CN110744154B - Device and method for alternately machining arc surface by electric spark electrolysis - Google Patents

Abstract

The patent relates to a device and a method for alternately machining a cambered surface by electric spark electrolysis, belonging to the technical field of electrolytic machining. This patent carries out periodic electric spark electrolysis alternative machining through the electric spark electrode that can rotate at a high speed and electrolysis electrode to titanium alloy material, gets rid of the oxide layer and the partial metal organism material that titanium alloy surface is difficult to get rid of by the electrolysis through electric spark machining, gets rid of metal organism material through the further high efficiency of electrolytic machining to with the uneven surperficial finish of electric spark processing back level and smooth, thereby realize the purpose of high-efficient processing titanium alloy cambered surface. The method has important significance for improving the arc-shaped electrolytic machining efficiency of the surface of the titanium alloy part.

Description

Device and method for alternately machining arc surface by electric spark electrolysis

technical field

The invention relates to a device and a method for alternately machining cambered surfaces by electric spark electrolysis, and belongs to the field of electrolytic machining.

Background technique

In order to reduce air resistance, many aerospace components are designed with curved structures. However, these curved aerospace components are difficult to be processed by traditional machining processes. Because a large number of metal materials such as superalloys and titanium alloys are used in modern aviation, aerospace, shipbuilding and other industrial fields. For example, GH4169 alloy accounts for 34%, 56% and 57% of the total weight of CF6 engine, CY2000 engine and PW4000 engine respectively; titanium alloy accounts for 41% of the total materials used in the fourth-generation fighter F-22, etc. The influence of some inherent characteristics of these materials, such as poor thermal conductivity, high strength, high hardness, etc., in the process of using traditional machining, the temperature of the processing area is high, and the cutting force is large, which is easy to cause tool wear, low processing efficiency, and processing. Long cycle and so on. Electrochemical machining is the use of electrochemical reactions to remove workpiece material, which is non-contact machining. Compared with traditional machining, it has the advantages of no residual stress, no cold work hardening, no plastic deformation, low surface roughness, and no tool loss on the surface of the workpiece. Because electrolytic machining does not rely on mechanical energy, it uses electrochemical energy to remove metal materials, and has the characteristics of no contact stress and independent of the hardness of the material. Therefore, the use of electrolytic machining is a processing method suitable for key components of aerospace.

However, during electrolytic machining, due to the self-passivation properties of difficult-to-machine materials such as titanium alloys, a dense oxide layer is easily formed on the surface of the workpiece during machining. Therefore, difficult-to-machine materials such as titanium alloys need to be electrolytically processed first. The oxide layer is removed before efficient electrochemical dissolution of the bulk material occurs.

SUMMARY OF THE INVENTION

The invention relates to a device and a method for alternately machining cambered surfaces by electric spark electrolysis, and belongs to the technical field of electrolytic machining.

An electric spark electrolysis composite high-speed rotary machining arc surface device, characterized in that: the device comprises a hollow rotating spindle, an insulating turntable, a reducer and a drive motor; wherein the upper part of the hollow rotating spindle is a hollow triangular cone cavity structure, and the lower part is a hollow Disc structure; the hollow rotating spindle is fixed on the upper end of the insulating turntable through its hollow disc structure, and the lower end of the insulating turntable is connected with the drive motor through a reducer; the device also includes a liquid inlet pipe located above the hollow rotating spindle, the liquid inlet pipe and the hollow rotary The main shaft is connected by a rotary joint. When working, the liquid inlet pipe is stationary, and the hollow rotating main shaft rotates; the device also includes a conductive slip ring and an electrode. The conductive slip ring is sleeved directly above the hollow rotating main shaft. It is composed of an electric spark electrode; the inside of the electrolysis electrode is a hollow structure with a circular section changing to a rectangular section, and the hollow structure is connected with the triangular conical cavity structure of the hollow rotating spindle; the electric spark electrode is a solid structure; the device also includes a protective plate ; The protective plate is composed of an upper protective plate and a lower protective plate, with a circular hole in the center of the two, which is sleeved on the hollow rotating spindle and located above the hollow disk structure of the hollow rotating spindle; the above-mentioned uniformly spaced electrolysis electrodes and spark electrodes are located at At the circular hole; a liquid return groove is opened on the lower surface of the upper protective plate and the lower protective plate; the device also includes a workpiece clamping and feeding device installed on the upper protective plate; Each clamping assembly is composed of a servo motor and a workpiece fixing block installed at the end of the servo motor push rod, and the workpiece to be processed is fixed on the workpiece fixing block by screws; the device also includes a top cover and a lower guard The top cover is installed and fixed above the protective plate; the side wall of the top cover has an opening matched with the above-mentioned workpiece fixing block; the lower protective cover is installed under the protective plate.

The method for using the described electric spark electrolysis composite high-speed rotary machining camber device is characterized by the following steps: installing the workpiece to be machined on the workpiece fixing block, and fixing it with screws; controlling the workpiece to be machined and the electrolytic electrode through a servo motor The initial gap between the electric spark electrode and the electric spark electrode; the reducer is driven to rotate by the drive motor, and the hollow rotating spindle is driven to rotate through the insulating rotating platform; the upper part of the rotary joint and the liquid inlet pipe are stationary, and the lower part of the rotary joint and the hollow rotating spindle start to rotate at high speed; Pass the electrolyte, the electrolyte quickly flows into the high-speed rotating hollow rotating spindle from the liquid inlet pipe, and is quickly sprayed from the electrolytic electrode and the EDM electrode to the surface of the workpiece to be processed; turn on the power control to start the electrolytic EDM composite machining; when When the EDM electrode is rotated to a position close to the surface of the workpiece, the surface of the workpiece is broken down by the electric spark, the oxide layer and the body material on the surface of the workpiece are largely removed, and the surface of the workpiece is uneven; At the same time, the EDM-machined surface will be removed by efficient electrolysis, and the surface of the workpiece will become flat; the product will flow out of the machining area from the return tank; at this time, the electro-machined surface may again produce an oxide layer that hinders the electrolysis. Efficiently; with the high-speed rotation of the hollow rotating spindle, the electric spark rotates again to a position closer to the surface of the workpiece, and the oxide layer formed on the surface of the workpiece is once again broken down by the electric spark and removed. EDM removes material in two ways, and finally forms the desired arc surface.

When electrolytic processing of difficult-to-machine materials such as titanium alloys, a dense oxide layer will be formed on the surface of the material. This oxide layer will seriously hinder the efficient progress of electrolytic machining. It is necessary to consume a certain amount of electricity to remove the oxide layer before continuing efficient electrolysis. processing, which reduces the processing efficiency. In this patent, EDM is performed on the surface of the workpiece by an EDM electrode. Driven by the high-speed rotation of the hollow spindle, the EDM electrode sweeps across the surface of the workpiece at a high speed to quickly remove oxides and part of the metal body on the surface of the workpiece. Since the spark electrode is scanned over the workpiece surface at high speed, there is no continuous spark discharge. When the EDM electrode scans from the surface of the workpiece at high speed, the electrolytic electrode rotates to the surface of the workpiece at a high speed, and the inner cavity sprays the electrolyte to the surface of the workpiece, and starts the electrolytic machining of the workpiece. Since the oxide layer on the surface of the workpiece that hinders the electrolytic reaction has been removed by the electric spark, an efficient electrolytic reaction occurs on the surface of the workpiece, and the surface material of the workpiece is further removed efficiently. The uneven surface that has been EDM is also electrolytically smoothed and flattened. The invention is of great significance for improving the electrolytic machining efficiency of the arc surface of parts of difficult-to-machine materials such as titanium alloys.

The electrolytic composite high-speed rotary machining arc surface device is characterized in that: the distance between the electrolytic electrode and the workpiece to be machined is 0.2-1 mm, and the distance between the electric spark electrode and the workpiece to be machined is 0.05-0.1 mm. This is because the electrolyte jet flow resistance must be considered in electrolytic machining, and a large processing gap must be reserved to reduce the flow resistance of the electrolyte and promote the discharge of products. In EDM, only a small machining gap can be maintained for rapid breakdown spark discharge, so the machining gap must be kept at a small value.

The electric spark electrolysis composite high-speed rotary machining arc surface device is characterized in that: the cross section of the liquid return tank is fan-shaped. The fan-shaped cross-section of the liquid return tank ensures that the flow channel of the electrolysis products and bubbles gradually widens and the flow resistance gradually decreases during the process of flowing out of the processing area, which is conducive to the rapid removal of electrolysis products and ensures that no electrolysis products remain in the processing space.

The electric spark electrolysis composite high-speed rotary machining arc surface device is characterized in that: a sealing ring is arranged at the connection between the hollow rotating spindle and the insulating turntable. The electrolyte in the processing area can be isolated from the drive motor, reducer, etc. through the sealing ring, so as to avoid the corrosion of the drive motor and reducer after the electrolyte leaks to the bottom.

The present invention has the following advantages

1. The electrolytic electrode and the EDM electrode are periodically processed by EDM alternately. The EDM quickly removes the oxide layer and part of the metal body material produced by the electrolysis. The material is further removed by electrolysis and the uneven surface processed by the EDM is electrolyzed. The processing is smooth and flat, and through the alternating action of the two, efficient and high-speed material removal is achieved.

2. During the machining process, the electrolytic electrode and the EDM electrode rotate at a high speed, which can quickly throw out the electrolyte and impact the surface of the part at a high speed, so that the processed product can be quickly washed away, so as to obtain a better surface quality. In addition, during the high-speed rotation and flushing of the electrode from one side of the arc surface of the workpiece to the other side of the workpiece, the rotary scanning flushing of the electrolyte can also take away the processed products from the processing surface.

3. A fan-shaped liquid return tank is opened at the bottom of the turntable of the device, and the section of the fan-shaped gradually expands, which is conducive to the rapid discharge of processing waste liquid from the processing area and ensures the efficient and stable electrolytic processing.

Description of drawings

Figure 1 Overall structure of the tool;

Figure 2 shows the internal structure of the tool after removing the protective cover;

Figure 3 is a structural diagram and a cross-sectional view of the internal rotation mechanism of the tool;

Fig. 4 is a schematic diagram of alternate cycle processing of electric spark electrolysis;

The label names are: 1 liquid inlet pipe, 2 protective cover, 3 rotary joint, 4 conductive slip ring, 5 servo motor, 6 workpiece fixing block, 7 liquid return tank, 8 sealing ring, 9 lower protective cover, 10 workpiece to be processed , 11 electrolysis electrodes, 12 hollow rotating spindles, 13 insulating turntables, 14 drive motors, 15 reducers, 16 spark electrodes, 17 top covers, 18 bubbles, 19 spark products, 20 electrolysis products, 21 outer insulating layer.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings:

With reference to Figure 1, Figure 2, Figure 3, Figure 4, the workpiece to be processed is installed on the workpiece fixing block, and fixed by a hexagon socket head screw. Three servo motors can realize precise control of the position of the workpiece to be processed, thereby controlling the initial distance between the electrolytic nozzle and the electric spark from the workpiece to be processed. When the electrolyte is switched on, the electrolyte quickly flows into the high-speed rotating hollow rotating spindle from the liquid inlet pipe, and is quickly sprayed from the hollow electrolytic electrode to the surface of the workpiece to be processed.

The reducer is driven to rotate by the drive motor, and the hollow rotating spindle is driven to rotate by the epoxy resin rotating platform. The upper part of the rotary joint and the liquid inlet pipe are stationary, and the lower part of the rotary joint and the hollow rotating spindle start to rotate at high speed. Electrolysis electrodes and spark electrodes on the hollow rotating spindle start to rotate at high speed.

Turn on the power control and start the electrolytic EDM alternate machining. When the electric spark rotates to a position close to the surface of the workpiece, the surface of the workpiece is broken down by the electric spark, the oxide layer and the body material on the surface of the workpiece are largely removed, and the surface of the workpiece is uneven, as shown in Figure 4(a); When the electrolytic nozzle rotates to a position close to the surface of the workpiece, the surface processed by EDM will be removed by efficient electrolysis, and the surface of the workpiece will become flat. As shown in Figure 4(b), the product flows out of the processing area from the fan-shaped liquid return tank. At this time, the electrolytically processed surface may again produce an oxide layer to hinder the efficient electrolysis; with the high-speed rotation of the hollow rotating spindle, the electric spark rotates again to a position closer to the surface of the workpiece, and the oxide layer formed on the surface of the workpiece at this time. The material layer is once again broken down by the electric spark and removed, and again and again, the surface of the workpiece is continuously removed by the electric spark electrolysis in two ways, and finally the required arc surface is formed.

Referring to Fig. 2 and Fig. 3, the drive motor is decelerated by the reducer, and the reducer is connected to the hollow rotating spindle through the epoxy resin rotating platform to realize the high-speed rotation of the hollow rotating spindle. The electrodes of the three rectangular nozzles rotate at a high speed, and the electrolyte sprayed from the electrolytic nozzle is driven by the high-speed rotation of the main shaft, and impacts the surface of the titanium alloy parts to be processed at high speed. quality. In addition, during the process of high-speed rotating and scouring of the rectangular nozzle electrode from one side of the arc surface of the workpiece to the other side of the workpiece, the rotating scouring of the electrolyte can also scour the processed products away from the machined surface.

Referring to Figure 1 and Figure 3, there is a sealing ring above the connection between the hollow rotating spindle and the epoxy resin rotating platform, which can prevent the electrolyte from falling on the epoxy resin rotating platform and ensure that the electrolyte flows out from the three fan-shaped liquid return tanks.

Claims (5)

1. an electric spark electrolysis composite high-speed rotary machining camber device, is characterized in that: The device comprises a hollow rotating main shaft (12), an insulating turntable (13), a reducer (15) and a drive motor (14); wherein the upper part of the hollow rotating main shaft (12) is a hollow triangular cone cavity structure, and the lower part is a hollow disc structure; the hollow rotating spindle (12) is fixed on the upper end of the insulating turntable through its hollow disc structure, and the lower end of the insulating turntable (13) is connected with the drive motor (14) through the reducer (15); The device further comprises a liquid inlet pipe (1) located above the hollow rotary main shaft (12), the liquid inlet pipe (1) and the hollow rotary main shaft (12) are connected through a rotary joint (3), and the liquid inlet pipe (1) is in operation. stationary, the hollow rotating spindle (12) rotates; The device further includes a conductive slip ring (4) and an electrode, the conductive slip ring (4) is sleeved directly above the hollow rotating spindle (12), and the electrode is composed of a plurality of electrolytic electrodes (11) and spark electrodes (16) that are evenly spaced wherein the electrolysis electrode (11) is a hollow structure with a circular cross-section gradually changing to a rectangular cross-section, and the hollow structure is communicated with the triangular conical cavity structure of the hollow rotating spindle (12); the spark electrode (16) is a solid structure; The device further comprises a protective plate (2); the protective plate is composed of an upper protective plate and a lower protective plate, and a circular hole is opened in the center of the two, which is sleeved on the hollow rotating spindle (12) and is located on the hollow disk of the hollow rotating spindle (12). Above the structure; the above-mentioned uniformly spaced electrolytic electrodes (11) and spark electrodes (16) are located at the circular hole; a liquid return groove (7) is provided on the lower surface where the upper protective plate and the lower protective plate are attached; The device also includes a workpiece clamping and feeding device installed on the upper protective plate; it is composed of a number of clamping components uniformly distributed on the upper protective plate along the circumferential direction; each clamping component is composed of a servo motor (5) and a servo motor installed on the The workpiece fixing block (6) at the end of the push rod is formed, and the workpiece to be processed (10) is fixed on the workpiece fixing block (6) by screws; The device further comprises a top cover (17) and a lower protective cover (9). The top cover (17) is installed and fixed above the protective plate (2); The lower protective cover (9) is installed under the protective plate (2). 2. The electric spark electrolysis composite high-speed rotary machining arc surface device according to claim 1, characterized in that: the distance between the above-mentioned electrolytic electrode (11) and the workpiece to be machined (10) is 0.2-1 mm, and the electric spark electrode (16) ) is 0.05-0.1 mm from the workpiece to be machined (10). 3 . The electric spark electrolysis composite high-speed rotary machining arc surface device according to claim 1 , wherein the cross section of the liquid return tank ( 7 ) is fan-shaped. 4 . 4. The electric spark electrolysis composite high-speed rotary machining arc surface device according to claim 1, characterized in that: a sealing ring (8) is provided at the connection between the hollow rotating spindle (12) and the insulating turntable (13). 5. utilize the processing method of the EDM composite high-speed rotary machining camber device of claim 1, it is characterized in that comprising the following process: The workpiece (10) to be processed is mounted on the workpiece fixing block (6), and fixed by screws; the initial position of the workpiece (10) to be processed and the electrolysis electrode (11) and the spark electrode (16) is controlled by the servo motor (5). gap; The reducer (15) is driven to rotate by the drive motor (14), and the hollow rotating spindle (12) is driven to rotate through the insulating turntable (13); the upper part of the rotary joint (3) and the liquid inlet pipe (1) are stationary, and the rotary joint ( 3) The lower part and the hollow rotating spindle (12) start to rotate at high speed; The electrolyte is switched on, the electrolyte quickly flows into the high-speed rotating hollow rotating spindle (12) from the liquid inlet pipe (1), and is rapidly sprayed from the electrolysis electrode (11) and the spark electrode (16) to the workpiece to be processed ( 10) the surface; Turn on the power control and start the EDM composite machining; when the EDM electrode rotates to a position close to the surface of the workpiece, the surface of the workpiece is broken down by the electric spark, the oxide layer and the body material on the surface of the workpiece are largely removed, and the surface of the workpiece is uneven. Morphology; when the electrolytic electrode rotates to a position close to the workpiece surface, the surface processed by EDM will be removed by efficient electrolysis, and the surface of the workpiece will become flat; the product flows out of the processing area from the liquid return tank; The oxide layer may be produced on the surface again to hinder the efficient electrolysis; with the high-speed rotation of the hollow rotating spindle, the electric spark rotates again to a position closer to the surface of the workpiece, and the oxide layer formed on the surface of the workpiece is struck by the electric spark again. Wear and remove, and again and again, the surface of the workpiece is continuously removed by two methods of electric spark electrolysis, and finally the required arc surface is formed.

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