JP3985585B2 - Ultrasonic processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ultrasonic processing apparatus that performs processing by ultrasonic vibration.
[0002]
[Prior art]
Conventionally, a tool is ultrasonically vibrated, and abrasive grains are supplied to the periphery of the tool, and the abrasive grains are applied to the work piece by the vibration of the tool, so that the surface of the work piece follows the surface of the tool. There is known an ultrasonic processing apparatus configured so as to be able to form a film.
Also known is an ultrasonic machining apparatus configured to supply abrasive grains around a tool in a state of an abrasive liquid dispersed in an appropriate liquid.
[0003]
And as a method for improving the processing efficiency and shortening the processing time in the ultrasonic processing apparatus configuration as described above, a method for increasing the vibration amplitude of the tool or a processing pressure for pressing the tool against the workpiece is increased. Methods are conventionally known.
[0004]
[Problems to be solved by the invention]
However, if the vibration amplitude of the tool is increased in the ultrasonic processing apparatus, the abrasive grains are spattered and scattered by the vibration of the tool before reaching the interface between the tool and the workpiece, and the abrasive grains are wasted. There is a problem that the ratio of increases.
In addition, when the workpiece is, for example, a brittle material, there is a risk that the workpiece may be damaged if the vibration amplitude or processing pressure of the tool is increased, and these methods have limitations. In particular, it has been very difficult to perform precision machining on brittle materials with high yield by conventional ultrasonic machining.
[0005]
[Means for Solving the Problems]
The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.
[0006]
That is, according to the first aspect of the present invention, in an ultrasonic processing apparatus that forms a shape following a tool shape on a workpiece by vibrating the tool with ultrasonic waves and transmitting the vibration to the abrasive grains, the abrasive grains are liquid Abrasive grain supply means that is supplied to the periphery of the tool in a state of being dispersed in the tool, and an excitation means that vibrates the tool in a mode in which the abrasive dispersion liquid is held around the tool. It is.
Such a vibration mode can be obtained by appropriately adjusting the arrangement of the vibration source and the configuration of the vibration transmission medium with respect to the tool.
[0007]
In claim 2, the tool is attached to a horn, and an ultrasonic vibrator is fixed to the horn, and the vibration of the ultrasonic vibrator is transmitted to the tool through the horn. is there.
[0008]
In claim 3, the tool is attached to a tool mounting surface formed on one side of the horn, and an ultrasonic vibrator is fixed to the other side of the horn so that the vibration of the ultrasonic vibrator is The exciter is configured to transmit to a tool through a horn, and the excitation means excites the edge of the tool mounting surface to be a vibration node and the center to be a vibration antinode. The attachment location for attaching the tool is formed in the central portion of the tool attachment surface.
[0009]
According to a fourth aspect of the present invention, the horn is configured to have a shape with an amplitude magnification factor smaller than 1.
[0010]
In Claim 5, the said horn is comprised so that it may have a part which increases the cross-sectional area as it goes to the said tool attachment surface side.
[0011]
In the present invention, the workpiece is a brittle material.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be specifically described with reference to the accompanying drawings.
[0013]
[Schematic configuration of the entire device]
An overall side view of an ultrasonic perforation apparatus (ultrasonic processing apparatus) as an embodiment of the present invention is shown in FIG. 1, and an overall front view is shown in FIG. As shown in FIGS. 1 and 2, the ultrasonic drilling apparatus 1 has a structure in which a column 3 is erected on a base 2 installed on a floor, and a drilling head portion 4 is supported on the column 3. It has become.
[0014]
A screw shaft 5 is disposed on the column 3 in the vertical direction, and is rotatably supported. A lifting / lowering body 6 is screwed onto the screw shaft 5, and the screw shaft 5 and the lifting / lowering body 6 constitute a known ball screw mechanism. The screw shaft 5 is connected to a motor shaft of a motor 7 installed on the column 3. In this configuration, the vertical position of the elevating body 6 can be changed by rotationally driving the motor 7 in the forward and reverse directions.
The column 3 is further provided with a linear guide (not shown) in the vertical direction, and a connecting body 8 is provided so as to be vertically displaced along the linear guide. By connecting the lifting / lowering body 6 to the connecting body 8, the connecting body 8 (and consequently the drilling head part 4 provided in the connecting body 8) can be moved in the vertical direction (Z direction).
[0015]
The piercing head unit 4 is supported on the connecting body 8 so as to be slidable in the vertical direction. A tool 9 for performing drilling is attached to the drilling head portion 4, and a mechanism (excitation means) for applying ultrasonic vibration to the tool 9 is provided. The tool 9 is configured as a high hardness diamond (PCD) tool.
[0016]
A movable table 10 movable in the horizontal direction (XY direction) is installed on the base 2, and on the movable table 10, as shown in FIG. 2, the lifting table 11, the camera unit 41, and the polishing device 42 are arranged. The three are arranged side by side.
A work 13 as a workpiece can be fixed at a position on the upper surface of the lifting table 11 that can face the tool 9. Various types of work 13 can be considered, but this embodiment shows a case where a piezoelectric ceramic material (PZT) used as a piezoelectric actuator for an inkjet head such as an inkjet printer is processed.
[0017]
The camera unit 41 is for taking an image of the tool 9 from below in order to facilitate adjustment of the direction of the tool 9. The polishing device 42 is for polishing the tool mounting surface 23a when a tool mounting surface 23a of the horn 23 described later is worn by abrasive grains.
[0018]
A cover 43 is installed on the base 2 so as to cover the entire apparatus, and consideration is given so that chips generated during drilling work and an abrasive liquid described later are not scattered around. A double-open door 44 that can be opened and closed is provided on the front of the apparatus (FIG. 1), and the inside of the cover 43 can be accessed by opening the door 44 as required for work replacement work or the like.
[0019]
[Configuration of drilling head]
The configuration of the piercing head unit 4 will be specifically described mainly with reference to FIG. 3 which is a side view, FIG. 4 which is a front view, and FIG. 5 which is a plan sectional view.
The drilling head portion 4 is configured such that a tool frame 17 for supporting the tool 9 is slidably connected to a base frame 14 supported by the connecting body 8. A support shaft 15 is installed horizontally on the base frame 14, and a central portion of a balance body 16 elongated in the front-rear direction is pivotally supported on the support shaft 15 so as to be swingable.
An air cylinder 18 is installed on the base frame 14 (FIGS. 3 and 4), and the cylinder rod 19 extends downward and is connected to one end of the balance body 16. The tool frame 17 is connected to one end of the balance body 16 to which the cylinder rod 19 is connected. The base frame 14 is provided with a displacement sensor 20 so that the relative displacement of the tool frame 17 with respect to the base frame 14 can be detected.
[0020]
As shown in FIG. 3, an annular horn support portion 21 is provided at the lower end of the tool frame 17 so as to be rotatable via a bearing 22, and a horn 23 is fixed to the horn support portion 21. The horn 23 is elongated in the vertical direction, and an ultrasonic vibrator 24 is fixed to the upper part of the horn 23. A flat tool attachment surface 23a is formed at the lower end of the horn 23. A tool 9 is detachably attached. The ultrasonic vibrator 24 is a main part of the excitation means for vibrating the tool 9. Details of the shape of the horn 23 will be described later.
A plate-like cover 45 is provided so as to cover the base frame 14 and the tool frame 17 so that the internal ultrasonic transducer 24 and the like can be protected. In addition, the tool frame 17 is provided with an adjustment knob 27 that is rotated to finely adjust the angle of the tool 9 and a fixing screw 36 for fixing the tool 9 so that it does not rotate carelessly after the fine adjustment. ing.
[0021]
[Configuration of lifting table]
The structure of the raising / lowering table 11 for fixing the workpiece | work 13 is demonstrated with reference to the side view of FIG.
The elevating table 11 has a base frame 29 that is erected and fixed on the movable table 10, and an elevating frame 31 that is provided on the base frame 29 through a linear guide (not shown) so as to be movable up and down. Yes.
[0022]
A lift cylinder 30 is attached to the base frame 29, the cylinder rod 32 extends upward, and the tip thereof is connected to the lift frame 31.
The lift cylinder 30 is configured as an air cylinder, and the vertical position of the lift frame 31 can be changed by supplying / draining compressed air. A displacement sensor 33 is installed on the base frame 29 so that the vertical position of the elevating frame 31 can be measured.
A box-shaped cover 46 is provided on the lifting frame 31 to protect the internal lift cylinder 30 and the displacement sensor 33.
[0023]
The upper part of the raising / lowering frame 31 is comprised horizontally, and the workpiece base 12 for attaching the workpiece | work 13 is installed on this. A clamp mechanism 34 is provided on the lifting frame 31 at a position beside the work table 12. The clamp mechanism 34 is composed of an air cylinder. When the air cylinder is operated in a state where the workpiece 13 is placed on the workpiece table 12, the extending cylinder rod 35 presses the workpiece 13 in the horizontal direction, and the workpiece table 12 is fixed in a state where it abuts against the guide portion provided on the main body 12.
[0024]
The ultrasonic drilling device 1 includes an abrasive liquid reservoir (not shown), and a liquid in which abrasive grains (for example, SiC having a particle diameter of about 4 to 6 μm) are dispersed is injected into the abrasive liquid reservoir. Yes. An abrasive liquid circulation path comprising a pipe, a flexible hose, a pipe joint and the like is formed by connecting to the abrasive liquid reservoir, and this path is connected to the relay pipe 47 (FIG. 1, FIG. 2 and 6). A supply hole 48 is formed in the relay pipe 47, and a guide rod 49 protrudes downward at a position near the supply hole 48. The guide bar 49 is formed in a curved shape and changes its direction in an oblique direction, and its tip is located immediately above the work table 12 on the lifting table 11.
With this configuration, when a pump (not shown) installed in the abrasive liquid reservoir is driven, the abrasive liquid is sent into the relay pipe 47, and a part thereof leaks to the outside through the supply hole 48. The abrasive liquid leaking to the outer surface of the relay pipe 47 falls on the work table 12 through the guide rod 49 and is used for processing by the tool 9. Thus, the above-mentioned pump, relay pipe 47, guide rod 49, and the like constitute an abrasive supply means for supplying the abrasive liquid around the tool 9.
[0025]
[Description of drilling operation]
In the configuration described above, an operation of actually vibrating the tool 9 by ultrasonic vibration of the work 13 will be described.
First, after the work 13 is fixed on the work table 12 by the clamp mechanism 34, the moving table 10 is moved in the X and Y directions, and the motor 7 is driven to lower the perforation head unit 4, and the chain line in FIG. As shown by the above, the tool 9 is positioned just above the workpiece 13 with a slight gap.
Then, while constantly measuring the position of the lifting frame 31 with the displacement sensor 33, compressed air is supplied to the lift cylinder 30, the cylinder rod 32 is gradually extended to move the lifting frame 31 upward, and the workpiece 13 is moved. Raise. Then, the position of the lifting frame 31 at the moment when the upper surface of the work 13 comes into contact with the tool 9 is stored as a zero position in an appropriate storage means of the controller that controls the apparatus 1.
Then, the ultrasonic vibrator 24 of the drilling head unit 4 is driven, and the workpiece 13 is raised by supplying compressed air to the lift cylinder 30 while applying vertical ultrasonic vibration to the tool 9 via the horn 23. And press against the tool 9. In addition, the abrasive liquid is supplied to the periphery of the tool 9 from the relay pipe 47 via the guide rod 49 by driving the pump of the abrasive liquid circulation path.
As a result, the workpiece 13 is scraped by the abrasive grains between the workpiece 9 and grooves or holes having a shape following the tool 9 are formed on the upper surface of the workpiece 13.
[0026]
The air cylinder 18 (FIG. 3) of the drilling head unit 4 described above supports the tool frame 17 by supplying and discharging compressed air as necessary while measuring the displacement of the tool frame 17 by the displacement sensor 20. The power is adjusted. This prevents the tool 9 from being pressed against the workpiece 13 with an excessive force during the drilling operation. Therefore, even when the workpiece 13 made of a brittle material such as the piezoelectric ceramic of the present embodiment is machined, The structure is such that damage is sufficiently avoided.
[0027]
The position of the elevating frame 31 is always measured by the displacement sensor 33 (FIG. 6) while the work 13 is drilled with the tool 9. When the elevating frame 31 is raised by a predetermined distance from the zero position, the supply of compressed air to the lift cylinder 30 is stopped and the work 13 is stopped from rising. As a result, the workpiece 13 can be formed with a hole or groove having a depth of exactly the distance.
[0028]
[Horn configuration]
Next, the horn 23 that transmits the vibration of the ultrasonic transducer 24 to the tool 9 in the above-described drilling head unit 4 will be described in detail.
In this embodiment, as will be described later, a horn having a shape indicated by reference numeral 23 in FIG. 3 is used to cause the tool 9 to vibrate in a mode for holding the abrasive liquid around it. The horn 23 is made of iron and has a round bar shape that is thin in the vertical direction. A thin flange 23b is formed at a position slightly above the center in the vertical direction, and the flange 23b is fixed to the horn support 21 described above.
[0029]
The shape of the horn 23 is determined so that the natural frequency of the system including the ultrasonic transducer 24 and the tool 9 is 20 kHz. At the time of machining the workpiece 13, consideration is given to stably obtaining the amplitude of the tool 9 by vibrating the ultrasonic vibrator 24 at the natural frequency of 20 kHz.
[0030]
The horn 23 has a first portion P1 having a slightly thin and substantially uniform thickness in order from the flange portion 23b and a second portion that gradually increases in thickness from the lower end of the first portion P1. Part P2 and a third part P3 having a uniform thickness slightly thicker than the first part P1, and the aforementioned tool mounting surface 23a is formed at the lower end of the third part P3. Yes. In this way, the horn 23 has a portion where the cross-sectional area (thickness) increases toward P1 → P2 → P3 toward the tool mounting surface 23a, and has a so-called divergent shape (substantially trumpet shape). ing.
[0031]
The reason why such a shape is adopted for the horn 23 is based on the simulation analysis result and the experimental result. Next, the contents of this simulation analysis and experiment will be described.
[0032]
First, as the shape of the horn 23, three types of models as shown in FIGS. 7A, 7B, and 7C were assumed.
The model (a) is a “Suehiro type (trumpet type)” model, and is a model actually adopted in the present embodiment.
The model (b) has a completely uniform thickness from just below the flange portion 23b to the tool mounting surface 23a, and is a “pipe-type” model.
The model (c) is a “tapered” model, although a thick portion once appears between the flange 23b and the tool mounting surface 23a, but becomes thinner again until reaching the tool mounting surface 23a.
In any of these models (a), (b), and (c), a mounting hole (mounting location) 23c is formed in the center of the tool mounting surface 23a at the lower end surface, and the tool 9 side is formed in the mounting hole 23c. The convex portion 9a can be attached by an appropriate method (for example, screwing or shrink fitting).
In addition, the models of these models (a), (b), and (c) are determined so that the natural frequency of the vibration system is 20 kHz.
[0033]
After inputting the shape data of the three types of horn models (a), (b), and (c) to the computer, the ultrasonic transducer 24 attached to the upper surface of each model has a predetermined amplitude of 20 kHz. The simulation of the vibration of the horn 23 when it vibrates was performed.
[0034]
FIG. 8 shows the analysis result of the vibration of each model. For each of the models (a), (b), and (c), the state when the horn is extended is shown on the left side, and the state when the horn is contracted is shown on the right side. The hatching attached represents the amplitude of each part, and indicates that the smaller the hatching interval is, the larger the amplitude is. In addition, the numerical value shown on the scale of FIG. 8 is a dimensionless value which remove | divided the amplitude of the location by the maximum amplitude of the horn.
Since each horn 23 has an axisymmetric shape, only the right half of the cross section taken along the plane including the axis is shown in the drawing. In the figure, each model is greatly deformed because it is exaggerated to facilitate understanding of the state of vibration, and the actual deformation (vibration) is a minute with an amplitude of less than 10 μm. It is a thing.
[0035]
As shown in FIG. 8, in each model, there is almost no amplitude in the portion of the flange portion 23b fixed to the horn support portion 21 (less than 0.1 times the maximum amplitude), and this portion becomes a vibration node. Yes.
In each model, as it goes downward from the flange 23b, it appears in the order of a portion with a larger amplitude (vibration antinode) → a portion with a smaller amplitude (node of vibration), and the amplitude increases again in the vicinity of the tool mounting surface 23a. I understand that.
[0036]
However, in (b) and (c), a relatively large amplitude (0.9 times or more of the maximum amplitude) appears near the tool mounting surface 23a of the horn, whereas the tool mounting surface 23a in the model of (a). It can be seen that the amplitude of is relatively small, 0.5 to 0.6 times the maximum horn amplitude.
[0037]
Next, these three types of model-shaped horns 23 (a), (b), and (c) were actually manufactured using iron. Then, the tools 9 were attached to the respective horns 23, and an experiment for actually performing the machining operation was performed under the same conditions such as the machining pressure of the tools 9, the supply flow rate of the abrasive liquid, and the vibration of the ultrasonic vibrator 24.
Then, the “suehiro type” model (a), which should have low vibration amplitude and low vibration energy, is expected to have several times more processing efficiency than the other models (b) and (c). The result was not obtained.
[0038]
Then, when the state of processing was observed in detail for each of the horns 23 of each shape, in the “Suehiro type” model of (a), even if the abrasive liquid contacts the vibrating tool 9, the tool 9 It was confirmed that the surface of the tool 9 was held by the vibration of the tool 9 rather than being scattered by the vibration of the tool 9.
On the other hand, in the horn 23 having the shapes (b) and (c), when the portion where the abrasive liquid is in contact with the vibrating tool 9 is observed, most of the abrasive liquid is scattered as small droplets. It was confirmed.
[0039]
From the above, in the “Suehiro type” model of (a) among the three models, according to the simulation result, a stable vibration having a small amplitude is obtained in the vicinity of the tool mounting surface 23a. It is considered that the tool 9 attached to the tool attachment surface 23a vibrates in such a manner that the abrasive liquid is held on the surface without being scattered.
When the tool 9 is vibrated in such a mode, the abrasive liquid is held on the surface of the tool 9, thereby reaching the interface between the tool 9 and the work 13 and contributing to the machining of the work 13. It is inferred that the above result of improving the processing efficiency would be obtained because the proportion of abrasive grains to be increased. In particular, since the abrasive grains easily spread not only at the peripheral portion of the interface between the tool 9 and the workpiece 13 but also at the central portion, the processing of the central portion of the tool 9 is facilitated, and the above-described good results were obtained. It is speculated that.
[0040]
This is because, in the “Suehiro type” model of (a), when the vibration propagates through the second portion P2 which increases the thickness, the amplitude is decreased, and the vibration remains as it is. It is considered that this is because it reaches the tool mounting surface 23a through the uniform third portion P3. That is, the shape of the “Suehiro type” model of (a) has an amplitude enlargement ratio smaller than 1 because of the presence of the second portion P2, and as a result, the amplitude of the model near the tool mounting surface 23a is reduced. It is considered that a small and stable vibration can be obtained.
On the other hand, the “slider trunk type” model of (b) does not have a portion that increases the thickness. Further, in the “tapered” model of (c), there is a portion that increases the thickness, but it is narrowed again until reaching the tool mounting surface 23a. Therefore, these models (b) and (c) cannot hold the abrasive liquid on the surface of the tool 9 because the vibration with suppressed amplitude is not obtained in the tool 9 like the “Suehiro type” model in (a). It is considered that the result is that the abrasive liquid is scattered around.
[0041]
FIG. 9 also shows the analysis result of the above-mentioned simulation as in FIG. 8, but shows an enlarged view of the vibration state of each model, particularly in the vicinity of the tool mounting surface 23a. For each model of (a), (b), and (c), the state when the horn is extended is shown on the lower side, and the state when the horn is contracted is shown on the upper side. In FIG. 9, as in FIG. 8, the right half of the cross section of each model is shown as a representative.
The hatching shown represents the amplitude of each part as in FIG. 8, and indicates that the smaller the hatching interval is, the larger the amplitude is. However, since the amplitude of the tool mounting surface 23a is significantly different between (a), (b), and (c), the corresponding scales of hatching intervals and amplitudes are different. Also in FIG. 9, as in FIG. 8, the numerical value shown in the scale portion is a dimensionless value obtained by dividing the amplitude of that portion by the maximum amplitude of the horn.
[0042]
As shown in FIG. 9A, in the “Suehiro type” model, the tool mounting surface 23a portion forms a curved surface that protrudes downward when the horn is extended, and at the moment when the horn contracts. It can be seen that forms a curved surface that is concave downward. That is, the horn 23 of this “Suehiro type” model has an edge portion of the tool attachment surface 23a serving as a vibration node, and a central portion thereof (a central portion where the attachment portion of the tool 9 is formed). It is excited to become a vibration belly.
On the other hand, in the “cylinder type” model of FIG. 9B and the “tapered type” model of FIG. 9C, almost no variation of the tool mounting surface 23a can be recognized.
[0043]
As described above, it is conceivable that the horn of the “Suehiro type” model (a) deforms the tool mounting surface 23a from the concave to the convex at the time of vibration, and the following effects can be obtained.
That is, as shown in FIG. 10, when the tool mounting surface 23a is deformed into a concave shape (upper side in the figure), the abrasive liquid around the horn 23 is sucked to the center of the tool mounting surface 23a. On the other hand, when deforming into a convex shape (lower side in the figure), the abrasive liquid near the center of the tool attachment surface 23a is pushed outward. In FIG. 10, the abrasive grains are indicated by small points, and an arrow from the point indicates the direction of the abrasive grain flow. Therefore, by the vibration of the tool mounting surface 23a, (i) new abrasive grains supplied around the tool 9 are sucked toward the tool 9, and (ii) the interface between the tool 9 and the work 13 has already been reached. Acts like a pump that discharges used abrasive grains used for processing to the surrounding area. Therefore, it is possible to intentionally create a flow in which abrasive grains circulate between the peripheral portion of the tool 9 and the interface between the tool 9 and the workpiece 13. This is because fresh abrasive grains supplied to the periphery of the tool 9 quickly reach the interface between the tool 9 and the workpiece 13, and used abrasive grains that contribute to the processing are the tool 9 and the workpiece 13. It means that it is discharged quickly from the interface between. This effect is also considered to contribute to the improvement of the processing efficiency described above.
[0044]
The following is a summary of what has been clarified by the above experiment and its discussion.
First, by setting the amplitude and frequency of the tool 9 to specific conditions (modes), the abrasive liquid that contacts the tool 9 is not scattered, but rather the abrasive liquid is held on the surface of the tool 9 It has been clarified that the tool 9 can be vibrated in such a manner.
Secondly, it has been clarified that when such a vibration is applied to the tool 9 and the workpiece 13 is machined, a higher machining efficiency can be obtained than in other cases.
Third, in order to stably obtain the vibration conditions as described above with the simplest configuration, it is desirable that the shape of the horn is a divergent shape (or a shape with an amplitude magnification factor of less than 1). It was made clear.
Fourthly, from the viewpoint of improving machining efficiency, it is possible to excite so that the edge of the tool mounting surface 23a of the horn 23 becomes a vibration node so that the center of the tool mounting portion becomes an antinode of vibration. Desired to be desirable.
[0045]
The ultrasonic drilling apparatus 1 of the present embodiment utilizes the above knowledge, and is configured to process the workpiece 13 by applying vibrations in the above-described mode to the tool 9. As a result, the processing efficiency can be improved as described above, and the amount of abrasive grains that are wasted can be reduced, so that the consumption of abrasive grains can be suppressed and the running cost can be reduced.
In the present embodiment, as described above, the abrasive liquid is supplied to the periphery of the tool 9 along the outer surface of the guide rod 49. This is a composition in which the abrasive liquid is a dispersion of abrasive grains and is easy to precipitate and solidify. In particular, when the supply flow rate of the abrasive liquid is suppressed as in this embodiment, the abrasive liquid is supplied through a thin pipe. This is because the pipe is easily clogged.
[0046]
In this embodiment, as shown in FIG. 8, the conditions for giving the above-described vibration to the tool 9 are an amplitude of about 5 to 6 μm and a frequency of 20 kHz. However, it is not limited to this condition. For example, the vibration conditions for holding the abrasive liquid on the surface of the tool 9 are slightly different depending on the physical properties of the abrasive liquid.
[0047]
For example, the following method may be used to determine whether or not the vibration of the tool 9 is vibration in a mode in which the abrasive liquid is held on the surface thereof.
That is, prepare an appropriate container filled with the abrasive liquid, vibrate the tool 9 with the tool 9 immersed in the abrasive liquid in the container, and gently lower the container while maintaining the vibration. The tool 9 is lifted relatively from the liquid surface of the abrasive liquid. At this time, if the abrasive liquid remaining on the surface of the tool 9 forms a large droplet as a whole so as to include the tool 9 therein, and the droplet does not fall, the tool 9 It can be determined that it vibrates in the mode. When the vibration of the tool 9 is stopped, or when the vibration condition is out of the above-described mode, the abrasive liquid on the tool 9 is almost scattered as a fine droplet, or the tool is immediately caused by gravity. It will fall from 9.
[0048]
The shape of the horn 23 is not limited to the shape of (a) described above. The point is that the tool 9 only needs to be vibrated to hold the abrasive liquid around it (surface). Therefore, even if the horn 23 having the shape (b) or (c) described above is used, the abrasive liquid can be held in the portion of the tool 9 by variously changing the amplitude of the ultrasonic vibrator 24 or the like. It seems that it is not impossible at least theoretically to obtain vibration.
However, the divergent horn 23 as shown in (a) is excellent in that a small amplitude vibration can be stably obtained in the portion of the tool 9 with a simple configuration.
[0049]
Furthermore, as described above, the workpiece 13 of the present embodiment is a piezoelectric ceramic material (PZT), but the technical scope of the present invention is not limited to processing this material. However, in the present invention, since the processing efficiency can be improved by efficiently using the abrasive grains in the abrasive liquid even if the processing pressure is low, it is particularly suitable for processing brittle materials that are easily damaged and cannot be increased too much. And the processing finish is also beautiful.
[0050]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0051]
That is, as shown in claim 1, in an ultrasonic processing apparatus for forming a shape following a tool shape on a workpiece by vibrating a tool with ultrasonic waves and transmitting the vibration to the abrasive grains, the abrasive grains are Abrasive grain supply means for supplying the periphery of the tool in a state of being dispersed in a liquid, and an excitation means for vibrating the tool in a mode in which the abrasive dispersion liquid is held around the tool. So
Since the abrasive dispersion liquid is not scattered unnecessarily by the vibration of the tool and is held around the tool, it reaches the interface between the tool and the workpiece among the abrasive grains supplied around the tool. The proportion of abrasive grains that contribute to processing increases. Therefore, the processing speed increases. In particular, since the abrasive grains easily spread not only at the peripheral part of the interface between the tool and the workpiece but also at the central part, machining of the central part of the tool becomes easy and it can contribute to shortening of the processing time by increasing the processing speed. .
Further, since the abrasive grains are hardly scattered by the vibration of the tool and waste is reduced, the running cost can be reduced.
[0052]
Since the tool is attached to the horn and an ultrasonic vibrator is fixed to the horn, the vibration of the ultrasonic vibrator is transmitted to the tool through the horn. ,
By setting the shape of the horn in various ways, it is possible to stably obtain vibration in a mode that can hold the abrasive liquid around the tool.
[0053]
According to a third aspect of the present invention, the tool is attached to a tool mounting surface formed on one side of the horn, and an ultrasonic vibrator is fixed to the other side of the horn so as to vibrate the ultrasonic vibrator. It is configured to transmit to the tool via the horn, and the excitation means excites so that an edge portion of the tool mounting surface becomes a vibration node and a central portion thereof becomes a vibration antinode. In addition, since an attachment point for attaching the tool is formed in the central portion of the tool attachment surface,
When the tool mounting surface is deformed into a concave shape, the abrasive particles flow toward the tool, and when the tool mounting surface is deformed into a convex shape, the abrasive particles flow away from the tool. In this way, it is possible to intentionally create a flow in which abrasive grains circulate between (1) the peripheral part of the tool and (2) the interface between the tool and the work piece. The supplied fresh abrasive grains easily reach the interface between the tool and the workpiece, and the processing efficiency is improved.
[0054]
As shown in claim 4, since the horn is configured in a shape having an amplitude magnification ratio smaller than 1,
Since the amplitude of the tool can be kept small, the abrasive liquid can be easily held around the tool. Moreover, the vibration of the tool can be obtained stably.
[0055]
As shown in claim 5, since the horn is configured to have a portion that increases its cross-sectional area toward the tool mounting surface side,
Such vibration that the tool mounting surface is concave ← → convex can be easily and stably obtained.
[0056]
As shown in claim 6, since the workpiece is a brittle material,
Since high processing efficiency can be obtained without increasing the processing pressure, even a brittle material that is easily damaged can be processed in a short time. Moreover, the finish of the process is also favorable.
[Brief description of the drawings]
FIG. 1 is a side view showing an overall configuration of an ultrasonic drilling apparatus according to an embodiment of the present invention.
FIG. 2 is a front view of the same.
FIG. 3 is a side sectional view of a perforation head part.
FIG. 4 is a front view of the same.
FIG. 5 is a plan sectional view of the same.
FIG. 6 is a side sectional view of the lifting table.
FIG. 7 is a perspective view showing a shape model of a horn assumed in an experiment. (A) shows a divergent type, (b) a barrel type, and (c) shows a tapered type.
FIG. 8 is a diagram showing a result of simulation analysis of horn vibration of each model.
FIG. 9 is a diagram showing a simulation analysis result of vibration in the vicinity of the tool mounting surface in each model.
FIG. 10 is a diagram showing the flow of abrasive grains when processing is performed using a horn having a divergent shape.
[Explanation of symbols]
1 Ultrasonic drilling device (ultrasonic processing device)
9 Tool 13 Workpiece (Workpiece)
23 Horn 23a Tool mounting surface 23c Mounting hole (Tool mounting location)
24 Ultrasonic transducer (excitation means)

Claims (6)

In an ultrasonic processing apparatus that forms a shape following a tool shape on a workpiece by vibrating the tool with ultrasonic waves and transmitting the vibration to the abrasive grains, the tool is in a state where the abrasive grains are dispersed in a liquid. Abrasive grain supply means for supplying to the periphery of
An excitation means for vibrating the tool in a mode in which the abrasive dispersion is held around the tool;
An ultrasonic processing apparatus comprising: The ultrasonic processing apparatus according to claim 1,
The ultrasonic processing characterized in that the tool is attached to a horn, an ultrasonic vibrator is fixed to the horn, and the vibration of the ultrasonic vibrator is transmitted to the tool through the horn. apparatus. The ultrasonic processing apparatus according to claim 2,
The tool is attached to a tool mounting surface formed on one side of the horn, an ultrasonic vibrator is fixed to the other side of the horn, and the vibration of the ultrasonic vibrator is applied to the tool via the horn. Configured to communicate,
The excitation means excites so that an edge portion of the tool mounting surface becomes a vibration node and a center portion thereof becomes a vibration antinode,
An ultrasonic machining apparatus, wherein an attachment location for attaching the tool is formed at the central portion of the tool attachment surface. 4. The ultrasonic processing apparatus according to claim 3, wherein the horn is configured to have a shape with an amplitude expansion ratio smaller than 1. 5. The ultrasonic processing apparatus according to claim 3 or 4, wherein:
The ultrasonic processing apparatus according to claim 1, wherein the horn has a portion whose cross-sectional area is increased toward the tool mounting surface. The ultrasonic processing apparatus according to any one of claims 1 to 5, wherein the workpiece is a brittle material.

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