Double-electrode high-precision synchronous rotation movement mechanism for rotary printing electrolytic machining

Abstract

The invention discloses a double-electrode high-precision synchronous rotation movement mechanism for rotary printing electrolytic machining, and relates to the technical field of electrolytic machining, the double-electrode high-precision synchronous rotation movement mechanism comprises an anode main shaft assembly, a cathode main shaft assembly and an electrolyte isolation assembly, comprising an inner and outer wall rotary printing electrolytic machining method and a'guiding-following 'control strategy of a main shaft; the main shaft assembly comprises a thrust centripetal cylindrical roller bearing, a deep groove ball bearing, a hollow stepped main shaft, a coupler, an absolute encoder, a direct drive motor and the like. The direct-drive motor is directly coupled to drive the main shaft, so that an intermediate transmission link is omitted, and mechanical errors are reduced; the spindle phase is fed back in real time based on an absolute encoder; a'guiding-following 'control strategy is adopted, high-precision synchronous contra-rotation of the cathode spindle and the anode spindle is achieved, reversing rotation can be achieved in the high-precision synchronization process, and the rotary printing electrolytic machining device is suitable for rotary printing electrolytic machining of the outer wall and the inner wall of a large thin-wall rotary body part.

Description

Technical Field

[0001] This invention relates to the field of electrochemical machining technology, and in particular to a dual-electrode high-precision synchronous rotary motion mechanism for rotary electrochemical machining. Background Technology

[0002] Spin-printing electrochemical machining is a method for manufacturing complex surface features on large, thin-walled rotating parts using electrochemical principles. During machining, the anode workpiece is connected to the positive terminal of the power supply, and the cathode tool is connected to the negative terminal. An electrolyte flow field exists between the workpiece and the tool, and the cathode tool has hollow windows on its surface. During machining, the cathode tool and anode workpiece rotate synchronously at the same angular velocity or double the rotational speed, with the cathode tool feeding normally towards the anode workpiece. The electrode reaction occurs in the machining gap. When the hollow window structure on the cathode surface enters the machining area, the dissolution of points on the workpiece surface corresponding to the hollow window of the tool is slower than that of points on the normal circumferential surface of the tool. Thus, the tool's surface structure is gradually copied onto the workpiece, and all convex structures can be generated in a single machining operation. However, this technology requires extremely high precision in the synchronous rotation of the cathode and anode. Traditional mechanical transmission methods suffer from large transmission errors and rapid mechanical wear, making it difficult to meet the demands of high-precision machining.

[0003] In existing technologies, although direct-drive rotary mechanisms directly drive the spindle via a direct-drive motor, eliminating intermediate transmission links and achieving closed-loop control of rotation angle with the help of a CNC encoder, significantly improving synchronous rotation accuracy, the following limitations still exist: 1. In rotary electrolytic machining, both the cathode tool and the anode workpiece are under high loads, and the motion mechanism needs to achieve synchronous rotation while bearing a huge inertial load, which makes the synchronization accuracy of the cathode tool and the anode workpiece prone to fluctuations; 2. In the electrolyte environment of rotary electrolytic machining, the electrolyte can easily seep into the interior of the motion mechanism, interfering with transmission and conductivity, and reducing equipment stability; 3. There is a lack of control strategies suitable for synchronous rotational motion in rotary electrolytic machining.

[0004] Therefore, in view of the above situation, a high-precision and high-stability synchronous rotary motion mechanism for rotary electrochemical machining and its corresponding electrochemical machining method are proposed to solve key technical problems such as multi-axis collaborative control and electrolyte protection in rotary electrochemical machining, as well as the control problem of synchronous rotary motion. Summary of the Invention

[0005] This invention provides a dual-electrode high-precision synchronous rotary motion mechanism for rotary electrochemical machining, which is suitable for rotary electrochemical machining of large, thin-walled, complex surface rotating parts. It can achieve high-precision synchronous rotation of the anode electrode spindle and the cathode electrode spindle, thereby improving the forming accuracy of parts in rotary electrochemical machining.

[0006] To achieve the above objectives, the present invention provides a dual-electrode high-precision synchronous rotary motion mechanism for rotary electrolytic machining, comprising an anode spindle assembly and a cathode spindle assembly arranged symmetrically, and an electrolyte isolation assembly. Both the anode and cathode spindle assemblies include a transmission mechanism, which comprises a hollow stepped spindle, a thrust radial cylindrical roller bearing, a deep groove ball bearing, a support platform, a mounting plate, a rotating platform, a coupling, an absolute encoder, and a direct-drive motor. The thrust radial cylindrical roller bearing and the deep groove ball bearing are respectively sleeved on the outer surface of the hollow stepped spindle. The absolute encoder is connected to the lower end of the small-diameter section of the hollow stepped spindle via a coupling. The mounting plate is fixed to the upper end of the large-diameter section of the hollow stepped spindle, and the rotating platform is mounted on the top of the mounting plate. The rotor of the direct-drive motor is sleeved on the outer surface of the hollow stepped spindle, and the stator of the direct-drive motor is fixed to the support platform via a motor bracket. The electrolyte isolation assembly is disposed on the outer periphery of the anode spindle assembly.

[0007] The direct drive motor is provided with a motor housing, on which a cooling water inlet and a cooling water outlet are provided; a surrounding water channel is provided between the stator of the direct drive motor and the motor housing, and the two ends of the surrounding water channel are respectively connected to the cooling water inlet and the cooling water outlet.

[0008] The electrolyte isolation assembly includes an outer isolation ring, an inner isolation ring, an isolation plate, and an anode support platform; the outer isolation ring includes an upper isolation ring and a lower isolation ring, the upper isolation ring and the isolation plate are disposed on the rotating platform, and the inner isolation ring and the lower isolation ring are disposed on the anode support platform.

[0009] This invention also provides a processing method for a dual-electrode high-precision synchronous rotary motion mechanism in rotary electrochemical machining, comprising the following steps:

[0010] S1, clamp the workpiece in the anode spindle assembly, and clamp the tool with surface features in the cathode spindle assembly;

[0011] S2, control the anode spindle assembly and the cathode spindle assembly to rotate synchronously, and control the cathode spindle assembly to feed towards the anode spindle assembly;

[0012] S3, an electrolyte is supplied between the anode workpiece and the cathode tool, and the surface features on the cathode tool are transferred to the anode workpiece through electrolytic machining.

[0013] Preferably, the synchronous rotation control process includes:

[0014] S21, with the anode main shaft as the guiding main shaft and the cathode main shaft as the following main shaft;

[0015] S22 sends a rotation command to the guide spindle and detects the feedback position signal through its absolute encoder to control the position accuracy of the guide spindle.

[0016] S23 controls the rotation of the follower spindle through the shaft synchronous coupling function, and detects the position signal in real time through its absolute encoder.

[0017] S24 compares the position signals of the guide spindle and the follower spindle, and performs compensation control on the follower spindle to maintain the synchronization accuracy of the two spindles.

[0018] Ideally, the spindle rotation direction can be reversed during the machining process, and synchronization accuracy can be maintained during the reversal.

[0019] The processing method includes an external wall rotary printing processing mode and an internal wall rotary printing processing mode:

[0020] In the external wall rotary printing mode, the tool is located outside the workpiece, and the tool and the workpiece rotate at the same angular velocity.

[0021] In the inner wall rotary printing mode, the tool is located inside the workpiece and rotates in the same direction at a double angular velocity as the workpiece.

[0022] Compared with related technologies, the dual-electrode high-precision synchronous rotary motion mechanism and electrolytic machining method provided by the present invention have the following advantages:

[0023] This invention provides a dual-electrode high-precision synchronous rotary motion mechanism for rotary electrochemical machining. By using a direct-drive motor to directly drive the spindle, intermediate transmission links are eliminated, reducing mechanical errors. Furthermore, the spindle phase can be fed back in real time based on an absolute encoder, ensuring the uniformity and consistency of rotary electrochemical machining. It is suitable for rotary machining of large thin-walled rotating parts on both the inner and outer walls.

[0024] This invention provides a high-precision rotary motion mechanism with dual electrodes and double rotation speed for rotary electrolytic machining. The electrolyte isolation component adopts a double barrier of Z-shaped upper and lower isolation rings and inner isolation ring to effectively block electrolyte splashing and protect the internal transmission and conductive mechanisms of the spindle.

[0025] This invention provides a synchronous rotation control strategy for anode and cathode in rotary electrochemical machining. It adopts a "guide-follow" control method to control the real-time high-precision synchronous rotation of two spindles, thereby realizing the real-time high-precision synchronous motion of the anode and cathode spindles. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure and control method of the present invention;

[0027] Figure 2 This is a schematic diagram of the synchronous rotation process of the electrolytic printing on the outer wall of the present invention.

[0028] Figure 3 This is a schematic diagram of the synchronous rotation process of the inner wall double-speed electrolytic printing process of the present invention;

[0029] Figure 4 This is a schematic cross-sectional view of the anode spindle assembly of the present invention;

[0030] Figure 5 This is a schematic cross-sectional view of the cathode spindle assembly of the present invention;

[0031] Figure 6 This is a schematic diagram of the electrolyte isolation component structure of the present invention.

[0032] Figure 7 This is a schematic diagram of the direct drive motor assembly and cooling method of the present invention;

[0033] The diagram labels are as follows: 1. Anode spindle assembly; 2. Cathode spindle assembly; 3. Conductive mechanism; 4. Direct drive motor; 5. Absolute encoder; 6. Cylindrical anode workpiece; 7. Cylindrical cathode tool; 8. Inner wall cathode tool; 9. Inner wall anode workpiece; 10. Thrust radial cylindrical roller bearing; 11. Deep groove ball bearing; 12. Hollow stepped spindle; 13. Mounting plate; 14. Cathode support platform; 15. Rotary platform; 16. Coupling; 17. Mounting bracket; 18. Insulating mounting bushing; 19. Motor housing; 20. Cooling water inlet; 21. Cooling water outlet; 22. Inner isolation ring; 23. Isolation plate; 24. Upper isolation ring; 25. Lower isolation ring; 26. Anode support platform. Detailed Implementation

[0034] Example 1

[0035] This embodiment provides a dual-electrode high-precision synchronous rotary motion mechanism for rotary electrochemical machining, suitable for rotary electrochemical machining of large, thin-walled, complex surface rotating parts, such as... Figure 1-7 As shown, the anode spindle assembly 1 and the cathode spindle assembly 2 adopt a symmetrical structural design, and the inner and outer wall spin-printing electrolytic machining method is synchronized with the spin-printing electrolytic machining rotation control strategy.

[0036] Figure 1 The diagram shown is a simplified schematic of the rotary motion mechanism and control of the anode spindle assembly 1 and the cathode spindle assembly 2.

[0037] In the rotary electrolytic machining process, the current is connected to the conductive mechanism 3 by the power supply and then led to the cathode tool and the anode workpiece.

[0038] The main shaft of the counter-rotation mechanism is directly driven by a direct-drive motor 4, which eliminates intermediate transmission links and reduces errors compared to traditional mechanical transmission methods (such as gear transmission and belt transmission). An absolute encoder 5 is used to detect the phase of the main shaft. A "guide-follow" control method is used to control the synchronous counter-rotation of the two main shafts. With the anode main shaft assembly 1 as the guide shaft and the cathode main shaft assembly 2 as the follower shaft, the movement of the anode main shaft assembly 1 is controlled. The absolute encoders 5 on the two main shafts provide real-time feedback on the phase of the shafts, compare the rotational phase data of the two main shafts in real time, and immediately compensate and correct the speed of the follower shaft to achieve synchronization.

[0039] Figure 2 The diagram shows a schematic of an electrolytic machining structure for external wall rotary printing using a cylindrical cathode tool 7 and a cylindrical anode workpiece 6. Figure 3 This is a schematic diagram of the rotating process for double-speed rotary electrolytic machining of the inner wall using the inner wall section anode workpiece 8 and the inner wall section cathode tool 9.

[0040] The cathode tool is mounted on the front end of the cathode spindle assembly 2 using a fixture, and the anode workpiece is mounted on the front end of the anode spindle assembly 1 using a fixture. For example... Figure 2 In the process, the cylindrical anode workpiece 6 and the cylindrical cathode tool 7 are respectively installed at the front end of the anode spindle assembly 1 and the cathode spindle assembly 2, and the machining gap between the cylindrical anode workpiece 6 and the cylindrical cathode tool 7 is controlled. During the machining process, the anode and cathode rotate in opposite directions at the same speed, and the tool is fed in the normal direction of the workpiece. Figure 3 In the process, the inner wall section anode workpiece 8 is installed at the front end of the anode spindle assembly 1, and the inner wall section cathode tool 9 is installed at the front end of the cathode spindle assembly 2. The cathode tool is located inside the anode workpiece and controls the circumferential machining gap between the inner wall section anode workpiece 8 and the inner wall section cathode tool 9. During the machining process, the cathode rotates in the same direction as the anode at a speed that is twice that of the anode, and the tool feeds in the normal direction of the workpiece. In both machining methods, there is an electrolyte flow field in the machining gap, and the electrolytic reaction occurs in the electrolyte flow field of the machining gap.

[0041] In this embodiment, both the anode spindle assembly 1 and the cathode spindle assembly 2 include a transmission mechanism; the anode spindle assembly 1 and the cathode spindle assembly 2 have similar structures and the same principle.

[0042] The transmission mechanism includes a thrust radial cylindrical roller bearing 10, a deep groove ball bearing 11, a hollow stepped spindle 12, a mounting plate 13, a rotary platform 15, a coupling 16, a direct drive motor 4, and an absolute encoder 5.

[0043] A thrust radial cylindrical roller bearing 10 is fitted onto the upper surface of the hollow stepped spindle 12, and a deep groove ball bearing 11 is fitted onto the upper circumferential surface of the hollow stepped spindle 12. An absolute encoder 5 is connected to the lower end of the small-diameter section of the hollow stepped spindle 12 via a coupling 16. The rotor of the direct drive motor 4 is fitted onto the surface of the hollow stepped spindle 12, and the stator is fixed to the support platform via a mounting bracket 17.

[0044] The thrust radial cylindrical roller bearing 10 and the deep groove ball bearing 11 of the anode spindle assembly 1 are both fixedly connected to the anode support platform 26. The anode spindle assembly 1 also includes a mounting bracket 17, on which the motor housing 19 and the coupling 16 of the anode spindle assembly 1 are mounted. The mounting bracket 17 is mounted on the anode support platform 26. The combination of the thrust radial cylindrical roller bearing 10 and the deep groove ball bearing 11 is used to withstand the huge axial and radial loads during the machining process, providing a stable mechanical foundation for high-precision synchronous rotation.

[0045] The absolute encoder 5 is used to monitor the rotation angle and position of the workpiece in real time, maintaining high-precision synchronous rotation of the cathode and anode. When the rotary platform 15 is about to stop, the direct drive motor 4 locks in place to achieve high-precision positioning. An insulating mounting bushing 18 is provided between the mounting plate 13 and the hollow stepped spindle 12, and all bolts used for structural connection are provided with insulating bushings on the outside.

[0046] In this embodiment, the transmission of machining current and the insulation between machining current and components such as direct drive motor 4 and absolute encoder 5 are ensured by the provided insulating mounting bushing 18 and insulating bushing.

[0047] The cathode spindle assembly 2 also includes a cathode support platform 14. The motor housing 19, thrust radial cylindrical roller bearing 10, and deep groove ball bearing 11 of the cathode spindle assembly 2 are all fixedly connected to the cathode support platform 14. The absolute encoder 5 is mounted on the cathode support platform 14 via a coupling 16.

[0048] This embodiment also provides a machining method for a dual-electrode high-precision synchronous rotary motion mechanism using rotary electrochemical machining, comprising the following steps:

[0049] S1, clamp the anode workpiece in the anode spindle assembly 1, and clamp the cathode tool with profile features in the cathode spindle assembly 2;

[0050] S2, control the anode spindle assembly 1 and the cathode spindle assembly 2 to rotate synchronously, and control the cathode spindle assembly 2 to feed towards the anode spindle assembly 1;

[0051] S3, an electrolyte is supplied between the anode workpiece and the cathode tool, and the surface features on the cathode tool are transferred to the anode workpiece through electrolytic machining.

[0052] Preferably, the synchronous rotation control process includes:

[0053] S21, with the anode main shaft as the guiding main shaft and the cathode main shaft as the following main shaft;

[0054] S22 sends a rotation command to the guide spindle and detects the feedback position signal through its absolute encoder 5 to control the position accuracy of the guide spindle.

[0055] S23 controls the rotation of the follower spindle through the shaft synchronous coupling function, and detects the position signal in real time through its absolute encoder 5.

[0056] S24 compares the position signals of the guide spindle and the follower spindle, calculates the position error, and performs compensation control on the follower spindle to maintain the synchronization accuracy of the two spindles.

[0057] During the machining process, the spindle rotation direction can be reversed, and synchronization accuracy is maintained during the reversal process.

[0058] The processing methods include external wall rotary printing and internal wall rotary printing.

[0059] In the external wall rotary printing mode, the tool is located outside the workpiece, and the tool and the workpiece rotate at the same angular velocity.

[0060] In the inner wall rotary printing mode, the tool is located inside the workpiece and rotates in the same direction at a double angular velocity as the workpiece.

[0061] Example 2

[0062] Based on Example 1, such as Figure 6 As shown, the direct drive motor 4 has a motor housing 19 on its surface. The motor housing 19 is fixedly connected to the anode support platform 26. The motor housing 19 has a cooling water inlet 20 and a cooling water outlet 21 respectively. A surrounding water channel is provided between the stator of the direct drive motor 4 and the motor housing 19. The two ends of the surrounding water channel are connected to the cooling water inlet 20 and the cooling water outlet 21 respectively. The remaining technical features are the same as in Embodiment 1.

[0063] In this embodiment, during the operation of the direct drive motor 4, cooling water or ultrapure water containing corrosion inhibitors is introduced through the cooling water inlet 20 on the motor housing 19. After fully contacting the stator of the direct drive motor 4 through the designed surrounding water channel, it flows out from the cooling water outlet 21, thus cooling the direct drive motor 4. This avoids damage to the direct drive motor 4 due to insufficient heat dissipation under high load and low speed conditions in rotary electrolytic machining.

[0064] Example 3

[0065] Based on Example 1, such as Figure 7As shown, in this embodiment, the electrolyte isolation assembly is disposed on the surface of the anode spindle assembly 1. The electrolyte isolation assembly includes an outer isolation ring, an inner isolation ring 22, an isolation plate 23, and an anode support platform 26. The outer isolation ring includes an upper isolation ring 24 and a lower isolation ring 25. The isolation plate 23 and the upper isolation ring 24 are disposed on the rotating platform 15, and the inner isolation ring 22 and the lower isolation ring 25 are disposed on the anode support platform 26. The remaining technical features are the same as in Embodiment 1.

[0066] In this embodiment, the working environment of the rotary electrolytic machining process includes an electrolyte flow field. To prevent the electrolyte from entering the anode spindle assembly 1 and interfering with the transmission mechanism and the conductive mechanism 3, an electrolyte isolation component is designed. The upper isolation ring 24 and the lower isolation ring 25 form a Z-shaped protection, which can effectively prevent the electrolyte from splashing into the spindle from all sides. The inner isolation ring 22 provides a second waterproof barrier.

Claims

1. A double electrode high precision synchronous rotary motion mechanism for electrochemical machining with rotary dielectric, characterized in that, The anode spindle assembly, the cathode spindle assembly and the electrolyte isolation assembly are symmetrically arranged; The anode spindle assembly and the cathode spindle assembly each comprise a transmission mechanism, which comprises a hollow stepped spindle, a thrust centripetal cylindrical roller bearing, a deep groove ball bearing, a support platform, a mounting plate, a rotating platform, a shaft coupling, an absolute encoder and a direct drive motor; The thrust centripetal cylindrical roller bearing and the deep groove ball bearing are respectively sleeved on the outer surface of the hollow stepped spindle; The absolute encoder is connected to the lower end of the small diameter section of the hollow stepped spindle through the shaft coupling; The mounting plate is fixed to the upper end of the large diameter section of the hollow stepped spindle, and the rotating platform is mounted on the top of the mounting plate; The rotor of the direct drive motor is sleeved on the outer surface of the hollow stepped spindle, and the stator of the direct drive motor is fixed to the support platform through a motor support; The electrolyte isolation assembly is arranged on the outer periphery of the anode spindle assembly.

2. The double-electrode high-precision synchronous rotary motion mechanism according to claim 1, wherein The direct drive motor is provided with a motor housing outside, and a cooling water inlet and a cooling water outlet are formed in the motor housing; A circumferential water channel is arranged between the stator of the direct drive motor and the motor housing, and the two ends of the circumferential water channel are respectively communicated with the cooling water inlet and the cooling water outlet.

3. The dual electrode high precision synchronous rotary motion mechanism according to claim 1, wherein The electrolyte isolation assembly comprises an outer isolation ring, an inner isolation ring, an isolation plate and an anode support platform; The outer isolation ring comprises an upper isolation ring and a lower isolation ring, the upper isolation ring and the isolation plate are arranged on the rotating platform, and the inner isolation ring and the lower isolation ring are arranged on the anode support platform.

4. A method of electrochemical machining by spinning using the motion mechanism according to any one of claims 1 to 3, characterized by, The method comprises the following steps: S1, clamping an anode workpiece on the anode spindle assembly and clamping a cathode tool with a profile feature on the cathode spindle assembly; S2, controlling the anode spindle assembly and the cathode spindle assembly to realize synchronous rotation, and controlling the cathode spindle assembly to feed towards the anode spindle assembly; S3, supplying electrolyte between the anode workpiece and the cathode tool, and transferring the profile feature on the cathode tool to the anode workpiece through electrochemical machining.

5. The electrochemical impression machining method of claim 4, wherein, The control process of the synchronous rotation comprises: S21, taking the anode spindle as a leading spindle and the cathode spindle as a following spindle; S22, issuing a rotation instruction to the leading spindle and detecting a feedback position signal through the absolute encoder of the leading spindle to control the position accuracy of the leading spindle; S23, controlling the following spindle to follow the rotation through the shaft synchronous coupling function and detecting the position signal in real time through the absolute encoder of the following spindle; S24, comparing the position signals of the leading spindle and the following spindle and performing compensation control on the following spindle to maintain the synchronous accuracy of the double spindles.

6. The electrochemical impression machining method of claim 5, wherein, The spindle rotation direction can be reciprocally reversed during the machining process, and the synchronous accuracy can be maintained during the reversing process.

7. The electrochemical impression machining method of claim 4, wherein The machining method comprises an outer wall rotary printing machining mode and an inner wall rotary printing machining mode: In the outer wall rotary printing machining mode, the tool is located on the outside of the workpiece, and the tool and the workpiece are reversely rotated at the same angular velocity; In the inner wall rotary printing machining mode, the tool is located on the inside of the workpiece, and the tool is co-rotated at the angular velocity of the workpiece.

Images