CN114473088A

CN114473088A - Discrete revolving body tool electrode for rotary printing electrolytic machining and method thereof

Info

Publication number: CN114473088A
Application number: CN202210216359.7A
Authority: CN
Inventors: 王登勇; 周烁方; 曹文见; 朱荻
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2022-03-07
Filing date: 2022-03-07
Publication date: 2022-05-13
Anticipated expiration: 2042-03-07
Also published as: CN114473088B

Abstract

The invention relates to a discrete revolving body tool electrode for spin-printing electrolytic machining and a method thereof, belonging to the field of electrolytic machining in the manufacturing technology. The device and the method are as follows: the tool cathode is in a discrete type, the whole body is equally divided into n blocks, each block is mutually insulated and fixed together by adopting an insulating base material; the workpiece is connected with the positive electrode of a power supply, the electric brush is connected with the negative electrode of the power supply, one or two tool electrodes are conducted at one time through the electric brush, and the rest electrode blocks are not electrified; the tool cathode rotates and feeds at a constant speed, the electric brush is fixed above the processing area and does not rotate to feed along with the constant speed of the tool cathode, so that the tool cathode block which is conducted every time can be ensured to be positioned in the processing area, the stray current of a non-processing area is greatly reduced by controlling the range of an electric field area, and the forming precision of the rotary printing electrolytic processing is improved; the method and the device have important significance for improving the surface quality of the electrolytic machining of the boss on the surface of the revolving body and the boss forming precision.

Description

Discrete revolving body tool electrode for rotary printing electrolytic machining and method thereof

Technical Field

A discrete revolving body tool electrode for rotary printing electrolytic machining and a method thereof belong to the field of electrolytic machining in manufacturing technology.

Background

In industrial production, there are many parts of a rotary body such as a roll in a roll forming process, an automobile piston ring, a stamp die, an aircraft engine case, and the like, among which the aircraft engine case part is the most typical. The casing is the most important part of an aircraft engine and plays a key role in the performance of the engine. The aeroengine casing is a large annular thin-walled part, the wall thickness is usually 2-3 mm, the local wall thickness is even less than 1 mm, and the aeroengine casing is made of a difficult-to-machine material and is a part with the most complex shape and structure and the largest machining difficulty in the aeroengine. Aiming at the structural characteristics of a cartridge receiver part, a rotary printing electrolytic processing technology is provided by the professor of Zhu Di Huang of Nanjing aerospace university. The technology can realize one-time processing and forming of a complex molded surface by only using a single revolving body tool electrode, thereby overcoming the problems that the traditional electrolytic machining tool is difficult to design, needs to subsequently remove 'tool connecting marks' and 'water outlet marks', has low machining precision and the like, and realizing the efficient, high-quality and low-cost electrolytic machining of the casing.

Stray corrosion is a common problem in electrolytic machining, cannot be avoided in spin-printing electrolytic machining, and is usually positioned in non-machining areas on two sides of a machining area, so that the forming precision and the surface quality of electrolytic machining are seriously influenced. In recent years, researchers have proposed solutions to inhibit stray corrosion during electrolytic processing. In a patent ' profile electrochemical machining composite magnetic field device ' (applicant's western ampere industry institute of applicant ' 200320109822.0 applicant, inventor's standard-planting ma baogoshui lingjiali), the finish machining problem of the complex profile electrochemical machining is effectively solved by combining the magnetic field and the electrochemical machining. In a patent of a micro-fine group pit electrolytic machining method adopting a bipolar electrode and the bipolar electrode thereof (Nanjing aerospace university, inventor Zhu Diqu Ningsong Shuangqing plum winter forest, application number 200810022327.3), the group pit electrolytic machining is carried out by adopting an electrode with positive and negative polarities, and the stray current of the side wall of the pit is reduced by utilizing an auxiliary electrode with positive electricity, so that the electrolytic machining precision is improved. In a patent "auxiliary electrode device and method for electrochemical machining of a boss on the surface of a revolving body" (the university of aerospace in Nanjing of the applicant of application No. 201910827937.9, inventor Wang Dangyong Zhang Cao wen who went on and went on Li jin), an auxiliary electrode with positive potential difference is adopted to suppress stray current so as to improve machining precision.

In the above patents, the electric field distribution is improved by adding auxiliary devices, which not only results in a complex system but also has low versatility. Therefore, there is a need to design a new tool cathode with strong versatility to fundamentally change the electric field distribution and eliminate stray corrosion.

Disclosure of Invention

The invention aims to design a discrete revolving body tool electrode and a method thereof, which can effectively inhibit the stray corrosion of the surface of a revolving body workpiece in the rotary printing electrolytic machining, and improve the forming precision and the surface quality of the electrolytic machining.

A discrete rotary body tool electrode for spin-printing electrochemical machining, comprising: comprises a workpiece anode, a tool cathode, an insulating matrix, an anode shaft, a cathode shaft, a fixing ring, an electric brush and a power supply; the workpiece anode is arranged on the anode shaft, the tool cathode is arranged on the cathode shaft through an insulating matrix, the tool cathode is a revolving body and is equally divided into n blocks, and insulating materials are coated between the blocks to be insulated from one another; the surface of the tool cathode is provided with a cathode window; the electric brush is positioned above the processing area, the electric brush is tightly contacted with the upper end face of the tool cathode, and the electric brush is fixed on the cathode shaft through a fixing ring; the fixing ring is made of non-conductive insulating materials and insulates the electric brush from the cathode shaft; the anode of the workpiece is connected with the positive pole of a power supply, the cathode of the tool is connected with the negative pole of the power supply through an electric brush, and the cathode of the tool is made of a material which is difficult to dissolve in electrochemical reaction or inert metal is coated on the surface of the cathode of the tool.

The electrolytic method using the discrete rotary body tool electrode for the spin-printing electrolytic machining is characterized by comprising the following processes: the cathode shaft and the anode shaft relatively rotate in opposite directions at the same angular speed; the workpiece anode surface boss is gradually generated under the opposite direction relative rotation motion of the workpiece anode and the tool cathode at the same angular speed and the feeding motion of the tool cathode, and the generation position of the boss corresponds to the cathode window on the surface of the tool cathode; in the processing process, the cathode block of the tool cathode in the processing area is conducted with the negative pole of the power supply through the electric brush; the cathode blocks in the non-processing area are all in an insulated state, so that the stray current on the surfaces of the rotary surfaces and the lug bosses on the two sides of the workpiece anode processing area is completely eliminated; during the machining process, the electric brush and the cathode of the tool are together subjected to a feeding motion to the anode of the workpiece at a constant speed through the fixing ring.

The invention has the beneficial effects that:

(1) by controlling the power supply area of the tool cathode, the electric field distribution can be effectively improved, and the stray current on the surfaces of the rotary surfaces and the bosses on the two sides of the workpiece anode processing area can be eliminated, so that the workpiece anode material is only dissolved in the processing area within the power-on range of the tool cathode, and the dissolving localization and boss forming precision of electrolytic processing are greatly improved.

(2) The equal parts n of the tool cathode can be dynamically adjusted according to the boss precision, so that the cathode manufacturing difficulty and cost are greatly reduced.

(3) The used discrete tool cathodes can be combined for use, and only part of the cathode block needs to be replaced when the machined workpiece anode lug boss changes, so that the method has good economical efficiency and practical application value.

(4) The local power supply mode adopted by the invention compresses the area of the processing area, the flow field is easy to control, the product is fully discharged, and the processing is more stable.

(5) The cathode block of the tool cathode in the processing area and the cathode block in the non-processing area have a potential difference during the processing, and corrosion phenomena can occur, so the tool cathode needs to adopt a material which is difficult to dissolve in the electrochemical reaction, such as graphite or an inert metal material, or to coat the surface of the tool cathode with an inert metal, and the like.

Drawings

FIG. 1 is a schematic view of a discrete rotary body tool electrode for suppressing stray corrosion in rotary imprint electrolytic processing;

FIG. 2 is a graph of the electric field distribution across the surface of a workpiece anode using a discrete rotary body tool electrode;

FIG. 3 is a graph of the electric field profile of the surface of the anode of a workpiece without the use of a discrete rotary body tool electrode;

number designation in the figures: 1. insulating base member, 2, tool cathode, 3, solid fixed ring, 4, negative pole axle, 5, brush, 6, power, 7, negative pole axle, 8, work piece positive pole, 9, boss, 10, negative pole window, 11, the ordinary negative pole of non-discrete formula, 12, processing district, 13, stray current.

Detailed Description

The implementation process of the invention is explained with the attached drawings:

the tool cathode 2 is equally divided into n parts, each part is insulated from the other part, and the n parts are connected into a ring through an insulating matrix 1. The value range of n is 8-72, and the value of n is increased along with the increase of the radius of the cathode of the tool; the cathode blocks of the tool are mutually insulated, the insulating material with a sheet structure is adopted to achieve an insulating effect, and the thickness range of the wall of the insulating layer of the sheet is 0.2-0.5 mm.

As shown in fig. 1, a tool cathode 2 is fixedly arranged on a cathode shaft 4 through an insulating base body 1, a workpiece anode 8 is arranged on an anode shaft 7, and the cathode shaft 4 and the anode shaft 7 rotate oppositely at the same angular speed; the tool cathode 2 feeds the workpiece anode 8 at a constant speed along with the cathode shaft 4; along with the opposite direction relative rotation motion of the tool cathode 2 and the workpiece anode 8 at the same angular speed and the feeding motion of the tool cathode 2, a boss 9 is gradually machined at the position, corresponding to the cathode window 10, on the surface of the workpiece anode 8;

an electric brush 5 is arranged above a processing area 12 at the tangent position of a tool cathode 2 and a workpiece anode 8, the electric brush 5 is arranged on a cathode shaft 4 through a fixing ring 3, and the electric brush 5 is always in close contact with the tool cathode 2 in the processing area; during the processing, the block of the tool cathode 2 in the processing area is conducted with the negative pole of a power supply 6 through an electric brush 5; the electrode blocks of the tool cathode 2 in the non-processing area are all in an insulating state, so that the stray current 13 on the rotary surfaces at two sides of the processing area 12 of the workpiece anode 8 and the surface of the boss 9 is completely eliminated;

fig. 2 shows a processing voltage U =30V of the workpiece anode 8, one electrode block of the tool cathode 2 in the processing area is conducted through the brush 5, and when the discrete tool cathode is adopted, the electric field distribution diagram of the surface of the workpiece anode 8 shows that the electric field is only concentrated in the processing area, and the electrochemical dissolution does not occur even if the electric field does not exist in the non-processing area, so that the stray corrosion can be effectively inhibited.

Fig. 3 shows the processing voltage U =30V of the workpiece anode 8, and the electric field distribution diagram of the surface of the workpiece anode 8 when the discrete tool cathode is not used, it can be seen that there are stray currents 13 on the surfaces of the revolved bodies and the surfaces of the bosses 9 on both sides of the processing area 12 of the workpiece anode 8, and the stray currents 13 flow out from the surface of the workpiece anode 8 to the surface of the tool cathode 2, which may cause serious stray corrosion.

Claims

1. A discrete rotary body tool electrode for spin-printing electrochemical machining, comprising:

the device comprises a tool cathode (2), a workpiece anode (8), an electric brush (5), a power supply (6), a cathode shaft (4), a fixing ring (3), an anode shaft (7) and an insulating matrix (1);

the tool cathode (2) is of a revolving body structure, the tool cathode (2) is equally divided into n parts, each part is mutually insulated, connected into a ring through an insulating base body (1), and integrally arranged on a cathode shaft (4); a window (10) is formed on the surface of the tool cathode (2), and an electric insulating material is coated on the inner wall of the window (10);

the workpiece anode (8) is arranged on the anode shaft (7);

the electric brush (5) is arranged on the cathode shaft (4) through a fixing ring (3), and the fixing ring (3) is made of a non-conductive insulating material and used for insulating the electric brush (5) from the cathode shaft (4); the position of the electric brush (5) is always kept above the processing area (12), and the electric brush (5) is kept in close contact with the tool cathode (2);

the tool cathode (2) is connected with the negative electrode of a power supply (6) through an electric brush (5); the workpiece anode (8) is connected with the positive electrode of the power supply (6);

the tool cathode (2) adopts a material which is difficult to dissolve in electrochemical reaction or coats inert metal on the surface of the tool cathode (2).

2. An electrolytic method using the discrete rotary body tool electrode for spin-printing electrolytic machining according to claim 1, characterized by comprising the steps of:

the cathode shaft (4) and the anode shaft (7) rotate oppositely at the same angular speed; the surface of the workpiece anode (8) gradually generates a required boss (9) structure under the opposite direction relative rotation motion of the workpiece anode (8) and the tool cathode (2) at the same angular speed and the feed motion of the tool cathode (2), and the generation position of the boss (9) corresponds to a cathode window (10) on the surface of the tool cathode (2);

in the processing process, the electrode block of the tool cathode (2) in the processing area is conducted with the negative electrode of the power supply (6) through the electric brush (5); the electrode blocks of the tool cathode (2) in the non-processing area are all in a non-conducting state, so that the stray current (13) on the surfaces of the rotary surfaces at two sides of the processing area (12) of the workpiece anode (8) and the boss (9) is eliminated;

during the machining process, the electric brush (5) and the tool cathode (2) perform feeding movement to the workpiece anode (8) at a constant speed through the fixing ring (3).

3. The electrolytic process according to claim 1, characterized in that: the value range of n is 8-72, and the value of n is increased along with the increase of the radius of the cathode of the tool; the cathode blocks of the tool are mutually insulated, the insulating material with a sheet structure is adopted to achieve an insulating effect, and the thickness range of the wall of the insulating layer of the sheet is 0.2-0.5 mm.