WO2008056896A1

WO2008056896A1 - Segment with grooves and diamond tools using the same

Info

Publication number: WO2008056896A1
Application number: PCT/KR2007/005177
Authority: WO
Inventors: Yong-Ki Shim
Original assignee: Dong Young Diamond Industrial Co., Ltd.
Priority date: 2006-11-08
Filing date: 2007-10-22
Publication date: 2008-05-15

Abstract

Disclosed are a segment for diamond tools, a manufacturing method thereof, and diamond tools using the same. The segment according to the present invention may be useful to improve machinability, enhance a cooling effect and induce an ideal abraded shape by ununiformly or uniformly arranging grooves in the segment. Also, the present invention provides a method for effectively producing the segment.

Description

SEGMENT WITH GROOVES AND DIAMOND TOOLS USING

THE SAME

Technical Field

[I] The present invention relates to a segment for diamond tools and diamond tools using the same, and more particularly to a segment with groove on a cutting surface to improve machinability, enhance a cooling effect and induce an ideally abraded shape by arranging the grooves uniformly or ununiformly, and diamond tools using the same. Background Art

[2] In general, diamonds have very high hardness values, and therefore they have been employed for cutting tools to facilitate cutting various materials since diamonds artificially synthesized at 1950s.

[3] In particular, diamonds may be integrated into processing tips of the cutting tools as hardness reinforcing components for the purpose of cutting hard workpiece such as granite, marble, brick, firebrick, concrete, asphalt, glass, and the like.

[4] In general, diamond tools for processing workpiece to be cut comprises a shank

(body) having a predetermined diameter; and processing tips coupled along a circumference of the shank.

[5] The processing tips are produced to comprise an abrasive having a high hardness, such as diamonds or cubic boron nitride. The tips are classified into a segment type and a rim type, depending on the shape coupled to the circumference of the shank.

[6] The segment-type tips are fan-shaped fragments or segments having predetermined length, width and height, and they are coupled to a processing wheel.

[7] The rim-type tips mean spherical ring-shaped materials having predetermined width and height, which are coupled to the circumference of the processing wheel.

[8] FIG. 1 is a perspective view showing a conventional segment-type diamond tool.

[9] As shown in the FIG. 1, the diamond tools mainly compries a shank 10 and a segment 20, wherein axial bores 11 having a predetermined diameter is formed in the shank so that it can be integrated into a rotation axis in order to transfer a rotary force from power tools.

[10] Also, slots 12 are formed in the circumferential surface of the shank 10 in a constant distance as much as a curved length of the segments 20 that are in contact with the shank 10 to attach a certain number of the segments 20.

[I I] The slots 12 are employed as a path for giving an impact force in a cutting process using saw blades and supplying cooling water.

[12] Meanwhile, saw blades, gang saws, chain saws, core drills and the like have been widely known as tools having these shapes of segments installed therein. [13] FIG. 2 is a schematic view showing a conventional manufacturing process of segments having a general single layer structure. [14] A mixture 20a is prepared by mixing diamonds and metal powders, and the mixture

20a is poured into a predetermined die and pressurized using an upper punch 80 and a lower punch 90, and then subject to a sintering process to prepare a segment 20. [15] FIG. 3 is a detail view showing a conventional segment having a general single layer structure, and FIG. 4 is a cross-sectional view taken from a line A-A" of FIG. 3. [16] As shown in FIGs. 3 and 4, a diamond powder 40 is randomly distributed inside the segment. [17] Because such diamond tools have a single layer structure, they have a high yield per unit time and an excellent initial cutting. [18] However, as the diamond tools get used for a long time, they are abraded into a centrally convex shape as shown in FIG. 5 since the abrasion in an edge region of the segment 20 is easier than its central region. [19] Accordingly, since a workpiece 60 is also cut while being roundly engraved as shown in 70, a contact area between the segment 20 and the workpiece 60 is increased to generate the heat with the increase in resistance, which badly affects vertically dropping cutting and horizontally moving cutting processes. [20] FIG. 6 is a schematic view showing a manufacturing process of a segment having a conventional sandwiched structure. [21] A mixture 30a is prepared by mixing diamonds and metal powders, and the mixture

30a is poured into a predetermined die and pressurized using an upper punch 80 and a lower punch 90 to prepare a first molded product 30A. [22] A mixture 30b is prepared on the first molded product 30A by mixing diamonds and metal powders, and the mixture 30b is poured into a predetermined die and pressurized using an upper punch 80 and a lower punch 90 to prepare a second molded product

30b. [23] In the similar manner, a mixture 30c like the mixture 30a is prepared on the second molded product 30b, and the mixture 30c is poured into a predetermined die and pressurized and molded using an upper punch 80 and a lower punch 90 to prepare a third molded product 30c. [24] Through this process, a molded product is subject to a sintering process and a sandwich-type segment 30 having a 3-layerd structure is finally manufactured. [25] FIG. 7 is a detail view showing a conventional segment having a sandwiched structure, and FIG. 8 is a cross-sectional view taken from a line B-B" of FIG. 7. [26] As shown in FIGs. 7 and 8, a diamond powder 40 is randomly distributed inside the segment. [27] Such a sandwich-type segments have problems that a yield per unit time is low and a manufacturing cost is high due to their 3-layered structure. Particylarly, they have a problem regarding to the manufacturing process of small tools since a mixture is pasted and unfolded on small blades to have a 3-layered structure.

[28] Meanwhile, a particle selected as cutting/abrasive materials is referred to as an abrasive grain, and all of the abrasive grain continuously forms new cutting edges through crystalline micro-crushing process, which is so called a self sharpening process of abrasive grain.

[29] In the case of the segment having a sandwiched structure, both of its side regions should have a high intensity index so as to exert a sandwich effect, but the segment has a problem that it hinders the self sharpening process of abrasive grain, which leads to the increase in cutting resistance. Disclosure of Invention Technical Problem

[30] Accordingly, the present invention is designed to solve such drawbacks of the prior art which the general segment having a single layer structure and the segment having a sandwiched structure have, and therefore an object of the present invention is to provide a segment with groove arranged uniformly or ununiformly in inner and outer parts of the segment for the purpose of suitable applications so as to improve machinability of the diamond tools, enhance a cooling effect and induce its ideally abraded shape, and diamond tools using the same.

Technical Solution

[31] One aspect of the present invention is achieved by providing a segment for diamond tools, including:

[32] a bonding surface contacted with a circumferential surface of a shank, and cutting surface contacted with a workpiece formed in an opposite side of the bonding surface,

[33] wherein at least one groove is formed on the cutting surface in the direction to the bonding surface.

[34] At this time, the segment for diamond tools according to the present invention may be compirsing,

[35] a first member including a first bonding surface contacted with a circumferential surface of a shank and a first cutting surface contacted with a workpiece formed in an opposite side of the first bonding surface, and a first coupling surface coupling the first bonding surface and the first cutting surface, the first coupling surface having at least one first concavely engraved portion connected to the first cutting surface and separated from the first bonding surface; and

[36] a second member including a secnond bonding surface contacted with a circum- ferential surface of a shank and a second cutting surface contacted with a workpiece formed in an opposite side of the second bonding surface, and a second coupling surface coupling the second bonding surface and the second cutting surface and facing the first coupling surface, the second coupling surface having at least one second concavely engraved portion connected to the second cutting surface and separated from the second bonding surface; and

[37] wherein the first concavely engraved portion and the second concavely engraved portion face each other to form at least one groove.

[38] At this time, the groove may be in a spherical, oval, or tetragonal shape.

[39] At this time, the segment for diamond tools according to the present invention may further include at least one third concavely engraved portion in the third coupling surface arranged opposite to the first coupling surface of the first member.

[40] At this time, the segment for diamond tools according to the present invention may further include at least one fourth concavely engraved portion in the fourth coupling surface arranged opposite to the second coupling surface of the second member.

[41] Another aspect of the present invention is achieved by providing a method for producing a segment for diamond tools, including:

[42] forming at least one groove on the cutting surface in the direction to the bonding surface.

[43] At this time, the method may comprise,

[44] molding a first member including a first bonding surface, a first cutting surface and a first coupling surface by pressing a first punch having a flat surface and a second punch having a uneven surface composed of at least one convexly engraved portion;

[45] molding a second member including a second bonding surface, a second cutting surface and a second coupling surface by pressing the first punch and the second punch;

[46] molding a second member by pressing the upper punch and the lower punch; and

[47] matching at least one first concavely engraved portion of the first member with at least one second concavely engraved portion of the second member to form at least one groove by, followed by sintering the formed groove.

[48] Still another aspect of the present invention is achieved by providing a method for producing a segment for diamond tools, including:

[49] molding a first member by pressing an upper punch having a uneven surface composed of at least one convexly engraved portion and a lower punch having a uneven surface composed of at least one convexly engraved portion;

[50] molding a second member by pressing the upper punch and the lower punch; and

[51] matching at least one first concavely engraved portion of the first member with at least one second concavely engraved portion of the second member to form at least one groove by, followed by sintering the formed groove.

[52] Yet another aspect of the present invention is achieved by providing a segment-type diamond tool composed of at least one segment for diamond tools and a shank coupled to the segment,

[53] wherein the segment for diamond tools is coupled to the shank, and comprises,

[54] a first member including a first bonding surface contacted with a circumferential surface of a shank and a first cutting surface contacted with a workpiece formed in an opposite side of the first bonding surface, and a first coupling surface coupling the first bonding surface and the first cutting surface, the first coupling surface having at least one first concavely engraved portion connected to the first cutting surface and separated from the first bonding surface; and

[55] a second member including a secnond bonding surface contacted with a circumferential surface of a shank and a second cutting surface contacted with a workpiece formed in an opposite side of the second bonding surface, and a second coupling surface coupling the second bonding surface and the second cutting surface and facing the first coupling surface, the second coupling surface having at least one second concavely engraved portion connected to the second cutting surface and separated from the second bonding surface;

[56] wherein the first concavely engraved portion and the second concavely engraved portion face each other to form at least one groove.

[57] At this time, the shank may be in a shape of disk or tube.

[58] Also, the segments for diamond tools may be coupled along the circumference of the disk or tube.

Advantageous Effects

[59] As described above, the diamond tools according to the present invention may be useful to induce their horizontal abrasion by adjusting the size and number of groove and improve their machinability by lowering power consumption. Also, they may be useful to enlarge their life span by effectively emitting the inner heat of the segment generated during the cutting process of a workpiece and prevent thermal deformation of the shank. Brief Description of the Drawings

[60] FIG. 1 is a perspective view showing a shank of a conventional segment-type diamond tool and segments coupled to the shank.

[61] FIG. 2 is a schematic view showing a conventional manufacturing process of a general segment having a single layer structure.

[62] FIG. 3 is a detail view showing a conventional segment having a single layer structure. [63] FIG. 4 is a cross-sectional view taken from a line A-A" of FIG. 3.

[64] FIG. 5 is a schematic view showing an abraded segment caused in the use of the conventional segment having a general single layer structure. [65] FIG. 6 is a schematic view showing a conventional manufacturing process of a segment having a sandwiched structure. [66] FIG. 7 is a detail view showing a conventional segment having a sandwiched structure.

[67] FIG. 8 is a cross-sectional view taken from a line B-B" of FIG. 7.

[68] FIG. 9 is a schematic view showing a manufacturing process of a segment according to the first embodiment of the present invention. [69] FIG. 10 is a detail view showing the segment according to the first embodiment of the present invention.

[70] FIG. 11 is a cross-sectional view taken from a line C-C" of FIG. 10.

[71] FIG. 12 is a perspective view showing a lower punch used for manufacturing the segment according to the first embodiment of the present invention. [72] FIG. 13 is a comparative graph of power consumptions between the conventional segment having a general single layer structure and the segment according to the first embodiment of the present invention. [73] FIG. 14 is a photograph showing an abraded shape of the conventional segment having a general single layer structure. [74] FIG. 15 is a photograph showing an abraded shape of the segment according to the first embodiment of the present invention. [75] FIG. 16 is a schematic view showing a manufacturing process of a segment according to the second embodiment of the present invention. [76] FIG. 17 is a detail view showing the segment according to the second embodiment of the present invention. [77] FIG. 18 is a perspective view showing an upper punch and a lower punch used for manufacturing the segment according to the second embodiment of the present invention.

Mode for the Invention [78] Hereinafter, exemplary embodiments according to the present invention will be described with reference to the accompanying drawings. Here, when a first element is described as being scribed as being coupled to a second element, the first element may be not only directly coupled to the second element but may also be indirectly coupled to the second element via a third element. Further, elements that are not essential to the complete understanding of the invention are omitted for clarity. Also, like reference numerals refer to like elements throughout. [79] FIG. 9 is a schematic view showing a manufacturing process of a segment according to the first embodiment of the present invention.

[80] A mixture 200 is prepared by mixing diamonds and metal powders, and the mixture

200 is poured into a predetermined die, and a first member 200 is then formed by pressing an upper punch 800 having a flat surface and a lower punch 900 having a uneven surface comprises at least one convexly engraved portion.

[81] The first member 200 includes a first bonding surface 200a contacted with a circumferential surface of the shank 100 and a first cutting surface 200b contacted with a workpiece formed in an opposite side of the first bonding surface 200a, and at least one first concavely engraved portion 200c is formed on a first coupling surface 20Od for coupling the first bonding surface 200a with the first cutting surface 200b. At this time, first concavely engraved portion 200c is prefered to be concavely engraved pattern connected to the first cutting surface 200b and separated from the first bonding surface 200a.

[82] Next, a second member 300 is formed by pressing the upper punch 800 and the lower punch 900 in the same manner as in the first member 200. The second member 300 includes a second bonding surface 300a contacted with a circumferential surface of the shank 100 and a second cutting surface 300b formed in an opposite side of the second bonding surface 300a to be in contact with a workpiece, and at least one second concavely engraved portion 300c is formed on a second coupling surface 300d for coupling the first bonding surface 300a with the second surface 300b. At this time, second concavely engraved portion 300c is prefered to be concavely engraved pattern connected to the second cutting surface 300b and separated from the second bonding surface 300a.

[83] Finally, at least one first concavely engraved portion 200c of the first member 200 and at least one second concavely engraved portion 300c of the second member 300 are matched with each other and sintered to form a segment. The segment has a shape where at least one groove 500 is formed. The groove 500 may be formed in various shape such as spherical, oval, and tetragonal shapes, etc.

[84] FIG. 10 is a detail view showing the segment according to the first embodiment of the present invention, and FIG. 11 is a cross-sectional view taken from a line C-C" of FIG. 10.

[85] As shown in FIGs. 10 and 11, the segment includes a bonding surface 400a contacted with a circumferential surface of a shank, and cutting surface 400b contacted with a workpiece formed in an opposite side of the bonding surface 400a. At least one groove is formed on the cutting surface 400b. The groove is extended to the direction of the bonding surface 400a, but not reachs the bonding surface 400a. Because the penetration of the segment by the groove reduces the segment's adhesive area to the shank and cause a groove blocking by silver solder when weldering.

[86] At this time, the first concavely engraved portion 200c and the second concavely engraved portion 300c may be matched with each other in one or large numbers to form a plurality of grooves on the segment, and the grooves on the segment may be formed in various shapes, such as spherical, oval, and tetragonal shapes, etc.

[87] FIG. 12 is a perspective view showing a lower punch used for manufacturing the segment according to the first embodiment of the present invention. [88] The lower punch 900 may allow the first member 200 and the second member 300 to form concavely engraved portions 200c, 300c since it has a uneven surface including at least one convexly engraved portion 900a.

[89] At this time, pattern of convexly engraved portion of the lower punch 900 is prefered to have a shape to be connected to the first cutting surface and separated from the first bonding surface.

[90] The concavely engraved portions 200c, 300c are finally matched and sintered to manufacture a segment 400. [91] FIG. 13 is a comparative graph of power consumptions between the conventional segment having a general single layer structure and the segment according to the first embodiment of the present invention. As listed in the following Table 1, average power consumptions, such as a cutting R.P.M of 1885 rpm, a table speed of 4 m/min and a cutting depth of 10 mm/path, of aplite in cutting conditions are compared using a 14"diameter tool.

[92] Table 1 [Table 1] [Table ] Cutting conditions for comparing average power consumptions

[93] The following Table 2 lists comparative data of power consumptions obtained by comparing the conventional segment having a general singly layer structure with the segment according to the first embodiment of the present invention. The graph of FIG. 13 is plotted on the basis of the Table 2. As compared in the Table 2 and FIG. 13, it is revealed that the power consumption of the segment having groove according to the first embodiment of the present invention is significantly low, compared to the conventional segment having a general single layer structure. By the low power consumption, it is meant that the cutting speed is rapid as much as the low power consumption, and the machinability is improved. [94] Table 2

[Table 2]

[Table ]

Comparative data of power consumptions

[95] (Unit : Kw.)

[96] FIG. 14 is a photograph showing an abraded shape of the conventional segment having a general single layer structure, and FIG. 15 is a photograph showing an abraded shape of the segment according to the first embodiment of the present invention.

[97] As the conventional segment having a general single layer structure is increasingly used, it is abraded into a centrally convex (round) shape as shown in FIGs. 14 and 15 since the abrasion in an edge region of the segment is more serious than its central region. On the contrary, the segment according to the first embodiment of the present invention is abraded into a flat shape since edge and central regions of the segment are abraded to the same level. Accordingly, the segment according to the first embodiment of the present invention may be useful to minimize a contact area between a segment and a workpiece, and to enlarge its life span and prevent thermal deformation of a shank by effectively emitting the inner heat of the segment.

[98] FIG. 16 is a schematic view showing a manufacturing process of a segment according to the second embodiment of the present invention.

[99] A mixture 1200 is prepared by mixing diamonds and metal powders, and the mixture

1200 is poured into a predetermined die, and a first member 1200 is then formed by pressing an upper punch 1800 having at least one convexly engraved portion and a lower punch 1900 having a uneven surface composed of at least one convexly engraved portion. The first member 1200 includes a first bonding surface 1200a contacted with a circumferential surface of the shank 100 and a second cutting surface 1200b formed in an opposite side of the first bonding surface 1200a to be in contact with a workpiece, and at least one first concavely engraved portion 1200c is formed on a first coupling surface 120Od for coupling the first bonding surface 1200a with the second cutting surface 1200b, and a third concavely engraved portion 1510 is formed on a third coupling surface 120Oe arrange in the other surface of the first coupling surface 120Od.

[100] Next, a second member 1300 is formed by pressing the upper punch 800 and the lower punch 900 in the same manner as in the first member 1200. The second member 1300 includes a second bonding surface 1300a contacted with a circumferential surface of the shank 100 and a second cutting surface 1300b formed in an opposite side of the second bonding surface 1300a to be in contact with a workpiece, and at least one second concavely engraved portion 1300c is formed in a second coupling surface 1300d for coupling the first bonding surface 1300a with the second cutting surface 1300b. A fourth concavely engraved portion 1520 is formed on a fourth coupling surface 1300e arranged in the other surface of the second coupling surface 1300d.

[101] Finally, at least one first concavely engraved portion 1200c of the first member 1200 and at least one second concavely engraved portion 1300c of the second member 1300 are matched with each other and sintered to manufacture a segment. The segment has a shape where at least one groove 1500 is formed. The groove 1500 may be formed in various shapes such as spherical, oval, and tetragonal shapes, etc.

[102] FIG. 17 is a detail view showing the segment according to the second embodiment of the present invention.

[103] As shown in FIG. 17, the segment includes a bonding surface 1400a contacted with a circumferential surface of a shank, and cutting surface 1400b contacted with a workpiece formed in an opposite side of the bonding surface 1400a. At least one groove is formed on the cutting surface 1400b. The groove is extended to the direction of the bonding surface 1400a, but not reachs the bonding surface 1400a. Because the penetration of the segment by the groove reduces the segment's adhesive area to the shank and causes a groove blocking by silver solder when welding.

[104] At this time, the first concavely engraved portion 1200c and the second concavely engraved portion 1300c may be matched with each other in one or large numbers to form a plurality of grooves on the segment, and the grooves on the segment may be formed in various shapes such as spherical, oval, and tetragonal shapes, etc.

[105] Also, the third concavely engraved portion 1510 of the first member and the fourth concavely engraved portion 1520 of the second member further serve to improve machinability and enhance a cooling effect.

[106] FIG. 18 is a perspective view showing an upper punch and a lower punch used for manufacturing the segment according to the second embodiment of the present invention.

[107] The upper punch 1800 and the lower punch 1900 may allow the first member 1200 and the second member 1300 to form a first concavely engraved portion 1200c to a fourth concavely engraved portion 1520 since they have a uneven surface composed of a plurality of spherical convexly engraved portion 1900a.

[108] The first concavely engraved portion 1200c of the first member 1300 and the second concavely engraved portion 1300c of the second member 1300b, each being formed respectively by the lower punch 1900 and the lower punch 1900, may be matched with each other and finally sintered to manufacture a segment 1400.

[109] The shank 100 of the diamond tools to which the above-mentioned segments 1400 are coupled may be formed in various shapes, for example a shape of disk or tube, and the segments will be coupled along the circumference of the disk or tube. Meanwhile, the shank 100 may include a power transfer means such as rotation axis, etc. The segment according to the present invention is not limited to the above shapes according to the shapes of the shank. Examples of these tools include saw blades, gang saws, chain saws, core drill bits, etc., and the segment according to this embodiment of the present invention may be easily coupled to the tools using a welding process, as apparent to those skilled in the art.

[110] Meanwhile, the concepts and exemplary embodiments disclosed in the present invention are for the purpose of being revised or designed into other ones to attain the same objects of the present invention, and therefore they may be easily used by those skilled in the art.

[I l l] Although exemplary embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes might be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

[112] For example, grooves of a segment may be arranged in a different manner from the above-mentioned embodiment.

[113] The segment may be produced so that its grooves can be formed inside or outside the segment, and the grooves of the segment may be uniformly or ununiformly arranged to be suitable for its use, and the size and number of the grooves may be adjusted. Industrial Applicability

[114] The segment for diamond tools according to the present invention may be effectively used for cutting tools and their manufacturing applications.

Claims

[1] A segment for diamond tools, comprising: a bonding surface contacted with a circumferential surface of a shank, and cutting surface contacted with a workpiece formed in an opposite side of the bonding surface, wherein at least one groove is formed on the cutting surface in the direction to the bonding surface.

[2] The segment for diamond tools according to claim 1, the segment comprising, a first member including a first bonding surface contacted with a circumferential surface of a shank and a first cutting surface contacted with a workpiece formed in an opposite side of the first bonding surface, and a first coupling surface coupling the first bonding surface and the first cutting surface, the first coupling surface having at least one first concavely engraved portion connected to the first cutting surface and separated from the first bonding surface; and a second member including a secnond bonding surface contacted with a circumferential surface of a shank and a second cutting surface contacted with a workpiece formed in an opposite side of the second bonding surface, and a second coupling surface coupling the second bonding surface and the second cutting surface and facing the first coupling surface, the second coupling surface having at least one second concavely engraved portion connected to the second cutting surface and separated from the second bonding surface; wherein the first concavely engraved portion and the second concavely engraved portion face each other to form at least one groove.

[3] The segment for diamond tools according to claim 1, wherein the groove is in a spherical shape.

[4] The segment for diamond tools according to claim 1, wherein the groove is in an oval shape.

[5] The segment for diamond tools according to claim 1, wherein the groove is in a tetragonal shape.

[6] The segment for diamond tools according to claim 2, further comprising at least one third concavely engraved portion in the third coupling surface arranged opposite to the first coupling surface of the first member.

[7] The segment for diamond tools according to claim 2, further comprising at least one fourth concavely engraved portion in the fourth coupling surface arranged opposite to the second coupling surface of the second member.

[8] A method for producing a segment for diamond tools, comprising: forming at least one groove on the cutting surface in the direction to the bonding surface.

[9] The method for producign a segment for diamond tools according to claim 8, the method comprising, molding a first member including a first bonding surface, a first cutting surface and a first coupling surface by pressing a first punch having a flat surface and a second punch having a uneven surface composed of at least one convexly engraved portion; molding a second member including a second bonding surface, a second cutting surface and a second coupling surface by pressing the first punch and the second punch; and matching at least one first concavely engraved portion of the first member with at least one second concavely engraved portion of the second member to form at least one groove by, followed by sintering the formed groove.

[10] A segment- type diamond tool including at least one segment for diamond tools and a shank coupled to the segment, the segment comprises: a first member including a first bonding surface contacted with a circumferential surface of a shank and a first cutting surface contacted with a workpiece formed in an opposite side of the first bonding surface, and a first coupling surface coupling the first bonding surface and the first cutting surface, the first coupling surface having at least one first concavely engraved portion connected to the first cutting surface and separated from the first bonding surface; and a second member including a secnond bonding surface contacted with a circu inferential surface of a shank and a second cutting surface contacted with a workpiece formed in an opposite side of the second bonding surface, and a second coupling surface coupling the second bonding surface and the second cutting surface and facing the first coupling surface, the second coupling surface having at least one second concavely engraved portion connected to the second cutting surface and separated from the second bonding surface; wherein the first concavely engraved portion and the second concavely engraved portion face each other to form at least one groove.

[11] The segment- type diamond tool according to claim 10, wherein the shank is in a shape of disk or tube.

[12] The segment- type diamond tool according to claim 11, wherein the segments for diamond tools are coupled along the circumference of the disk or tube.

[13] The segment for diamond tools according to claim 10, further comprising at least one third concavely engraved portion in the third coupling surface arranged opposite to the first coupling surface of the first member.

[14] The segment for diamond tools according to claim 10, further comprising at least one fourth concavely engraved portion in the fourth coupling surface arranged opposite to the second coupling surface of the second member.