JP2003205410A - Drilling tool for brittle material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent edge chipping when a through hole is formed in a work W of brittle material. <P>SOLUTION: In a drilling tool for brittle material which drills a hole in a work formed of brittle material, a cutting blade part 15 having the outline that the rotational locus around the axis O is semi-spherical is formed on a tip of a columnar tool body 11 rotated around the axis O, a surface part in which at least the rotational locus of the cutting blade part 15 is semi-spherical is covered by a film 16 consisting of a diamond coating film, a diamond electro- deposited film, or a CBN electro-deposited film, or a surface part in which at least the rotational locus of the cutting blade part 15 is semi-spherical is formed of a diamond sintered body or a CBN sintered body. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to silicon, various ceramics, glass, or tungsten carbide (W).
The present invention relates to a drilling tool for a brittle material, which drills a highly hard brittle material including a cemented carbide material such as C).

[0002]

2. Description of the Related Art For example, in the case of manufacturing a shower head used in a semiconductor device manufacturing apparatus, laser processing has often been used exclusively for drilling a brittle material such as single crystal silicon. However, such laser processing has a problem that the laser processing apparatus required for the processing is expensive and the running cost is high, which is uneconomical. However, when attempting to drill such brittle materials with a sharp-edged drilling tool that is used for drilling ordinary metal materials, such materials are generally used for metal materials such as steel materials. Cracks and cracks are much more likely to occur as compared with the case where drilling is performed. Especially, such cracks and cracks
When the sharp tip of the drilling tool bites into the work piece, it becomes point contact, and the load is likely to concentrate, which is likely to occur.

Therefore, the inventors of the present invention have previously proposed Japanese Patent Application No. 2000-33150 in order to solve such a problem.
In No. 8, as shown in FIG. 5, the tip end portion of the cylindrical tool body 1 that is rotated around the axis O is brought into surface contact with the workpiece by making the tip end surface 2 a flat surface orthogonal to the axis O. It has been proposed that a drilling tool for brittle materials, which is capable of biting and is coated with a diamond coating 3 on at least the tip surface 2 of the tool body 1. As a tool for making a hole in such a brittle material, for example, in Japanese Patent Laid-Open No. 11-165313, a handle portion 4 attached to a machine spindle and a plurality of twisted grooves (not shown) are shown in FIG. It is also proposed that a drill having a blade portion 5 provided with a diamond abrasive grain 6 fixed to the tip of the blade portion 5 has a frustoconical shape in which the drill tip has a plane 7 perpendicular to the axis.

[0004]

However, when an attempt is made to form a through hole in a workpiece (workpiece) W made of the brittle material as described above, as shown in FIGS. 7 and 8, by using these drilling tools. Since the tip end surface 2 of the tool body 1 is a flat surface, the thrust force due to the tool feed is applied to the work W as a surface pressure in the feed direction. On the other hand, since the work W is a brittle material, when the distance between the hole bottom immediately before the tool penetrates and the back surface P of the work W becomes small, the work W cannot withstand this surface pressure. It has been found that a part A from the bottom of the hole toward the back surface P is peeled off in a skirt-like manner at a stretch, and as a result, a new problem occurs in that a chipped edge C is generated at the opening of the through hole.

The present invention has been made under such a background, and in the case of forming a through hole in a work made of a brittle material, it is possible to prevent the occurrence of an edge chip when the through hole is pulled out. The aim is to provide a possible drilling tool for brittle materials.

[0006]

In order to solve the above problems and achieve such an object, the present invention is a drilling tool for brittle material, which drills a workpiece made of brittle material. Firstly, at the tip of the tool body in the form of a cylindrical shaft that is rotated around the axis, a cutting edge portion having an outer shape in which the rotation locus around the axis is hemispherical is formed, and at least the cutting edge portion described above is formed. A diamond coating, diamond electrodeposition coating, or C
It is characterized by being coated with a BN electrodeposition coating. Therefore, in such a brittle material drilling tool, similar to the above-mentioned proposed drilling tool, diamond particles grown in the diamond coating film coated on the surface portion of the cutting edge portion of the tool body tip. , Diamond, CBN, CBN electrodeposited diamond, CBN
Microscopic unevenness is formed on the surface portion by particles,
Cutting is performed by the convex portions of the concavities and convexities, and the concave portions function as chip pockets to make holes in the brittle material. Since the cutting edge portion has a semi-spherical outer shape in the rotation locus around the axis, it is close to surface contact when the cutting edge bites the work, and cracks due to concentration of load at the time of biting. While it is possible to prevent the generation of the thrust force, it is possible to disperse the thrust force due to the feed of the tool and to prevent the chipping of the edge due to the concentration of the thrust force in the feed direction when the through hole is removed. it can.

Here, in order to make the rotation locus of the cutting edge part hemispherical, it is only necessary to form the surface of the cutting edge part in a hemispherical shape. In this case, this surface is formed. The diamond coating film or diamond to be coated on,
The CBN electrodeposition coating allows the entire surface to act as a cutting edge to perform efficient drilling. In addition, as another one, a plurality of curved surfaces, which are convex on the surface of the cutting edge portion from the tool rotation center of the inner circumference of the tip of the cutting edge portion toward the outer circumference of the rear end, are arranged in the circumferential direction of the tool body. It is possible to form by providing the curved edges adjacent to each other in the circumferential direction and extending from the tool rotation center to the outer peripheral side of the rear end so as to form a hemispherical shape in the rotation locus around the axis. In this case, since the intersecting ridge line acts as a cutting edge, and the curved surface can be recessed with respect to the rotational trajectory to act as a chip discharge groove, fine chips generated during drilling can be processed. It is possible to prevent a situation in which the hole is bitten between the tool body and impairs the surface accuracy of the inner circumference of the hole.

Secondly, the present invention relates to a brittle material drilling tool for drilling a workpiece, which is also made of a brittle material, wherein the tip of a cylindrical shaft-shaped tool body rotated about its axis. A cutting edge portion having an outer shape in which the rotation locus around the axis is hemispherical, and at least the surface portion of the cutting edge portion in which the rotation locus is hemispherical is formed into a diamond sintered body or a CBN sintered body. And the surface of the cutting edge portion is provided with a plurality of curved surfaces which are convex in the circumferential direction of the tool body from the tool rotation center of the inner circumference of the tip of the cutting edge portion toward the outer circumference of the rear end. And a crossing ridge line extending from the tool rotation center of the curved surfaces adjacent to each other in the circumferential direction to the outer peripheral side of the rear end is formed in a hemispherical shape in the rotation locus around the axis line. Therefore, in such a drilling tool for brittle materials, the intersecting ridge line between the curved surfaces of the cutting edge portion formed of the diamond sintered body or the CBN sintered body acts as a cutting blade, Has a hemispherical shape in the rotation trajectory,
As with the first brittle material drilling tool, it is possible to prevent cracks at the time of biting and edge chipping at the time of pulling out of the through hole.

When the cutting edge portion is formed of a diamond sintered body or a CBN sintered body in this way, or when the cutting edge portion surface is a diamond coating film, a diamond electrodeposition coating film,
Alternatively, even when the surface of the cutting edge is formed by a plurality of curved surfaces as described above even when it is covered with a CBN electrodeposition coating, and when the rotation locus of the ridge line intersecting these curved surfaces is hemispherical, this intersection is used. If the ridge is formed on a plane including the axis, it is easy to mold the tool body, and if the intersecting ridge is formed so as to be twisted from the tool rotation center toward the outer periphery of the rear end, the cutting edge can be formed. Since the intersecting ridge line that acts as a part is gradually cut into the work as the tool body rotates, it is possible to prevent the concentration of the impact load and to more reliably prevent the occurrence of edge chipping and cracks. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of the present invention. In the present embodiment, the tool body 11
Is integrally formed of a hard material such as cemented carbide, and is inserted into a workpiece to perform a drilling process.
Is a multi-stage cylindrical shaft centered on an axis O which is reduced by one step with respect to the rear end 13 which is gripped by the main shaft of the machine tool and serves as a shank portion, and a portion between both ends 12, 13. Are connected by a taper portion 14 whose diameter gradually decreases toward the tip side. Further, in the present embodiment, the tip end portion 12 is formed into a cutting edge portion 15 by forming it into a convex hemisphere having the same diameter as the columnar tip portion 12 and having a center on the axis O. Therefore, the surface is hemispherical, and the rotation locus around the axis O is also hemispherical, and the diamond coating, diamond electrodeposition coating,
A coating 16 made of one of the CBN electrodeposition coatings is coated. In the present embodiment, the coating 16 is applied from the hemispherical cutting edge portion 15 to the tip side portion of the cylindrical tip portion 12 that smoothly connects to the cutting edge portion 15.

Here, such a coating 16 is, for example, when it is a diamond coating, from the cutting edge portion 15 to the tip portion 1 of the tool body 11 made of cemented carbide.
The surface of No. 2 extending to the tip side is covered by growing diamond particles by a microwave plasma CVD method or a hot filament CVD method. When the coating 16 is a diamond electrodeposition coating or a CBN electrodeposition coating, the diamond or CBN particles are also electroplated on the surface of the tool body 11 from the cutting edge portion 15 to the tip portion 12. Is fixed and coated with a plating phase such as Ni.

FIG. 2 shows a case where a through hole is formed in a work W made of a brittle material by using such a drilling tool. In the drilling tool having the above-described configuration, first, since the cutting edge portion 15 has a hemispherical shape, the center of rotation X on the inner peripheral side of the tip, which is the most distal end portion on the axis O thereof.
Since the periphery is close to a flat surface and therefore the cutting edge portion 15 hits the surface Q of the work W in a state close to surface contact even when biting on the surface Q of the work W, like a general drilling tool, 1
The load is not concentrated at the points and therefore no cracks occur during this bite. Then, as the tool body 11 is fed to the tip end side in the direction of the axis O, the diamond particles and CBN of the coating film 16 coated on the surface of the cutting edge portion 15 are provided.
Due to the fine unevenness caused by the particles, the work W made of a brittle material is punched out as it is scraped off while generating fine chips. At this time, the rotation locus of the cutting edge portion 15 around the axis O is as described above. Since it has a hemispherical shape, the thrust force due to the feed of the tool body 11 is distributed radially from the center of the hemisphere and acts, so that a large load acts in the feed direction even when the hole is removed. It is possible to avoid the occurrence of edge chipping as shown in the drawing. When feeding the tool body 11 in this way, more desirably, step feed machining is performed in which the tool body 11 is gradually fed and retracted to gradually cut into the work W. Further, it is more desirable to supply the cutting oil to the hole-making portion of the work W during the hole-making process.

Next, FIG. 3 shows a second embodiment of the present invention. The parts common to those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. That is, in the first embodiment, the entire surface of the cutting edge portion 15 is formed in a convex spherical shape, whereas in the present embodiment, the surface of the cutting edge portion 21 has a cross section of a plane including the axis O. Cutting edge 21
A plurality of curved surfaces 22 (six in the present embodiment) are provided in the circumferential direction of the tool body 11 so as to project from the rotation center X of the inner circumference of the tip toward the outer circumference of the rear end. The intersecting ridgelines 23 extending from the center of rotation X of the convex curved surfaces 22 adjacent to each other in the circumferential direction to the outer peripheral side of the rear end are hemispherical in the rotation locus around the axis O. Furthermore, the intersecting ridgeline 23 in the present embodiment is formed on a plane including the axis O.

Here, all of the plurality of (the same as the convex curved surface 22 in this embodiment, six) the intersecting ridge lines 23 ... Composed of the plurality of curved surfaces 22 ... All intersect the rotation center X and are on the axis O. The curved surfaces 2 are formed in a 1/4 circular arc shape having a center at the center and are arranged at equal intervals in the circumferential direction.
In the present embodiment, 2 is formed so as to extend straight between the intersecting ridgelines 23, 23 on both sides in the circumferential direction of the tool body 11, whereby the cutting edge portion 21 is formed in a cross section orthogonal to the axis O. The shape is a regular polygon (a regular hexagon in this embodiment) having a center on the axis O. Therefore, a cross section orthogonal to the axis O has a shape in which both ends of an arc are connected by the chords between each curved surface 22 and the hemisphere formed by the intersecting ridges 23 ... A gap portion whose width and thickness increase from X toward the outer periphery of the rear end is formed. Then, the entire curved surface 2 including the intersecting ridgelines 23 ... Of the cutting edge portion 21.
2 ... and the tip end side portion of the tip end portion 12 of the tool body 11 connected to the rear end side are entirely covered with a coating film 16 made of one of a diamond coating film, a diamond electrodeposition film, and a CBN electrodeposition film. .

Therefore, in the drilling tool constructed as described above, the intersecting ridge lines 23 of the plurality of curved surfaces 22 ... Of the cutting edge portions 21 act as cutting edges, and these intersecting ridge lines 23. Since the rotation locus around the axis O of is a hemispherical shape, as in the first embodiment, a crack occurs when biting into a work made of a brittle material, or a brittle material is used when the through hole is pulled out. It is possible to prevent chipping of the edge of the workpiece. Further, in the present embodiment, as described above, a gap is formed between the hemisphere formed by the intersecting ridgelines 23 ... And the curved surface 22. Therefore, this intersecting ridgeline that acts as the cutting edge during drilling. It becomes possible to discharge the fine chips of the work W generated by 23 ... through this gap, and such chips are processed holes and the cutting edge part 21 or the tip part 1 of the tool body 11.
It is possible to prevent the robot from being bitten between the two and damaging the inner circumference of the hole and increasing the tool rotation driving force. Moreover, the gap is made larger toward the outer peripheral side of the rear end of the cutting edge portion 21 in which the diameter from the axis O to the intersecting ridge line 23 is increased, so that the cutting amount is increased and the generated chips are increased. Therefore, it becomes possible to promote more efficient chip discharge. In addition, in the present embodiment, the intersecting ridge lines 23 are arranged on a plane including the axis O, the convex curved surfaces 22 are formed straight in the circumferential direction, and the intersecting ridge lines 23 are circumferentially formed. Since the curved surfaces 22 are formed at equal intervals, the curved surfaces 22 and their intersecting ridgelines 23 can be easily and accurately formed.

In this embodiment, the curved surface 2 is formed as described above.
2 are formed straight in the circumferential direction and the intersecting ridge lines 23 are formed on a plane including the axis O, but this is the rotation locus about the axis O as in the third embodiment shown in FIG. In, the intersecting ridge lines 26 of the curved surfaces 25 of the cutting edge portion 24 forming a hemisphere may be formed so as to be twisted from the rotation center X toward the rear end outer peripheral side. Here, in order to form the intersecting ridge line 26 in such a twisted manner, for example, the curved surface 25 described above is used.
May be formed in a twisted surface shape that is convex from the rotation center X toward the outer peripheral side of the rear end of the cutting edge portion 24 and is twisted in accordance with the twist of the intersecting ridge line 26. In this case, the cutting edge portion 2 is formed.
The cross section orthogonal to the axis O of No. 4 has a polygon (having a regular hexagon in the case of the third embodiment) having a center on the axis O and an apex on the intersecting ridges 26 ... The shape becomes such that the size gradually increases while keeping a similar shape while twisting in accordance with the twist of the intersecting ridgelines 26 ...

In the drilling tool of the third embodiment having the above-mentioned structure, the intersecting ridge lines 26 ... Which act as cutting edges are twisted around the axis O as in the second embodiment. Therefore, the intersecting ridge lines 26 ... Are gradually cut into the work W as the tool body 11 is rotated and fed. For example, the intersecting ridge lines 23 ... Which are cutting edges as in the case of the second embodiment. The work W does not bite into the work W all at once and is prevented from being concentrated, and at that time prevents the impact load from being concentrated, and the work W made of a brittle material.
It is possible to more reliably prevent the occurrence of edge chipping and cracks. Further, in the third embodiment in which the curved surfaces 25 are formed as described above, the rear end is formed between the curved surfaces 25 and the hemisphere formed by the rotation loci of the intersecting ridge lines 26, similarly to the second embodiment. A gap portion whose width and thickness increase toward the outer peripheral side is formed. At this time, the crossing ridge lines 26 ... Are moved from the rotation center X toward the rear end outer peripheral side of the tool main body 11 during drilling. If it is formed so as to be twisted toward the rear side in the rotation direction, it becomes possible to push out the chips contained in the gap portion to the rear end side by the rotation of the tool body 11 during this drilling, which is more efficient. It becomes possible to promote the discharge of various chips.

When the cutting blades 21, 24 are constructed by the plurality of curved surfaces 22, ..., 25 ... In this way, in the second and third embodiments, the cutting blades 21, 24 are orthogonal to the axis O thereof. The cross section to be crossed is the ridge line 23 ... 26 as described above.
... Although it is designed to have a polygonal shape with a vertex on top,
These curved surfaces 22 ..., 25 ... are made to be convex toward the rear end outer peripheral side from the rotation center X in the section of the plane including the axis O, but in the section orthogonal to the axis O in the circumferential direction. It may be formed to be concave toward the axis O between the intersecting ridgelines 23, 26 ,. With this configuration, the size of the gap formed between the curved surfaces 22 ..., 25 ... And the intersecting ridgelines 23. ,
It is possible to further improve the chip discharge property, and even if relatively large granular chips are generated due to peeling of brittle material during drilling, these are stored in the above-mentioned gap to damage the drilled hole. It is also possible to discharge it without causing it. Further, groove-shaped recesses extending from the center of rotation X toward the outer periphery of the rear end may be formed on the curved surfaces 22.

On the other hand, in the above-mentioned first to third embodiments, as described above, the cutting blades 15, 21,
The surface of 24 is coated with a coating 16 composed of a diamond coating, a diamond electrodeposition coating, or a CBN electrodeposition coating, and the fine irregularities on the surface scrape away the work W made of a brittle material to make a hole. However, among these, as in the second and third embodiments, the cutting edge portions 21, 24
When the surface of is constituted by a plurality of curved surfaces 22 ..., 25 ... which are convex toward the rear end outer peripheral side from the rotation center X, and the intersecting ridgelines 23 ..., 26 ... Are made to act as cutting edges, At least the cutting blade portions 21 and 24 whose rotation loci are hemispherical may be formed of a diamond sintered body or a CBN sintered body. In this case, the intersecting ridge line portions 23, ..., 26 of the cutting edge portions 21, 24 formed of the diamond sintered body or the CBN sintered body directly serve as the cutting edges to scrape off the work made of the brittle material. Drilling will be performed, but at that time as well, since the rotation loci of the cutting edge portions 21 and 24 are hemispherical,
When biting on the work, it is possible to prevent the concentration of load and prevent the occurrence of cracks, while avoiding the concentration of thrust force in the feed direction even when the through hole is removed and the occurrence of edge chipping can be prevented. That is, the same effect as that of the first to third embodiments can be obtained.

When at least the cutting edge portions 21 and 24 are formed of a diamond sintered body or a CBN sintered body instead of coating the coating film 16 as described above, the rotation locus of the tip of the tool body 11 is hemispherical. Cutting edges 21, 24
Joining such a sintered body to the tool body 11 by brazing or the like to a portion or a portion including the end portion to the tip side of the tip portion 12 (a portion indicated by reference numeral 16 in FIGS. 3 and 4). Or the front end side portion formed of such a sintered body and the rear end side portion formed of cemented carbide are integrally sintered to form the tool main body 11. It may be formed. In such a case, the portion indicated by the dots in the drawings as the coating film 16 in FIGS. 3 and 4 is replaced with the sintered body 16.

[0021]

As described above, according to the present invention,
In particular, when forming a through hole in a work made of a brittle material, it is possible to prevent the occurrence of edge chipping when the through hole is pulled out. Therefore, it is possible to open a shower head used in a semiconductor device manufacturing apparatus. It is possible to improve the product yield even when using a drilling tool instead of laser processing.

[Brief description of drawings]

1A is a front view and FIG. 1B is a side view showing a first embodiment of the present invention.

FIG. 2 shows a state of removal when a through hole is formed in a work W made of a brittle material according to the embodiment shown in FIG. 1 (a).
It is a cross-sectional view, (b) a bottom view seen from the back surface P side of the work W.

FIG. 3 is (a) a front view and (b) a side view showing a second embodiment of the present invention.

FIG. 4 is (a) a front view and (b) a side view showing a third embodiment of the present invention.

5A and 5B are (A) front view and (B) side view of the drilling tool previously proposed by the inventors of the present invention.

6 (a) is a front view and FIG. 6 (b) is a side view showing an example of a conventional drilling tool.

FIG. 7 is a sectional view showing a state in which a chipped edge C is generated at the time of removal when a through hole is formed in a work W made of a brittle material by the drilling tool shown in FIG. It is a bottom view seen from the back surface P side.

8A and 8B are views showing a state in which an edge chip C has occurred when the through hole is formed in the work W made of a brittle material by the drilling tool shown in FIG. It is a bottom view seen from the back surface P side.

[Explanation of symbols]

11 Tool body 12 Tip of tool body 11 15, 21, 24 Cutting edge part 16 film 22,25 convex surface 23,26 crossing ridge O Axis of tool body 11 X rotation center

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI theme code (reference) B24D 7/18 B24D 7/18 A (72) Inventor Yasushi Ota 179 Kanegasaki Nishioike Kanegasaki, Akashi City, Hyogo Prefecture 1 MMC Kobelco Tool Co., Ltd. F term (reference) 3C037 BB00 CC01 CC08 3C063 AB05 BA02 BA24 BB02 BC02 CC11 CC12 EE15 EE20 FF06

Claims (6)

[Claims] 1. A drilling tool for brittle materials, which drills a workpiece made of a brittle material, wherein a rotation locus around the axis is formed at the tip of a tool body having a cylindrical shaft shape that is rotated around the axis. A cutting edge portion having a hemispherical outer shape is formed, and at least a surface portion of the cutting edge portion where the rotation locus has a hemispherical shape is covered with a diamond coating film, a diamond electrodeposition film, or a CBN electrodeposition film. A drilling tool for brittle materials that is characterized by 2. The drilling tool for brittle material according to claim 1, wherein the surface of the cutting edge portion is formed in a hemispherical shape. 3. The surface of the cutting edge portion is provided with a plurality of curved surfaces which are convex in the circumferential direction of the tool main body from the tool rotation center of the inner circumference of the tip end of the cutting edge portion toward the outer circumference of the rear end. Is formed by, the intersection ridge line extending from the tool rotation center of these curved surfaces adjacent to each other in the circumferential direction to the rear end outer peripheral side,
The drilling tool for brittle material according to claim 1, wherein the rotational trajectory around the axis is hemispherical. 4. A brittle material drilling tool for drilling a workpiece made of a brittle material, wherein a rotation locus about the axis is formed at the tip of a tool body having a cylindrical shaft shape that is rotated about the axis. A cutting edge portion having a hemispherical outer shape is formed, and at least a surface portion of the cutting edge portion where the rotation locus has a hemispherical shape is formed of a diamond sintered body or a CBN sintered body, and The surface of the blade portion is formed by arranging a plurality of curved surfaces that are convex toward the rear end outer peripheral side from the tool rotation center of the tip inner periphery of the cutting blade portion in the circumferential direction of the tool body, A perforating tool for brittle materials, characterized in that an intersecting ridge line extending from the tool rotation center of the curved surfaces adjacent to each other in the circumferential direction to the outer peripheral side of the rear end is hemispherical in a rotation locus around the axis line. 5. The drilling tool for brittle material according to claim 3, wherein the intersecting ridge line is formed on a plane including the axis line. 6. The drilling tool for brittle material according to claim 3, wherein the intersecting ridge line is twisted from the tool rotation center toward the outer periphery of the rear end.