Segment for diamond tool and method of manufacturing the same

Abstract

To provide a segment and its manufacturing method capable of simplifying a dressing process for the segment manufactured by sintering or hot pressing, favorably maintaining diamond abrasive grains, and reducing thermal deformation of a shank.SOLUTION: The segment 20 for the diamond tool includes a segment manufactured by mixing diamond abrasive grains and first powder and sintered or hot-pressed, and an auxiliary grinding wheel part 30 printed on the segment by 3D printing in which the diamond abrasive grains and second powder are melted by a laser and laminated.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a segment for a diamond tool and a manufacturing method thereof, and more particularly to a segment for a diamond tool that can obtain a good initial cutting force even without a dressing process that is performed to expose diamond abrasive grains on the surface of a segment manufactured by sintering or hot pressing, and a manufacturing method thereof. [Background technology]

[0002] Diamond tools are used to cut workpieces or polish their surfaces. They consist of a shank, which is connected to the machine, and a cutting tip, which is located at the end of the shank and uses diamond abrasive grains to cut or polish the workpiece.

[0003] The shank, which corresponds to the tool body, is mainly made of metal. The shank of a tool used for drilling work is cylindrical as shown in Figure 1, while the shank of a tool used for cutting or polishing work is disc-shaped as shown in Figure 2.

[0004] Cutting tips come in two types: one in which diamond abrasive grains are mixed with another powder and sintered or hot-pressed to form segments attached to a shank, and one in which diamond abrasive grains are fused or electroplated to the tip of the shank.

[0005] Diamond abrasives used in diamond tools typically consist of one or more abrasive particles of natural or synthetic diamond, cubic boron nitride (CBN), alumina oxide (Al2O3), silicon carbide (SiC), and titanium carbide (TiC).

[0006] The shank and segments are joined together by laser welding, brazing, diffusion bonding, or the like.

[0007] Segments manufactured in a mold by sintering or hot pressing do not have sharp diamond abrasive grains protruding from the surface, which makes initial cutting difficult. For this reason, a dressing process is essential to make the diamond abrasive grains protrude from the surface.

[0008] The dressing process involves removing part of the binder of the segment by grinding, laser ablation, electrolysis, or other methods, and this type of dressing process has the problem of being time-consuming and costly.

[0009] The present applicant disclosed in Patent Document 2 a segment manufacturing method in which diamond abrasive grains are fused to the surface of a sintered segment, eliminating the need for a dressing process and allowing smooth initial cutting.

[0010] To form a new auxiliary grinding stone on a segment surface using the applicant's conventional segment manufacturing method, a paste containing a mixture of lead and diamond abrasive grains is applied to the segment surface, dried, and then the lead is melted and fused using a non-metallic heating element, a high-frequency induction coil, or an electric furnace. This conventional segment manufacturing method has problems such as the possibility of thermal deformation of the shank due to the high heat during the fusion process, and limitations on the size of the diamond tool that can be processed due to factors such as the size of the electric furnace. Even when electrodeposition is used instead of fusion, it is necessary to perform masking and undercoating, followed by hot-dip galvanization in a plating bath, resulting in a very complicated process and the problem of the diamond abrasive grains easily falling off. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 10-2014-0003751 [Patent Document 2] Korean Patent Registration No. 10-0950256 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made to solve the problems of the prior art described above, and the object of the present invention is to provide a segment and a manufacturing method thereof that can simplify the manufacturing process by eliminating the dressing process for segments manufactured by sintering or hot pressing, that maintains the diamond abrasive grains well, and that can reduce thermal deformation of the shank. [Means for solving the problem]

[0013] The segment for a diamond tool of the present invention is characterized by comprising a segment produced by mixing diamond abrasive grains and a first powder and sintering or hot pressing it, and an auxiliary grinding stone portion printed on the segment by 3D printing, in which the diamond abrasive grains and the second powder are melted and layered with a laser.

[0014] It is preferable that a part or all of the auxiliary grindstone portion is exposed on the main cutting surface of the segment.

[0015] It is also preferable that a plurality of the auxiliary grindstone portions are formed at regular intervals on the surface of the segment.

[0016] It is also preferable that one or more recesses are formed in the segment, and auxiliary grindstone portions are formed so as to completely or partially fill all or some of the recesses.

[0017] The recesses are preferably formed in one or more of the cutting surfaces where the segments contact the workpiece.

[0018] The second powder is preferably a ceramic powder, a Cu-based alloy powder, a Ni-based alloy powder, a Sn-based alloy powder, or a mixture of one or more of these.

[0019] The size of the diamond abrasive grains supplied to the auxiliary grindstone portion is preferably 75 to 750 μm.

[0020] The method for manufacturing a segment for a diamond tool of the present invention is characterized by including the steps of: mixing diamond abrasive grains and a first powder and manufacturing a segment by sintering or hot pressing; and printing an auxiliary grinding wheel portion by 3D printing in which the diamond abrasive grains and the second powder are melted by a laser and laminated on the surface of the segment.

[0021] It is preferable that 3D printing is performed by irradiating a laser beam with an output of 200 to 2000 Watts while the segment or laser beam moves at a speed of 500 to 2000 mm / min.

[0022] The supply rate of the diamond abrasive grains supplied to form the auxiliary grindstone portion is preferably 0.005 to 0.5 g / sec, and the supply rate of the second powder is preferably 0.05 to 0.5 g / sec. [Effects of the Invention]

[0023] According to the present invention having the above-described configuration, the dressing process can be omitted, which not only provides time / cost benefits during production, but also automates the formation of the auxiliary grinding stone portion, reduces the initial cutting load and heat generation of the diamond tool, shortens the processing time of the workpiece, and provides a good cutting feel. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a diagram of a diamond tool with a conventional segment attached. [Figure 2] FIG. 1 is a diagram of a diamond tool with a conventional segment attached. [Figure 3] FIG. 1 illustrates a conventional segment. [Figure 4] FIG. 4 is a diagram showing the segment of FIG. 3 with an auxiliary grindstone portion formed thereon. [Figure 5] FIG. 4 is a diagram showing the segment of FIG. 3 with an auxiliary grindstone portion formed thereon. [Figure 6]This is a diagram showing the segment of FIG. 2(b) with an auxiliary grinding stone portion formed thereon. [Figure 7] This is a diagram showing the segment of FIG. 2(b) with an auxiliary grinding stone portion formed thereon. [Figure 8] This is a diagram showing the segment of FIG. 2(b) with an auxiliary grinding stone portion formed thereon. [Figure 9] 10 is a photograph of a segment in use according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] Figure 3 shows a conventional segment 20 attached to the diamond drilling tool of Figure 1, and Figures 4 and 5 show an embodiment in which an auxiliary grinding stone portion 30 is formed on the segment 20 of Figure 3.

[0027] The segments 20 attached to the tip or circumference of the shank come into contact with the workpiece as the shank rotates, grinding or cutting the workpiece. Of the surfaces that make up the segments, the surface that directly grinds or cuts the workpiece will be called the "main cutting surface" 23.

[0028] The segment of the present invention is produced by mixing diamond abrasive grains and a first powder, and then sintering or hot pressing the mixture.

[0029] The first powder can be any powder used for sintering or hot pressing, and is selected from the group consisting of ordinary powder, ceramic powder, glassy powder, or a mixture thereof.

[0030] As mentioned above, sintering and hot pressing involve pressurizing / heating a mixture of diamond abrasive grains and the first powder in a mold, so the diamond abrasive grains on the surface are not exposed enough to perform cutting or polishing well.

[0031] Therefore, in this embodiment, the auxiliary grindstone portion 30 is separately formed to improve the initial cutting force of the segment manufactured by sintering or hot pressing.

[0032] The auxiliary grinding stone portion 30 is formed by printing diamond abrasive grains and a second powder on the surface of the segment by 3D printing, melting them with a laser and layering them.

[0033] In this embodiment, the size of the diamond abrasive grains supplied to form the auxiliary grinding stone portion is 75 to 750 μm, and nickel is used as the second powder.

[0034] The second powder may be ceramic powder, Cu-based alloy powder, Ni-based alloy powder, Sn-based alloy powder, or a mixture of one or more of these.

[0035] The Cu-based alloy powder, Ni-based alloy powder, and Sn-based alloy powder include powders consisting of only Cu, Ni, and Sn themselves.

[0036] The laser device used for 3D printing may be any of a CO2 laser device, Nd-YAG laser device, fiber laser device, diode laser device, and disk laser device that emits a laser with a wavelength that can penetrate diamond abrasive grains.

[0037] 3D printing involves irradiating a laser beam with an output of 200 to 2000 watts, moving at a speed of 500 to 2000 mm / min. The laser beam is moved by moving the laser output unit or segments. The laser beam pitch is approximately 0.1 to 2.0 mm. Diamonds are sensitive to heat, so the output of the laser device must be adjusted so that the temperature of the molten pool where the second powder is melted does not deviate from a preset temperature range that will not damage the diamond abrasive grains.

[0038] The supply rate of the diamond abrasive grains supplied to form the auxiliary grinding stone portion is preferably 0.005 to 0.5 g / sec, and the supply rate of the second powder is preferably 0.05 to 0.5 g / sec. The diamond abrasive grains of the auxiliary grinding stone portion formed by 3D printing are exposed on the surface so that they can cut or polish the workpiece.

[0039] The segment of the present invention has an auxiliary grindstone portion formed or exposed on the surface corresponding to the main cutting surface.

[0040] The auxiliary grinding stone portion in Figure 4 has multiple auxiliary grinding stone portions printed at intervals according to the segment movement direction, while the auxiliary grinding stone portion in Figure 5 has multiple auxiliary grinding stone portions printed at intervals in a direction perpendicular to the segment movement direction.

[0041] When a diamond tool having a segment of the above-mentioned shape cuts or polishes a workpiece, the auxiliary grinding stone portion formed on the main cutting surface of the segment comes into contact with the workpiece first, and the exposed diamond abrasive grains of the auxiliary grinding stone portion cut or polish the workpiece, and the diamond abrasive grains and / or bonding material of the auxiliary grinding stone portion that are broken or separated during the cutting or polishing process remove the bonding material of the segment, exposing the diamond abrasive grains of the segment to the surface.

[0042] 6 to 8 are diagrams showing an embodiment in which an auxiliary grindstone portion is formed on the segment of FIG. 2(b).

[0043] 2(b) shows a diamond cutting tool, in which recesses 22 are formed along the side surfaces of the segments 20. The recesses 22 are usually formed for the purpose of discharging chips, etc.

[0044] In this embodiment, the auxiliary grinding stone portion 30 was formed in such a recess by 3D printing. Fig. 6 shows the shape in which the auxiliary grinding stone portion is completely filled, and Figs. 7 and 8 show the shape in which the auxiliary grinding stone portion is filled only in part of the recess. The auxiliary grinding stone portions in Figs. 6 to 8 are configured so that the auxiliary grinding stone portion is exposed on all main cutting surfaces, ensuring initial cutting force.

[0045] In this embodiment, a recess provided in the segment is used for ejecting the segment, etc., but it is also possible to form a separate recess for 3D printing. Although not shown, the recess may be formed in the main cutting surface.

[0046] When the auxiliary grindstone portion is formed using the recessed portion, the bonding force between the segment and the auxiliary grindstone portion is further strengthened.

[0047] During 3D printing, the diamond abrasive grains and the second powder are preferably supplied through separate nozzles, but may also be supplied in a mixed form through a single nozzle.

[0048] When supplied through separate nozzles, the deeper part of the recess may be filled with only the second powder, while the upper end of the recess (i.e., near the main cutting surface) may be 3D printed with both the diamond abrasive grains and the second powder.

[0049] Table 1 shows the hardness (HRB) of the auxiliary grinding stone part. Considering that the hardness of a segment that is normally sintered is 60 to 150 HRB, it can be confirmed that the auxiliary grinding stone part of the present invention has sufficient hardness to grind the binder of the segment.

[0050] [Table 1]

[0051] Figure 9 shows a photograph of the surface of a segment after drilling a workpiece 20 times using a diamond drilling tool equipped with a segment of the present invention. It can be seen that the auxiliary grinding stone portion is in a normal state of wear and has not peeled off.

[0052] As a result, the segment of the present invention can easily form an auxiliary grinding stone portion in the desired position and shape using 3D printing, ensuring excellent initial cutting force even without a dressing process. [Explanation of symbols]

[0053] 1 Diamond tools 2 Diamond abrasive grains 10 shank 20 segments 21 Binding material 22 recess 23 Main cutting surface 30 Auxiliary grinding wheel section

Claims

1. a segment produced by mixing diamond abrasive grains and a first powder and sintering or hot pressing the mixture; An auxiliary grinding stone portion printed on the segment by 3D printing in which diamond abrasive grains and a second powder are melted and laminated by a laser; A segment for a diamond tool comprising:

2. 2. The segment for a diamond tool according to claim 1, wherein a part or all of the auxiliary grinding stone portion is exposed on the main cutting surface of the segment.

3. 2. The segment for a diamond tool according to claim 1, wherein a plurality of the auxiliary grinding stone portions are formed at regular intervals on the surface of the segment.

4. A segment for a diamond tool as described in claim 1, characterized in that one or more recesses are formed in the segment, and an auxiliary grinding stone portion is formed in such a way that all or some of the recesses are completely or partially filled.

5. 5. A segment for a diamond tool according to claim 4, wherein the recesses are formed in one or more of the cutting surfaces where the segment comes into contact with a workpiece.

6. 2. The diamond tool segment according to claim 1, wherein the second powder is a ceramic powder, a Cu-based alloy powder, a Ni-based alloy powder, a Sn-based alloy powder, or a mixture of one or more of these.

7. 2. The segment for a diamond tool according to claim 1, wherein the size of the diamond abrasive grains supplied to the auxiliary grinding stone portion is 75 to 750 μm.

8. mixing the diamond abrasive grains and the first powder to produce a segment by sintering or hot pressing; a step of printing an auxiliary grinding stone portion by 3D printing in which the diamond abrasive grains and the second powder are melted by a laser and laminated on the surface of the segment; A method for manufacturing a segment for a diamond tool, comprising:

9. A method for manufacturing a segment for a diamond tool as described in claim 8, characterized in that 3D printing is performed by irradiating a laser beam with an output of 200 to 2000 Watts while the segment or laser beam moves at a speed of 500 to 2000 mm / min.

10. A method for manufacturing a segment for a diamond tool as described in claim 8, characterized in that the supply rate of the diamond abrasive grains supplied to form the auxiliary grinding stone portion is 0.005 to 0.5 g / sec, and the supply rate of the second powder is 0.05 to 0.5 g / sec.

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