DRILLING TOOL

Abstract

The invention relates to a drilling tool (50), in particular a dowel hole drill, for the machining of workpieces, in particular workpieces made of wood, plastics, composite materials, comprising a drill shaft (56) with a front surface (60), and to a drill head (58) with at least one cutting edge (66), which is firmly connected, such as soldered, to the drill shaft (56). In order to make available a drilling tool of the type mentioned at the start, which has a broad range of application and is simple to produce, it is provided that the drill head (58) is formed from a composite material with exclusively two layers (38), namely a hard metal layer (36) and an ultra-hard layer (38) which is connected to the hard metal layer (36) and preferably formed from polycrystalline diamond or polycrystalline boron nitride, that the ultra-hard layer (38) is connected directly to the front surface (60) of the drill shaft (56) and that the at least one cutting edge (66) is formed by the ultra-hard layer (38), and a drill bit (62) such as a centering tip is formed by the hard metal layer (36).

Claims

1. A drilling tool (30, 50), in particular a dowel hole drill, for the machining of workpieces, in particular workpieces made of wood, plastics, composite materials, comprising a drill shaft (34, 56) with a front surface (32, 60) as well as a drill head (40, 58) with at least one cutting edge (42, 64, 66), which is firmly connected, such as soldered, to the drill shaft (34, 56), characterized in that the drill head (40, 58) is formed from a composite material with exclusively two layers (36, 38), namely a hard metal layer (36) and an ultra-hard layer (38) connected to the hard metal layer (36), which is formed from preferably polycrystalline diamond or polycrystalline boron nitride, that the ultra-hard layer (38) is connected directly to the front surface (60) of the drill shaft (34, 56), and that the at least one cutting edge (42, 64, 66) is formed by the ultra-hard layer (38), and a drill bit (62), such as a centering tip, is formed by the hard metal layer (36).

2. The drilling tool according to claim 1, characterized in that the ultra-hard layer (16, 38) is soldered, in particular vacuum soldered, to the basic body (10, 34, 56).

3. The drilling tool according to claim 1, characterized in that the cutting edge (42, 64, 66) and an adjoining chipping surface (44, 74, 78) is produced by ablation in some areas of the hard metal support layer (36), preferably by a grinding, laser or die sinking process, in a surface of the ultra-hard layer (38), which adjoins the hard metal support layer (36), or that the sections of the cutting edge (42, 64, 66) of the drill bit or cutting bit with adjoining chipping surface (44, 76, 78) are formed in the hard metal support layer (36) and the ultra-hard layer (38), wherein the sections of the cutting edge (42) of the drill bit or cutting bit preferably transition continuously into one another.

4. The drilling tool according to claim 1, characterized in that the active portion (46) of the cutting element (35) is produced preferably by a grinding, laser or die sinking process from the hard metal support layer (14, 36).

5. The drilling tool according to claim 1, characterized in that the drilling tool (30, 50) is designed as a spiral drill, a dowel hole drill, a sickle drill or a step drill, wherein the cutting element (40) or the drill head (58) is connected, such as soldered, in the form of a cylindrical body with its ultra-hard layer (38) on the front surface (32) of a cylindrical steel, ceramic or hard metal shaft as basic body (34), and wherein the active portion (46) forms the drill bit of the drill.

6. The drilling tool according to claim 1, characterized in that a thickness ratio D.sub.HB/D.sub.SB exists between a thickness of the hard metal layer and a thickness D.sub.SB of the ultra-hard layer in the range of 0.2≤D.sub.HB/D.sub.UB≤5.0, preferably 0.3≤D.sub.HB/D.sub.UB≤2.0.

Description

[0039] FIG. 1 shows a side view of a basic body with a cutting element blank for producing a cutting tool,

[0040] FIG. 2 shows a section of the basic body according to FIG. 1 with soldered cutting element blank,

[0041] FIG. 3 shows a side view of a first embodiment of a cutting tool,

[0042] FIG. 4 shows a detail C from FIG. 3 at an enlarged scale,

[0043] FIG. 5 shows a side view of a second embodiment of a cutting tool,

[0044] FIG. 6 shows a perspective representation of a cutting element blank consisting of two layers,

[0045] FIG. 7 shows a perspective representation of a drilling tool according to the invention,

[0046] FIG. 8 shows a side view of the drilling tool,

[0047] FIG. 9 shows a side view of the drilling tool in a position rotated by 90° with respect to FIG. 8,

[0048] FIG. 10 shows a detail A of the drilling tool according to FIG. 8,

[0049] FIG. 11 shows a detail B of the drilling tool according to FIG. 9, and

[0050] FIG. 12 shows a top view of the drilling tool.

[0051] FIGS. 1 and 2 show in general a side view of a basic body 10 with a cutting element blank 12 for producing a cutting tool. The production of the cutting tool occurs in such a manner that first the cutting element blank 12 is cut out in a fitting manner from a round, disk-shaped commercially available blank such as a PCD round blank or a PCBn round blank consisting of an ultra-hard layer 16 made of polycrystalline diamond (PCD) or polycrystalline boron nitride (PCBn), which is firmly connected, such as sintered, to a hard metal support layer 14. According to the invention, the cutting element blank is soldered with its ultra-hard layer 16 in a recess 18 of the basic body 10. The soldering process occurs preferably in a vacuum.

[0052] FIG. 2 shows a section of the basic body 10 with a soldered-in cutting element blank 12.

[0053] FIGS. 3 and 4 show purely as an example a cutting tool 20 in the form of a cutting plate with chip breaker function.

[0054] After the soldering, the cutting element blank 12 is formed to a cutting element 21, preferably by means of a grinding, laser or die sinking process. The hard metal support layer 14 is ablated at least in some areas in order to form, in a surface adjoining the hard metal support layer 14, a cutting edge 22 as well as a chipping surface 24 adjoining the cutting edge 22.

[0055] In the embodiment example represented, the hard metal support layer 14 is formed at least in some areas as a chip guiding portion 26 such as a chip breaker with a chip guiding surface 28 adjoining the chipping surface 24, preferably by a grinding, laser or die sinking process.

[0056] According to the invention, it can be provided that preferably, but not in a manner which limits the scope of protection, a thickness ratio exists between the hard metal support layer 14 and the ultra-hard layer 16 in the range of 0.2≤D.sub.HS/D.sub.US≤5.0, preferably in the range of 0.3≤D.sub.HS≤D.sub.US≤1.5.

[0057] In accordance with the method according to the invention, it is also possible to produce cutting tools in the form of drilling tools, for example, spiral drills, dowel hole drills, sickle drills or step drills or milling tools such as end mills, for example.

[0058] FIG. 5 shows an embodiment of a drilling tool 30 in a side view. In this embodiment, a cylindrical cutting element blank 35 is soldered, for example, on a front surface 32 of a cylindrical, preferably spiral-shaped basic body 34.

[0059] The cutting element blank 35 is represented in FIG. 6 and comprises exclusively two layers, namely a hard metal support layer 36 and an ultra-hard layer 38, such as a PCD layer or PCBn layer, which is firmly connected, such as sintered, to said hard metal support layer.

[0060] According to the invention, the cutting element blank 35 is soldered, preferably vacuum soldered, directly with its ultra-hard layer 38 to the front surface 32 of the basic body 34. In this way, a cutting element 40 can be formed from the cutting element blank, preferably by means of a grinding, laser or die sinking process. By the ablation of material in some areas, a cylinder shell-shaped section is formed from the ultra-hard layer 38, which transitions in a first section of a cutting edge 42 with chipping surface 44 of a drill bit 46. From the hard metal support layer 36, an active portion in the form of the drill bit 46 with a second section of the cutting edge 42 is formed. The sections of the cutting edge 42 transition continuously into one another. The cutting edges 42 and chipping surfaces 44 formed in the ultra-hard layer 38 and the hard metal layer 36 transition into or adjoin chipping grooves 48 which are formed in the steel, ceramic or hard metal basic body.

[0061] FIG. 7 shows, in a perspective view, a drilling tool 50 in the form of a dowel hole drill for producing dowel holes in materials constructed preferably in layers, such as coated wood materials. The drilling tool 50 comprises a basic body 52 with a clamping shaft 54 and a drill shaft 56, on the free end of which, a drill head 58 is arranged. The drill head 58 is produced from the cutting element blank 35, as represented in FIG. 6. The blank 35 consists exclusively of two layers, namely the hard metal support layer 36 and the ultra-hard layer 38 such as a PCB layer or a PCBn layer, which are connected, such as sintered, to the hard metal layer 36.

[0062] FIGS. 8 and 9 show side views of the drilling tool 50 in different turning positions.

[0063] According to the invention, for the formation of the drill head 58, the cutting element blank 35 is connected, such as soldered, with the ultra-hard layer 38 to a front surface 60 of the drill shaft 56. Subsequently, a drill bit 62, such as a centering tip, and cutting edges 64, 66 are formed in the cutting element blank 35 by grinding, laser and/or electric die sinking processes.

[0064] FIGS. 10 and 11 show the drill head 58 in each case as a detail in different turning positions. The drill head 58 comprises a conical drill bit 62 such as a centering tip, which is formed along a central axis of the drilling tool by material ablation from the hard metal layer 36 of the cutting element blank. In the ultra-hard layer 38, cutting edges 64, 66 are also formed by material ablation, which are represented in a front view in FIG. 10, in a side view in FIG. 11, and in a top view in FIG. 12.

[0065] The cutting edges 64, 66 transition continuously into the conical drill bit 62. In each case free surfaces 68, 70 which are also formed by material ablation in the ultra-hard layer 38 adjoin the cutting edges 64, 66. The free surfaces transition seamlessly, on the one hand, into the surface of the conical drill bit 62 and, on the other hand, into chipping grooves 72, 74 which are formed in the shape of spirals in the drill shaft 56.

[0066] Moreover, in the ultra-hard layer 38, adjoining the cutting edges 64, 66, chipping surfaces 76, 78 are formed in each case, which transition seamlessly into the chipping grooves 72, 74 of the drill shaft 56.

[0067] FIG. 10 shows the cutting edges 64, 66 in a front view. The cutting edges extend from the frustoconical drill bit 62 in the shape of an arc radially outward and end in each case in diametrically opposite tips 80, 82.