JP2001277137A - Chip saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chip saw capable keeping sharpness over a long period from the initial stage of use by improving the arrangement of segments formed from super abrasive grains into a chip type, so that the segments perform functions such that if abrasive grains on the front side along the direction of rotation of the chip saw wear out, following abrasive grains act as cutting edges. SOLUTION: A plurality of segment chips 2 each shaped to have a rake angle θ1 and a clearance angle θ2 are mounted on the outer periphery of a disc-shaped base 1 and are each formed of an abrasive layer formed by binding abrasive grains together using a metal bond. The interval between the abrasive grains of the abrasive layer as seen in the direction of the outer periphery of the base is less than twice the diameter of the abrasive grain and the segment chips 2 are each supported by the abrasive layer having a lower degree of concentration of abrasive grains than the abrasive layer of the segment chip 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip saw having a chip provided with a cutting edge on the outer periphery of a disk-shaped substrate.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a chip saw 40 in which a plurality of chips 43 having cutting edges 42 are provided at regular intervals on the outer peripheral surface of a disk-shaped substrate 41 has been used for wood-based boards and ceramic-based boards. It is used for cutting difficult-to-cut materials such as siding boards and fiber-reinforced plastics. The substrate 41 is generally made of steel, and the chip 43 is generally in the shape of a sawtooth. The cutting edge 42 is made of a cemented carbide or a sintered diamond.

[0003] In the cutting of difficult-to-cut materials as described above, the wear of the cutting edge of the insert is remarkable, and various measures are taken to extend the life of the insert saw. For example, JP-A-7
Japanese Patent Application Publication No. 148613 discloses that at least one of a plurality of chips is formed from a super-hardened sintered body such as a diamond sintered body, while another chip is formed from a hard material such as a cemented carbide, A chip saw formed such that the cutting blade provided on the chip made of the hard sintered body is projected to the radially outer side of the substrate and the outer surface in the thickness direction of the substrate than the cutting blade provided on the chip made of the hard material. Has been described.

Japanese Patent Application Laid-Open No. 11-277329 discloses that a tip having a cutting edge formed of a diamond sintered body and a tip having a cutting edge formed of a cemented carbide are arranged, respectively, and a cutting edge formed of a diamond sintered body is provided. There is disclosed a tip saw in which the rake angle and the clearance angle are smaller than the respective angles of the cutting edge formed of a cemented carbide.

Further, Japanese Patent Application Laid-Open No. 11-277331 discloses a tip saw in which a tip made of a diamond sintered body and a tip made of a hard material such as a cemented carbide are provided, and the hard tip has a specific shape. .

[0006] The tip material and shape of the tip saw as described above are selected optimally according to the kind and material of the material to be cut. The tip saw described in Japanese Patent Application Laid-Open No. The tip saw described in Japanese Patent Application Laid-Open No. H11-277329 is suitable for cutting aluminum alloys, and the tip saw described in Japanese Patent Application Laid-Open No. H11-277331 is suitable for cutting ceramic siding boards. It is suitable for cutting boards, ceramic boards, FRP, and the like.

On the other hand, as a rotary cutting grindstone used for cutting and grinding asphalt, concrete, stone and the like, a plurality of segments 52 are arranged at regular intervals on the outer peripheral surface of a disk-shaped substrate 51 as shown in FIG. And each segment 52
A so-called segment type rotary cutting grindstone 50 in which a slit 53 is formed in the outer peripheral portion of the substrate between them is used. The segment 52 generally has a generally rectangular shape as shown in the figure, and super-abrasive grains such as diamond abrasive grains and CBN abrasive grains are added together with a bond such as resin, metal, and vitrified. It is manufactured by pressing and firing.

[0008] This segment type cutting whetstone has good sharpness at the beginning of use of the whetstone, but the abrasive grains are worn as the cutting operation progresses, and the worn abrasive grains whose sharpness is lost become resistance. The sharpness decreases. If the cutting performance is further reduced and the cutting operation is continued, the abrasive grains will fall off, and on the other hand, the replacement of the abrasive grains will occur and new perfect abrasive grains will appear and become cutting edges, so the sharpness will improve again After that, there is a characteristic that a stable cutting operation can be continued thereafter.

[0009]

By the way, the segment
Of abrasive grains in actual cutting with a cutting wheel
As a result of various studies by the present inventors on dropout, the following points were found.
Was revealed. Conventional cutting wheel segment smell
The concentration of abrasive grains should be within the range of about 10-30.
The entire coating is formed with a uniform concentration, and adjacent abrasive grains
The spacing between them is usually at least twice the abrasive grain size.
You. For this reason, as shown in FIG.
D₁, D_Two, D_ThreeThere is a large gap between
Grain D₁, D_Two, D_ThreeSurface layer of bond layer B between
And all the abrasive grains D on the surface₁, D _Two, D_ThreeBut with a cutting edge
Act. Abrasion of abrasive grains is greater on the front side in the grinding wheel rotation direction
It gradually wears off from the abrasive grains on the front side,
In the segment of the cutting whetstone, as shown in FIG.
And the abrasive grains D on the front side₁When the upper half of the
Abrasive D on the back side_Two, D_ThreeThe top of the polished already about 1/10
Worn, acting as a resistance rather than as a cutting edge,
The taste decreases. By repeating this, instead
Therefore, even though the sharpness is improved, the overall cut
The taste can not be so expected. These things are especially
This is noticeable on the front side in the rotation direction of the segment.

The present invention relates to a novel tip saw in which the cutting edge is an eclectic type of a segment type and a tip type. The present invention relates to a tip having a rake angle and a clearance angle, and the sharpness due to the change of abrasive grains. It is an object of the present invention to provide a tip saw capable of maintaining good sharpness for a long period of time from the beginning of use by combining the characteristics of a segment that can be recovered.

The problem to be solved in order to obtain such a tip saw is that a segment formed in a tip shape with superabrasive grains causes a subsequent abrasive grain to act as a cutting edge in accordance with wear of the abrasive grains on the front side in the rotational direction of the tip saw. An object of the present invention is to improve the configuration of a segment so that the segment has a function.

[0012]

The tip saw according to the present invention comprises:
A chip saw in which a plurality of segment chips having a rake angle and a clearance angle are attached to an outer periphery of a disk-shaped substrate, wherein the segment chips are formed of an abrasive material layer in which abrasive grains are bonded by a metal bond. The abrasive grain spacing in the abrasive material layer as viewed in the outer peripheral direction of the substrate is less than twice the abrasive grain size.

By making the shape of the segment tip into a shape having a rake angle and a clearance angle, the same shape effect as the tip of the conventional tip saw can be obtained. In other words, by forming a rake angle in the front of the substrate rotation direction, cutting can be performed with small chips, resulting in excellent sharpness and an excellent chip discharging effect. In addition, by forming a clearance angle behind the substrate rotation direction, the contact resistance between the segment chip and the material to be cut can be reduced, burning during cutting can be prevented, and the cut surface of the material to be cut can be cleaned. These rake angles and clearance angles can be formed by a laser beam or an electron beam. Further, by forming the lateral flank in the side direction of the segment chip, the contact resistance with the material to be cut can be reduced.

Further, since the segment chips are formed of the abrasive material layer, a tip saw having an effect of restoring sharpness by changing abrasive grains can be obtained. By increasing the degree of concentration of the abrasive grains in the abrasive layer, only the frontmost abrasive grains act as cutting blades, and subsequent abrasive grains are worn in a state hidden by the shadow of the frontmost abrasive grains. As long as the foreground abrasive grain is present, the subsequent abrasive grains do not crush and fall off, and after the foreground abrasive grains are worn and crushed and fall off, the subsequent abrasive grains become As a result, it functions as a cutting blade, so that good sharpness can be maintained from the beginning to the end of use.

In the case of a conventional segment type cutting wheel,
Since the abrasive grains are crushed and fall off when the upper half of the abrasive grains are worn out, only the upper half of the front side of the abrasive grains acts as a cutting blade, and only about 1% of the abrasive grains contribute to cutting. However, in the tip saw of the present invention, the foremost abrasive grain of the segment tip crushes and drops off at the stage when about half of the front side wears out, but acts as a cutting blade until this dropping, About one half of the abrasive will contribute to cutting. Furthermore, since the foremost end of the segment chip serves as the cutting blade, the amount of bite into the material to be cut also increases.

As the abrasive grains forming the abrasive layer of the segment chip, super abrasive grains such as diamond abrasive grains and CBN abrasive grains can be used, but diamond abrasive grains having the highest abrasive grain strength are suitable. Particularly, diamond abrasive grains having a grain size of # 30 to # 320 and a crushing value of 60% or less are suitable.
With coarse particles having a particle size of less than # 30, the abrasive particles have a large particle size and cannot be a sharp cutting edge. In the case of fine particles having a particle size exceeding # 320, the amount of the abrasive particles protruding from the bond surface is small, and the sharpness is deteriorated. On the other hand, when the crushing value exceeds 60%, the strength of the abrasive grains is reduced, and the abrasive grains are crushed and fall off by the impact at the time of cutting.

Here, the crushing value is an index indicating the brittleness of the abrasive grains, and has the opposite meaning to the toughness or impact strength. The crushing value is determined by using particles remaining on the third sieve after passing through the second sieve at the time of particle size distribution measurement, and quenching the particles to obtain a cylindrical steel capsule (inner diameter of about 12. 5m
m, depth 26 mm, hardness HRC60) in a hard sphere (diameter about 7.9 mm, weight 2.045 to 2.025 g, hardness HR)
C65) put together with one, the number of rotations 2400min ^-1 ,
The sample is fixed in a vibrator having an amplitude of 8.255 mm and vibrated for a certain period of time. After the vibration is completed, the sample in the capsule is taken out, sieved using a sieve one stage below (ie, the fourth stage), and calculated by the following equation. Crushing value = (weight of powder passing through sieve at fourth stage / total weight of recovered sample) × 100 Table 1 shows the opening size of the second stage sieve and the third stage sieve used for the sample of each particle size and the vibration time of the vibrator. Show.

[0018]

[Table 1]

Further, the segment chip may be supported by an abrasive layer having a lower degree of concentration of abrasive grains than the segment chip. In the conventional chip saw, the outer periphery of the substrate is formed in a sawtooth shape, and a cutting blade made of a cemented carbide or a diamond sintered body is attached to the front surface of the sawtooth portion in the rotation direction of the substrate. When attaching to a board | substrate, it is difficult to join a segment chip with a short board | substrate outer peripheral direction length firmly to a board | substrate. Therefore, in the present invention, the segment chip is supported by another abrasive layer, and the supporting abrasive layer is bonded to the substrate. The support abrasive layer is formed between the segment chip and the substrate and on the rear side in the substrate rotation direction of the segment chip in order to firmly join the segment chip to the substrate and absorb the impact applied to the cutting blade during cutting. Is good.

It is desirable that the length of the segment chip in the outer peripheral direction of the substrate is 0.5 to 3 mm. If the length is less than 0.5 mm, the wear balance of the abrasive grains in the abrasive layer is lost, and the abrasive layer cannot maintain a flat surface. on the other hand,
If the length exceeds 3 mm, the subsequent abrasive grains come into contact with the material to be cut, which acts as resistance, and reduces sharpness. Therefore, the above range is desirable.

The ratio (chip ratio) of the total length of the individual segment chips in the substrate outer peripheral direction to the substrate outer peripheral length is preferably 5 to 25%. If the chip ratio is less than 5%, the number of cutting blades will be small, and the abrasive grains will not be able to withstand the impact during cutting, and the abrasive grains will be crushed and dropped. On the other hand, when this ratio exceeds 25%, the interval between the chips becomes narrow, the amount of penetration of the foreground abrasive grains becomes small, and the action as a cutting edge becomes small.

A metal bond is used as a binder for the abrasive grains of the abrasive layer of the segment chip and the abrasive layer of the supporting abrasive layer. It is preferable to use a large number of metals having a Young's modulus of the abrasive layer in the range of 50 to 150 Gpa, for example, Co, Ni, Fe, W, and the like. Young's modulus of the abrasive layer is 10-1
Metals in the range of 00 Gpa, such as Cu, Sn, T
It is preferable to use i, Ag and the like in large amounts.

[0023]

1 is a front view of a tip saw according to a first embodiment of the present invention, and FIG. 2 is a partially enlarged view of FIG.

The chip saw 10 of this embodiment is a chip saw in which 16 segment chips 2 each having a rake angle and a clearance angle are attached to the outer periphery of a disk-shaped substrate 1 via a support abrasive layer 3. . The substrate 1 is made of iron and has an outer diameter of 1
It has a thickness of 05 mm and a thickness of 1.8 mm.

The segment chip 2 is formed of an abrasive layer in which diamond abrasive grains are bonded by a metal bond, and when attached to the substrate 1, the rake angle (θ1) shown in FIG. It is formed to have a shape of 10 degrees, a lateral clearance angle (θ3) of 3 degrees, and a length L of 2.5 mm in the circumferential direction of the substrate. The total length of the segment chips 2 in the substrate outer peripheral direction is 40 mm, and the ratio of the segment chips 2 to the substrate outer peripheral length is 1 mm.
2%.

The supporting abrasive layer 3 is an abrasive layer in which the same diamond abrasive grains as those of the segment chips 2 are bonded by metal bonding. And a supporting tip 3b.

The grain size of the diamond abrasive grains of the segment chip 2 is # 60 to # 80, and the crushing value is about 55%. The diamond abrasive grains are bonded by metal bond as an abrasive grain concentration degree (about 75) at which an abrasive grain interval as viewed in the outer peripheral direction of the segment chip 2 becomes about 1.5 times the grain diameter of the abrasive grains.
The particle size of the diamond abrasive grains of the support abrasive layer 3 is # 40 to #
At 50, the crushing value is about 50%, and the degree of concentration of the abrasive grains is lower than that of the segment chip 2 (about 10).

As the metal bond as the abrasive binder, a metal having a Young's modulus of the sintered abrasive layer in the range of 50 to 150 Gpa for the segment chip 2 is used. The Young's modulus of the abrasive layer after sintering is 10 to 1
A metal having a range of 00 Gpa is used.

The tip saw 10 of the present embodiment is formed with a rake angle in the segment tip 2 so that it can be cut with small chips and is excellent in sharpness. By forming the lateral clearance angle, the contact resistance with the material to be cut can be reduced. Furthermore, by forming the segment chip 2 with the abrasive material layer,
A tip saw having an effect of restoring sharpness by changing abrasive grains can be obtained. Further, by increasing the degree of concentration of the abrasive grains of the segment chips 2, good sharpness can be maintained from the beginning to the end of use.

Further, since the segment chips 2 are supported by the supporting abrasive material layer 3 having the same abrasive grains as the segment chips 2 and having a low concentration of abrasive grains, the segment chips 2 are firmly joined to the substrate 1. In addition, it is possible to absorb the impact applied at the time of cutting.

[0031]

According to the present invention, the following effects can be obtained.

(1) By making the shape of the segment tip a shape having a rake angle and a clearance angle, the same shape effect as that of a conventional tip saw tip is obtained, and the segment tip is formed of an abrasive material layer. As a result, a chip saw having an effect of restoring sharpness by changing abrasive grains can be obtained. By increasing the degree of concentration of the abrasive grains in this abrasive layer,
Only the foreground abrasive grain acts as a cutting edge, and the subsequent abrasive grains are hidden by the shadow of the foreground abrasive grains, but wear, but the subsequent abrasive grains are crushed as long as the foreground abrasive grains are present After the abrasive grains on the forefront wear out and are crushed and fall off, the subsequent abrasive grains become the foreground abrasive grains and act as cutting blades. Good sharpness can be maintained from the beginning to the end.

(2) As abrasive grains for forming the abrasive layer of the segment chip, a particle size of # 30 to # 320 and a crushing value of 60%
By using the following diamond abrasive grains, good sharpness can be maintained without the abrasive grains being crushed or dropped by the impact at the time of cutting.

(3) A structure in which the segment chips are supported by an abrasive layer having the same abrasive grains as the segment chips and a lower concentration of abrasive grains than the segment chips can be provided. In particular, by forming the supporting abrasive layer between the segment chip and the substrate and on the rear side of the segment chip in the direction of substrate rotation, the segment chip can be firmly joined to the substrate and the impact on the cutting blade during cutting can be improved. Can be absorbed.

(4) By setting the length of the segment chip in the outer peripheral direction of the substrate at 0.5 to 3 mm, the wear balance of the abrasive grains of the abrasive layer can be maintained, and the flatness of the abrasive layer can be maintained.

(5) By making the ratio of the sum of the lengths of the individual segment chips in the outer peripheral direction of the substrate to the outer peripheral length of the substrate 5 to 25%, the abrasive grains can withstand the impact at the time of cutting, In addition, a sufficient bite amount can be obtained.

(6) The metal bond used for the supporting abrasive layer is a metal bond made of a metal having a smaller Young's modulus of the abrasive layer after sintering than the metal bond used for the abrasive layer of the segment chip. Thereby, the impact absorption of the supporting abrasive layer can be increased.

[Brief description of the drawings]

FIG. 1 is a front view of a tip saw showing a first embodiment of the present invention.

2A is a partially enlarged view of FIG. 1, and FIG. 2B is a cross-sectional view.

FIG. 3 is a diagram showing an example of a conventional tip saw.

FIG. 4 is a diagram showing an example of a segment type rotating disk grindstone.

FIG. 5 is an explanatory view of abraded and dropped abrasive grains.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Segment chip 3 Supporting abrasive material layer 3a Annular part 3b Tip part 10 Tip saw θ1 Rake angle θ2 Escape angle θ3 Side relief angle

Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court I (Reference) B24D 3/34 B24D 3/34 5/06 5/06 (72) Inventor Minoru Takakura Tanushimarucho, Ukiha District, Fukuoka Prefecture 210 Noritake Diamond Co., Ltd. (72) Inventor Jin Makihara 210 Takeno, Oji-gun, Tanushimaru-cho, Ukiha-gun, Fukuoka F-term (reference) 3C063 AA02 AB03 BA04 BA08 BB02 BB07 BB23 BC02 BC10 BG03 BG07 BH17 CC02 EE31FF FF23

Claims (6)

[Claims] 1. A chip saw having a plurality of segment chips each having a rake angle and a clearance angle attached to an outer periphery of a disk-shaped substrate, wherein the segment chips are bonded with abrasive grains by a metal bond. A chip saw characterized in that an abrasive grain interval of the abrasive material layer as viewed in the outer peripheral direction of the substrate is less than twice an abrasive grain diameter. 2. The tip saw according to claim 1, wherein the abrasive grains are diamond abrasive grains having a particle size of # 30 to # 320 and a crushing value of 60% or less. 3. The tip saw according to claim 1, wherein said segment chip is supported by an abrasive layer having a lower degree of concentration of abrasive grains than an abrasive layer of said segment chip. 4. The chip saw according to claim 1, wherein the length of the segment chip in the outer peripheral direction of the substrate is 0.5 to 3 mm. 5. A ratio of the total length of the segment chips in the substrate outer peripheral direction to the substrate outer peripheral length being 5 to 2%.
The tip saw according to any one of claims 1 to 4, wherein the content is 5%. 6. The metal bond used for the abrasive layer supporting the segment chip is a metal bond made of a metal having a smaller Young's modulus after sintering than the metal bond used for the abrasive layer of the segment chip. Item 6. A tip saw according to any one of Items 3 to 5.