JP3112542B2 - Ultrasonic polishing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus using ultrasonic vibration in polishing glass such as lenses and prisms.

[0002]

2. Description of the Related Art A technique for grinding a glass such as a lens or a prism using ultrasonic vibration is known. Literature on polishing by ultrasonic vibration includes:
For example, there is JP-A-64-78748. According to the technical content described in this publication, according to FIG. 1 shown in the publication, an electrostrictive material (or a magnetostrictive material) 2 is adhered and fixed to the upper surface of a ring-shaped ultrasonic vibrator 1, and the excitation vibration A traveling wave of ultrasonic vibration circulating in the ring is generated in the vibrator 1. A notch cut radially is formed at the tip end surface of the annular ultrasonic vibrating body 1 so that the amplitude of the ultrasonically propagating ultrasonic wave that propagates and propagates to the grindstone to improve the grinding vibration effect. I have to. For this purpose, a grindstone 3 is fixed to the tip of the ultrasonic vibrator 1 and the surface to be polished is processed by pressing.

However, in the grinding apparatus disclosed in the above publication, the amplitude obtained by the ultrasonic vibration of the traveling wave is usually about 3 μm (outer diameter φ609 wavelength, applied voltage 150 Vp
-P), in order to obtain a large amplitude, the wavelength must be increased or the applied voltage must be increased. However, if the wavelength is increased, the outer diameter of the vibrator increases,
Since the voltage also exceeds 200 Vp-p, safety is a major 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 requiring a large amplitude.

[0004] The present ultrasonic wave generating means for generating a traveling wave includes a ring-shaped vibrating body for inverting the polarization direction of a piezoelectric element (electrostrictive material) at every predetermined wavelength or for expanding the vibrating body in amplitude. To form a notch radially cut at the tip of the
Problems such as extremely high costs also occurred.

[0005]

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

[0006]

According to the present invention, there is provided an ultrasonic polishing apparatus for performing polishing using ultrasonic vibration, a work fixing table provided rotatably and having an object to be polished disposed on its surface,
A polishing grindstone configured to be mounted on the upper surface of the object to be polished on the work fixing table to polish the object to be polished, and provided integrally with the upper surface of the polishing wheel, and connected to the driving means at a central position on the upper surface. An elastic body provided with a polishing shaft and embedded in this elastic body,
A lamination type piezoelectric actuator provided so that the polishing grindstone is reciprocated in the circumferential direction through the elastic body by its own ultrasonic vibration to be excited and vibrated in the plane of the standing wave on the polishing surface; And a polishing liquid for transmitting ultrasonic vibrations from the piezoelectric actuator.

[0007]

The ultrasonic polishing apparatus having the above-described structure generates an in-plane vibration of a standing wave on the polishing surface of the polishing grindstone to perform ultrasonic polishing. The use of the above-mentioned laminated piezoelectric actuator allows a large amplitude of vibration to be obtained at a low voltage, so that the polishing amount is large and the polishing time is reduced as compared with ordinary ultrasonic polishing. The in-plane vibration is transmitted not only to the polishing grindstone but also to the polishing liquid, and the polishing effect is improved by the action of the ultrasonic vibration of the abrasive grains contained in the polishing grindstone. Further, the actuator as the standing wave ultrasonic wave generating means has advantages such as that it can be manufactured relatively inexpensively, and the vibration generating means of the large amplitude ultrasonic wave can be made smaller than the ultrasonic polishing means of the traveling wave. is there.

[0008]

Embodiment 1 A specific example of the present invention will be described with reference to the drawings. FIG. 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 of. FIG. 2 is a sectional view taken along the line AA shown in FIG.
It is a top view from a line. Reference numeral 1 shown in the figure is an annular grinding wheel having a thickness of 5 to 10 mm and a width of 3 to 8 mm. This polishing wheel 1 is configured to contain diamond abrasive grains and a metal bond or a resist bond. Also,
An elastic body 2 is formed on the upper surface of the grinding wheel 1 with the same diameter and made of a material that transmits vibration of the laminated piezoelectric actuator efficiently, such as bronze, aluminum alloy, duralumin, stainless steel, etc. Are integrally mounted. At the center of the upper surface of the elastic body 2, a column-shaped polishing shaft 5 whose base end is connected to a driving means is disposed, and the elastic body 2 and the polishing grindstone 1 are configured to be movable up and down. It is configured to reciprocate in the indicated arrow (left-right) direction.

Oval grooves 15 and 16 are formed on the upper surface of the elastic body 2 in a direction inclined at a certain angle from the normal direction, and the center of each of the grooves 15 and 16 is formed in a direction inclined at a constant angle. Laminated piezoelectric actuators 3 and 4 (10 × 10-18 mm) each having a rectangular shape so as to be displaced are fixedly mounted with an epoxy-based adhesive. Moisture-proof resins 17, 18, 19, and 20 are embedded in gaps formed between the laminated piezoelectric actuators 3, 4 and the oval-shaped grooves of the elastic body 2, respectively. The laminated piezoelectric actuators 3 and 4 are connected in parallel, apply an alternating voltage by a drive circuit (not shown), and reciprocate the elastic body 2 and the polishing wheel 1 in parallel with the polishing surface 6 (arrows). ) Is configured to be.

On the side of the polishing surface (lower surface) 6 of the polishing grindstone 1, a work fixing base 8 having a larger diameter than the polishing grindstone 1 is provided. Glasses 9, 10, and 11, which are abrasives, are adhered and fixed to the upper surface of the work fixing table 8 by a hot melt adhesive. At the center of the lower surface of the work fixing table 8, a columnar work fixing table shaft 7 connected to a driving means is mounted at the base end thereof to uniformly polish the polished objects 9, 10 and 11. It is disposed so as to be driven in a state of being shifted from the polishing shaft 13 by a predetermined distance. At a position above the work fixing table 8, a polishing liquid 14 is polished with a polishing object (glass) 9, 1 from a pipe 13 connected to a polishing liquid supply means.
It is configured to squirt onto 0,11.

Next, the operation of this embodiment having the above-described configuration will be described. Glass 9, 1 fixed on work fixing table 8
The polishing wheel 1 and the elastic body 2 are lowered on the upper surfaces of 0 and 11,
While rotating the work fixing table 8 at 6 to 300 rpm,
A polishing liquid 14 is jetted onto the glass 9, 10, 11 from a pipe 13. Subsequently, a voltage is applied to the multilayer piezoelectric actuator. By this application, a vibration amplitude corresponding to the voltage is generated (approximately 10 μm amplitude 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 shaft 5, the elastic body 2 and the polishing grindstone 1 reciprocate in the circumferential direction as shown by the arrow. Excitation of ultrasonic vibration.

The above-mentioned vibration accelerates the polishing of the glasses 9, 10, 11 on the work fixing table 8, and the glass 9, 1
The polished surfaces 0 and 11 can be finished to a predetermined surface roughness in a short time. Also, the polishing liquid enters between the contact surfaces of the polishing grindstone 1 and the glasses 9, 10, and 11, and the ultrasonic vibration of the polishing grindstone 1 is also transmitted to the polishing liquid 14, causing the abrasive grains in the polishing liquid 14 to vibrate at high speed. Thereby, polishing is further promoted.

According to this embodiment having the above configuration and operation,
Since the laminated piezoelectric actuator is used, the device can be manufactured in a small size, a large amplitude is easily obtained even at the time of non-resonance, and heat is hardly generated. Further, since the device is constituted only by fixing and mounting the small-sized laminated piezoelectric actuator to the elastic body with an adhesive, it can be manufactured at very low cost. In addition, the polishing is promoted by the in-plane vibration of the standing wave, and the polishing time can be reduced to about one third as compared with the normal (conventional) polishing time. The polished surface is also very dense as compared with the normal polishing. Can be formed. In the case of performing rough polishing, if the applied voltage is increased to 100 Vp-p, the amplitude increases to about 20 μm, and rough polishing can be performed. Conversely, when the voltage is lowered, precision polishing can be formed more densely.
If the vibration width is less than or equal to, the polishing effect by the ultrasonic wave decreases.

[0014]

Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a sectional view from the front showing a main part of a polishing plate of an ultrasonic polishing apparatus according to a second embodiment of the present invention.
FIG. 4 is a top view from line BB shown in FIG. In the drawing, the same members, the same shape and the same configuration as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. Reference numeral 21 shown in the figure indicates a thickness of 5 to 10 mm and a width of 3
It is an annular grinding wheel formed to a size of about 8 mm. The polishing grindstone 21 has a configuration containing diamond abrasive grains and a metal bond or a resin bond. The upper surface of the grinding wheel 21 has the same diameter as the grinding wheel 21 made of a material having excellent vibration transmission, such as bronze, aluminum alloy, duralumin, and stainless steel, so as to efficiently transmit the displacement of the laminated piezoelectric actuator. The elastic body 22 is integrally fixed.

In the elastic body 22, notches 23, 24, 25 are formed at a desired depth and at equal intervals on the periphery of the circumference, and a laminated piezoelectric actuator (not shown) is formed inside the notches 23, 24, 25. 10 × 10-18 mm) 26, 27, 2
8 is buried by bonding with an adhesive. Further, between the laminated piezoelectric actuators 26 and 27, 27 and 28, and 28 and 26 buried in the peripheral edge of the elastic body 22, a bar 29 for supporting and fixing between the polishing shaft 5 implanted at the center is provided. ,
30 and 31 are provided. That is, bars 29 and 30, 3
Between each of 0 and 31, and 31 and 29, fan-shaped recesses 32, 33, and 34 are formed to constitute 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 reciprocates in an arc in the direction shown by the arrow via the elastic body 22. Other configurations are omitted as in the first embodiment.

The operation of this embodiment having the above configuration will be described. When a voltage is applied to the laminated piezoelectric actuators 26, 27, 28, the vibration of the ultrasonic wave reciprocates in an arc shape on the polishing surface 6. For this reason, the abrasive grains of the polishing liquid 14 are easily taken in (inserted) between the polishing grindstone 21 and the glasses 9, 10, 11. Further, by adjusting the driving frequency of the multilayer 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 the time of resonance can be obtained.

According to this embodiment having the above configuration and operation,
In the case of precision polishing, the actuator is driven at a non-resonant drive frequency.In the case of rough polishing, the actuator is driven at a resonant drive frequency. Is very efficient because it can be selectively polished. In addition, there is an advantage that a very compact design can be achieved.

[0018]

According to the present invention having the above configuration and operation, the laminated piezoelectric actuator is used as the ultrasonic vibration generating means for generating the in-plane vibration of the standing wave on the polishing surface of the polishing grindstone. A large amplitude vibration is obtained. Therefore, the polishing time can be shortened, and rough polishing and fine polishing can be selected for each application. In addition, the in-plane vibration of the standing wave is transmitted not only to the polishing grindstone but also to the polishing liquid, so that the abrasive grains are interposed between the polished object and the polished surface, so that the polishing effect is improved, and high-precision polishing is shortened. Can be in time. Further, since the actuator, which is a means for generating ultrasonic vibration of standing waves, can be easily mounted, the apparatus can be reduced in size,
In addition, various effects such as being able to be inexpensive are achieved.

[Brief description of the 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 line AA shown in FIG.

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

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

[Explanation of symbols]

 1,21 Polishing whetstone 2,22,38 Elastic body 3,4,26,27,28 Laminated piezoelectric actuator 5 Polishing shaft 6 Polishing surface 7 Work fixing table shaft 8 Work fixing table 9,10,11 Polished 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

Continuation of the front page (56) References JP-A-63-114855 (JP, A) JP-A-63-236577 (JP, A) JP-A-3-234451 (JP, A) JP-A-3-213257 (JP) , A) JP-A-64-78748 (JP, A) JP-A-64-20956 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B24B 1/04 B24B 7/04

Claims (1)

(57) [Claims] 1. An ultrasonic polishing apparatus for performing polishing using ultrasonic vibration, comprising: a work fixing table rotatably provided, and a work to be polished disposed on a surface thereof; A polishing whetstone configured to polish an object to be polished placed on the upper surface of the polishing whetstone; an elastic body provided integrally with the upper surface of the polishing whetstone, and provided with a polishing shaft connected to a driving means at a central position on the upper surface; A lamination buried in this elastic body and provided so as to be excited by the reciprocating movement of the polishing grindstone in the circumferential direction through the elastic body by its own ultrasonic vibration, and to vibrate the standing wave in the plane on the polishing surface. An ultrasonic polishing apparatus, comprising: a piezoelectric actuator; and a polishing liquid for transmitting ultrasonic vibration by the laminated piezoelectric actuator.