JP2002355710A - Cutting tool for brittle material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain crazing and cracking of a work and to attempt extension of longevity of a cutting tool in the case of applying cutting work on a brittle material. SOLUTION: Head end surfaces 15, 15 made of two flat surfaces are formed on a head end of a columnar axial knife edge part 12, and a linear crossing crest line of these head end surfaces 15, 15 is made into a cutting blade 16. The overall surface of the knife edge part 12 is covered with a diamond film. The cutting blade 16 extends in the diametrical direction of the knife edge part 12 as seen from the head end side in the axis O direction, extends in a direction orthogonal with the axis O as seen from a side surface of a tool main body 11, and it reaches an outer peripheral surface 12A of the knife edge part 12. A holding angle θ made by the two head end surfaces 15, 15 is set in a range of 45 deg.<=θ<=175 deg.. Two chip discharge grooves 41, 41 extending to the base end side from the head end are formed on an outer periphery of the knife edge part 12. Central thickness d of the tool main body is set more than 0.5D against an outside diameter D of the cutting blade 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to silicon, various ceramics, glass, and tungsten carbide (W).
The present invention relates to a cutting tool for brittle material that performs cutting on a high-hardness 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, when drilling a brittle material such as single crystal silicon, laser processing has been more often performed than in the past. However, such laser processing has a problem that the laser processing equipment required for the processing is expensive, the running cost is high, and it is uneconomical. Then, the inventors of the present invention,
In the case of such a brittle material, for example, two cutting edges are formed at a tip of a tool body rotated around an axis with a predetermined tip angle in the same manner as ordinary drilling of a metal material. At the same time, it was attempted whether drilling could be performed using a drill-like drilling tool having two chip discharge grooves.

[0003]

However, when an attempt is made to drill a brittle material with such a drill-shaped drilling tool, such a material is brittle, so that a general metal such as steel material is used. Cracks and cracks are more likely to occur at the entrance of the drilled hole than when drilling holes in the material.In particular, such cracks and cracks reduce the tip angle of the cutting edge located on the axis of the tool body tip. It is easy to occur when a sharp tip (so-called chisel edge) bites into a workpiece. This is because, on this axis, the rotational speed of the tool body becomes 0, so that the protruding end of the cutting blade comes into contact with the work so as to be pressed against the work at one point, whereby an excessive load acts on the work. This is considered to be due to cracking.

On the other hand, brittle materials often have high hardness, which causes chipping of the cutting edge of a drill-like drilling tool and breakage of the cutting edge, resulting in relatively few holes. There has also been a problem that the life of the tool is exhausted by the number of machining operations. And such a tendency, as in the case of using a perforated brittle material for a shower head in a semiconductor device manufacturing apparatus described above,
This is particularly noticeable when the diameter of the machined hole is extremely small, and therefore the outer diameter of the cutting edge of the drilling tool must be extremely small.

[0005] Further, in addition to the case where a workpiece made of a brittle material as described above is drilled, for example,
Similarly, in the case of a general cutting process in which grooving is performed on a workpiece made of a brittle material, cracks, cracks, and the like are likely to occur in the workpiece, and the life is shortened due to chipping and breakage. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and when cutting a brittle material, it is possible to suppress the occurrence of cracks and cracks in the workpiece and to extend the life of the cutting tool. An object is to provide a cutting tool for materials.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve such an object, the present invention provides a cutting tool for a brittle material for cutting a workpiece made of a brittle material, At the tip of a cylindrical shaft-shaped tool main body that is rotated around an axis, there are two tip surfaces that intersect with each other while being inclined with respect to the axis, and the intersection ridge line between the two tip surfaces is a cutting edge. The cutting edge extends in the diametrical direction of the tool main body as viewed from the distal end side in the axial direction to reach the outer peripheral surface of the tool main body, and at least the cutting edge portion is covered with a hard carbon coating. Or at least the cutting edge portion is formed of a hard carbon body. With such a configuration, in the case of a cutting tool, the protruding end of the cutting blade located on the axis line does not contact the work so as to be pressed against the work at one point as in the related art. Even if it is a brittle material, it is possible to prevent cracks from occurring, and furthermore, it is possible to keep the strength of the cutting edge high and make it difficult for chipping to occur. In addition, since the rigidity of the tool body can be kept remarkably high by forming a cylindrical shaft, it is possible to prevent breakage of the blade edge portion and obtain good machining accuracy. Furthermore, since at least the cutting edge portion used for cutting the workpiece is covered with the hard carbon film, or is formed of the hard carbon body, the wear resistance of the cutting edge portion can be improved. At the same time, fine irregularities are formed on the surface of the cutting blade part, and as a result of this fine irregularity, it is as if grinding with a grindstone, but due to the cutting action by many cutting blades extremely small than the abrasive grains of the grindstone In addition, it is possible to reliably perform a cutting process on a workpiece made of a brittle material.

In the present invention, it is preferable that the hard carbon film is composed of a diamond film or a DLC film, or that the hard carbon body is composed of a diamond sintered body or a diamond single crystal.

Further, the present invention is characterized in that the cutting blade has a linear shape extending in a direction perpendicular to the axis when viewed from a side surface of the tool body. With such a configuration, the cutting edge bites into the workpiece in line contact during cutting, so that the load received by the workpiece during biting is distributed and acted on the entire length of the cutting edge. And the work piece can be less likely to crack.

Further, the present invention is characterized in that the cutting blade has a convex curved shape bulging toward the tip end in the axial direction. With this configuration, during cutting, the cutting edge gradually cuts into the workpiece from the gentle curved part that protrudes most toward the tip end of the tool body, so machining at one point as in the past It is possible to reduce the possibility of cracking without sticking to an object, to prevent an impact load from acting on the cutting blade, and to make chipping less likely to occur.

Further, the present invention is characterized in that the included angle θ between the two end surfaces is set in a range of 45 ° ≦ θ ≦ 175 °. With such a configuration, the strength of the cutting edge formed by the intersection ridge line of the two front end surfaces can be kept high, so that chipping can be more reliably prevented and the sharpness of the cutting edge is not reduced.

Further, the present invention is characterized in that at least one chip discharge groove extending from a tip end to a base end side is formed on an outer periphery of the tool main body. With this configuration, chips generated by the cutting edge at the tip of the tool main body can be reliably released to the base end side of the tool main body by the chip discharge groove, so that the chips can be removed from the inner peripheral surface of the machining hole and the tool. It is possible to eliminate the possibility that the machining accuracy is impaired due to being caught between the outer peripheral surface of the main body and the main body.

Further, according to the present invention, the center thickness of the tool body is preferably
The outer diameter D of the cutting edge is set to 0.5D or more. With such a configuration, the rigidity of the tool body can be secured, and even if the outer diameter of the tool body (outer diameter of the cutting edge) must be extremely small, the tool body may be broken. Can be prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a cutting tool for a brittle material according to the present invention is applied to a drilling tool will be described below with reference to the accompanying drawings as an embodiment of the present invention. FIG. 1 is a side view of a brittle material drilling tool according to the first embodiment of the present invention, FIG. 2 is a front perspective view of the brittle material drilling tool,
FIG. 3 is a front end view of the brittle material drilling tool, and FIG.
FIG. 4 is a sectional view taken along line AA in FIG. 3.

As shown in FIG. 1, a drilling tool 10 for a brittle material according to the first embodiment is formed integrally with a hard material such as a cemented carbide and has a tool body 11 rotated about an axis O. The tip portion forms a cutting edge portion 12 that is inserted into a workpiece to perform drilling, and the base portion forms a shank portion 13 that is gripped by a main shaft of a machine tool. Further, the cutting edge portion 12 is reduced in diameter by one step with respect to the shank portion 13, and the cutting edge portion 12 and the shank portion 13 are connected by a tapered portion 14 whose diameter gradually decreases toward the tip end side of the tool body 11. Accordingly, the tool body 11 has a multi-stage cylindrical shaft shape in which the cutting edge portion 12 having a cylindrical shaft shape and the shank portion 13 also having a cylindrical shaft shape are coaxially connected.

The tip of the cutting edge 12 (the tool body 11
Are formed at the front end of the cutting edge 16, each of which is formed of a plane and has a substantially semi-elliptical shape, and a cutting edge 16 whose intersection ridge line of the two front end surfaces 15, 15 forms a straight line. It has become. That is, the cutting edge 1 having a cylindrical shaft shape
The two front end portions are cut out by two front end surfaces 15, 15, and have a shape like a flathead screwdriver. This cutting blade 16 is
When viewed from the side of the tool body 11, as shown in FIG. 1, it forms a straight line extending in a direction perpendicular to the axis O. When viewed from the tip side of the tool body 11 in the direction of the axis O, as shown in FIG. It has a linear shape passing through O and extending in the diameter direction of the cutting edge portion 12. Moreover, the cutting blade 16 has both ends 1
Since 6A and 16A are located on the outer peripheral surface 12A of the cutting edge portion 12, they reach the outer peripheral surface 12A of the cutting edge portion 12 (the outer peripheral surface of the tool body 11). Here, for example, a chisel edge in a conventional drill-shaped drilling tool is extended to reach the outer peripheral surface of the tool body,
It can also be considered that it corresponds to the cutting blade 16 in the first embodiment.

When the cutting edge portion 12 is viewed in a cross section (a cross section taken along the line AA in FIG. 3) in a plane orthogonal to the cutting blade 16 among the planes including the axis O, as shown in FIG.
The two tip surfaces 15, 15 are each inclined at the same inclination angle with respect to the axis O, and these two tip surfaces 1
The included angle θ between 5, 5 and 15 is set in a range of 45 ° ≦ θ ≦ 175 °. Therefore, the blade angle of the cutting blade 16 is set in the range of 45 ° ≦ θ ≦ 175 °. Further, since the cutting edge 12 has a cylindrical shaft shape, the center thickness d of the cutting edge 12 (the center thickness d of the tool body 11) is:
1. With respect to the outer diameter D of the cutting blade 16 (the outer diameter D of the cutting edge portion 12).
0D.

Here, the drilling tool 10 for a brittle material according to the first embodiment can be applied to a brittle material such as single crystal silicon when manufacturing a shower head used in a semiconductor device manufacturing apparatus as described above. Since this is for forming a processing hole having a very small diameter, the outer diameter D of the cutting edge portion 12 (outer diameter D of the cutting blade 16) for performing drilling on a brittle material is also small, and is about 0.2 to 3 mm. In addition, the length of the cutting edge 12 is also set to about 1 to 10 mm.

In the first embodiment, the surface of the cutting edge portion 12 including the cutting edge 16 (the outer peripheral surface 12A of the cutting edge portion 12)
And the entire tip surface 15, 15) is covered with a diamond film as shown by the dots in the figure.
The diamond coating covering the surface of the cutting edge 12 is applied to the cutting edge 12 of the tool body 11 made of cemented carbide or the like.
For example, microwave plasma CVD or hot filament C
It is formed by a method such as the VD method, in which a mixed gas of hydrogen and methane or CO is used as a raw material gas, and a processing temperature is about 800 to 9
The temperature is generally 00 ° C., the thickness of the coating layer is about 5 to 25 μm, and the diameter of the diamond particles to be formed is about 0.1 to 10 μm. In the first embodiment, for example, if the thickness of the diamond coating layer is 1
About 0 μm, the diameter of the formed diamond particles is 1 μm
m.

In the brittle material drilling tool 10 according to the first embodiment having the above-described configuration, the shank portion 13 of the tool body 11 is gripped by the main shaft of the machine tool, and is rotated about the axis O while the axis line is rotated. Drilling is performed on a workpiece made of a brittle material such as single-crystal silicon, which is sent to the front end side in the O direction. Therefore, the brittle material drilling tool 10 according to the first embodiment forms a straight line extending in the direction perpendicular to the axis O in the side view of the tool main body 11 by forming the intersection ridgeline of the tip surfaces 15, 15 of the cutting edge portion 12 thereof. The cutting blade 16 in the shape of a bar bites into the workpiece in line contact.

The axis O of the tool body 11 at this time is
The feed amount to the tip side in the direction is, for example, 0.025 to 0.1
By setting it as extremely small as 5 μm / rev and sufficiently small with respect to the height of the fine unevenness of the diamond film, the convex portion of the fine unevenness of the diamond film applied to the cutting edge 16 acts as a cutting edge. In addition, the recess acts as a chip pocket for storing the very fine chip-like chips of the workpiece cut off by this cutting edge, and as if grinding with a grindstone, however, there were many small chips smaller than the abrasive grains of the grindstone. By the cutting action of the blade, it is possible to reliably perform drilling on a workpiece made of a brittle material. At the time of drilling, it is desirable to supply cutting oil to the drilled portion of the workpiece.

According to the brittle material drilling tool 10 according to the first embodiment, the cutting edge 16 of the cutting edge portion 12 bites into the workpiece in line contact as described above, and the workpiece is received at the time of biting. The load can be distributed and acted on over the entire length of this cutting edge 16 and, for example, on a workpiece made of a brittle material such as single crystal silicon, such a drilling tool 10 for a brittle material can be used.
Even when a drilled hole is formed, the load at the time of biting of the brittle material drilling tool 10 is prevented from concentrating at one point, thereby preventing the cracked workpiece from being formed. It is possible to prevent cracks and cracks from occurring due to the above. For this reason, cracks and cracks at the entrance of the processing hole due to cracks and cracks can be suppressed, and a high-quality processing hole can be formed with high accuracy. In addition, the processing hole can be formed mechanically using a rotating drilling tool. Can be formed, so that drilling can be performed economically and efficiently even on a brittle material as described above.

In the first embodiment, the core thickness d of the cutting edge portion 12 is set to 1.0D and the cutting edge portion 12 has a cylindrical shaft shape. Thus, the breakage of the cutting edge portion 12 can be reliably prevented, and the hole position accuracy can be kept good. Moreover, the included angle θ formed by the two tip surfaces 15, 15
However, since the angle is set in the range of 45 ° ≦ θ ≦ 175 °, the strength of the cutting edge 16 can be kept high, and chipping can be made more difficult to occur, and the sharpness thereof does not decrease. If the included angle θ is smaller than 45 °, a high strength of the cutting blade 16 cannot be secured, while the included angle θ is 175 °.
If it is larger than ゜, the sharpness of the cutting blade 16 is reduced, and the processing efficiency is deteriorated. In order to further ensure the above-described effects, it is preferable that the included angle θ formed by the two end surfaces 15 is set in the range of 90 ° ≦ θ ≦ 175 °.

Further, in the first embodiment, the cutting edge 1
From the tip surfaces 15 and 15 including the two cutting blades 16
Since the outer peripheral surface 12A is coated with the diamond film, the wear resistance of the entire cutting edge portion 12 of the tool body 11 can be improved, and the damage to the cutting edge portion 12 can be more reliably prevented. In addition to this, the outer peripheral surface 12A of the cutting edge portion 12 coated with diamond in this way is inserted into a machining hole along with the feed of the tool body 11 and slidably contacts the inner peripheral surface thereof.
There is also obtained an advantage that the inner peripheral surface of the processing hole can be processed with higher finished surface accuracy by the fine irregularities of the diamond film on the outer peripheral surface 12A.

Next, a description will be given of a brittle material drilling tool according to a second embodiment of the present invention. The same reference numerals are used for the same parts as those in the first embodiment, and the description is omitted. FIG. 5 is a side view of a brittle material drilling tool according to a second embodiment of the present invention, FIG. 6 is a perspective view of a tip portion of the brittle material drilling tool, and FIG. 7 is a brittle material drilling tool. 8 is a sectional view taken along the line BB in FIG.

The drilling tool 20 for a brittle material according to the second embodiment has two tip surfaces, each of which is formed of a convex curved surface and has a substantially semi-elliptical shape, at the tip of the cutting edge 12 (tip of the tool body 11). 21 and 21 are formed, and the intersection ridge line of the two front end surfaces 21 and 21 forms a gentle curved cutting edge 22 having a large radius of curvature. In other words, the tip of the cutting edge portion 12 having a cylindrical axis shape is cut off by the tip surfaces 21 and 21 formed of two convex curved surfaces. When viewed from the side surface of the tool body 11, the cutting blade 22 has a convex curve shape that gently swells toward the tip end in the direction of the axis O as shown in FIG. When viewed, as shown in FIG.
It has a linear shape that passes through the axis O and extends in the diametrical direction of the cutting edge portion 12. Moreover, the cutting blade 22 has two end portions 22.
A, 22A are located on the outer peripheral surface 12A of the cutting edge portion 12, so that the cutting blade 22
A has been reached.

According to the brittle material drilling tool 20 according to the second embodiment having such a configuration, the same effect as that of the above-described first embodiment can be obtained. Has a large convex curve with a large radius of curvature that gently swells toward the tip end in the direction of the axis O in a side view, so that when cutting into the workpiece, the cutting edge 22 has the gentlest protrusion most protruding toward the tip end of the tool body 11. It gradually bites from the curved part, reducing the possibility of cracking without having to bite into the work piece at a single point as before, and also prevents the impact force from acting on the cutting edge Therefore, chipping can be made more difficult to occur.

Next, a drilling tool for a brittle material according to a third embodiment of the present invention will be described. The same parts as those in the above-described first and second embodiments are denoted by the same reference numerals and description thereof is omitted. I do. FIG. 9 is a perspective view of a tip of a drilling tool for brittle material according to a third embodiment of the present invention, and FIG.
It is a front view of the drilling tool for brittle materials.

As shown in FIGS. 9 and 10, the drilling tool 30 for a brittle material according to the third embodiment has substantially the same configuration as that of the first embodiment described above.
The second outer peripheral surfaces 12A are formed so as to be one step thinner at a predetermined second outer depth 12a. The second cutting surfaces 31, 31 are provided at both ends 16 of the cutting blade 16 on the outer peripheral surface 12 </ b> A at the tip of the cutting edge 12.
A, 16A is formed except for the portion where it is located, and is formed in a spiral shape that is twisted rearward in the tool rotation direction T from the tip end of the cutting edge portion 12 toward the base end side. In the second embodiment, the second face 31
31 is also covered with a diamond film. In addition, the core thickness d of the cutting edge portion 12 in the third embodiment is the diameter of an imaginary circle having the second cutting surfaces 31 and 31 as arcs with the axis O as the center in the cross section of the cutting edge portion 12 (secondary diameter). Since the chamfered surfaces 31, 31 are one step thinner from the outer peripheral surface 12A of the cutting edge portion 12 at a predetermined second cutting depth a, the core thickness d of the cutting edge portion 12 becomes D = D-2a. Outer diameter D of
(Outer diameter D of the blade edge portion 12) is set to be 0.5D or more.

According to the brittle material drilling tool 30 according to the third embodiment having such a configuration, the same effects as those of the above-described first embodiment can be obtained, but the first and second embodiments described above. The outer peripheral surface 12 of the cutting edge portion 12 comes into contact with the inner peripheral surface of the machining hole although the rigidity of the cutting edge portion 12 is slightly
Since the area of A is reduced, it is suitable for the case where the frictional resistance between the workpiece and the cutting edge 12 increases. Further, the small gap formed between the second cutting surfaces 31 and 31 and the inner peripheral surface of the processing hole can be used to discharge fine chips.

Next, a description will be given of a brittle material drilling tool according to a fourth embodiment of the present invention. Parts similar to those of the above-described first to third embodiments are denoted by the same reference numerals, and description thereof is omitted. I do. FIG. 11 is a perspective view of a tip portion of a drilling tool for brittle material according to a fourth embodiment of the present invention.
FIG. 2 is a front end view of the brittle material drilling tool.

The brittle material drilling tool 40 according to the fourth embodiment has substantially the same configuration as the third embodiment described above, as shown in FIGS. Two chip discharge grooves 41, 41 are formed on the outer circumference on opposite sides of the axis O. The chip discharge grooves 41 are formed on the outer peripheral surface 12 at the tip of the blade edge portion 12.
In A, it is located immediately forward in the tool rotation direction T at a position where both ends 16A, 16A of the cutting blade 16 are located,
The cutting edge 12 is formed by a concave curved surface that is recessed toward the axis O, and is formed in a spiral shape that is twisted rearward in the tool rotation direction T from the tip of the cutting edge 12 toward the base end. In the fourth embodiment, the chip discharge grooves 4
The concave curved surfaces constituting 1, 41 are also covered with the diamond film. The core thickness d of the cutting edge 12 in the fourth embodiment is a diameter of a circle centered on the axis O in the cross section of the cutting edge 12 and inscribed in the groove bottom of the concave curved surface constituting the chip discharge grooves 41, 41. And is set to be 0.5D or more with respect to the outer diameter D of the cutting blade 16 (the outer diameter D of the cutting edge portion 12).

According to the brittle material drilling tool 40 according to the fourth embodiment having such a configuration, the same effects as those of the above-described first and third embodiments can be obtained. Since the two chip discharge grooves 41, 41 are formed in the 12A, the extremely fine chip-like chips generated by cutting the workpiece with the diamond film covering the cutting blade 16 portion are removed. Through the discharge grooves 41, 41, it can be reliably sent to the base end side of the tool body 11 and discharged from the machining hole, and chips are formed on the inner peripheral surface of the machining hole and the cutting edge 12.
Can be prevented from being lost between the outer peripheral surface 12A and the finished surface accuracy of the machined hole. This is because the outer diameter D of the cutting edge portion 12 also has an extremely small diameter as a very small hole is formed in a brittle material such as single crystal silicon for a shower head of a semiconductor device manufacturing apparatus as in this embodiment. This is particularly effective when it is necessary to do so. Further, if the cutting oil is supplied at the time of drilling, the cutting oil can be sent to the bottom of the machining hole instead of the chip being discharged from the chip discharge grooves 41, and the cutting edge 1
The bottom of the processing hole cut by the second cutting blade 16 can be efficiently cooled and lubricated, and the generated chips can be smoothly discharged.

In the third and fourth embodiments, the second cutting surfaces 31, 31 or the second cutting surfaces 31, 3 are used.
1 and the chip discharge grooves 41 are formed in a spiral shape that is twisted rearward in the tool rotation direction T from the distal end of the cutting edge portion 12 toward the base end side, but is not limited thereto. It does not have to be twisted. Further, as in the fourth embodiment, the number of chip discharge grooves formed on the peripheral surface of the cutting edge portion 12 may be one or three or more, instead of two. In addition, when the workpiece to be drilled as in the present embodiment is a brittle material and is generated as extremely fine chip-shaped chips, and when the feed amount is extremely small as described above, 10 and 12, the direction is opposite to the tool rotation direction T at the time of drilling, that is, the direction opposite to the twist direction of the chip discharge grooves 41, 41 toward the tip end side of the tool body 11. The tool body 11 may be rotated in the direction of, so that the discharge of chips is not hindered.

Further, in each embodiment, the blade tip 1
Although the entire surface of No. 2 is covered with the diamond film, the present invention is not limited to this, and it is sufficient that at least the cutting blade 16 (22) is covered.
2 may be coated only with the diamond coating, or only the tip surfaces 15, 15 (21, 21) may be coated with the diamond coating. Further, instead of the diamond film, another hard carbon film such as a DLC (diamond-like carbon) film may be used, or the hard carbon film may be formed by electrodeposition of diamond abrasive grains as described above. Effects can be produced without any inferiority.

In addition, at least the cutting blade 16 of the blade tip 12
Instead of coating the (22) portion with a hard carbon film, at least the cutting edge 16 (22) portion, for example, the entire cutting edge portion 12 indicated by a dot in the drawing, is hardened with a hard carbon such as a diamond sintered body or a diamond single crystal. It may be formed by a body, and may be joined by brazing or the like to the tips of the shank portion 13 and the tapered portion 14 integrally formed from a cemented carbide or the like.
The same effect as above can be obtained with such a brittle material drilling tool.

Here, in each of the above embodiments,
Although the cutting tool for brittle materials according to the present invention is described as being applied to a drilling tool, the present invention is not limited to this, and when having the above configuration, the rigidity of the tool and the special cutting form Therefore, for example, it is also possible to use as a cutting tool for performing a cutting process such as an end mill, such as grooving and side processing, even in such a case, cracks and cracks in the work made of brittle material. Generation can be suppressed and the life of the cutting tool can be extended.

[0038]

As described above, according to the present invention,
In the cutting process, as in the prior art, the protruding end of the cutting blade located on the axis line does not contact so as to be pressed against the workpiece at one point, and a crack occurs even if the workpiece is a brittle material. Thus, it is possible to suppress the occurrence of cracks and cracks in the workpiece due to the cracks. In addition, while keeping the strength of the cutting blade high to prevent chipping, the rigidity of the tool body is kept high to prevent breakage,
The tool life can be extended and good hole position accuracy can be obtained. Furthermore, since at least the cutting edge portion is coated with a hard carbon film or is formed of a hard carbon body, it is possible to improve the wear resistance of the cutting edge portion and obtain a cutting tool having a longer life. it can.

[Brief description of the drawings]

FIG. 1 is a side view of a drilling tool for brittle material according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a tip of a drilling tool for brittle material according to the first embodiment of the present invention.

FIG. 3 is a front view of a drilling tool for brittle material according to the first embodiment of the present invention.

FIG. 4 is a sectional view taken along line AA in FIG.

FIG. 5 is a side view of a drilling tool for brittle material according to a second embodiment of the present invention.

FIG. 6 is a perspective view of a tip portion of a drilling tool for brittle material according to a second embodiment of the present invention.

FIG. 7 is a front end view of a drilling tool for brittle material according to a second embodiment of the present invention.

8 is a sectional view taken along line BB in FIG. 7;

FIG. 9 is a perspective view of a tip portion of a drilling tool for brittle material according to a third embodiment of the present invention.

FIG. 10 is a front view of a drilling tool for brittle material according to a third embodiment of the present invention.

FIG. 11 is a perspective view of a tip portion of a drilling tool for brittle material according to a fourth embodiment of the present invention.

FIG. 12 is a front view of a drilling tool for brittle material according to a fourth embodiment of the present invention.

[Explanation of symbols]

 10, 20, 30, 40 Drilling tool for brittle material 11 Tool body 12 Cutting edge 13 Shank portion 15, 21 Tip surface 16, 22 Cutting blade 31 Second cut surface 41 Chip discharge groove O Axis d Core thickness D Cutting blade Outer diameter θ Include angle

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Ikeuchi 179-1 Kanegasaki Nishi-Oike, Uozumi-cho, Akashi-shi, Hyogo Inside MMC Kobelco Tool Co., Ltd. -1 Inside MMC Kobelco Tool Co., Ltd. (72) Inventor Hiroshi Hayasaki 179-1 Kanegasaki Nishi-Oike, Uozumi-cho, Akashi-shi, Hyogo Prefecture Inside MMC Kobelco Tool Co., Ltd. (72) Inventor Tetsumitsu Tominaga Kanegasaki-Nishi, Uozumi-cho, Hyogo Prefecture 179-1 Oike FMC Term in MMC Kobelco Tool Co., Ltd. (Reference) 3C037 BB00 CC01 DD01 FF08

Claims (9)

[Claims] 1. A cutting tool for a brittle material for performing a cutting process on a workpiece made of a brittle material, wherein the cutting tool is inclined with respect to the axis at the tip of a cylindrical shaft-shaped tool main body rotated about an axis. It has two intersecting tip surfaces, and an intersection ridge line between the two tip surfaces is a cutting edge, and the cutting edge extends in the diameter direction of the tool main body as viewed from the front end side in the axial direction. A cutting tool for brittle material, wherein the cutting tool reaches an outer peripheral surface of a tool body, and at least the cutting edge portion is covered with a hard carbon film. 2. The cutting tool for a brittle material according to claim 1, wherein the hard carbon film is formed of a diamond film or a DLC film. 3. A cutting tool for a brittle material for performing a cutting process on a workpiece made of a brittle material, wherein the cutting tool is provided at a tip end of a cylindrical shaft-shaped tool body which is rotated around an axis and is inclined with respect to the axis. It has two intersecting tip surfaces, and an intersection ridge line between the two tip surfaces is a cutting edge, and the cutting edge extends in the diameter direction of the tool main body as viewed from the front end side in the axial direction. A cutting tool for brittle material, wherein the cutting tool extends to an outer peripheral surface of a tool body, and at least the cutting edge portion is formed of a hard carbon body. 4. The cutting tool for a brittle material according to claim 3, wherein the hard carbon body is composed of a diamond sintered body or a diamond single crystal. 5. The cutting tool for a brittle material according to claim 1, wherein the cutting edge has a linear shape extending in a direction perpendicular to the axis when viewed from a side surface of the tool body. A cutting tool for brittle materials. 6. The cutting tool for a brittle material according to claim 1, wherein the cutting edge has a convex curve shape bulging toward a tip end in the axial direction. Cutting tool for brittle materials. 7. The cutting tool for a brittle material according to any one of claims 1 to 6, wherein the included angle θ between the two end surfaces is 45 ° ≦ θ ≦ 175.
A cutting tool for brittle materials, wherein the cutting tool is set in the range of ゜. 8. The cutting tool for a brittle material according to claim 1, wherein at least one chip discharge groove extending from a tip to a base end is formed on an outer periphery of the tool body. A cutting tool for brittle materials, characterized in that it is made. 9. The cutting tool for a brittle material according to claim 1, wherein a core thickness of the tool main body is equal to 0.
A cutting tool for brittle materials, wherein the cutting tool is set to 5D or more.