High frequency, small amplitude vibration-assisted laser cladding apparatus and method for large workpieces

Abstract

The present invention discloses a high-frequency, small-amplitude vibration-assisted laser cladding apparatus and method for large workpieces. In the apparatus, parallel wavy cams are installed coaxially and with equal phase difference and mounted on the main shaft of an upper stationary box. The wavy cams are short-amplitude outer linear cams. The parallel wavy cams and corresponding cantilever beams form a vibration source. The corresponding cantilever beam assemblies are mounted inside a lower movable box. The upper stationary box assembly and the lower movable box assembly form a closely spaced movable pair. The lower movable box is mounted on a vibration receiving plate. The right end of the high-natural frequency spring is fixedly supported by a pair of high-natural frequency springs, the lower end of which is fixedly supported by a frame. The wavy cams are driven by a motor via a pulley. The amplitude of the processed workpiece can be adjusted according to needs, and the vibration frequency of the processed workpiece can be changed by changing the number of wavy cams and the corresponding cantilever beams. This method is particularly applicable to grain refinement, stress relief, homogeneous phases, and forged structure formation through vibration-assisted laser cladding.

Description

[Technical Field]

[0001] The present invention relates to the mechanical vibration technology field of a vibrator device that can achieve 500Hz-1000Hz and an amplitude of 5μm-50μm, and particularly to a high-frequency, fine-amplitude vibration-assisted laser cladding device and method for large workpieces. [Background technology]

[0002] Laser cladding, a typical additive remanufacturing technology, boasts advantages such as good formability, dense structure, fine grains, and a relatively small heat-affected zone, and is being continuously promoted in industrial fields such as remanufacturing and surface strengthening. However, the intensive heat input and high solidification rate of the molten pool in laser cladding can lead to defects such as uneven distribution of elements and hard phase additives, segregation, and porosity, preventing this technology from achieving better forming quality. Therefore, optimizing the laser cladding process to improve the performance of the cladding layer is urgently needed based on the defect generation mechanism.

[0003] High-frequency, small-amplitude mechanical vibration is an effective auxiliary process for destroying dendrites during casting or welding, refining crystal grains, promoting turbulence in the molten pool, improving the uniform distribution of elements and hard phases, promoting gas discharge, and reducing residual stress, thereby significantly improving the mechanical properties of the workpiece. Laser cladding is a rapid solidification and cooling process, and conventional high-frequency, small-amplitude mechanical vibration cannot achieve the above effects during laser cladding of large workpieces. Therefore, a vibration exciter with a frequency of 500 Hz to 1000 Hz and an amplitude of 5 μm to 50 μm is required. In the present invention, a vibration exciter with a frequency of 800 Hz is used as a parameter, and the desired objectives are achieved in practice.

[0004] The main forms of realizing mechanical vibration are as follows:

[0005] (1) Eccentric and centrifugal type vibrators have a simple structure, but they vibrate circularly and at low frequencies.

[0006] (2) The electrohydraulic type vibration exciter device has a large amplitude but a narrow frequency range (100-150Hz).

[0007] (3) Hydraulic and pneumatic vibration exciter devices have small amplitudes and low frequencies.

[0008] (4) Electromagnetic and magnetostrictive exciters have high frequencies (up to 10,000 Hz), small amplitudes (less than 50 μm), and extremely small excitation forces, making it difficult to drive large mass exciter platforms. For laser surface strengthening and remanufacturing of medium- to large-sized workpieces, it is necessary to develop high-frequency, fine-amplitude equipment suitable for laser cladding strengthening or remanufacturing of large workpieces. Summary of the Invention [Problem to be solved by the invention]

[0009] technical purpose To address the above technical issues, the present invention proposes a high-frequency, small-amplitude vibration-assisted laser cladding apparatus and method for large workpieces, which can generate vibrations of 500Hz-1000Hz and 5μm-50μm, and is particularly applicable to grain refinement, stress relief, homogeneous phase and forged structure formation through vibration-assisted laser cladding. [Means for solving the problem]

[0010] To achieve the above objectives, the present invention adopts the following technical solutions:

[0011] High frequency, small amplitude vibration assisted laser cladding equipment for large workpieces: a frame located at the bottom of the device; a bracket installed on the frame to which an upper stationary box having an open bottom is supported and connected; a main shaft mounted within the upper stationary box and rotatably supported and connected at both ends to the upper stationary box; a plurality of wave-shaped cams attached to the main shaft at equal phase differences along the axial direction of the main shaft; a lower movable box having an open top and installed below the bottom opening of the upper stationary box, the inner wall of the lower movable box and the outer wall of the upper stationary box being slidably and hermetically connected, a cantilever beam being provided in the lower movable box corresponding to each wave cam in the upper stationary box, the cantilever end of the cantilever beam contacting the wave cam via a rolling element, and the bottom of the lower movable box being supported on the frame via a high natural frequency spring; a vibration receiving plate disposed horizontally on the frame, one end of which is hingedly connected to a frame hinge disposed at one end of the frame, a lower movable box attached to the other end, and a workpiece attached to an intermediate region of the vibration receiving plate, the one end of which is attached to the lower movable box being connected to a high natural frequency spring to form a simply supported beam; and a motor for driving the main shaft to rotate, thereby rotating a plurality of wavy cams installed with equal phase difference on the main shaft, wherein the convex portion of the wavy cam excites the rolling element at the end of the cantilever beam to generate a downward displacement, and when it rotates into the concave portion of the wavy cam, the cantilever beam is reset by elastic rebound, up to which point the system completes a single excitation, and the vibration generated by the cantilever beam is transmitted to the vibration receiving plate via the cantilever beam and the fixed support end of the lower movable box, causing the workpiece mounted on the vibration receiving plate to receive high-frequency micro-vibrations exceeding 800 Hz.

[0012] The vibration receiving plate is provided with a long groove for adjusting the vertical distance between the workpiece and the lower movable box.

[0013] The upper stationary box includes a top cover, a left open-end cover, and a right closed-end cover, the left open-end cover and the top cover being welded together, and the right closed-end cover and the top cover being connected together with bolts.

[0014] The rolling elements are rolling bearings connected to the ends of the cantilever beams, and the rolling bearings contact the outer contour of the wave cam, converting sliding friction between the members into rolling friction. The length of the cantilever beams is half the width of the lower movable box, and the cantilever beam assemblies are fixedly supported in two rows on both the left and right sides of the lower movable box.

[0015] A groove is drilled on the inside periphery of the lower movable box and a polytetrafluoroethylene plate is placed in it, thereby realizing sealing and lubrication between the inside of the lower movable box and the outside of the upper stationary box, and the outer surface of the upper stationary box and the inner surface of the lower movable box form a movable pair. Lubricating oil is injected into the inside of the lower movable box to cover the rolling elements at the cantilever end of the cantilever, thereby reducing friction and removing heat.

[0016] The upper end of the high natural frequency spring supports the vibration receiving plate, and the lower end is fixedly connected to the frame.

[0017] The output shaft of the motor is transmitted to the main shaft at a variable speed by a pair of pulleys, and a motor biasing device for biasing the belt drive device is fixed on the frame.

[0018] The high natural frequency spring is a rigid arc-shaped shaft segment with a certain curvature, with a pin hole drilled at the end of the rigid arc-shaped shaft segment. The natural frequency of the rigid arc-shaped shaft segment is 1300 Hz or more, and the stiffness is 14.3 kN / mm or more. It can output micron-level amplitude and meet the needs of vibration test benches.

[0019] The present invention further discloses a method for vibrating a workpiece using the high-frequency, small-amplitude vibration-assisted laser cladding device for large workpieces, in which the processed workpiece is fixed on the vibration receiving plate through the through-hole on the fixture, and the motor is energized, thereby rotating the main shaft of the motor and causing a plurality of wavy cams installed on the main shaft with equal phase difference to rotate, the convex part of the wavy cam excites the rolling element at the end of the cantilever beam to generate a downward displacement, and when it rotates into the concave part of the wavy cam, the cantilever beam is reset by elastic rebound, and up to this point, the system has completed a single excitation; The vibration generated by the cantilever beam is transmitted to the vibration receiving plate through the fixed support end of the lower movable box, and the workpiece mounted on the vibration receiving plate receives high-frequency micro-vibrations exceeding 800 Hz; The long groove can change the distance position between the workpiece on the vibration receiving plate and the lower movable box, and can change the amplitude of the processed workpiece within the range of 5 μm to 50 μm. By changing the motor rotation speed, the vibration frequency of the machined workpiece can be changed within the range of 500Hz to 1000Hz. [Effects of the Invention]

[0020] The present invention provides a high-frequency, small-amplitude vibration-assisted laser cladding apparatus for large workpieces, which finally achieves the effects of grain refinement, stress relief, uniform phase distribution, and forged structure during the laser strengthening and remanufacturing process, and has the following technical advantages over conventional apparatuses:

[0021] 1. This invention relates to a high-frequency, small-amplitude vibration-assisted laser cladding device for large workpieces, in which parallel wavy cams and corresponding cantilevers arranged coaxially and with equal phase difference generate vibrations of 500Hz-1000Hz and 5μm-50μm, the wavy cams are short-amplitude outer line cams with any order of differential continuity, and the cantilever assembly corresponding to the wavy cams is driven by a rolling bearing attached to the right end of the cantilever and a unilateral force from the wavy cam, and the elasticity of the cantilever is used to realize the return of displacement, thereby reducing the impact of double-sided contact on manufacturing errors and deformation. The cantilever assembly is excited and displaced, and then resets using its own elasticity, thereby avoiding high manufacturing precision.

[0022] 2. The present invention uses a high natural frequency spring made of 65Mn material to support the box section, which has a high natural frequency and meets the needs of high-frequency, small-amplitude vibration.

[0023] 3. The upper stationary box assembly and the lower movable box assembly described in the present invention form a closely spaced movable pair, thereby isolating the vibration of the device from the drive system, and the upper stationary box assembly and the brackets on both ends form fixed hinges, realizing stable and continuous transmission of drive.

[0024] 4. In the working area of ​​the vibration receiving plate, the present invention uses the long groove to adjust the vertical distance between the workpiece and the lower movable box, thereby adjusting the amplitude of the workpiece. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 2 is a power transmission diagram of the device according to the present invention. [Figure 2] FIG. 2 is a schematic view of the installation of a wave cam of the device according to the present invention. [Figure 3] 1 is a logic diagram of a short-amplitude outer line of a device according to the invention; [Figure 4] FIG. 1 is a front view of a wave cam of a device according to the present invention. [Figure 5]FIG. 1 is a mechanical model diagram of a cantilever beam of a device according to the present invention. [Figure 6] FIG. 1 is an isometric view of a cantilever assembly of a device according to the present invention. [Figure 7] FIG. 1 is an isometric view of a lower movable box assembly of the apparatus of the present invention. [Figure 8] 1 is an isometric view of the cantilevered joint plate of the lower movable box of the device according to the present invention. FIG. [Figure 9] 1 is a schematic diagram of the upper stationary box assembly of the apparatus of the present invention; FIG. [Figure 10] 1 is a schematic diagram of the assembly of the upper box and the lower box of the device according to the present invention. FIG. [Figure 11] 1 is a schematic diagram of the engagement between the wave cam and the cantilever beam of the device according to the present invention; FIG. [Figure 12] 1 is a schematic diagram of a high natural frequency spring for a device according to the invention; FIG. [Figure 13] 1 is an isometric view of a frame of the device according to the invention; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0026] In order to help those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below with reference to the drawings of the present invention, and any other embodiments obtained by those skilled in the art based on the embodiments of the present application without requiring creative work will also fall within the scope of protection of the present application. In addition, the directional terms such as "up", "down", "left", "right", "inside", "outside" and the like mentioned in the following embodiments only refer to the directions in the drawings, and therefore the use of directional terms is for explanation rather than limitation of the present invention.

[0027] Example As shown in FIG. 1, for a high frequency, small amplitude vibration-assisted laser cladding apparatus for large workpieces, a motor 71 transmits torque to a large pulley 74 through a small pulley 73 with a certain transmission ratio.

[0028] As shown in Figure 2, the torque of the large pulley 74 is transmitted to the main shaft 12 by the large pulley key 75, and the main shaft is supported and fixed by deep groove ball bearings 14 at both ends, and the wavy cam key 13 transmits the power of the main shaft 12 to the wavy cam 11, and a total of 10 wavy cams (four wavy cams at the ends are hidden for ease of observation) are attached to the shaft with equal phase differences, thereby increasing the number of excitations per unit time.

[0029] Specifically, as shown in Figures 3 and 4, the profile of the wavy cam 11 is designed using parametric equations, and through holes 111 are drilled around the periphery to reduce the mass of the component. A boss 112 is machined in the center to fix the position on the shaft, and at the same time, a key groove 113 is machined. The thickness of the wheel rim of the wavy cam 11 is slightly larger than the thickness of the cantilever rolling bearing 23.

[0030] As shown in Figures 5 and 6, the relevant calculation parameters of the cantilever 21 are shown in Figure 5. The cantilever assembly 2 is composed of a cantilever 21, a support shaft 22, and a rolling bearing 23. The rolling bearing 23 is positioned through a positioning pin 24, thereby ensuring that it is aligned with the contour surface of the wave cam 11. A through hole 211 is drilled at the fixed support end of the cantilever 21 for connecting the cantilever connecting plate 51 of the lower movable box.

[0031] As shown in FIG. 7, the length of the cantilever beams 21 is half the length of the side connecting plates 53, the cantilever beam assemblies 2 on both sides of the lower movable box are arranged in a staggered manner, five pairs of cantilever beam assemblies 2 are fixedly supported on the cantilever beam connecting plates 51 by cylindrical elastic pins 52, and there is a groove 511 near the top for embedding a polytetrafluoroethylene plate, and the two symmetrical cantilever beam connecting plates 51, two symmetrical side connecting plates 53, and one bottom plate 54 are welded to one complete open-top box.

[0032] Specifically, as shown in FIG. 8, the cantilever beam joining plate 51 is made by welding a long flat plate with a groove 511 to a fixed block 512 with a through hole, and the fixed block 512 with a through hole is concentric with the through hole of the cantilever beam 21 and is fixed by a cylindrical elastic pin 52.

[0033] As shown in FIG. 9, the left side of the upper stationary box 6 is formed by welding an open end cover 61 and a top cover 62, and the right closed end cover 63 is connected to the bracket 81 via six screw blocks 621 welded on the top cover 62, with the left end cover boss 611 and the right end cover boss 631. A bearing seat is provided inside the end cover to mount the deep groove ball bearing 14 of the main shaft. After assembling the wave cam assembly 1, the right closed end cover 63 is covered and connected to the top cover 62 via six bolts through the through holes 632 to form a complete lower open box.

[0034] As shown in Figures 10 and 11, the upper stationary box 6 is supported by a bracket 81, a main shaft 12 is mounted inside the upper stationary box 6, and the main shaft 12 is supported on a bearing seat in the boss of the end cover via a deep groove ball bearing 14. The length and width of the inner wall of the lower movable box are slightly larger than those of the outer wall of the upper stationary box 6. Ten wavy cams 11 are mounted along the axis of the main shaft 12, offset at a certain angle, and each wavy cam 11 corresponds to a set of lower cantilever beam assemblies 2. Each wavy cam 11 drives the cantilever beams 21 to displace downward continuously at equal intervals, thereby generating continuous and stable vibration. The lower movable box is supported by high natural frequency springs 3.

[0035] Specifically, as shown in FIG. 12, the high natural frequency spring 3 is composed of two quarter circles, connectors 31 at both ends, and a limiting portion 32. The upper connector and the vibration receiving plate 41 are connected by an elastic pin 42, and the lower connector and the frame 8 are also connected by an elastic pin 42. This limits the horizontal degree of freedom of the spring, and when the upper end is subjected to a vibration force, the spring only deforms slightly in the vertical direction.

[0036] As shown in FIG. 13, the high natural frequency spring 3 is connected to the vibration receiving plate 41 and the frame 8 by an elastic pin 42, the other end of the vibration receiving plate 41 is a hinge 411, which is connected to the frame hinge 82 by a pin shaft 43, the workpiece to be processed is attached to the working area of ​​the vibration receiving plate 41, and the vertical distance between the workpiece and the lower movable box can be adjusted through the long groove 412, and the amplitude can be adjusted, and the motor driving device 72 is fixed to the frame 8 to realize the driving of the belt drive device.

[0037] The mechanical model of the cantilever beam is shown in Figure 5, where the cantilever beam is a thin plate (b × h × 1) made of 65Mn spring steel, where h is the thickness of the cantilever beam, b is the width of the cantilever beam, and 1 is the length of the cantilever beam. Moment of inertia J of the cantilever beam along the center of gravity axis y =b×h 3 / 12, and the stiffness of the cantilever beam is k=3EJ y / 1 3 where E is the elastic modulus of the 65Mn material; Elastic restoring force

number

[0038] Calculate the mass m1 of a single cantilever based on the length 1 of the thin cantilever, the width b of the cantilever, and the thickness h of the cantilever. The concentrated mass m at the end of the cantilever is determined by the rolling bearing. When calculating, the mass of the cantilever is equivalent to the end, m e The mass of the vibration displacement point is m0=m e +m.

[0039] Natural circular frequencies of a single cantilever beam

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[0040] On the short-amplitude outer line of the moving point on the outer-ring planetary gear shown in FIG. 3, assuming that the radius of the circle is r3, the radius of the moving circle is r2, the distance from the point P on the moving circle to the center 02 is b (b < r2), and φ1 is the included angle between the line connecting the centers and the x-axis, the parametric equations of the P point on the curve with respect to the x and y axes are represented by trigonometric functions, then

Number

[0041] The above describes in detail only the preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and various modifications may be made within the scope of knowledge of those skilled in the art without departing from the scope of the present invention, and all such modifications should be included in the scope of protection of the present invention. [Explanation of symbols]

[0042] 01 Cam center 02 Roller center r2 roller radius φ1 The angle between the line connecting the centers of the circles and the x-axis b(b <r2) 移動円上の点pからその円心02までの距離h thickness of the cantilever b Width of cantilever 1. Length of cantilever beam m1 Mass of the cantilever beam m Mass of the roller at the end of the cantilever beam S is the deformation of the cantilever end of the cantilever beam F Force acting on the cantilever end d diameter of the rolling element at the cantilever end of the cantilever beam R1 Top quarter arc R2: Lower quarter arc 11 Wave Cam 111 through hole 112 Boss 113 Keyway 12 spindle 13 Wavy Cam Key 14 Deep groove ball bearing 2. Cantilever Assembly 21 Cantilever beam 211 Through hole 22 Support shaft 23 Rolling bearings 24 Locating pin 3 High natural frequency springs 31 Connectors on both ends 32 Restricted Section 4 Vibration receiving plate 411 Hinge 412 Long Groove 42 Elastic pin 43 pin shaft 51 Cantilever beam joint plate 511 Groove 512 Fixing block with through holes 52 Cylindrical elastic pin 53 Side joint plate 54 Bottom plate 61 Left side open end cover 611 Left end cover boss 62 Top cover 621 Screw Block 63 Right closed end cover 631 Right end cover boss 632 through hole 71 Motor 72 Motor energizing device 73 Small Pulley 74 Large Pulley 75 Large Pulley Key 81 Bracket 82 Frame hinge

Claims

1. 1. A high frequency, small amplitude vibration assisted laser cladding apparatus for large workpieces, comprising: a frame located at the bottom of the device; a bracket installed on the frame to which an upper stationary box having an open bottom is supported and connected; a main shaft mounted within the upper stationary box and rotatably supported and connected at both ends to the upper stationary box; a plurality of wave-shaped cams attached to the main shaft at equal phase differences along the axial direction of the main shaft; a lower movable box having an open top and installed below the opening at the bottom of the upper stationary box, the inner wall of the lower movable box and the outer wall of the upper stationary box being slidably and hermetically connected, a cantilever beam being provided in the lower movable box corresponding to each wave cam in the upper stationary box, the cantilever end of the cantilever beam contacting the wave cam via a rolling element, and the bottom of the lower movable box being supported on the frame via a high natural frequency spring; a vibration receiving plate disposed horizontally on the frame, one end of which is hingedly connected to a frame hinge disposed at one end of the frame, a lower movable box attached to the other end, and a workpiece attached to an intermediate region of the vibration receiving plate, the one end of which is attached to the lower movable box being connected to a high natural frequency spring to form a simply supported beam; and a motor for driving the main shaft to rotate, thereby rotating a plurality of wavy cams installed with equal phase difference on the main shaft, wherein the convex portion of the wavy cam excites the rolling element at the end of the cantilever beam to generate a downward displacement, and when it rotates into the concave portion of the wavy cam, the cantilever beam is reset by elastic rebound, up to this point the system completes a single excitation, and the vibration generated by the cantilever beam is transmitted to the vibration receiving plate via the cantilever beam and the fixed support end of the lower movable box, and the workpiece mounted on the vibration receiving plate obtains high-frequency micro-vibration of more than 800 Hz.

2. 2. The high-frequency, small-amplitude vibration-assisted laser cladding apparatus for large workpieces as claimed in claim 1, wherein the vibration receiving plate is provided with a long groove for adjusting the vertical distance between the workpiece and the lower movable box.

3. 2. The high-frequency, small-amplitude vibration-assisted laser cladding apparatus for large workpieces according to claim 1, wherein the upper stationary box includes a top cover, a left open-end cover, and a right closed-end cover, the left open-end cover and the top cover are welded together, and the right closed-end cover and the top cover are connected together with bolts.

4. 2. The high-frequency, fine-amplitude vibration-assisted laser cladding apparatus for large workpieces as claimed in claim 1, wherein the rolling elements are rolling bearings connected to the ends of cantilever beams, the rolling bearings contact the outer contour of the wave cam to convert sliding friction between the members into rolling friction, the length of the cantilever beam is half the width of the lower movable box, and the cantilever beam assemblies are fixedly supported in two rows on both the left and right sides of the lower movable box.

5. 2. The high-frequency, small-amplitude vibration-assisted laser cladding apparatus for large workpieces according to claim 1, characterized in that a groove is drilled on the inner periphery of the lower movable box and a polytetrafluoroethylene plate is placed therein to realize sealing and lubrication between the inside of the lower movable box and the outside of the upper stationary box, the outer surface of the upper stationary box and the inner surface of the lower movable box form a movable pair, and lubricating oil is injected into the inside of the lower movable box to cover the rolling elements at the cantilever ends of the cantilever beams, thereby reducing friction and dissipating heat.

6. 2. The high-frequency, small-amplitude vibration-assisted laser cladding apparatus for large workpieces as claimed in claim 1, wherein the upper end of the high-natural frequency spring supports a vibration receiving plate, and the lower end is fixedly connected to a frame.

7. 2. The high-frequency, small-amplitude vibration-assisted laser cladding apparatus for large workpieces as claimed in claim 1, wherein the output shaft of the motor is transmitted to the main shaft at a variable speed by a pair of pulleys, and a motor driving device is fixed on the frame to realize the driving of the belt driving device.

8. 2. The high frequency fine amplitude vibration-assisted laser cladding apparatus for large workpieces as claimed in claim 1, wherein the high natural frequency spring is a rigid arc-shaped shaft segment with a certain curvature, and a pin hole is drilled at the end of the rigid arc-shaped shaft segment, the natural frequency of the rigid arc-shaped shaft segment is 1300 Hz or more, and the stiffness is 14.3 kN / mm or more, and the output amplitude is at the micron level, which can meet the use needs of a vibration test stand.

9. A method for vibrating a workpiece using the high-frequency, small-amplitude vibration-assisted laser cladding apparatus for large workpieces according to any one of claims 2 to 8, comprising: The processed workpiece is fixed on the vibration receiving plate through the through hole on the fixture, and the motor is energized, causing the motor's main shaft to rotate, and the multiple wave cams installed on the main shaft with equal phase difference are driven to rotate, and the convex part of the wave cam excites the rolling element at the end of the cantilever beam to generate a downward displacement, and when it rotates into the concave part of the wave cam, the cantilever beam is reset by elastic rebound, and up to this point, the system has completed a single excitation; The vibration generated by the cantilever is transmitted to the vibration receiving plate via the cantilever and the fixed support end of the lower movable box, and the workpiece mounted on the vibration receiving plate receives high-frequency micro-vibrations exceeding 800 Hz; The distance position between the workpiece on the vibration receiving plate and the lower movable box can be changed through the long groove, and the amplitude of the processed workpiece can be changed within the range of 5 μm to 50 μm; The method for vibrating a workpiece using the high-frequency, small-amplitude vibration-assisted laser cladding device for large workpieces according to any one of claims 2 to 8, characterized in that the vibration frequency of the processed workpiece can be changed within the range of 500Hz to 1000Hz by changing the motor rotation speed.

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