JPH0698559B2 - Ultrasonic polishing equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic polishing apparatus suitable for polishing an object to be polished such as a mold having a surface to be polished in each direction.

2. Description of the Related Art Polishing of a mold using a tool such as a grindstone that vibrates ultrasonically is widely used due to its effective polishing action.

An example of such a polishing apparatus is composed of an ultrasonic oscillator and a vertical vibrator, and the tip of the vertical vibrator can be interchanged with a sintered diamond grindstone, an electrodeposited diamond file, a resin grindstone, brass. Tools such as wood, bamboo, etc. are attached as needed.

An example of such a vertical vibrator and a tool is shown in FIG. In the figure, a vibrator 1 is a vertical vibrator that vibrates in the axial direction,
The two annular electrostrictive elements 2 are overlapped with the electrode plate 3 sandwiched therebetween, and the common electrode plate 11 and the metal material 4 and the metal material 6 having the step portion 5 are integrally fastened together from both surfaces by a central bolt or the like. It was done. A female screw is provided on the shaft at the tip portion 7 of the vibrator 1, a tool 8 has a step portion 9, and a grindstone 10 made of sintered diamond or the like is fixed to the output end portion by silver brazing. There is. A male screw is provided on the large-diameter end of the tool 8 and is screwed and fastened to a female screw provided on the tip 7 of the vibrator 1. Then, various kinds of tools are prepared as the tools 8, and the tools are replaced with the necessary tools by removing the screws according to the processing object.

When the vibrator 1 is driven by a resonance frequency including the tool 8 by an ultrasonic oscillator (not shown), the vibration generated by the electrostrictive element 2 resonates and vibrates over the entire length, and the whetstone 10 has its amplitude expanded by the steps 5 and 9. Is axially 20 at 30Khz for example
μm ^p-p ~30μm ultrasonic vibration as ^p-p of the arrow in amplitude.

As shown in FIG. 9, holding the vibrator 1 obliquely and rubbing the polishing surface 12 while the tip of the grindstone 10 is obliquely applied to the polishing surface 12 of the die 16, the surface is effectively polished by ultrasonic vibration. It is what is done.

When a grindstone that vibrates ultrasonically in the axial direction is applied obliquely to the polishing surface in this manner, it is effectively polished, and this is used for rough polishing. As a matter of course, a large amount of polishing cannot be expected at the time of finish processing in which vibration is performed in parallel with the polishing surface.
Therefore, it is inconvenient for rough polishing for a narrow polished portion that cannot be provided with oblique vibration.
For example, when polishing the side surface 15 of the narrow groove 14 of the mold 13 shown in FIG. 10, the vibration direction of the grindstone is parallel to the polishing surface, so that the polishing effect is reduced. That is, it is not suitable for rough polishing of a rough surface such as an electric discharge machined surface or a cutter mark only by vibration parallel to the polished surface.

Therefore, a polishing device is already provided in Japanese Patent Application No. 62-153020 (see Japanese Patent Application Laid-Open No. 63-318248), in which a polishing tool is provided at the output end of a vibrator that vibrates flexibly, and the tool resonates and vibrates in a direction perpendicular to the axis. ) Proposed by the applicant.

Although the mounting means of the tool is slightly different, an example of the above-described flexural vibrator and tool is shown in FIGS. 11 to 14. The flexural vibrator 20 has metal members 21,2
Two electrostrictive elements 23, 24, which are sandwiched by 2 and are annularly polarized in the thickness direction, having electrodes 26, 27 provided on one surface leaving the insulating portion 25 and an entire electrode 28 on the other surface, The electrodes 26, 27 are provided so as to face each other, and electrode plates 29, 30 are provided therebetween.

In addition, a common electrode plate 31 is inserted between the electrostrictive element 23 and the metal material 21, and they are integrally fastened by a bolt 33 at the center of the shaft to form a flexural vibrator, which serves as a small-diameter output end of the metal material 22. The part is provided with a male screw 32.

The tool 35 having the left male screw 33 provided at the end has a sintered diamond grindstone 39 further joined by silver brazing to the end of the plate member 38 fitted in the slit 37 and joined by silver brazing. The fastening ring 42 has a right female screw 34, a left female screw 36, and a spanner hook 41 provided on the outer periphery on its inner circumference, and a tool 35 having a left male screw 33 on its end and an output end of the vibrator 20. Right male screw
32 and 32 are fastened tightly by matching the angle in the circumferential direction.

When a driving voltage having a flexural resonance frequency in which the phases are inverted to each other is applied to the electrode plates 29 and 30 using the common electrode plate 31 as a common terminal, resonance vibration occurs in the flexural vibration distribution shown in FIG. 11 (b),
The tip of the grindstone 39 vibrates greatly in the direction perpendicular to the axis as indicated by arrow 40.

Therefore, as shown in FIG. 15, when the antinode of the grindstone 39 is applied to the polishing surface 46 of the work 45 by the surface and the surface is rubbed in the axial direction, the polishing surface 46 of the work 45 is
It is effectively polished by the ultrasonic vibration acting perpendicular to the. Further, when the grindstone 39 is applied diagonally and rubbed in parallel with the polishing surface 46, the vertical component of the vibration that obliquely strikes the polishing surface 46 acts similarly to the example of the vertical oscillator shown in FIG. Polishing is performed.

Problems to be Solved by the Invention Although it is effective for rough machining of groove side surfaces, etc. by using a flexural vibrator that solves the drawbacks of the vertical vibrator,
It cannot be used for finishing where vibration parallel to the polishing surface is suitable.

Means for Solving the Problems A flexural vibrator equipped with a polishing tool is longitudinally vibrated and flexibly vibrated. In addition, each vibration intensity is controlled to the optimum composite vibration depending on the processing target.

Action The tool is effectively abraded by various combined vibrations in the axial direction and the bending direction on various machining surfaces by the vibrations of the parallel component and the perpendicular component acting on the surface. Further, by controlling the respective vibration intensities, an optimum vibration state can be obtained from roughing to finishing.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 7. This embodiment can also be achieved by changing the driving method of the conventional flexural vibrator and the tool described in FIG.

FIG. 1 is a flexural vibrator of FIG. 11 cited as a conventional example.
20 and a tool 56 provided with a sintered diamond 58 are fastened together by a fastening ring 60 having left and right screws.
The shape of 56 is the same as that of the conventional tool 8 shown in FIG. Since the flexural vibrator 20 is the same as the conventional example, the description is omitted.

The flexural vibration means is driven from the high frequency power source 63 adjusted to the flexural resonance frequency. That is, a voltage whose phases are mutually inverted by the secondary coil of the output transformer 61 is applied to the electrode plates 29, 3
When applied to 0, the lower half of the electrostrictive elements 23, 24 contracts at the moment when the thickness of the upper half of them expands, and the cycle including reversing after half a cycle causes the entire length including the tool to bend as shown in Fig. 2 (a). A mode vibration distribution is generated and the output end of the grindstone 58 vibrates at right angles to the axis as indicated by arrow 71.

Next, the longitudinal vibration means is driven from the high frequency power source 69 having the longitudinal resonance frequency. That is, through the output transformer 66, the transformer
When voltage is applied to the center tap 65 of the secondary coil 64 of 61,
Since the same voltage is applied to the electrode plates 29 and 30, the electrostrictive elements 23 and 24 are vertically extended at the same time, so that longitudinal vibration in the axial direction is generated and vibration in the longitudinal mode as shown in FIG. 2B is generated. The distribution is generated and the tip of the grindstone 58 vibrates in the axial direction as shown by the arrow 72.

Since the respective resonance frequencies change as the tool 56 is replaced or the grindstone 58 is worn or loaded, it is preferable that the frequencies of the high frequency power supplies 63 and 69 can oscillate by tracking the respective resonance frequencies. Since each oscillation frequency oscillates independently, there is no relation between frequency and phase,
The composite compound vibration changes in random directions. The composite compound vibration at the output end is a combination of the flexural vibration 71 and the vertical vibration 72. By controlling the amplitude of each vibration, the shape of the envelope of the vibration locus is as shown in FIG. It can be a straight line, a rectangle, or a square, and is appropriately selected depending on the shape of the work and the processing content.

FIG. 4 shows a second embodiment of the present invention, which is a vibrator 80 composed of deflection driving electrostrictive elements 83, 84 and longitudinal driving electrostrictive elements 87, 88, which is made of a metal material. It is sandwiched by 81 and 82 and they are fastened together by bolts. Electrostrictive element
Reference numerals 83 and 84 are the same as the electrostrictive elements 23 and 24 (FIG. 1) having electrodes divided into two by the insulating part 25 on one surface, and electrostrictive elements 87 and 88 are circles having full surface electrodes on both sides which are usually used. It is an annular electrostrictive element.

The high frequency power supply 92 drives the flexural vibration means. That is, driving voltages of opposite phases are applied to the electrode plates 85 and 86 via the output transformer 91 to cause flexural vibration. Further, the high frequency power supply 94 drives the longitudinal vibration means. That is, the drive voltage for vertical vibration is applied to the electrode plate 89 through the output transformer 93. By separately providing the electrostrictive elements for each mode as in this example, it is possible to obtain a vibration output of higher power, which is functionally similar to that of FIG.

Furthermore, FIG. 5 and FIG. 6 show a third embodiment of the present invention. First, a vibrator and its driving circuit that generate longitudinal vibration are generated together with a combined flexural vibration that is a combination of the first flexural vibration and the second flexural vibration that is driven in a direction perpendicular to it with a phase difference of 90 degrees. Show. That is, it is driven by the vertical vibrating means and the combined flexural vibrating means.

The electrostrictive elements 101 and 102 that generate the first flexural vibration have electrodes divided into upper and lower halves on one surface and are energized by the electrode plates 108 and 109. Then, the electrostrictive elements 103 and 104 which generate the second flexural vibration at right angles to the first flexural vibration have electrodes divided into left and right on one surface and are energized by the electrode plates 110 and 111. They are sandwiched by the metal materials 105 and 106 together with the common electrodes 112 and 113, and are integrally fastened by the central bolt 107 to form the composite flexural vibrator 100. When a voltage whose phase is inverted by the output transformer 114 from the flexural vibration driving high-frequency power supply 115 is applied to the electrode plates 108 and 109, the electrostrictive elements 101 and 102 are vertically driven to be inverted to generate the first flexural vibration in the vertical direction.

A part of the power supply 115 is shifted in phase by 90 degrees by the phase shifter 117 and is applied to the electrode plates 110 and 111 via the output transformer 116 to drive the electrostrictive elements 103 and 104 to the right and left in the second direction in the left and right direction.
Generates flexural vibration.

The high frequency power supply 119 for driving longitudinal vibration is connected to the secondary winding intermediate taps of the output transformers 114, 116 for deflection via the output transformer 118, and drives all the electrode plates 108, 109, 110 and 111 in the same phase, so that longitudinal vibration in the axial direction is generated. To excite. Oscillator
A tool 120 having a cylindrical grindstone 122 is tightly fastened to an output end of 100 by a fastening nut 123 having left and right female threads.

FIG. 7 shows the vibration mode of the tool 120 and the tip. A first flexural vibration 125 and a second flexural vibration 126 are generated at the tip of the grindstone 122 as shown by arrows in FIG. 7 (b).
Since it is synchronized with a phase difference of 0 degree, its vibration mode becomes a circular vibration 127 as shown in Fig. 7 (c), and a cylindrical compound vibration that vibrates in random directions due to a longitudinal vibration 128 not synchronized with them. Occur.

Further, when the dimensions of the tool are considerably different in the left-right direction and the vertical direction, the first and second flexural resonance frequencies are separated from each other, and it becomes difficult to generate the circular vibration 127. However, in such a case, a good effect can be obtained by individually and independently tracking the resonance frequency.

Such a grindstone and a vibration mode are useful for polishing the R-shaped corner portion.

In the above embodiment, in the case of the side surface polishing of the deep groove, both the longitudinal vibration and the flexural vibration are strongly adjusted, and after the rough machining, the flexural component is gradually reduced and the finishing machining is performed. In the bottom surface polishing of deep grooves, after the rough processing by using both vibration components together, the vertical component is reduced toward the finishing,
Polish with a flexible component.

For machining a round hole, a side surface of an R corner, or a bottom surface of a round hole, a combined vibration of a combined bending vibration (circular vibration) and a longitudinal vibration by a round bar (cylindrical) grindstone is effective. Similar to the above example, the flexural vibration component on the side surface and the longitudinal vibration component on the bottom surface act as an auxiliary to increase the polishing effect.

In this way, even if the longitudinal and flexural resonance frequencies of the vibrator are not matched, the effect is the same.The combined vibration of the longitudinal vibration component and the flexural vibration component perpendicular to it is Changes randomly, but the random change in the vibration direction does not adversely affect the polishing effect.

So the tool has a lot of freedom in its dimensions,
This can greatly simplify the configuration of the vibration system.

According to such a wrapper, since the vibration of the grindstone contains a large amount of components in the direction perpendicular to the polishing surface, it is suitable for polishing hard brittle materials such as cemented carbide and ceramics.

As described above, the present invention provides a flexural vibrator provided with a polishing tool, a longitudinal vibrating means for longitudinally vibrating the flexural vibrator, and a flexural vibrating means or a composite flexural vibration for flexibly vibrating the flexural vibrator. Since it is configured by means and
Compared to the conventional polishing action using vertical or flexural vibration alone, it can be combined with vertical vibration to produce a significant increase in polishing effect.In addition, depending on the shape of the polishing surface and the machining conditions, By controlling the amplitude of the bending component to an optimum value, it is possible to perform effective polishing from rough polishing to finishing.

[Brief description of drawings]

FIG. 1 is a side view showing the first embodiment of the present invention, FIG. 2 is a waveform diagram showing the relationship between the flexural mode vibration distribution and the longitudinal mode vibration distribution, and FIG. 3 is the envelope of various vibration loci. FIG. 4 is a side view showing a second embodiment of the present invention, FIG. 5 is a side view showing a third embodiment of the present invention, and FIG. 6 is a perspective view of an electrode plate. Fig. 7 is a perspective view showing a tool and its vibration mode, Fig. 8 is a perspective view showing a conventional example, Fig. 9 is a front view showing a state in which a flat surface is polished, and Fig. 10 is a groove polished. Fig. 11 is a side view showing another conventional example, Fig. 12 is a side view in which a part of the fastening portion is cut away, and Fig. 13 is a perspective view of an electrode plate. FIG. 14 is a perspective view of the electrostrictive element, and FIG. 15 is a side view in a polished state. 20,80,100 …… Flexural vibrator, 56,120 …… Polishing tool, 66,
93,118 …… Vertical vibration means, 61,91 …… Flexible vibration means, 11
4,116 …… Complex flexural vibration means

Claims (2)

[Claims] 1. An ultrasonic wave comprising a flexural vibrator provided with a polishing tool, a longitudinal vibrating means for longitudinally vibrating the flexural vibrator, and a flexural vibrating means for flexibly vibrating the flexural vibrator. Polishing equipment. 2. A flexural vibrator provided with a polishing tool, a vertical vibrating means for longitudinally vibrating the flexural vibrator, and a composite flexural vibrating means for composite flexural vibration of the flexural vibrator. Ultrasonic polishing device.