Tangential vibration and gradient magnetic field assisted micro-electric spark wire cutting device and method

Abstract

The present invention provides a tangential vibration and gradient magnetic field assisted micro-electro-discharge wire cutting device and method, which relates to the field of special processing technology. It includes a vibration generating component and a magnetic field generating component. The vibration generating component includes a base, two piezoelectric ceramics and a connector. The two piezoelectric ceramics are orthogonally installed on one side of the base. The connector is arranged at the orthogonal center of the two piezoelectric ceramics. The two ends of the connector are respectively connected to the two piezoelectric ceramics. A wire rack is installed on the outside of the connector. An electrode wire is installed on the wire rack. The electrode wire is arranged on the axial symmetry center line of the two piezoelectric ceramics and is perpendicular to the axial symmetry center line. The magnetic field generating component includes a mechanical arm and a magnet. The magnet is fixed on the mechanical arm. The magnet is controlled to move by the mechanical arm to generate a gradient magnetic field along the axial direction of the electrode wire. The present application adopts tangential vibration and gradient magnetic field composite auxiliary processing to accelerate the discharge of the electro-erosion products between the electrodes, lengthen the discharge channel, shallowen the discharge pit, and improve the surface quality.

Description

Technical Field

[0001] The invention relates to the technical field of special processing, in particular to a tangential vibration and gradient magnetic field assisted micro-electric spark wire cutting device and method. Background Art

[0002] Micro-EDM wire cutting is a method that uses the principle of discharge etching to create micro-straight-grain parts or structures. This processing method is not limited by the hardness and strength of the material, but is only related to the conductive and thermal properties of the material. It can process all conductive materials.

[0003] Micro-EDM wire cutting belongs to non-contact processing, but the wire cutting technology in the past has a complex wire trajectory, and often causes abnormal discharge phenomena such as arcing and short circuits due to poor removal of electrical products, which will reduce processing efficiency and affect processing accuracy. In response to the above problems, a large number of scholars have emerged to study them. Changchun University of Science and Technology in China took the lead in studying the research on micro-EDM wire cutting assisted processing. This method uses ultrasound and magnetic field to improve the inter-electrode discharge state during EDM processing, thereby improving processing efficiency and processing quality. Taiyuan University of Technology proposed magnetic field EDM composite processing. This method adds the designed electromagnet magnetic supply device to both ends of the electrode of the EDM machine tool. The magnetic field strength is 480-520 millitesla, thereby reducing the surface roughness of the parts and promoting chip removal during EDM processing. Huazhong University of Science and Technology proposed laser-induced plasma assisted EDM under the action of magnetic field. This method organically combines laser-induced plasma processing unit, EDM processing unit and composite magnetic field unit to solve processing problems such as difficult-to-process low-conductivity materials and insufficient processing quality. Harbin Institute of Technology proposed ultrasonically modulated micro-spark discharge pulses to improve processing stability and processing effects.

[0004] However, in the prior art, there is no literature reporting a micro-wire electric discharge machining method that simultaneously assists machining by tangential vibration of the electrode wire along the trajectory and gradient magnetic field along the axial direction of the electrode wire. Summary of the invention

[0005] In view of the above problems, the present invention is proposed to provide a tangential vibration and gradient magnetic field assisted micro wire electric discharge cutting device and method that overcome the above problems or at least partially solve the above problems.

[0006] In order to solve the above problems, the present invention discloses a tangential vibration and gradient magnetic field assisted micro-electric spark wire cutting device, including a vibration generating component and a magnetic field generating component, wherein the vibration generating component is installed on one side of a workpiece to be processed, and includes a base, two piezoelectric ceramics and a connecting piece, wherein the two piezoelectric ceramics are installed on the same side of the base, and the two piezoelectric ceramics are perpendicular to each other, the connecting piece is arranged at the orthogonal center of the axes of the two piezoelectric ceramics, and the two ends of the connecting piece are respectively connected to the two piezoelectric ceramics, a wire rack is installed on the outer side of the connecting piece, and an electrode wire is installed on the wire rack, and the electrode wire is arranged on the axial symmetry center line of the two piezoelectric ceramics and is perpendicular to the axial symmetry center line;

[0007] The magnetic field generating assembly is installed on one side of the workpiece to be processed and the vibration generating assembly, and includes a mechanical arm and a magnet. The magnet is fixed on the mechanical arm and is controlled to move by the mechanical arm to generate a gradient magnetic field along the axial direction of the electrode wire.

[0008] Preferably, the connecting member is pre-tightened and connected to the base via pre-tightening bolts, and the connecting member is connected to the wire rack via connecting bolts.

[0009] Preferably, the base is L-shaped, the two piezoelectric ceramics are respectively fixed on both sides of the inner corners of the L-shaped base, the bending part of the base is arc-shaped, and the pre-tightening bolt passes through the bending part of the base to be connected to the connecting piece.

[0010] Preferably, the vibration amplitude of the piezoelectric ceramic is 1 μm-2 μm.

[0011] Preferably, a plurality of mounting holes are provided on the base, and the vibration generating assembly is mounted on a mobile device through the mounting holes to control the movement of the electrode wire.

[0012] Preferably, the two piezoelectric ceramics are symmetrical along the axis of the pre-tightening bolt, and the electrode wire is arranged on the axisymmetric center line.

[0013] The present invention also provides a tangential vibration and gradient magnetic field assisted micro-electrical spark wire cutting method, comprising the following steps:

[0014] The vibration generating assembly and the magnetic field generating assembly are respectively installed on one side of the workpiece to be processed, and two mutually perpendicular piezoelectric ceramics are energized to vibrate;

[0015] Controlling the movement of the vibration generating assembly to move the electrode wire along the cutting track direction of the workpiece to be processed;

[0016] The mechanical arm is controlled to drive the magnet to move relatively along the workpiece to be processed, thereby generating a gradient magnetic field along the axial direction of the electrode wire.

[0017] Preferably, the step of controlling the robot arm to drive the magnet to move relatively along the workpiece to be processed to generate a gradient magnetic field along the axial direction of the electrode wire includes:

[0018] Calculating the motion trajectory parameters of the magnet according to the target gradient magnetic field magnitude and direction parameters between the workpiece to be processed and the electrode wire;

[0019] According to the motion trajectory parameters, the robot arm drives the magnet to move relatively along the workpiece to be processed, thereby generating a gradient magnetic field along the axial direction of the electrode wire.

[0020] The present invention includes the following advantages:

[0021] In an embodiment of the present application, a vibration generating component and a magnetic field generating component are used, and the vibration generating component is installed on one side of a workpiece to be processed, including a base, two piezoelectric ceramics and a connecting piece, the two piezoelectric ceramics are installed on the same side of the base, and the two piezoelectric ceramics are perpendicular to each other, the connecting piece is arranged at the orthogonal center of the two piezoelectric ceramics, and the two ends of the connecting piece are respectively connected to the two piezoelectric ceramics, a wire rack is installed on the outer side of the connecting piece, and an electrode wire is installed on the wire rack, and the electrode wire is arranged on the axial symmetry center line of the two piezoelectric ceramics and is perpendicular to the axial symmetry center line; the magnetic field generating component is installed on one side of the workpiece to be processed and the vibration generating component, and includes a robotic arm and a magnet, the magnet is fixed on the robotic arm, and the magnet is controlled to move by the robotic arm to generate a gradient magnetic field along the axial direction of the electrode wire. By installing two piezoelectric ceramics orthogonally and fixing the electrode wire on the axially symmetrical center line of the two piezoelectric ceramics, the combined vibration direction of the two piezoelectric ceramics is always the tangential direction of the electrode wire's motion trajectory. By exciting with different phases and amplitudes, ultrasonic vibration in any tangential direction of the motion trajectory can be generated, making it easier for the electro-etching products to separate from the processing surface. The movement of the magnet is controlled by a robotic arm to generate a gradient magnetic field along the axial direction of the electrode wire, which generates a magnetic field gradient force on the particles of the electro-etching product, accelerates the discharge of the electro-etching products, and improves the processing efficiency and the surface quality of the processed parts. The ultrasonic vibration and magnetic field will also affect the formation of the discharge channel and improve the discharge environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of a vibration sound-generating component according to an embodiment of the present invention;

[0023] Figure 2 1 is a schematic diagram of the synthesis of the vibration direction of the vibration sound-generating component in an embodiment of the present invention;

[0024] Figure 3 Schematic diagram of the movement trajectory and vibration direction of the electrode wire in an embodiment of the present invention;

[0025] Figure 4is a schematic structural diagram of a magnetic field generating assembly in an embodiment of the present invention;

[0026] Figure 5 is a schematic diagram of an axial gradient magnetic field in an embodiment of the present invention;

[0027] Figure 6 It is a flow chart of the steps of the tangential vibration and gradient magnetic field assisted micro-EDM wire cutting method in an embodiment of the present invention.

[0028] Description of the drawings: 1. Base, 2. Piezoelectric ceramics, 3. Connectors, 4. Wire racks, 5. Electrode wires, 6. Robotic arms, 7. Magnets, 8. Pre-tightening bolts, 9. Connecting bolts, 10. Mounting holes. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Reference Figure 1-Figure 6 , showing a schematic structural diagram of a tangential vibration and gradient magnetic field assisted micro-wire electric discharge cutting device according to an embodiment of the present invention;

[0031] Specifically, it may include: a vibration generating component and a magnetic field generating component, wherein the vibration generating component is installed on one side of the workpiece to be processed, and includes a base 1, two piezoelectric ceramics 2 and a connector 3, wherein the two piezoelectric ceramics 2 are installed on the same side of the base 1, and the two piezoelectric ceramics 2 are perpendicular to each other, the connector 3 is arranged at the orthogonal center of the two piezoelectric ceramics 2, and the two ends of the connector 3 are respectively connected to the two piezoelectric ceramics 2, a wire rack 4 is installed on the outer side of the connector 3, and an electrode wire 5 is installed on the wire rack 4, and the electrode wire 5 is arranged on the axial symmetry center line of the two piezoelectric ceramics 2 and is perpendicular to the axial symmetry center line;

[0032] The magnetic field generating component is installed on one side of the workpiece to be processed and the vibration generating component, and includes a robotic arm 6 and a magnet 7. The magnet 7 is fixed on the robotic arm 6 and is controlled to move by the robotic arm 6 to generate a gradient magnetic field along the axial direction of the electrode wire 5.

[0033] In an embodiment of the present application, through a vibration generating component and a magnetic field generating component, the vibration generating component is installed on one side of a workpiece to be processed, including a base 1, two piezoelectric ceramics 2 and a connector 3, the two piezoelectric ceramics 2 are installed on the same side of the base 1, and the two piezoelectric ceramics 2 are perpendicular to each other, the connector 3 is arranged at the orthogonal center of the two piezoelectric ceramics 2, and the two ends of the connector 3 are respectively connected to the two piezoelectric ceramics 2, a wire rack 4 is installed on the outer side of the connector 3, an electrode wire 5 is installed on the wire rack 4, the electrode wire 5 is arranged on the axial symmetric center line of the two piezoelectric ceramics 2, and is perpendicular to the axial symmetric center line; the magnetic field generating component is installed on one side of the workpiece to be processed and the vibration generating component, including a robotic arm 6 and a magnet 7, the magnet 7 is fixed on the robotic arm 6, and the magnet 7 is controlled to move by the robotic arm 6 to generate a gradient magnetic field along the axial direction of the electrode wire 5. By installing two piezoelectric ceramics 2 orthogonally and fixing the electrode wire 5 on the axially symmetrical center line of the two piezoelectric ceramics 2, the combined vibration direction of the two piezoelectric ceramics 2 is always the tangential direction of the motion trajectory of the electrode wire 5. By exciting with different phases and amplitudes, ultrasonic vibration in any tangential direction of the motion trajectory can be generated, making it easier for the electro-etching products to separate from the processing surface. The movement of the magnet 7 is controlled by the mechanical arm 6 to generate a gradient magnetic field along the axial direction of the electrode wire 5. The magnetic field gradient force generated on the particles of the electro-etching product accelerates the discharge of the electro-etching products and improves the processing efficiency and the surface quality of the processed parts. The ultrasonic vibration and magnetic field will also affect the formation of the discharge channel and improve the discharge environment.

[0034] Next, the tangential vibration and gradient magnetic field assisted micro wire electric discharge cutting device in this exemplary embodiment will be further described.

[0035] In one embodiment of the present application, Figure 1 As shown, the vibration generating component is installed on one side of the workpiece to be processed. Specifically, the vibration component is installed on a movable device, which can control the movement of the vibration component. The vibration component includes a base 1, two piezoelectric ceramics 2 and a connector 3. The two piezoelectric ceramics 2 are installed on the same side of the base 1, and the two piezoelectric ceramics 2 are perpendicular to each other. The connector 3 is arranged at the orthogonal center of the two piezoelectric ceramics 2. The two ends of the connector 3 are respectively connected to the two piezoelectric ceramics 2. A wire rack 4 is installed on the outer side of the connector 3. An electrode wire 5 is installed on the wire rack 4. The electrode wire 5 is arranged on the axial symmetry center line of the two piezoelectric ceramics 2 and is perpendicular to the axial symmetry center line.

[0036] In a specific embodiment, the connecting member 3 is pre-tightened by connecting bolts 8 to the base 1, and the connecting member 3 is connected to the wire rack 4 by connecting bolts 9; the base 1 is L-shaped, and the two piezoelectric ceramics 2 are respectively fixed on both sides of the inner corners of the L-shaped base 1, that is, the two piezoelectric ceramics 2 are fixed on the inner sides of the two horizontal axes and the vertical axis of the L-shape, and are respectively perpendicular to the horizontal axis and the vertical axis of the L-shape, so that the two piezoelectric ceramics 2 are perpendicular to each other, and the bending part of the base 1 is arc-shaped, and the pre-tightening bolt 8 passes through the bending part of the base 1 to be connected to the connecting member 3, and the arc-shaped bending part is more convenient for the pre-tightening bolt 8 to pass through, that is, one end of the pre-tightening bolt 8 passes through the bending part of the L-shaped base 1 and extends forward to be connected to the connecting member 3, and the outer end is locked by a nut, and the wire rack 4 is fixed to the outer wall of the connecting member 3, and is fixed by passing the connecting bolt 9 through the wire rack 4.

[0037] In a specific embodiment, the wire rack 4 is in a concave shape, and the electrode wire 5 is installed on one side of the groove of the wire rack 4 so that the electrode wire 5 can cut the workpiece to be processed.

[0038] In a specific embodiment, a plurality of mounting holes 10 are provided on the base 1, and the vibration generating assembly is mounted on a mobile device through the mounting holes 10 to control the movement of the electrode wire 5 so that the electrode wire 5 can move along the cutting track direction.

[0039] like Figure 2 As shown, by arranging the electrode wire 5 on the axially symmetrical center lines of two orthogonal piezoelectric ceramics 2, the two piezoelectric ceramics 2 are used to generate ultrasonic vibrations in two directions respectively. The direction of the ultrasonic vibration after vibration synthesis is always tangent to the electrode wire 5, so that the electrode wire 5 produces a vibration effect in the tangent direction of the trajectory, thereby promoting the discharge of the electro-corrosion products.

[0040] As an example, Figure 3 As shown, by applying different phase and amplitude excitations to the piezoelectric ceramic 2, ultrasonic vibrations in any trajectory tangential direction can be generated, and the vibration amplitude is controlled within the range of 1μm-2μm, which does not affect the cutting of the electrode wire 5 and makes it easier for the electro-etching products to detach from the processed surface.

[0041] In one embodiment of the present application, Figure 4 As shown, the magnetic field generating assembly is installed on one side of the workpiece to be processed and the vibration generating assembly, and includes a robotic arm 6 and a magnet 7. The magnet 7 is fixed on the robotic arm 6, and the magnet 7 is controlled to move by the robotic arm 6 to generate a gradient magnetic field along the axial direction of the electrode wire 5.

[0042] It should be noted that the mechanical arm 6 can be any structure that can control the movement of the magnet 7, and is not limited to the mechanical arm 6 structure shown in the drawings of the present application. Any type of mechanical arm 6 can be substituted. The mechanical arm 6 is controlled to move by an external controller. The controller receives a movement instruction. The above instruction is obtained by obtaining the size and direction parameters of the target magnetic field according to the positional relationship between the electrode wire 5 and the workpiece to be processed. According to the instruction, the magnet 7 is driven to move along a specified trajectory, so that the magnet 7 can generate a gradient magnetic field along the axial direction of the electrode wire 5 with the cutting movement of the electrode wire 5. By applying a gradient magnetic field along the axial direction of the electrode wire 5, the electro-erosion products are accelerated to be discharged from the processing area, thereby improving the processing efficiency and the surface quality of the processed parts.

[0043] As an example, Figure 5 As shown, the magnetic field generating assembly generates an adjustable gradient magnetic field along the axial direction of the electrode wire 5, thereby generating a magnetic field gradient force on the electro-erosion product, which can promote the rapid removal of debris generated by the electric spark wire cutting, improve processing efficiency, and avoid short circuit conditions.

[0044] like Figure 6 As shown, in an embodiment of the present application, a tangential vibration and gradient magnetic field assisted micro-electric spark wire cutting method is also provided, comprising the following steps:

[0045] S110, respectively installing a vibration generating assembly and a magnetic field generating assembly on one side of the workpiece to be processed, and energizing two mutually perpendicular piezoelectric ceramics 2 to cause them to vibrate;

[0046] S120, controlling the vibration generating assembly to move so that the electrode wire 5 moves along the cutting track direction of the workpiece to be processed;

[0047] S130 , controlling the robot arm 6 to drive the magnet 7 to move relatively along the workpiece to be processed, thereby generating a gradient magnetic field along the axial direction of the electrode wire 5 .

[0048] As described in step S130, the step of controlling the robot arm 6 to drive the magnet 7 to move relative to the workpiece to be processed to generate a gradient magnetic field along the axial direction of the electrode wire 5 specifically includes: calculating the motion trajectory parameters of the magnet 7 based on the target gradient magnetic field size and direction parameters between the workpiece to be processed and the electrode wire 5; and controlling the robot arm 6 to drive the magnet 7 to move relative to the workpiece to be processed to generate a gradient magnetic field along the axial direction of the electrode wire 5 based on the motion trajectory parameters.

[0049] It should be noted that the above calculation process is completed by computer software, and the running trajectory parameters of the magnet 7 are calculated according to the parameters of the required target magnetic field, so that the magnet 7 can generate a gradient magnetic field along the axial direction of the electrode wire 5 when running along its trajectory.

[0050] Beneficial effects: Tangential vibration and gradient magnetic field composite processing, while the electrode wire 5 runs along the cutting track, it is assisted by ultrasonic vibration tangential to the track. The ultrasonic vibration causes the electro-erosion products to separate from the processing surface and enter the medium. At this time, under the action of the gradient magnetic field, the electro-erosion products are accelerated to be discharged from the inter-electrode. On the other hand, ultrasonic vibration and magnetic field will also affect the formation of the discharge channel and improve the discharge environment. Ultrasonic vibration will lengthen the discharge channel, make the discharge pit shallower, and improve the surface quality, while the magnetic field will cause the discharge channel to migrate and strengthen the lifting effect.

[0051] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0052] The tangential vibration and gradient magnetic field assisted micro-electric spark wire cutting device and method provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technicians in this field, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A tangential vibration and gradient magnetic field assisted micro-electrical discharge wire cutting device, characterized in that: It includes a vibration generating component and a magnetic field generating component. The vibration generating component is installed on one side of a workpiece to be processed, and includes a base, two piezoelectric ceramics and a connecting piece. The two piezoelectric ceramics are installed on the same side of the base, and the two piezoelectric ceramics are perpendicular to each other. The connecting piece is arranged at the orthogonal center of the axes of the two piezoelectric ceramics. Both ends of the connecting piece are respectively connected to the two piezoelectric ceramics. A wire rack is installed on the outer side of the connecting piece. An electrode wire is installed on the wire rack. The electrode wire is arranged on the axial symmetry center line of the two piezoelectric ceramics and is perpendicular to the axial symmetry center line. The magnetic field generating assembly is installed on one side of the workpiece to be processed and the vibration generating assembly, and includes a mechanical arm and a magnet. The magnet is fixed on the mechanical arm and is controlled to move by the mechanical arm to generate a gradient magnetic field along the axial direction of the electrode wire.

2. The tangential vibration and gradient magnetic field assisted micro-wire electric discharge cutting device according to claim 1, characterized in that: The connecting piece is pre-tightened by connecting with the base through pre-tightening bolts, and the connecting piece is connected with the wire rack through connecting bolts.

3. The tangential vibration and gradient magnetic field assisted micro-electric discharge wire cutting device according to claim 2, characterized in that: The base is L-shaped, and the two piezoelectric ceramics are respectively fixed on both sides of the inner corners of the L-shaped base. The bending part of the base is arc-shaped, and the pre-tightening bolt passes through the bending part of the base to be connected with the connecting piece.

4. The tangential vibration and gradient magnetic field assisted micro-wire electric discharge cutting device according to claim 1, characterized in that: The vibration amplitude of the piezoelectric ceramic is 1 μm-2 μm.

5. The tangential vibration and gradient magnetic field assisted micro-wire electric discharge cutting device according to claim 1, characterized in that: The base is provided with a plurality of mounting holes, through which the vibration generating assembly is mounted on a mobile device to control the movement of the electrode wire.

6. The tangential vibration and gradient magnetic field assisted micro-wire electric discharge cutting device according to claim 2, characterized in that: The two piezoelectric ceramics are symmetrical along the axis of the pre-tightening bolt, and the electrode wire is arranged on the axisymmetric center line.

7. A tangential vibration and gradient magnetic field assisted micro-electrical discharge wire cutting method, characterized in that: The method is based on the device according to any one of claims 1 to 6, comprising the following steps: The vibration generating assembly and the magnetic field generating assembly are respectively installed on one side of the workpiece to be processed, and two mutually perpendicular piezoelectric ceramics are energized to vibrate; Controlling the movement of the vibration generating assembly to move the electrode wire along the cutting track direction of the workpiece to be processed; The mechanical arm is controlled to drive the magnet to move relatively along the workpiece to be processed, thereby generating a gradient magnetic field along the axial direction of the electrode wire.

8. The tangential vibration and gradient magnetic field assisted micro-wire electric discharge cutting method according to claim 7, characterized in that: The step of controlling the robot arm to drive the magnet to move relatively along the workpiece to be processed to generate a gradient magnetic field along the axial direction of the electrode wire includes: Calculating the motion trajectory parameters of the magnet according to the target gradient magnetic field magnitude and direction parameters between the workpiece to be processed and the electrode wire; According to the motion trajectory parameters, the robot arm drives the magnet to move relatively along the workpiece to be processed, thereby generating a gradient magnetic field along the axial direction of the electrode wire.

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