected to the processed piece 1 through a wire, and the negative pole of the direct current power source 6 is connected to the processed piece 1 through a wire.

[0062] In the embodiment, the electrolytic processing salt solution 7 is between the tool electrode and the processed piece 1.

[0063] In the embodiment, the metal ions in the electrolytic processing salt solution 7 are copper.

[0064] In the embodiment, the material of the metal shaft 5 is copper.

[0065] In the embodiment, the material of the insulating layer 4 is epoxy resin.

[0066] In the embodiment, the material of the outer metal sleeve 2 is copper.

[0067] In the embodiment, the thickness of the insulating layer 4 is 0.1mm.

[0068] In the embodiment, the metal shaft 5 is a cylindrical metal shaft, and the insulating layer 4 is uniformly wrapped on the surface of the cylindrical metal shaft.

[0069] In the embodiment, the height of the insulating layer 4 wrapped on the metal shaft 5 in the axial direction is higher than the height of the outer metal sleeve 2.

[0070] In the embodiment, the maximum outer diameter of the outer metal sleeve 2 and the insulating layer 4 forms a minimum interference fit.

[0071] Furthermore, the embodiment also provides a use method of the tool electrode for improving stray corrosion of electrolytic machining, and specific steps are as follows:

[0072] S1, the positive pole of the direct current power supply 6 is connected to the outer metal sleeve 2, and the negative pole of the direct current power supply 6 is connected to the workpiece 1, so as to form a closed loop circuit of electrodeposition;

[0073] S2, the positive pole of the pulse power supply 3 is connected to the workpiece 1, and the negative pole of the pulse power supply 3 is connected to the metal shaft 5, so as to form a closed loop circuit of electrolytic machining;

[0074] S3, the pulse power supply 3 and the direct current power supply 6 are turned on at the same time, and the electrodeposition and the electrolytic machining are reacted in the electrolytic machining salt solution 7;

[0075] S4, the region corresponding to the end of the metal shaft 5 connected to the negative pole of the pulse power supply 3 is subjected to anodic etching, the region corresponding to the end of the outer metal sleeve 2 connected to the positive pole of the direct current power supply 6 is subjected to electrodeposition, and the stray corrosion of the non-machining region of the workpiece 1 is inhibited.

[0076] The application has certain universal applicability, for example: if the workpiece is stainless steel 304, the metal shaft can be selected from commonly used tungsten rods, copper rods and stainless steel as the cathode of electrolytic machining, the insulating layer can be selected from non-conductive insulating materials such as organic glass and epoxy resin, in the electrodeposition system, the anode can be selected from metal, for example, copper, and the corresponding electrodeposition and electrolytic machining salt solution is the salt solution corresponding to the electrodeposition anode metal, for example, a mixture of copper sulfate and sulfuric acid.

[0077] The purpose of the application is to solve the stray corrosion phenomenon commonly existing in electrolytic machining, not only for fixed machining objects, in the electrolytic machining system, the cathode is fixed, in most cases, tungsten steel, red copper or stainless steel is mainly used, in the electrochemical deposition system, the electrodeposition metal cathode and the corresponding salt solution need to be considered at the same time, and it is necessary to ensure that the salt solution can be completely ionized.

[0078] The electrochemical deposition and the electrolytic machining are two independent reaction systems, when the reactions are realized at the same time, there is no material dissolution blocking efficiency, the electrodeposition will occur in the region corresponding to the anode end face, thereby directly blocking the corrosion of the electrolytic machining.

[0079] The above description of the embodiments is for the convenience of the ordinary skilled person in the technical field to understand and use the application. Those skilled in the art can obviously easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without having to undergo creative labor. Therefore, the application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the application should be within the protection scope of the application.

Claims

1. A tool electrode for improving electrolytic machining stray corrosion, characterized by It comprises a metal shaft (5), an insulating layer (4) and an outer metal sleeve (2), the metal shaft (5) is provided with the insulating layer (4) between the outer metal sleeve (2), the metal shaft (5) is connected with the negative pole of the pulse power (3) in use, the outer metal sleeve (2) is connected with the positive pole of the direct current power (6) in use, the positive pole of the pulse power (3) and the negative pole of the direct current power (6) are used for connecting the workpiece (1); When the pulse power (3) and the direct current power (6) are synchronously turned on, the electrolytic machining and the electrodeposition share a set of electrochemical solution system, the end of the metal shaft (5) connected with the negative pole of the pulse power (3) is subjected to the anodic etching of the workpiece (1), the end of the outer metal sleeve (2) connected with the positive pole of the direct current power (6) is synchronously subjected to the electrodeposition, the material dissolution of the non-machining area of the workpiece (1) is blocked, and then the stray corrosion of the non-machining area of the workpiece (1) is effectively inhibited.

2. A tool electrode for improving stray corrosion in electrochemical machining according to claim 1, characterized in that The metal shaft (5) is connected with the negative pole of the pulse power (3) through a wire, the outer metal sleeve (2) is connected with the positive pole of the direct current power (6) through a wire, the positive pole of the pulse power (3) is connected with the workpiece (1) through a wire, and the negative pole of the direct current power (6) is connected with the workpiece (1) through a wire, The tool electrode and the workpiece (1) are connected through an electrolytic machining salt solution (7), and metal ions in the electrolytic machining salt solution (7) are selected from copper, nickel, zinc, chromium or tin.

3. A tool electrode for improving electrolytic machining stray corrosion according to claim 2, characterized in that The metal shaft (5) is made of an electrolytic machining cathode material. The insulating layer (4) is made of a non-metal material. The outer metal sleeve (2) is made of a metal corresponding to metal ions in the electrolytic machining salt solution (7).

4. A tool electrode for improving electrolytic machining stray corrosion according to claim 3, characterized in that The metal shaft (5) is made of copper, tungsten or stainless steel. The insulating layer (4) is made of organic glass, silica gel or epoxy resin. The outer metal sleeve (2) is made of a copper, nickel, zinc, chromium or tin layer.

5. A tool electrode for improving stray corrosion in electrochemical machining according to claim 1, wherein The thickness of the insulating layer (4) is 0.05-0.15 mm.

6. A tool electrode for improving electrolytic machining stray corrosion according to claim 5, characterized in that The thickness of the insulating layer (4) is 0.1 mm.

7. A tool electrode for improving electrolytic machining stray corrosion according to claim 1, wherein The metal shaft (5) is a cylindrical metal shaft, and the insulating layer (4) is wrapped on the surface of the cylindrical metal shaft.

8. A tool electrode for improving electrolytic machining stray corrosion according to claim 7, characterized in that The height of the insulating layer (4) wrapped on the metal shaft (5) in the axial direction is higher than the height of the outer metal sleeve (2).

9. A tool electrode for improving electrolytic machining stray corrosion according to claim 1, wherein The outer diameter of the outer metal sleeve (2) and the insulating layer (4) forms a minimum interference fit.

10. A method of using a tool electrode for improving stray corrosion in electrochemical machining according to any one of claims 1 to 9, characterized in that The specific steps are as follows: S1, the positive pole of the direct current power (6) is connected to the outer metal sleeve (2), and the negative pole of the direct current power (6) is connected to the workpiece (1), forming a closed loop circuit for electrodeposition; S2, the positive pole of the pulse power (3) is connected to the workpiece (1), and the negative pole of the pulse power (3) is connected to the metal shaft (5), forming a closed loop circuit for electrolytic machining; S3, the pulse power (3) and the direct current power (6) are turned on at the same time, and the electrodeposition and the electrolytic machining are both reacted in the electrolytic machining salt solution (7). S4, the region corresponding to the end of the metal shaft (5) connected to the negative pole of the pulse power supply (3) is anodically etched, and the region corresponding to the end of the outer metal sleeve (2) connected to the positive pole of the direct current power supply (6) is electrodeposited, thereby inhibiting stray corrosion of the non-processed region of the workpiece (1).

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