JP2011110693A - Grinding tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinding tool of small grinding resistance, hard to cause a partial abrasion of a grinding wheel. <P>SOLUTION: This grinding tool 1 connects two connecting parts 3a and 3b of an annular grinding wheel installing plate, to a support plate 10 vertically fixed to a rotary shaft 8 in a lower end of the rotary shaft 8, with an unillustrated bolt. The grinding wheel installing plate 2 has the ring-shaped connecting parts 3a and 3b connected to a ring-shaped grinding wheel holding part 4 and the support plate 10 for holding the grinding wheel 5, and is also adhered to the upper surface of the grinding wheel installing plate 2 using an epoxy resin by making the average diameter of an annular ultrasonic vibrator 7 coincide with the average diameter of the ring-shaped connecting parts 3a and 3b. The grinding tool 1 is fixed to the lower end of the rotary shaft 8 with, for example, the bolt 9. The grinding wheel installing plate 2 has the ring-shaped grinding wheel holding part 4. A peripheral groove 6 is formed on the lower surface of the grinding wheel holding part 4. The grinding wheel 5 is fitted and fixed to this peripheral groove 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polishing tool used for polishing the surface of an object to be polished.

  Conventionally, a sapphire substrate, a glass substrate, a silicon carbide substrate, a silicon substrate, an alumina-titanium carbide substrate, or the like has been used for manufacturing electronic components. The surfaces of these substrates are polished smoothly using a polishing apparatus comprising a polishing tool including an annular grindstone and a driving device thereof.

  The polishing tool disclosed in Patent Document 1 has an annular support plate (connection plate) fixed to the lower end portion of the rotation shaft of the drive device perpendicularly to the rotation shaft, and a plurality (6 in total) below the support plate. An annular grindstone mounting plate (annular elastic body) supported by a connecting member (connecting portion) and having an annular grindstone mounted on the lower surface, and a plurality (6 in total) of super wheels fixed to the grindstone mounting plate It consists of a sound wave vibrator.

  The width of each connecting member (the length along the radial direction of the grindstone mounting plate) is made equal to the width of the grindstone mounting plate. By screwing the bolts into the screw holes of the support plate, the screw holes of the connection members, and the screw holes of the connection members, the support plate and the grindstone mounting plate are fixed to each other via the plurality of connection members.

  In a polishing apparatus provided with a polishing tool, the surface of an object to be polished is polished as follows. First, the rotating shaft of the driving device is rotated together with the polishing tool. Next, by applying electrical energy (eg, AC voltage) to each ultrasonic transducer, ultrasonic vibration is generated in each transducer. Since this ultrasonic vibration is applied to the grindstone via the grindstone mounting plate, the grindstone vibrates ultrasonically. Then, the surface of the polishing object is polished by bringing the grindstone of the polishing tool into contact with the polishing object.

  The part between the connection members adjacent to each other on the grindstone mounting plate of the polishing tool is likely to vibrate ultrasonically as compared with the part connected to the connection member. Therefore, the ultrasonic vibration generated by each ultrasonic vibrator is hardly transmitted to the rotating shaft via the connecting member and the support plate, and most of the vibration is applied to the grindstone via the grindstone mounting plate. For this reason, the grindstone vibrates ultrasonically with a large amplitude. As a result, the frictional resistance between the grindstone and the object to be polished is reduced, heat generation is suppressed by this friction, and thermal expansion and alteration of the object to be polished are suppressed, so that polishing is performed on the surface of the object to be polished. ing.

  In the polishing tool disclosed in Patent Document 2, the annular grindstone has an annular outer groove on the outer peripheral surface of the disk portion fixed to the lower end portion of the rotating shaft of the driving device and the cylindrical portion extending downward from the periphery thereof, and An annular inner groove is formed on the peripheral surface. The sum of the depths of the grooves is set larger than the thickness of the cylindrical portion. Therefore, the groove and the groove are formed in the cylindrical portion with a space therebetween in the vertical direction.

  In the polishing tool, the ultrasonic vibration generated by the ultrasonic vibrator is reflected by the ultrasonic reflecting surface formed from the interface between the cylindrical portion and the air layer inside the groove, and most of the ultrasonic vibration is reflected in the groove of the cylindrical portion. It is applied to the grindstone through the lower part. For this reason, it describes that the surface of a grinding | polishing target object is grind | polished with high precision.

  International Publication No. 06/137453 Pamphlet   International Publication No. 08/108463 Pamphlet

  In the polishing tool disclosed in Patent Document 1, the portion connected to the connecting member of the grindstone mounting plate is relatively smaller in ultrasonic vibration than the other portions, and therefore the grindstone mounted on the grindstone mounting plate corresponding to the connecting member. The ultrasonic vibration of this part is also small. For this reason, uneven wear of the grindstone (the grindstone is worn unevenly in the circumferential direction) may cause a reduction in polishing accuracy due to long-term use.

  In the polishing tool disclosed in Patent Document 2, ultrasonic vibration is likely to occur in parallel with the polishing surface of the polishing object in order to polish the surface of the polishing object with high accuracy. However, the ultrasonic vibration in the direction perpendicular to the polishing surface is small compared to the direction parallel to the polishing surface. In order to reduce the polishing resistance, it is desired that the ultrasonic vibration in the vertical direction is larger than that in the parallel direction.

  An object of the present invention is to provide a polishing tool in which uneven wear of a grindstone hardly occurs and the polishing resistance is small.

  The present invention has a support plate fixed perpendicularly to the rotating shaft at the lower end of the rotating shaft, two concentric ring-shaped connecting portions on the annular grindstone mounting plate, and There is a grindstone holding part in the center of the connection part and the inner peripheral connection part, and the two connection parts of the grindstone mounting plate and the support plate are connected, and are continuous or discontinuous to the grindstone holding part of the grindstone mounting plate. A polishing tool is provided in which an annular grindstone is mounted and an ultrasonic vibrator is fixed to the grindstone mounting plate.

  The polishing tool of the present invention can reduce the frictional force between the object to be polished and the grindstone, so that the polishing rate can be improved, and the heat generation of the object to be polished and the grindstone can be reduced. You can get a plane.

It is sectional drawing which shows the structural example of the polishing tool of this invention. It is sectional drawing of the grinding | polishing tool cut | disconnected along the cutting line AA entered in FIG. It is the schematic explaining the vibration mode conversion of a grindstone mounting plate.

  The configuration of the polishing tool of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a configuration example of the polishing tool of the present invention, and FIG. 2 is a cross-sectional view of the polishing tool cut along a cutting line AA written in FIG.

  The polishing tool 1 shown in FIGS. 1 and 2 has two connection portions 3a and 3b of an annular grindstone mounting plate on a support plate 10 fixed to the lower end portion of the rotation shaft 8 perpendicularly to the rotation shaft 8. Are connected by bolts (not shown). The grindstone mounting plate 2 has a ring-shaped grindstone holding portion 4 that holds the grindstone 5 and ring-shaped connecting portions 3 a and 3 b that are connected to the support plate 10. In addition, the upper surface of the grindstone mounting plate 2 is bonded using an epoxy resin so that the average radius of the annular ultrasonic transducer 7 is matched with the average radius of the ring-shaped connecting portions 3a and 3b.

  The polishing tool 1 is fixed to the lower end portion of the rotating shaft 8 using, for example, a bolt 9. As the drive device, for example, the drive device provided in the polishing apparatus described in Patent Document 1 or Patent Document 2 can be used. The rotating shaft may be arranged in the horizontal direction. In this case, the “upper side” of the polishing tool of the present invention means the side of the support plate, and the “lower side” means the side of the grindstone.

  The support plate 10 fixes the connecting portions 3a and 3b of the grindstone mounting plate using, for example, bolts (not shown). Here, the connecting portions 3 a and 3 b of the grindstone mounting plate may be separated from the grindstone mounting plate 2. And you may join the grindstone mounting plate 2 and the connection parts 3a and 3b with a volt | bolt, or it may join with an adhesive agent.

  The grindstone mounting plate 2 has a ring-shaped grindstone holding portion 4. The ring-shaped grindstone holding part 4 may have a shape in which the ring becomes narrower as the grindstone 5 approaches. This is because the grinding stone 5 is not given unnecessary vibration in the radial direction. A circumferential groove 6 is formed on the lower surface of the grindstone holding portion 4. A grindstone 5 is fitted into the circumferential groove 6 and fixed. The grindstone holding part 4 and the grindstone 5 can also be fixed using an adhesive, for example. In addition, there is no restriction | limiting in particular in each fixing method of the rotating shaft 8 and the support plate 10, the connection parts 3a and 3b of the support plate 10 and a grindstone mounting plate, and the grindstone holding part 4 and the grindstone 5 of a grindstone mounting plate.

  Since a material with small attenuation of ultrasonic vibration is suitable for the grindstone mounting plate 2, the material of the grindstone mounting plate 2 is formed from a metal material typified by, for example, aluminum, bronze, stainless steel, aluminum alloy, and titanium alloy. can do.

  As the annular grindstone 5, for example, a grindstone (continuous annular grindstone) set in a continuous annular shape by binding abrasive grains represented by diamond abrasive grains with metal bonds or resin bonds is used. Can do. Usually, the average particle diameter of the abrasive grains is set within a range of 0.1 to 50 μm.

  As the annular grindstone 5, an “aggregate of a plurality of (for example, 2 to 200) grindstone pieces arranged in a ring” (discontinuous annular grindstone) can be used. The discontinuous annular grindstone is easy to create (particularly when the diameter of the annular grindstone is large) as compared to the continuous annular grindstone. Further, since the stress generated in the grindstone during polishing is reduced, the occurrence of breakage of the grindstone is suppressed.

  In the polishing tool 1, twelve arc-shaped ultrasonic transducers 7 are used, which are combined to form an annular shape. As the ultrasonic vibrator 7, for example, a piezoelectric vibrator having a configuration in which an electrode layer is provided on each of an upper surface and a lower surface of a piezoelectric body is used.

  Examples of the piezoelectric material include lead zirconate titanate-based piezoelectric ceramic materials. For example, the piezoelectric body is polarized in the thickness direction (vertical direction in FIG. 1). Examples of the material for the electrode layer include metal materials such as silver, gold, and phosphor bronze.

  The ultrasonic vibrator 7 is fixed to the grindstone mounting plate 2 using, for example, an epoxy resin. It is preferable to fix to the upper surface of the grindstone mounting plate 2. Thereby, an electrical short circuit of the electrode layers on the upper and lower surfaces of the ultrasonic vibrator 7 through the grinding auxiliary liquid (typical example, water) supplied to the surface of the object to be polished at the time of polishing is prevented.

  The ultrasonic vibrator 7 generates ultrasonic vibration when electrical energy generated by a power source is attached to the electrode layer. This ultrasonic vibration is applied to the grindstone 5 via the grindstone mounting plate 2. The ultrasonic transducer 7 and the power source are electrically connected to each other via, for example, a rotary transformer or a slip ring. The electrical connection method between the ultrasonic vibrator 7 and the power source is described in detail in each of Patent Document 1 and Patent Document 2 described above.

  As shown in FIG. 3, the present inventor provides an annular grindstone mounting plate 2 with an outer peripheral support portion 3a and an inner peripheral support portion 3b, and by fixing the end faces of the support portions 3a and 3b, It has been proposed to excite the wheel 5 substantially perpendicular to the surface of the object to be polished.

  By exciting the vibration mode indicated by the dotted line in FIG. 3, ultrasonic vibration in the direction perpendicular to the surface of the object to be polished can be generated in the grindstone 5. This ultrasonic vibration can reduce the frictional resistance between the grindstone 5 and the object to be polished, thereby suppressing heat generation due to friction between the grindstone 5 and the object to be polished, suppressing thermal expansion of the object to be polished, and increasing the surface of the object to be polished. It can be polished accurately. Similarly, since the heat generation of the grindstone 5 is suppressed, the life of the grindstone 5 is extended.

  The frequency of the AC voltage applied to the ultrasonic vibrator 7 of the polishing tool 1 can be determined as follows, for example. The natural vibration mode of the grindstone mounting plate 2 to which the grindstone 5 is mounted and the ultrasonic transducer 7 is fixed under the condition that the end faces of the connecting portions 3a and 3b of the grindstone mounting plate are fixed by the finite element method is calculated. Then, the natural frequency of the desired vibration mode is calculated in advance.

  Next, the frequency characteristic of the ultrasonic vibrator 7 fixed to the grindstone mounting plate 2 on which the actual grindstone 5 is mounted is measured using, for example, an impedance analyzer. Then, the frequency of the alternating voltage having the peak of the frequency characteristic close to the natural frequency of the desired natural vibration mode calculated using the finite element method is applied to the ultrasonic vibrator 7 bonded to the grindstone mounting plate 2.

  And in order to confirm that it is a desired vibration mode, the displacement amount of the ultrasonic vibration of the grindstone 5 and the grindstone mounting plate 2 is measured, for example with a laser Doppler vibrometer.

  The position of the ultrasonic vibrator 7 of the polishing tool 1 is preferably substantially at the center of the connection portion between the outer periphery and the inner periphery of the grindstone mounting plate 2. In addition, the shape of the ultrasonic transducer 7 is preferably an arc shape. A plurality of these are arranged into an annular shape. The interval between adjacent arc-shaped ultrasonic transducers should be as small as possible. Desirably, the spacing is 1 mm or less. This is to provide uniform vibration in the entire circumferential direction.

DESCRIPTION OF SYMBOLS 1 Polishing tool 2 Whetstone mounting plate 3 Connection part 4 Whetstone holding part 5 Whetstone 6 Circumferential groove 7 Ultrasonic vibrator 8 Rotating shaft 9 Bolt 10 Support plate

Claims (1)

  There is a supporting plate fixed perpendicularly to the rotating shaft at the lower end of the rotating shaft, two concentric ring-shaped connecting portions on the annular grindstone mounting plate, and inner and outer connecting portions A grindstone holding portion is provided at the approximate center of the peripheral connection portion, and two connecting portions of the grindstone mounting plate and the support plate are connected, and a continuous or discontinuous annular grindstone is connected to the grindstone holding portion of the grindstone mounting plate. A polishing tool which is mounted and an ultrasonic transducer is fixed to the grindstone mounting plate.

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