JPH05200659A - Ultrasonic polishing device - Google Patents

Abstract

PURPOSE:To perform a highly accurate abrasion in a short time by installing an ultrasonic wave generating means so as to be connected to a stacked piezoelectric actuator and to do its in-plane vibration on a polished surface. CONSTITUTION:Voltage is impressed on each of stacked piezoelectric actuators 3, 4, therefore a vibro-amplitude conformed to this voltage is produced there. An ultrasonic vibration out of these actuators 3 and 4 due to this vibro- occurrence is inclined as far as the specified angle from the normal direction of a polished surface 6, so that it reciprocates an elastic body 2 and an abrasive wheel 1 in the circumferential direction as shown in an arrow, exciting the ultrasonic vibration. With this vibration, glass polishing surfaces 9, 10 and 11 on a work clamping table 8 are finished up to the specified surface roughness in a short time. In addition, an abrasive fluid gets into each contact surface between the abrasive wheel 1 and these glass faces 9, 10 and 11, and the ultrasonic vibration of the abrasive wheel 1 is also transferred even to this abrasive fluid 14, vibrating abrasive grains in this fluid 14 at high speed, thus abrasion is yet more promoted in this way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing device that uses ultrasonic vibrations in polishing glass such as lenses and prisms.

[0002]

2. Description of the Related Art A technique for grinding glass such as lenses or prisms by using ultrasonic vibration is known. As literatures on polishing by this ultrasonic vibration,
For example, there is JP-A-64-78748. According to FIG. 1 shown in the publication, the technical content described in this publication is that an electrostrictive material (or a magnetostrictive material) 2 is adhered and fixed to the upper surface of an annular ultrasonic vibrating body 1. A traveling wave of ultrasonic vibration that circulates in the ring is generated in the vibrating body 1. A radial notch is formed on the tip surface of the circular ultrasonic vibrating body 1 so as to increase the amplitude of the ultrasonically propagating ultrasonic traveling wave and propagate it to the grindstone to improve the grinding vibration effect. I have to. Therefore, a grindstone 3 is fixedly mounted on the tip of the ultrasonic vibrating body 1 and the surface to be polished is pressed.

However, in the grinding device according to the above publication, the amplitude obtained by ultrasonic vibration of a traveling wave is usually about 3 μm (outer diameter φ609 wavelength, applied voltage 150 Vp
-P), it is necessary to increase the wavelength or increase the applied voltage to obtain a large amplitude. However, increasing the wavelength increases the outer diameter of the vibrating body,
Since the voltage exceeds 200 Vp-p, safety is a serious problem. Therefore, the conventional traveling wave ultrasonic polishing apparatus is
Although it is suitable for precision polishing performed with a small vibration amplitude, it is not suitable for rough polishing that requires a large amplitude.

Further, the present ultrasonic wave generating means for generating a traveling wave is a ring-shaped vibrating body for reversing the polarization direction of a piezoelectric element (electrostrictive material) at every constant wavelength or for expanding the amplitude of the vibrating body. Forming notches that are cut radially at the tip of
There were also problems such as extremely high costs.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a simple structure and is inexpensive, and is a compact ultrasonic polishing apparatus capable of polishing a wide range of applications from rough polishing to precision polishing. It is intended to provide.

[0006]

DISCLOSURE OF THE INVENTION The present invention is an ultrasonic polishing apparatus for polishing by using ultrasonic vibration, and a workpiece fixing table rotatably provided with an object to be polished on its surface, and this workpiece. A polishing grindstone that is placed on the upper surface of an object to be polished on a fixed table and configured to grind the object to be polished, and a polishing shaft that is integrally provided on the upper surface of this polishing grindstone and that is connected to the driving means on the upper surface. An elastic body, a laminated piezoelectric actuator disposed on the elastic body, and an ultrasonic vibration generation unit that is connected to the laminated piezoelectric actuator to generate in-plane vibration on a polishing surface or elliptical vibration perpendicular to the polishing surface. And an abrasive liquid that transmits ultrasonic vibration generated by the ultrasonic wave generating means.

[0007]

In the ultrasonic polishing apparatus having the above-described structure, the in-plane vibration of the standing wave vibrating on the polishing surface of the grinding wheel and the elliptical vibration of the standing wave vibrating perpendicular to the polishing surface are generated, and the ultrasonic polishing is performed. Done. The standing wave ultrasonic vibration generating means includes a laminated piezoelectric actuator, a Langevin vibrator, etc., and by using these, a large amplitude vibration amplitude can be obtained at a low voltage. A large amount of polishing reduces the polishing time. The in-plane vibration and the elliptical vibration are transmitted not only to the grinding wheel but also to the grinding liquid, and the polishing effect is improved by the action of the ultrasonic vibration of the abrasive grains contained in the grinding wheel.
Further, the standing wave ultrasonic wave generating means is advantageous in that it can be manufactured at a relatively low cost, and the large amplitude ultrasonic wave vibration generating means can be made smaller than the traveling wave ultrasonic wave polishing means.

[0008]

Embodiment 1 A specific example of the present invention will be described with reference to the drawings. 1 is a first embodiment of an ultrasonic polishing apparatus according to the present invention.
It is a front view which shows the principal part. FIG. 2 is A-A shown in FIG.
It is a top view from a line. Reference numeral 1 shown in the drawing is a grinding wheel having an annular shape and a thickness of 5 to 10 mm and a width of 3 to 8 mm. The polishing whetstone 1 is configured to contain diamond abrasive grains and a metal bond or a resin bond. Also,
On the upper surface of the polishing grindstone 1 is integrally formed an elastic body 2 having the same diameter and formed of a material such as bronze, aluminum alloy, duralumin, stainless steel, or the like, which is capable of efficiently transmitting the displacement of the piezoelectric element by a material having excellent vibration transmission. Have been installed. At the center position of the upper surface of the elastic body 2, a cylindrical polishing shaft 5 having a base end connected to a driving means is arranged to make the elastic body 2 and the polishing grindstone 1 movable up and down. It is configured to reciprocate in the indicated arrow (left and right) direction.

Oval grooves 29 and 30 are formed on the upper surface of the elastic body 2 in a direction inclined at a constant angle from the normal direction, and the centers of the grooves 29 and 30 are inclined at a constant angle. The laminated piezoelectric actuators 3 and 4 (10 × 10 −18 mm), which are configured to have a rectangular shape so as to be displaced, are fixed and mounted with an epoxy adhesive. Further, the moisture-proof resin 30, 3 is provided in the gap formed in the oval shape between the laminated piezoelectric actuators 3, 4 and the elastic body 2.
1, 32, 33 are buried respectively. The laminated piezoelectric actuators 3 and 4 are connected in parallel, and an alternating voltage is applied by a drive circuit (not shown) to reciprocate the elastic body 2 and the polishing grindstone 1 in parallel with the polishing surface 5 (arrows). ) Is configured to be.

On the polishing surface (lower surface) 5 of the polishing grindstone 1, a work fixing base 8 having a diameter larger than that of the polishing grindstone 1 is arranged. On the upper surface of the work fixing table 8, glass 9, 10, 11 which is a polishing object is adhered and fixed by a hot melt adhesive. Further, at the center position of the lower surface of the work fixing base 8, a cylindrical work fixing base shaft 7 connected to the drive means is attached to the base end thereof, and the polishing objects 9, 10, 11 are evenly ground. The polishing shaft 4 is arranged so as to be driven with a constant gap therebetween. The work fixing table 8
At the upper position of the polishing liquid 14, the polishing liquid 14 is supplied from the pipe 13 connected to the polishing liquid supply means to the polishing object (glass) 9, 10, 1.
1 is configured to jet.

Next, the operation of this embodiment having the above structure will be described. Glass 9,1 fixed on the work fixing table 8
The polishing grindstone 1 and the elastic body 2 are lowered onto the upper surfaces of 0 and 11,
While rotating the work fixing table 8 at 6 to 300 rpm,
The polishing liquid 14 is jetted from the pipe 13 onto the glass 9, 10, 11. Then, a voltage is applied to the laminated piezoelectric actuator. By this application, a vibration amplitude according to the voltage is generated (amplitude of about 10 μm is generated at an applied voltage of 50 Vp-p and a driving frequency of 25 kHz). Since the ultrasonic vibrations from the actuators 3 and 4 caused by this generation are inclined at a predetermined angle from the normal direction of the polishing surface 6, the elastic body 2 and the polishing grindstone 1 reciprocate in the circumferential direction as shown by the arrow. , Exciting ultrasonic vibration.

The above-mentioned vibration promotes the polishing of the glass 9, 10, 11 on the work fixing base 8, and the glass 9, 1
The 0, 11 polished surface can be finished to a predetermined surface roughness in a short time. Further, the polishing liquid enters between the contact surfaces of the polishing grindstone 1 and the glass 9, 10, 11 and ultrasonic vibrations of the polishing grindstone 1 are transmitted to the polishing liquid 14 to vibrate the abrasive grains in the polishing liquid 14 at high speed. By this, polishing is further promoted.

According to this embodiment having the above structure and operation,
Since the laminated piezoelectric actuator is used, the device can be manufactured in a small size, a large amplitude can be easily obtained even in the non-resonance state, and almost no heat is generated. Further, since the device is constructed only by fixing and mounting the small-sized laminated piezoelectric actuator to the elastic body with the adhesive, it is possible to manufacture at a very low cost. In addition, the in-plane vibration of the standing wave accelerates the polishing, and it can be shortened to about one-third of the normal (conventional) polishing time. The polishing surface is also very dense compared to the normal polishing. Can be formed into Further, when performing rough polishing, if the applied voltage is raised to 100 Vp-p, the amplitude increases to about 20 μm, and rough polishing can be performed. On the contrary, if the voltage is lowered, precise polishing can be formed more densely, but about 1 μm
If the vibration width is less than the above, the polishing effect by ultrasonic waves will decrease.

[0014]

Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a cross-sectional view from the front showing the essential part of the polishing dish of the second embodiment of the ultrasonic polishing apparatus according to the present invention.
FIG. 4 is a top view taken along the line BB shown in FIG. In the drawings, the same members, shapes and configurations as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 21 shown in the drawing has a thickness of 5 to 10 mm and a width of 3
It is a disk-shaped polishing grindstone having a size of up to 8 mm. The polishing grindstone 21 is configured to contain diamond abrasive grains and a metal bond or a resin bond. On the upper surface of the polishing grindstone 21, an elastic body having the same diameter as that of the polishing grindstone 21 is formed of a material having excellent vibration transmission, such as bronze, aluminum alloy, duralumin, and stainless steel, and configured to efficiently transmit the displacement of the piezoelectric element. 22 is integrally fixed

Notches 23, 24, 25 are formed in the elastic body 22 at a desired depth and at equal intervals on the circumferential edge of the elastic body 22, and the laminated piezoelectric actuator () is formed inside the notches 23, 24, 25. 10 × 10-18 mm) 26, 27, 2
8 is bonded and embedded with an adhesive. Further, between the laminated piezoelectric actuators 26 and 27, 27 and 28, and 28 and 26 embedded in the circumferential edge of the elastic body 22, a bar 29 for supporting and fixing the polishing shaft 5 implanted in the center is provided. ，
30 and 31 are installed. Ie bars 29 and 30, 3
Between 0 and 31, 31 and 29, fan-shaped recesses 32, 33 and 34 are formed to form a polishing dish. The laminated piezoelectric actuators 26, 27, 28
Are connected in parallel to each other, an alternating voltage is applied by a drive circuit (not shown), and the polishing grindstone 21 is reciprocated in an arc in a direction indicated by an arrow through the elastic body 22. The other configurations are omitted as in the first embodiment.

The operation of this embodiment having the above structure will be described. When a voltage is applied to the laminated piezoelectric actuators 26, 27 and 28, ultrasonic vibration reciprocates in an arc shape on the polishing surface 6. Therefore, the abrasive grains of the polishing liquid 14 can be easily taken in (inserted) between the polishing grindstone 21 and the glasses 9, 10, 11. Further, by adjusting the driving frequency of the laminated piezoelectric actuators 26, 27, 28 to the resonance frequency of the bending mode in the circumferential direction of the elastic body 22, a large vibration amplitude at resonance can be obtained.

According to this embodiment having the above-mentioned structure and operation,
During precision polishing, the actuator is driven with a non-resonant drive frequency, and during rough polishing, the drive is performed with a resonance drive frequency, so that the drive frequency can be changed at a constant voltage to perform rough polishing and precision polishing. It is very efficient because it can be selected and polished. In addition, it has an advantage that it can be made very compact.

[0018]

Third Embodiment A third embodiment of the ultrasonic polishing apparatus of the present invention will be described with reference to FIGS. 5 and 6. FIG. 5 is a front sectional view showing a main part of a polishing dish of an ultrasonic polishing apparatus according to a third embodiment of the present invention. FIG. 6 is an enlarged view showing the polarization direction of the piezoelectric element shown in FIG. In the drawings, the same members, shapes and configurations as those of the first and second embodiments are designated by the same reference numerals and the description thereof will be omitted. On the upper surface of the ring-shaped polishing grindstone 1 shown in the figure, an elastic body 38 that efficiently transmits the displacement of the piezoelectric element 36 is made of a material having excellent vibration transmission such as phosphor bronze, aluminum alloy, duralumin, and stainless steel. Etc. are fixed integrally. As shown in FIG. 6, on the upper surface of the elastic body 38, a piezoelectric element 36 having a diameter of 1 mm and having a thickness of 1 mm for generating a torsional vibration 39 polarized in an oblique direction 37 is formed by an adhesive. Etc. are fixed integrally.

An alternating voltage (not shown) is applied to a desired circumferential end of the piezoelectric element 39 by an externally provided drive circuit to cause the elastic body 38 and the polishing grindstone 1 to twist and vibrate 39 parallel to the polishing surface 6. It is configured as follows. In addition, the piezoelectric element 3
A polishing shaft 5 is planted in the center of the upper surface of 6 and is attached to a support member (not shown) so that it can be moved up and down.

According to the polishing dish having the above structure, the piezoelectric element 36
Is polarized in the oblique direction 37 in advance, it is possible to cause torsional vibration of the polishing grindstone 1 in parallel to the polishing surface 6 simply by applying an alternating voltage to the piezoelectric element 36. You can

According to the present embodiment having the above-described structure and operation, since the elastic body 38 is provided with the piezoelectric element 36 which generates the torsional vibration 39 polarized in the oblique direction 37, the polishing grindstone 1
The mechanism that generates torsional vibration can be significantly downsized. Further, by stacking a large number of piezoelectric elements 36 of 1 mm in thickness for sliding vibration, a large amplitude can be generated, and by controlling the magnitude of the applied voltage, it is possible to perform a wide range of polishing processes from rough polishing to precision polishing. There is.

[0022]

Fourth Embodiment A fourth embodiment of the ultrasonic polishing apparatus of the present invention will be described with reference to FIG. FIG. 7 is a front view showing a main part of a fourth embodiment of the ultrasonic polishing apparatus according to the present invention. In addition,
In the drawings, the same members, shapes and configurations as those of the above-mentioned first embodiment or second and third embodiments are designated by the same reference numerals, and the description thereof will be omitted. On the upper surface of the ring-shaped grinding wheel 1 shown in the figure, the grinding wheel 1 is made of a material having excellent vibration transmission, such as phosphor bronze, aluminum alloy, duralumin, and stainless steel having a polishing shaft 40 planted in the center of the upper surface. An elastic body 41 formed to have the same diameter as that of is integrally attached by an adhesive or the like.

In the polishing shaft 40 connected to the elastic body 41, as shown in the figure, a piezoelectric element 42 that generates secondary vibration and a piezoelectric element 43 that generates torsional vibration are made of the same material as the elastic body 41, that is, It is sandwiched by a resonator 44 made of a material such as phosphor bronze, aluminum alloy, duralumin, and stainless steel and having the same diameter as the polishing shaft 40, and is integrally attached to the shaft center by a fixing bolt 45 made of stainless steel. Is fixed by pressure bonding to a Langevin oscillator 46.

A two-phase alternating piezoelectric having a quarter wavelength shift is applied to the above-mentioned piezoelectric elements 42 and 43 by a drive circuit (not shown) to generate an elliptical vibration 47 perpendicular to the polishing surface 6 of the polishing wheel 1. The polishing object 9 is polished at high speed. Since the Langevin oscillator 46 is used for the ultrasonic vibration generating means, a very large vibration amplitude is generated at the resonance frequency even at a low voltage. Further, since the vibration state is the elliptical vibration, the polishing grindstone 1 instantaneously floats from the polishing object 9 such as glass, the grinding liquid 14 is easily taken in (entered) between the polishing surfaces 6, and the vibration is generated. Since it works perpendicularly to the polishing surface 6, it can be polished at a very high speed. The device can be manufactured at a low cost, for example, by simply fixing the piezoelectric elements 42 and 43 with a resonator with bolts 45 to obtain a Langevin vibrator which is an ultrasonic vibration generating means.
Furthermore, since the polishing time can be shortened and the polishing surface 6 acts perpendicularly, it is extremely effectively used especially in rough polishing.

[0025]

According to the present invention having the above-described structure and operation, an ultrasonic wave which causes an in-plane vibration of a standing wave vibrating on the polishing surface of a grinding wheel and an elliptical vibration of a standing wave vibrating perpendicularly to the polishing surface. Since a laminated piezoelectric actuator, a Langevin oscillator, or the like is used as the vibration generating means, a large amplitude vibration can be obtained at a low voltage. Therefore, the polishing time can be shortened and the rough polishing and the fine polishing can be selected according to the use. Further, since the in-plane vibration and the elliptical vibration are transmitted not only to the polishing grindstone but also to the polishing liquid, the abrasive grains are present between the polishing object and the polishing surface, the polishing effect is improved, and highly accurate polishing is performed in a short time. You can In addition, since the standing wave ultrasonic wave generation means can be easily attached, various effects can be obtained such that the apparatus can be made compact and inexpensive.

[Brief description of drawings]

FIG. 1 is a front view showing a main part of a first embodiment of an ultrasonic polishing apparatus according to the present invention.

FIG. 2 is a top view taken along the line AA shown in FIG.

FIG. 3 is an explanatory diagram showing a main part of a polishing dish of an ultrasonic polishing apparatus according to a second embodiment of the present invention.

FIG. 4 is a top view taken along the line BB shown in FIG.

FIG. 5 is a front view showing a main part of a polishing dish of an ultrasonic polishing apparatus according to a third embodiment of the present invention.

6 is an enlarged plan view showing a polarization direction of the piezoelectric element shown in FIG.

FIG. 7 is a front view showing a main part of an ultrasonic polishing apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 1,21 Polishing whetstone 2,22,38,41 Elastic body 3,4,26,27,28 Laminated piezoelectric actuator 5,40 Polishing shaft 6 Polishing surface 7 Work fixing base shaft 8 Work fixing base 9,10,11 Polishing Material (glass) 13 Pipe 14 Polishing liquid 15,16 Groove 17,18,19,20 Resin 23,24,25 Notch 29,30,31 Bar 32,33,34 Recess 35 Venting 36 Piezoelectric element 37 Diagonal direction 39 Torsional vibration 42 Vertical piezoelectric element 43 Torsional piezoelectric element 44 Resonator 45 Fixing bolt 46 Langevin oscillator 47 Elliptical vibration

Claims (2)

[Claims] 1. An ultrasonic polishing apparatus for polishing using ultrasonic vibration, wherein a workpiece fixing table rotatably provided on the surface of the workpiece fixing table, and an object to be polished on the workpiece fixing table. A polishing grindstone that is placed on the upper surface of the grinding wheel and configured to grind an object to be ground; an elastic body that is integrally provided on the upper surface of the grinding grindstone and that has a polishing shaft that is connected to the driving means on the upper surface; A laminated piezoelectric actuator disposed on the body, an ultrasonic wave generation means connected to the laminated piezoelectric actuator so as to vibrate in-plane on a polishing surface, and a polishing for transmitting ultrasonic vibration by the ultrasonic wave generation means. An ultrasonic polishing apparatus comprising: a liquid. 2. An ultrasonic polishing apparatus for polishing using ultrasonic vibration, wherein a work fixing table rotatably provided on the surface of which a workpiece is arranged, and an object to be polished on the workpiece fixing table. Mounted on the upper surface of the polishing grindstone, configured to grind an object to be polished, an elastic body integrally provided on the upper surface of the grinding grindstone, and an elastic body having a polishing shaft connected to the driving means on the upper surface; A laminated piezoelectric actuator disposed on the body, an ultrasonic vibration generating means that is connected to the laminated actuator and generates elliptical vibration perpendicular to the polishing surface, and a polishing liquid that transmits ultrasonic vibration by the ultrasonic generating means. An ultrasonic polishing apparatus comprising: