Diamond cutting head and method of manufacturing the same

Abstract

This invention discloses a diamond cutting tool head and its manufacturing method. The diamond cutting tool head is in the shape of a sheet and includes: a connecting part, which is mainly made of tungsten steel; and a diamond cutting part, which is sintered and bonded to the connecting part, the diamond cutting part having a cutting tip.

Description

Technical Field

[0001] This invention discloses a diamond cutting tool head. Prior Technology

[0002] The first generation of diamond cutting tips was a high-speed steel twist drill, as shown in Figure 1. This was a one-piece design where the drill bit at the front end and the metal plate body were formed as a single piece, with the body being a spiral shank. "Metal plate" is a general term in the industry for metal layers, mostly referring to tungsten steel, but sometimes including non-tungsten steel.

[0003] With the evolution of processed materials, high-speed steel is no longer sufficient. Therefore, replaceable tungsten carbide drill bits are used as cutting heads, attached to the front end of the helical shank for cutting operations. This tungsten carbide drill bit is shown in Figure 2.

[0004] Today, tungsten steel has become the material being processed. In order to process tungsten steel, it is necessary to use integral diamond blades, which have a similar shape to the tungsten steel blades in Figure 2 but are made of a harder material, to replace the tungsten steel blades in Figure 2. However, because integral diamond blades are not easy to weld to the high-speed steel shank, it is not possible to use traditional welding methods to weld the diamond blades to the high-speed steel shank.

[0005] To address this issue, one approach, as shown in Figure 3, is to modify the diamond cutting head structure into a sandwich-structure diamond insert design. In this design, the outer layer of the sandwich diamond insert is tungsten steel, while the middle layer is a diamond insert. This structure can be easily welded to a high-speed steel shank. However, due to the difference in thermal expansion coefficients between diamond and tungsten steel, the sandwich diamond insert experiences uneven stress, making it prone to breakage.

[0006] Therefore, it is necessary to provide a diamond cutting tool head that can improve the aforementioned problems and can be integrated into a spiral shank. Summary of the Invention

[0007] To overcome the shortcomings of conventional technology, the present invention provides a diamond cutting head with a polycrystalline diamond cutting section.

[0008] According to a preferred embodiment, the diamond cutting tip of the present invention preferably has a sheet-like structure of a diamond composite sheet, comprising a diamond cutting portion of polycrystalline diamond and a bonding portion mainly made of tungsten steel, thus presenting the appearance of a diamond sheet. This composite sheet-like structure, consisting of a diamond cutting portion and mainly tungsten steel, solves the problem of the difficulty in welding a monolithic diamond sheet to high-speed steel by allowing the diamond cutting portion to be used for cutting, while the tungsten steel portion is easily welded to the high-speed steel shank, thus overcoming the problem of uneven stress in the sandwich diamond sheet of Figure 3.

[0009] According to a preferred embodiment, in manufacturing the diamond cutting head of the present invention, the tungsten carbide layer is first shaped into the desired interface shape, preferably a wavy interface. Next, diamond powder is sprinkled onto the wavy interface, and the composite material sheet, having a diamond layer and a tungsten carbide layer bonded together, is pressed into a mold under high temperature and pressure to form a polycrystalline diamond composite sheet. Finally, the composite material sheet is cut to obtain multiple sheet-shaped diamond cutting heads, each having a diamond cutting portion and a bonding portion mainly composed of tungsten carbide.

[0010] The drill bit of this invention has the following structural features: the front end of the drill bit is made of diamond material, which has excellent hardness and wear resistance, making it suitable for processing various hard materials; while the weld joint uses traditional materials such as tungsten steel to ensure a firm connection between the drill bit and the diamond cutting head. Furthermore, the design and process of the weld joint ensure the durability and reliability of the drill bit, making it suitable for use in various high-intensity working environments.

[0011] The conventional technology of diamond cutting tool heads of the present invention is not limited to specific types or application scenarios of diamond cutting tool heads, but can also be applied to various drilling operations, including but not limited to metal processing, stone processing, and construction. The superior performance and long life of diamond cutting tool heads make them an ideal choice for various industrial applications, while also bringing higher efficiency and lower costs to drilling operations. Simple Explanation of the Diagram

[0012] Figure 1 is a schematic diagram of a conventional high-speed steel twist drill.

[0013] Figure 2 is a schematic diagram of the cutting end of a tungsten carbide drill bit.

[0014] Figure 3 is a schematic diagram of a conventional sandwich diamond sheet.

[0015] Figure 4 is a schematic diagram of the diamond cutting head with a polycrystalline diamond cutting section according to the present invention.

[0016] Figure 5 is a schematic diagram of the wavy bonding structure of the tungsten carbide layer and the diamond powder layer.

[0017] Figure 6 is a schematic diagram of the composite sheet structure of the tungsten steel layer and the diamond layer pressed according to Figure 5.

[0018] Figure 7 is a photograph of a semi-finished product, which is a circular piece with the shape shown in Figure 6, cut into a diamond cutting tool.

[0019] Figure 8A is a schematic diagram of further cutting the semi-finished diamond cutting head of Figure 7 to form a diamond cutting part.

[0020] Figure 8B is a comparison diagram of the cutting of the semi-finished product in Figure 8A and the semi-finished product without an interface structure with an undulating shape.

[0021] Figure 9 shows another embodiment of the composite sheet, in which the diamond layer has a wavy upper surface.

[0022] Figure 10 shows a schematic diagram of a diamond cutting tip mounted on the helical shank of a cutting tool. Implementation

[0023] The polycrystalline diamond (PCD) material used in this invention has the advantages of good thermal conductivity, high hardness, and good wear resistance. It can achieve high machining accuracy and efficiency in cutting. Therefore, using polycrystalline diamond as the cutting part can achieve very good performance.

[0024] Figure 4 shows a preferred embodiment of the present invention, wherein the diamond cutting head 100 is preferably a composite structure of diamond and tungsten steel, and is a thin sheet structure. The diamond cutting head 100 includes a diamond cutting portion 110 of polycrystalline diamond and a bonding portion 120 mainly of tungsten steel. The diamond cutting head 100, in appearance like a diamond blade, is manufactured by pressing a composite material sheet 200 with a bonded diamond layer 210 and a tungsten steel layer 220, as shown in Figures 5 and 6, under high temperature and high pressure, and then cutting it. Therefore, the diamond cutting portion 110 and the bonding portion 120, mainly of tungsten steel, are not easily separated from each other. The manufacturing process will be described below. The diamond cutting portion 110 has a diamond cutting edge, or diamond cutting edge, for cutting. The bonding portion 120, mainly of tungsten steel, has the advantage of being easy to weld onto high-speed steel and is used to bond to the shank of the cutting tool. Figure 10 shows an embodiment in which the diamond cutting head 100 is attached to the shank of a cutting tool via a joint 120, which is mainly made of tungsten steel.

[0025] Because the structure of this diamond cutting head 100 has a better joint 120, which is mainly made of tungsten steel, it is easy to weld onto high-speed steel, thus solving the problem that the integral diamond blade in Figure 2 is not easy to weld onto high-speed steel, and also overcoming the problem of uneven stress in the sandwich diamond blade in Figure 3.

[0026] Please refer to Figures 5 and 6, along with the following description, to understand the manufacturing process of the diamond cutting head 100 of the present invention. To obtain the diamond cutting head 100 of Figure 4, and to manufacture the diamond cutting head 100 of this invention, a composite material sheet 200 as shown in Figures 5 and 6 needs to be prepared first, namely the "PCD disc" described in this invention. For this purpose, a tungsten carbide layer 220 is first prepared. This tungsten carbide layer 220 is mainly made of tungsten carbide, usually has a flat bottom, and is usually circular. The upper surface of the tungsten carbide layer 220 provides an interface structure / shape for bonding with a diamond layer 210 to be formed. This interface structure / shape generally has an undulating shape, preferably including a wavy interface with an arcuate convex surface and / or an arcuate concave surface. Next, diamond micropowder is sprinkled onto the tungsten carbide layer 220. The tungsten carbide layer and diamond micropowder are then pressed under high temperature and pressure in a mold (not shown), causing the diamond micropowder at the interface to sinter, forming a diamond layer 210, thus obtaining a composite material sheet 200 with both a diamond layer 210 and a tungsten carbide layer 220. The undulating interface structure, preferably a wavy interface, allows for a larger contact area between the diamond layer and the tungsten carbide layer, and the bonding structure at the interface is stable and can withstand forces in different directions. The undulating interface structure refers to a structure mainly composed of convex and concave portions. Viewed from the side of the composite material sheet 200, the undulating interface forms a sawtooth shape or a wavy shape as shown in Figures 5 and 6 on the sidewall of the composite material sheet 200.

[0027] According to the present invention, the interface structure of the composite material sheet 200 with its undulating shape forms an included angle α between the two sides of each convex portion, suitable for forming a cutting tip, preferably between 118 and 120 degrees. If the convex portion is an arcuate convex portion, the included angle between the two arcuate sides of the arcuate convex portion is also preferably between 118 and 120 degrees. Generally, the design of the included angle α varies depending on the material being processed, most commonly 118 degrees, but the minimum can be as low as 60 degrees (e.g., hard rubber) and the maximum can be as high as 150 degrees (e.g., hard materials).

[0028] After the composite material sheet 200 in Figure 6 is formed, it is preferable to cut the composite material sheet 200 with a laser to obtain a plurality of semi-finished diamond cutting heads 100 as shown in Figure 7, which are sheet-shaped and have not yet formed cutting tips in the diamond cutting portion 110. These semi-finished products 110' have diamond cutting portions 110 and a bonding portion 120, mainly made of tungsten steel, which are bonded together by sintering. To obtain the structure of the diamond cutting head 100 shown in Figure 4, which has a wavy bonding surface between the diamond cutting portion 110 and the bonding portion 120, which is mainly made of tungsten steel, the semi-finished product 110' needs to be further cut.

[0029] Please refer to Figures 7 and 8A simultaneously. Figure 7 shows a semi-finished product 110' of the diamond cutting head 100, which is roughly rectangular. Figure 8A is a schematic diagram of further cutting the semi-finished product 110' to obtain the diamond cutting head 100 with the diamond cutting portion 110. As mentioned earlier, after the composite material sheet 200 is prepared, the composite material sheet 200 is first cut with a laser to obtain a plurality of semi-finished products 100' of the diamond cutting head 100 shown in the photograph of Figure 7. This semi-finished product 100' has not yet formed a sharp cutting end, but it is visible that a convex portion 130 (or arc-shaped convex portion) with a joint portion 120 forms an interface extending into the diamond layer, forming the diamond cutting portion 110. The convex portion 130 (or arc-shaped convex portion) is derived from the undulating shape or wavy interface of the tungsten carbide layer 220 of the composite material sheet 200, and the included angle between its two sides is approximately the included angle of the cutting tip, preferably an included angle between about 118 and 120 degrees. During cutting, as shown in Figure 8A, it is preferable to use a laser to cut along both sides (or two arcuate sides) of the convex portion 130 (or arcuate convex portion) of the semi-finished product to remove excess material, thereby obtaining an optimized diamond cutting portion 110 with a cutting tip. Cutting is performed along the cutting lines shown by dashed lines A and B in Figure 8A to obtain a diamond cutting head 100 with the diamond cutting portion 110. Of course, dashed lines A and B are preferably located within the diamond portion rather than passing through the tungsten carbide to ensure that the diamond cutting portion 110 has sufficient diamond thickness for cutting.

[0030] Traditionally, the technology for creating composite diamond material PCD wafers by combining a diamond layer and a hard layer, such as the applicant's patent I605954 (application number 104138718) "A Diamond Composite Sheet with a Variable Three-Dimensional Formation and a Method for Manufacturing the Same," involves pressing the wafer under high temperature and pressure. The resulting PCD wafer has a flat interface between the diamond layer and the hard layer. The thickness of the diamond layer is typically a maximum of 1.0 mm, which is the optimal thickness considering the sweeping of cobalt from tungsten carbide into the diamond layer. Of course, a cobalt-mixing method can also be used to press the diamond wafer; however, while this eliminates the thickness limitation of the diamond layer, the quality is inferior.

[0031] The composite material sheet 200 of the present invention does not recommend a PCD disc structure with a "flat interface between the diamond layer and the hard layer." This is because, besides the different applications, a PCD disc structure with a "flat interface between the diamond layer and the hard layer" will result in insufficient thickness of the diamond cutting portion when cutting it, as illustrated in the left example of Figure 8B. In contrast, the present invention provides an undulating interface structure or wave structure in the tungsten carbide layer 220 of the composite material sheet 200. When the semi-finished product 100' is cut, the diamond area of ​​the obtained diamond cutting portion is larger, as illustrated in the right example of Figure 8B.

[0032] Figure 9 shows a composite sheet 300, which is a variation of the composite sheet 200, and the manufacturing processes of both are largely similar. The composite sheet 300 has a diamond layer 310 and a tungsten carbide layer 320. The upper surface of the tungsten carbide layer 320 provides an interface structure / shape for bonding with the diamond layer 310 to be formed. This interface structure / shape generally has an undulating shape mainly composed of a plurality of convex and concave portions, preferably a wavy interface. Similarly, the upper surface 330 of the diamond layer 310, located at the interface away from the tungsten carbide layer 320, also provides an undulating shape mainly composed of a plurality of convex and concave portions. The undulating shape of the upper surface 330 can be obtained by forming a corresponding undulating shape in a mold, and by subjecting the composite sheet 300 to high temperature and high pressure in the mold.

[0033] Preferably, each convex portion of the undulating shape of the upper surface 330 has two sides suitable for serving as the cutting tip of the diamond cutting section. Thanks to this undulating shape, or preferably wavy upper surface 330, the amount of diamond powder used to form the diamond layer 310 can be reduced during the manufacturing process, and the resulting diamond cutting head can have a sufficient thickness of the diamond layer. In particular, when each convex portion of the undulating shape of the upper surface 330 has two sides suitable for serving as the cutting tip of the diamond cutting section, the composite material sheet 300 only needs to be laser-cut into a sheet shape once, without the need for a second cutting process to form the cutting tip, to obtain an optimized diamond cutting head 100 with a cutting tip formed after pressing and a diamond cutting section 110 and a connecting section 120.

[0034] Figure 10 shows a schematic diagram of the diamond cutting head 100 of the present invention mounted on the spiral shank 400, illustrating an embodiment in which the diamond cutting head 100 is attached to the shank of the cutting tool via a joint 120, which is mainly made of tungsten steel.

[0035] The above description and accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Any minor modifications made in accordance with the spirit of the invention, such as replacing tungsten steel with tungsten-containing high-speed steel to obtain a product with slightly lower performance, are considered to be utilizing the invention. Therefore, whether something falls within the scope of protection of this patent application shall be determined by the contents of the claims.

[0036] 100: Diamond cutting tool head 100': Semi-finished product 110: Diamond cutting section 120: Joint 130: Convex part 200: Composite material sheet 210: Diamond Layer 220: Tungsten steel layer 300: Composite material sheet 310: Diamond Layer 320: Tungsten steel layer 330: Upper surface 400: Spiral Handle A: Dashed line B: Dashed line

Claims

1. A method for manufacturing a diamond cutting tool tip, comprising: Prepare a tungsten steel layer, primarily composed of tungsten steel, which has an upper surface forming an interface. This interface has an undulating structure mainly composed of a plurality of convex and concave portions. Sprinkle diamond micropowder onto the upper surface of the tungsten steel layer. Press the tungsten steel layer and diamond micropowder in a mold under high temperature and pressure, causing the diamond micropowder on the upper surface of the tungsten steel layer to sinter into a diamond layer, thereby obtaining a composite material sheet having the diamond layer and the tungsten steel layer bonded together. Cut the composite material sheet to form at least one diamond cutting head in the shape of a sheet, wherein the at least one diamond cutting head has: a diamond cutting portion, a bonding portion, and a convex portion respectively corresponding to the convex portions of the diamond layer, the tungsten steel layer, and the interface.

2. The method of claim 1, wherein the undulating structure of the interface forms one of the following two structures on one side wall of the composite material sheet: a serrated shape and a wavy shape.

3. As in request item 1, where, The diamond cutting head is a semi-finished product, which includes the diamond cutting portion, the joint portion, and the convex portion, but the diamond cutting portion has not yet formed a cutting tip; the method further includes: cutting the diamond cutting portion with a laser along both sides of the convex portion of the semi-finished diamond cutting head to form the cutting tip.

4. The method of claim 3, wherein the included angle of the cutting tip formed by the cutting is between 118 and 120 degrees.

5. As in request item 1, wherein, After pressing, the diamond layer of the composite sheet forms an undulating shape consisting of a plurality of convex and concave portions on its upper surface away from the tungsten steel layer.

6. A diamond cutting tool head, which is manufactured by the method of claim 1, wherein: The diamond cutting part has a cutting tip; the connecting part can be connected to a shank of a cutting tool, and the convex portion of the interface between the diamond cutting part and the connecting part has two sides, and the two sides form an angle suitable for serving as the cutting tip.

7. The diamond cutting tool head as claimed in claim 6, wherein the convex portion is an arc-shaped convex portion.

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