CN110802288B

CN110802288B - Electrochemical machining tool and method with periodic fluctuation of flow field

Info

Publication number: CN110802288B
Application number: CN201910986141.8A
Authority: CN
Inventors: 刘洋; 曲宁松; 谢洲; 冯瑞
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2019-10-17
Filing date: 2019-10-17
Publication date: 2020-10-20
Anticipated expiration: 2039-10-17
Also published as: CN110802288A

Abstract

An electrochemical machining tool with periodically fluctuating flow field and a method thereof belong to the technical field of electrochemical machining. According to the invention, the thorn-containing cam mechanism is arranged in the device flow channel, so that the flow and the flow speed of the electrolyte in the processing flow channel are periodically fluctuated, the electrolyte is promoted to wash the surface of the workpiece in a wave manner, the processed product is quickly taken away, and the surface quality of electrolytic processing is improved. In addition, the sharp spines distributed on the surface of the barbed cam can pierce the bubbles generated in the electrolytic action of the workpiece, so that the influence of the bubbles on the electrolytic machining of the workpiece behind is reduced, and the stability and the uniformity of the electrolytic machining are improved. The invention has important significance for improving the surface quality, the processing stability and the uniformity of electrolytic processing.

Description

Electrochemical machining tool and method with periodic fluctuation of flow field

Technical Field

The invention relates to an electrochemical machining tool with periodically fluctuating flow field and a method thereof, belonging to the field of electrochemical machining.

Background

With the development of society and the progress of science and technology, more and more special metal materials are used in the fields of modern aerospace and the like, and for the special materials such as high-temperature alloy, titanium alloy and the like, the traditional mechanical processing is not suitable due to poor heat conductivity and high strength and hardness, while the electrochemical processing is distinguished due to the unique non-contact processing characteristics.

The electrolytic machining process has no cutting force, no loss to the cutter, no requirement on material hardness, strength and the like, so that the method is very suitable for machining some difficult-to-machine materials in the fields of aerospace and the like. How to rapidly discharge electrolytic machining products and bubbles in electrolytic machining so as to ensure the stability of the electrolytic machining process is a key problem for research of a plurality of research institutions and scholars.

Studies have shown that products and bubbles produced by electrolysis of a preceding workpiece must be rapidly discharged from the machining area during one-time electrolytic machining of a large number of workpieces in order not to interfere with electrolytic machining of a succeeding workpiece. Researchers find that by applying certain interference to the flow field, electrolyte is promoted to generate fluctuation, products in a processing area can be rapidly discharged, and the quality of the processed surface is improved, such as ultrasonic electrolytic processing, vibration electrolytic processing and the like. However, both ultrasonic electrolytic machining and vibration electrolytic machining require a large amount of modification of the apparatus, and the apparatus is complicated.

Disclosure of Invention

The invention aims to provide an electrochemical machining tool and method capable of rapidly discharging machined products and improving stability and uniformity of an electrochemical machining process.

An electrolytic machining tool with periodically fluctuating flow field comprises a machining cavity body consisting of an upper cavity clamp and a lower cavity clamp, wherein an electrolyte flow channel is arranged on the upper surface of the lower cavity clamp;

the left clamp body is connected with the liquid inlet pipe, and the right clamp body is connected with the liquid outlet pipe;

the workpiece is arranged on the upper surface of the lower cavity clamp and positioned in the electrolyte flow channel; wherein the cathode is arranged in the upper cavity clamp;

the method is characterized in that:

and a plurality of barbed cam mechanisms are also arranged in the electrolyte flow channel, are arranged on the upper surface of the lower cavity clamp and are connected with a driving motor.

The machining method of the electrochemical machining tool with the periodically fluctuating flow field is characterized by comprising the following steps of:

an electrolyte flow channel is arranged between the upper cavity clamp and the lower cavity clamp, and electrolyte flows in from the liquid inlet pipe and flows out from the liquid outlet pipe through the flow channel;

the cam mechanism with the thorn is driven by the driving motor to rotate, so that the electrochemical machining flow field generates periodic fluctuation, machining products are quickly discharged, and a large amount of bubbles generated by the electrochemical machining of the front workpiece can be punctured and removed through the sharp thorn on the surface of the cam, so that the stability and the uniformity of the electrochemical machining process of the rear workpiece are improved.

When the tool is used, electrolyte flows through the cam rotating at a high speed after entering the inner cavity of the tool, the flow field of the inner cavity of the tool generates periodic fluctuation under the action of the high-speed rotation of the cam, the frequency of the periodic fluctuation of the flow field can also change along with the difference of the rotation speed of the cam, and the periodically fluctuating flow field can wash away an electrolysis product in a machining gap by one wave as sea waves impact sand beaches.

The electrolyte flow channel is in a form that two ends are wide and the middle is narrow; the width transition parts at the two ends are provided with a cam mechanism with thorns. This constricted flow path promotes increased electrolyte flow rates in the processing region, thereby rapidly flushing away the processed product. However, according to the fluid mechanics principle, the flow velocity at the narrowing part of the flow channel is increased, the pressure is reduced, and the bubbles in the fluid are gradually enlarged and increased, so that the sharp pricks arranged on the surface of the pricking cam can effectively prick the bubbles, and the processing stability and the processing efficiency are improved.

The electrolyte flow channel is of a snake-shaped structure, and a barbed cam mechanism is arranged at each corner of the snake-shaped structure. The serpentine structure enables the number of workpieces to be increased as much as possible in the flow channel, and machining efficiency is improved. Due to the influence of the previous processing, bubbles in the electrolyte become variable and large, and the subsequent processing is not favorable. The thorn cam is placed at the corner to puncture bubbles, so that the bubble rate in the electrolyte in the machining gap is reduced, the conductivity of the electrolyte is improved, and a positive effect is generated on subsequent machining. Meanwhile, the rotating speed of the cam can be controlled by changing the rotating speed of the motor, and the pulse change period of the electrolyte flow field is changed.

The workpiece consists of a plurality of workpiece blocks, is arranged in the corresponding hole of the lower cavity clamp in an embedding manner, and a conductive layer is padded between the workpiece blocks and the corresponding hole; the cathode is composed of a plurality of cathode units, the cathode units are fixed on the lower surface of a cathode guide block, the cathode guide block is positioned above the upper cavity clamp and is fixedly connected with the upper cavity clamp, the cathode units are arranged in the upper cavity clamp, and the upper part of the cathode guide block is connected with a cathode fixing rod. The anode workpiece is connected with the anode of an external power supply through a conducting layer, and the cathode unit is connected with the cathode of the external power supply through a cathode guide block and a fixing rod, so that the condition of electrolytic machining is achieved.

The invention has the following advantages

1. The thorn-containing cam mechanisms are arranged at the liquid inlet and the liquid outlet of the device and the corners of the flow channel, the cam mechanisms rotate at a high speed, so that the flow field is promoted to periodically fluctuate, and a processing product adsorbed on the surface of a workpiece is quickly discharged, so that the quality of the processed surface is improved.

2. According to the fluid mechanics principle, at the narrow part of the flow channel, the flow speed is increased, the pressure is reduced, and the bubbles in the fluid are increased; meanwhile, due to the influence of the previous processing, bubbles in the electrolyte become variable and large, and the bubbles are gradually accumulated along with the increase of the processing area, so that the subsequent processing is greatly influenced. The surface of the cam rotating at high speed is distributed with sharp pricks, which can pierce air bubbles mixed in the electrolyte and improve the stability of electrolytic processing.

3. The rotating speed of the barbed cam is adjusted through the motor, so that the fluctuating frequency of the electrolyte flow field can be controlled, and the electrolytic machining experiment of periodic fluctuation of the electrolyte under different frequencies is realized.

Drawings

FIG. 1 is a schematic view of the apparatus as a whole;

FIG. 2 is a schematic view of bubble distribution prior to electrolytic machining of a large batch of workpieces;

FIG. 3 is a schematic view of a surface of a cam for removing gas bubbles during electrolytic machining of a large batch of workpieces;

FIG. 4 is a graph of the periodic variation of flow and velocity;

FIG. 5 is a schematic diagram of a periodic pulsating flow field for efficient removal of anode surface artifacts;

FIG. 6 is a schematic diagram showing the periodic variation of flow rate and velocity at different speeds of the cam;

number designation in the figures: 1. the device comprises a liquid outlet pipe, 2 a right clamp body, 3 an upper cavity clamp, 4 a cathode fixing rod, 5 a cover plate, 6 a cathode guide block, 7 a cathode unit, 8 a liquid inlet pipe, 9 a left clamp body, 10 a barbed cam mechanism, 11 a driving motor, 12 a workpiece, 13 a cathode conducting layer, 14 a lower cavity clamp, 15 electrolyte, 16 bubbles, 17 electrolysis products and 18 an electrolyte flow channel.

Detailed Description

The invention is further described below with reference to the accompanying drawings:

according to the electrochemical machining tool and method for promoting periodic fluctuation of the flow field by rotating the barbed cam, as shown in figure 1, a workpiece 12 and a cathode unit 7 are arranged in a clamp body, and electrolyte flows in from a liquid inlet pipe 8, passes through an inner flow passage which is narrowed continuously, flows through a machining area of the barbed cam mechanism 10 and the workpiece 12, and then flows out from a liquid outlet pipe 1.

As shown in FIG. 3, at the contraction section and the corner of the flow channel, the barbed cam mechanism 10 rotates at high speed under the control of the driving motor 11, and the sharp thorn on the cam surface can pierce the air bubble to prevent the air bubble from affecting the subsequent processing area.

As shown in fig. 2, 4 and 6, with the high-speed rotation of the barbed cam mechanism 10, the flow rate and the flow velocity of the flow field in the tool cavity periodically change, and the change frequency can be adjusted by controlling the rotation speed of the barbed cam mechanism 10 by the driving motor 11.

Fig. 5 (a) shows a constant processing flow field, and since the fluid velocity and flow rate are basically kept constant, some electrolytic products 17 are adhered in the processing groove and are difficult to be washed away by the electrolyte, thereby influencing the subsequent processing. As can be seen from fig. 5 (b), since the barbed cam mechanism 10 rotates at a high speed during the machining process, and the flow rate and the flow velocity of the flow field in the tool flow channel change periodically in a wavy manner, the electrolysis products 17 and the bubbles 16 generated by electrolysis in the machining area of the workpiece 12 are washed away by the wavy flow field, and the conductivity of the electrolyte in the machining area is always kept stable, thereby improving the machining stability and the machining efficiency.

Claims

1. An electrolytic machining tool with periodically fluctuating flow field,

the device comprises a processing cavity consisting of an upper cavity clamp (3) and a lower cavity clamp (14), wherein an electrolyte flow channel (18) is arranged on the upper surface of the lower cavity clamp (14);

the device also comprises a left clamp body (9) and a right clamp body (2) which are fixed at the left end and the right end of the processing cavity, wherein the left clamp body (9) is connected with a liquid inlet pipe (8), and the right clamp body (2) is connected with a liquid outlet pipe (1);

the device also comprises a workpiece and a cathode, wherein the workpiece (12) is arranged on the upper surface of the lower cavity clamp (14) and is positioned in the electrolyte flow channel (18); wherein the cathode is arranged in the upper cavity clamp (3);

the method is characterized in that:

the electrolyte runner (18) is also internally provided with a plurality of barbed cam mechanisms (10) which are arranged on the upper surface of the lower cavity clamp (14) and are connected with a driving motor (11).

2. The electrochemical machining tool of claim 1 with periodic undulations in the flow field, wherein: the electrolyte flow channel (18) is in a form that two ends are wide and the middle is narrow; the width transition parts of the two ends are provided with a cam mechanism (10) with thorns.

3. An electrochemical machining tool with periodically fluctuating flow field according to claim 1 or 2, characterized in that: the electrolyte flow channel (18) is of a serpentine structure, and a barbed cam mechanism (10) is arranged at each corner of the serpentine structure.

4. The electrochemical machining tool of claim 1 with periodic undulations in the flow field, wherein:

the workpiece consists of a plurality of workpiece blocks, is arranged in a corresponding hole of the lower cavity clamp (14) in an embedding manner, and a conductive layer (13) is padded between the workpiece blocks and the corresponding hole;

the cathode is composed of a plurality of cathode units (7), the cathode units (7) are fixed on the lower surface of a cathode guide block (6), the cathode guide block (6) is located above an upper cavity clamp (3) and is fixedly connected with the upper cavity clamp (3), the cathode units (7) are arranged in the upper cavity clamp (3), and the upper portion of the cathode guide block (6) is connected with a cathode fixing rod (4).

5. A method of machining an electrochemical machining tool using periodic oscillations of the flow field as set forth in claim 1, characterized by comprising the following processes:

an electrolyte flow channel is arranged between the upper cavity clamp (3) and the lower cavity clamp (14), and electrolyte flows in from the liquid inlet pipe (8) and flows out from the liquid outlet pipe (1) through the flow channel;

the cam mechanism (10) with the thorn is driven by the driving motor (11) to rotate, so that the electrochemical machining flow field generates periodic fluctuation, machining products are quickly discharged, a large amount of bubbles generated by electrochemical machining of the front workpiece can be punctured and removed through the sharp thorn on the surface of the cam, and the stability and uniformity of the electrochemical machining process of the rear workpiece are improved.