JP2987427B2 - Drilling method for zirconium dioxide ceramics - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for performing high-precision drilling on zirconium dioxide ceramics.

[0002]

2. Description of the Related Art Heretofore, when drilling hard-to-cut ceramics having a high fracture toughness value, such as alumina ceramics and silicon nitride ceramics, a diamond core drill to which a high-frequency vibration of 40 kHz is applied is used.
It is known that machining is performed at a low rotational speed of 2 to 7 m / min under the condition of 28 μm (November 1995
(Published on May 7, 1995, Japan Society of Precision Engineering, Kyushu Branch, Kagoshima Regional Lectures, p. 59). However, such a low-speed rotation results in a low processing speed, which is not suitable for practical use.

On the other hand, when drilling a brittle and hard material such as a silicon single crystal, the present inventors used a diamond core drill to which a high frequency vibration of 60 kHz was applied, and under a condition of an amplitude of 1.5 μm and a rotation speed of 3000 rpm. It was found that drilling can be performed at a high feed rate of up to 6.0 mm / min without chipping of the edge part (issued on October 20, 1996, co-sponsored by the 1996 Society of Precision Engineering, Chugoku-Shikoku Branch and Kyushu Branch, 1996). Conference Lectures, 9th page). However, hitherto, there has been no known method for drilling hard ceramics such as zirconium dioxide ceramics with high speed and high processing efficiency and without causing chipping at the edges.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for forming a fine hole of 0.1 to 0.5 mm in a zirconium dioxide ceramic with high accuracy and at high speed without causing edge chipping. It was done in.

[0005]

The present inventors have conducted various studies on drilling of zirconium dioxide ceramics, and as a result, have found that 60 kHz which has not been used so far.
When a diamond core drill to which a high frequency vibration of z is applied is used, the feed rate is 0.1 mm / min to 0.3 mm.
The present inventors have found that high-precision drilling with little chipping can be performed at a relatively high speed of mm / min and without reducing the rotation speed, and based on this finding, the present invention has been accomplished.

That is, according to the present invention, when drilling zirconium dioxide ceramics with a diamond core drill to which high-frequency vibration is applied, the frequency is 60 ± 1.
kHz, amplitude 1-5 μm, feed rate 0.1-
It is intended to provide a drilling method characterized by performing at a rate of 0.3 mm / min.

[0007]

Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a side view for explaining an example of the structure of a processing apparatus used for carrying out the method of the present invention. A high-frequency vibration is applied to a rotating diamond core drill 1 via a horn 3 from an oscillator 2. Is added,
The sample is supported by the support unit 4 and is in contact with the sample 6. The high frequency generator 5 has a maximum frequency of 40 kHz conventionally used.
Which is much higher than that of 60 kHz, which is directly connected to the oscillator 2. When the diamond core drill 1 in the processing apparatus having such a structure is brought into contact with the surface of the zirconium dioxide ceramic sample 6, drilling is performed by rotation and vertical vibration of the drill. The main parts 1 to 4 of the processing apparatus are usually driven via a belt. However, when the main parts are directly connected to a motor and driven, the rotation accuracy is increased. Further, since a high frequency of 60 kHz is used, the horn is shortened in design and the amplitude is also reduced, so that it is possible to reduce the size and weight and to achieve high precision and fine processing, which is advantageous. .

In the present invention, a hole is formed by using such an apparatus at a frequency of 60 ± 1 kHz and an amplitude of 1 to 5 μm, preferably 1.5 to 2.5 μm. In this case, the number of rotations of the diamond core drill is 1000 to 6000 r which is used for drilling with a normal drill.
pm can be arbitrarily selected. In this way, at a relatively high feed rate of 0.1 to 0.3 mm / min, a processing force of about 10 N to 30 N (rotation speed 3000 rpm)
The value in (1) allows highly accurate drilling of zirconium dioxide ceramics. In addition, machining can be performed with little wear of the tool used.

[0009]

According to the present invention, zirconium dioxide ceramics can be drilled with high efficiency by using a feed rate approximately three times that of the prior art and a high-speed rotation of a drill, and high-frequency sound is reduced by using a high frequency. In addition to reducing noise to the surrounding environment, the axial machining force is as small as about 15% of the conventional one, and the horn is shortened, so that accuracy can be improved and the tool life is long. There are advantages. Furthermore, since the acting force is very small, the surface processed according to the present invention suffers less damage due to the processing, and therefore can perform high-quality processing.

[0010]

Next, the present invention will be described in more detail with reference to examples.

REFERENCE EXAMPLE A high-frequency vibration processing apparatus having the structure shown in FIG. 1 was used. The function related to the vibration system in this device has a frequency of 60 ± 1.
kHz, amplitude 1-5 μm, oscillator output 100 W, functions related to spindle system, motor output 400 W, rotation speed 0
６6000 rpm. A grindstone with a 3.0 mm diameter electrodeposited diamond internal shaft (# 150)
Was attached with a tool holder, and a through hole was made in a 50 × 50 mm, 0.5 mm thick zirconium dioxide ceramics bonded to a glass plate with wax. A solution type was used as a working fluid, and the solution was injected into the working portion from the side at a rate of 1.5 L / min. The processing force was measured for axial component force and rotational force using a tool dynamometer (Kistler). FIG. 2 shows the fluctuation state of the axial processing force and the rotational force when the hole is drilled at the feed rate of 0.1 mm / min and the rotation number of 3000 rpm. In this figure, area A (left side in the figure) is based on the conventional processing method without adding a high frequency, and area B (right side in the figure) is based on the processing method of the present invention. Thus, in the conventional processing method, about 1
While an axial working force of 30 N is applied, the working method of the present invention is very small, about 20 N (about 15% of the conventional method), and is stable.

Next, a plurality of holes were drilled using the same processing equipment and conditions, and the limit at which the diamond core drill became unusable due to wear was examined. As a result, even if 10 or more holes were drilled, the degree of wear of the diamond core drill was small, and the diamond core drill was still usable for processing. This was almost the same as the degree of wear when the conventional high-frequency vibration was not applied.

Example Using the same processing apparatus as used in the reference example, 50 × 50 m
m and a zirconium dioxide ceramic sample having a thickness of 0.5 mm, the feed rate was changed by 0.1 mm / min in the range of 0.1 to 0.4 mm / min, and the other conditions were the same as in the reference example. A 0 mm hole was drilled. This result is shown in FIG. 3 as a graph. As is clear from this figure, in the case of the method of the present invention, the axial processing force increases as the feed rate increases, but the processing force is about 30 mm up to 0.3 mm / min.
It can be seen that small and stable processing is possible at N or less. This feed rate of 0.3 mm / min is about three times the value of the conventional method that does not apply high-frequency vibration, and the method of the present invention enables high-precision drilling even when processing is performed at high speed. It can be seen that it is. When chipping of the edge of the hole was observed, almost no chipping was observed at any feed speed.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of the structure of a processing apparatus used in the method of the present invention.

FIG. 2 is a graph showing the axial working force in the conventional method and the method of the present invention.

FIG. 3 is a graph showing a relationship between a feed rate and an axial processing force in the conventional method and the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diamond core drill 2 Oscillator 3 Horn 4 Support part 5 High frequency generator 6 Sample

Continued on the front page (72) Yoshihiro Take, 1-36 Otani, Kasuga-shi, Fukuoka Japan Shogun Inc. Norio Nishikawa (56) References JP-A-60-60980 (JP, A) JP-A-3-256658 (JP, A) JP-A-9-220716 (JP, A) JP-A-10-71612 (JP, A A) Takeshi Michitsu, Yoshihiro Take, and Hideki Yanagimoto, "Microfabrication of Si Single Crystal by Applying High Frequency Vibration at 60kHz", Proc. Of the Japan Society of Precision Engineering, Chugoku-Shikoku Branch and Kyushu Branch, 1996. Published October 20, P9-10 (58) Fields investigated (Int. Cl. ⁶ , DB name) B28D 1/14 B23B 35/00

Claims (1)

(57) [Claims] 1. When drilling a zirconium dioxide ceramic with a diamond core drill to which a high frequency vibration is applied, a frequency of 60 ± 1 kHz and an amplitude of 1 to 5 are used.
A drilling method, wherein the drilling is performed at a feed rate of 0.1 to 0.3 mm / min under a condition of μm.