Cutting tool with multi-component cutting head

Abstract

The present invention relates to a tool blank (30) for a cutting tool (1), such as an end mill, drill or engraving tool, comprising a tool shank (2) adapted to be received in a rotary tool holder of a processing machine and a cutting head blank (3) fixedly connected to the tool shank (2). The cutting head blank (3) comprises a plurality of cutting head blank elements (5) which are fixedly connected to one another, preferably soldered to one another and made of a hard material, in particular polycrystalline diamond. Furthermore, the present invention relates to a cutting tool (1), such as an end mill, drill or engraving tool, in which at least one tool cutting edge (15) is generated in the tool blank (30) according to the invention, which extends over the plurality of fixedly interconnected cutting head blank elements (5). Furthermore, the present invention relates to a method for manufacturing a tool blank and a method for manufacturing a cutting tool.

Description

[Technical Field]

[0001] The present invention relates to a tool blank and to a cutting tool having such a tool blank. Furthermore, the present invention relates to a method for manufacturing the tool blank and to a method for manufacturing a cutting tool. In particular, the present invention relates to a cutting tool having a multi-component cutting head. [Background technology]

[0002] A cutting tool consists of a tool shank made of steel or solid carbide. The cutting head is usually soldered onto the tool shank. One or more tool cutting edges are generated on the cutting head, typically by using a laser. Depending on the intended use of the cutting tool, different cutting materials are used for the cutting head.

[0003] When high wear resistance, high processing reliability, and long tool life are required, high hardness materials are used as cutting materials in cutting tools. High-hardness materials are materials that are harder than carbide and cutting ceramics. Specifically, among high-hardness materials, polycrystalline diamond (PCD), CVD thick diamond (CVD-D), binderless diamond (UltraDiamond), polycrystalline cubic boron nitride (CBN), single crystal diamond (MKD), and natural diamond are included. The hardness HV of high-hardness materials is usually 2000 to 10000 kg / mm 2 is within the range.

[0004] Hard materials are expensive. For example, polycrystalline diamond is provided in the form of so-called blanks for further processing, and the blanks become disproportionately expensive as their volume increases. For this reason, the use of cutting tools with large cutting heads leads to increased costs. Furthermore, the strength of PCD blanks decreases as their volume increases.

[0005] From US Pat. No. 5,649,999 a polycrystalline compact is known. The polycrystalline compact comprises a substrate having a first surface and a second surface. A first polycrystalline layer is applied to the first surface of the substrate, and a second polycrystalline layer is applied to the second surface of the substrate. The compact makes it possible to increase the effective thickness of the tool. The compact is manufactured using a high-pressure, high-temperature process.

[0006] Patent Document 2 describes a heat-resistant polycrystalline diamond body that includes at least two different homogeneous diamond layers stacked on top of each other, the diamond layers being separated by an intermediate metal diffusion barrier layer between each diamond layer.

[0007] Patent Document 3 describes a sintered compact insert for cutting. This sintered compact insert includes an intermediate layer made of at least one of cemented carbide, iron-based metal, and high-melting-point metal, and a first layer and a second layer made of a hard sintered body containing cubic boron nitride or diamond, which are respectively arranged on upper and lower opposing surfaces sandwiching the intermediate layer. The first layer and the second layer are joined to the intermediate layer by sintering.

[0008] From US Pat. No. 5,629,999 a diamond insert for use as a cutting tool is known in which a plurality of rod-shaped elements made of polycrystalline diamond (PCD) are arranged in a matrix body.

[0009] US Pat. Nos. 5,699,949 and 5,729,263 describe cutting tools that include inserts made of a carbide carrier and a PCD-like crystalline structure sintered thereon. Against this background, the technical problem underlying the present invention is to provide a cutting tool with high wear resistance and at lower cost. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] International Publication No. 2005 / 025805 [Patent Document 2] U.S. Patent No. 4,766,040 [Patent Document 3] U.S. Patent No. 5,712,030 [Patent Document 4] U.S. Patent No. 5,205,684 [Patent Document 5] German Patent Application Publication No. 102017107101 [Patent Document 6] DE 4341503 Summary of the Invention

[0011] According to a first aspect of the present invention, the above-mentioned technical problem is solved by providing a tool blank for a cutting tool, such as an end mill, drill or engraving tool, comprising a tool shank configured to be received in a rotary tool holder of a processing machine and a cutting head blank fixedly connected to the tool shank. The cutting head blank then comprises a plurality of cutting head blank elements fixedly connected to one another, preferably soldered to one another, and made of a high-hardness material, in particular polycrystalline diamond.

[0012] The concept underlying the present invention is to first connect together a plurality of individually available, low-cost cutting head blank elements made of a high-hardness material, for example by soldering, gluing, etc., and then produce one or more tool cutting edges on this multi-component cutting head blank in a known manner, for example by laser cutting. In other words, according to the present invention, a plurality of individual high-hardness material blanks, such as PCD blanks, are first joined together to form a larger cutting head.

[0013] By connecting individual cutting head blank elements together, larger cutting head blanks can be produced that avoid the aforementioned drawbacks of increased cost and decreased strength as volume increases compared to a cutting head blank of the same size made with only one cutting head blank element. Additionally, by connecting cutting head blank elements together, cutting tools having longer cutting head blanks and correspondingly longer tool cutting edges can also be produced from high hardness materials.

[0014] A tool cutting edge having any desired cutting geometry can be produced on the cutting head blank. Preferably, the cutting geometry is laser machined. The tool cutting edge extends across multiple cutting head blank elements, specifically across the joint between two interconnected cutting head blank elements, such as two PCD blanks soldered together.

[0015] If the cutting head blank elements are connected together, for example by solder connections, the solder connections preferably have a thickness in the range of 0.01 mm to 0.02 mm. High hardness materials in the sense of the present disclosure include in particular polycrystalline diamond (PCD), CVD thick diamond (CVD-D), binderless diamond (UltraDiamond), polycrystalline cubic boron nitride (CBN), single crystal diamond (MKD) and natural diamond.

[0016] Cutting tools in the sense of the present disclosure are to be understood as, for example, end mills, drills, lathe tools, turning thread cutters or styli. Furthermore, abrasive tools and smoothing tools are also to be understood as cutting tools in the sense of the present disclosure, and since in abrasive tools and smoothing tools one usually speaks of the outer contour rather than the tool edge, the outer contour is to be included in the present disclosure in the sense of the term tool edge.

[0017] In an exemplary embodiment, the cutting head blank elements of the tool blank are stacked on top of each other in the form of a plurality of stack columns extending in the direction of and arranged around the rotation axis of the tool blank.

[0018] Adjacent cutting head blank elements in a stack column abut against each other at abutment surfaces and are connected to each other at these abutment surfaces. The cutting head blank elements can be configured such that adjacent cutting head blank elements form a form-fit connection in the area of ​​their abutment surfaces. Preferably, the cutting head blank elements are connected to each other at their abutment surfaces by means of solder connections.

[0019] Within a stack column, the individual cutting head blank elements may be rotationally offset relative to one another, such that the cutting head blank elements of a stack column may be rotationally offset at different angles about the axis of rotation of the cutting tool.

[0020] In another exemplary embodiment, a first cutting head blank element in one stack column is positioned offset along the axis of rotation from an adjacent second cutting head blank element in another stack column.

[0021] By offsetting the cutting head blank elements, continuous joints within the cutting head blank can be avoided. A joint that extends along any flat interface throughout the entire cutting head blank is understood to be a continuous joint. Such continuous joints constitute weak points in the cutting head blank. By offsetting the cutting head blank elements, such continuous joints, and therefore weak points, can be avoided.

[0022] In a stack structure of cutting head blanks with two parallel stack columns along the rotation axis, the offset can be achieved in a simple way by varying the thickness of the cutting head blank elements in the direction of the rotation axis.

[0023] By positioning the cutting head blank elements in this manner, the abutment surface between a first cutting head blank element and a cutting head blank element of a first stack column adjacent to the first cutting head blank element is spaced apart by an offset V relative to the abutment surface between a second cutting head blank element and a cutting head blank element of a second stack column adjacent to the second cutting head blank element.

[0024] In another exemplary embodiment of the tool blank, the offset is in the range of 20% to 80% of the height of the first cutting head blank element or the second cutting head blank element measured in the direction of the rotation axis.

[0025] An offset of this magnitude ensures that a continuous interface is avoided. According to another exemplary embodiment, a third cutting head blank element in a stack column is positioned at a rotational offset angle about the rotational axis relative to an adjacent fourth cutting head blank element in the same stack column.

[0026] Due to such rotational offset, the abutment surface between the third cutting head blank element and a cutting head blank element of another stack column adjacent to the third cutting head blank element is rotationally offset at a rotational offset angle relative to the abutment surface between the fourth cutting head blank element and a cutting head blank element of another stack column adjacent to the fourth cutting head blank element.

[0027] The rotational offset of the cutting head blank elements about the rotation axis creates an offset in the circumferential direction of the cutting head, thus avoiding continuous joints within the cutting head blank.

[0028] In another exemplary embodiment of the tool blank, the rotational offset angle is in the range of 10° to 80°. An offset of this magnitude ensures that a continuous interface is avoided.

[0029] In another exemplary embodiment, the tool blank has a first stack column and a second stack column. The cutting head blank elements have a semi-cylindrical shape and are arranged such that the cutting head blank has a cylindrical shape.

[0030] This is a simple and good stack structure. In another exemplary embodiment, the cutting head blank elements of the cutting head blank are arranged in a single stack column and have a cylindrical shape, with adjacent cutting head blank elements of the stack column abutting and connected to each other at abutment surfaces.

[0031] Preferably, the cutting head blank elements are connected together at their abutment surfaces using solder connections. This embodiment constitutes a simple structure in which the cutting head blank comprises only cylindrical cutting head blank elements. Multiple cylinders are stacked on top of each other to form a larger cylinder, which is shaped so that at least one tool cutting edge can be machined on its outer periphery. For example, the multiple cutting head blank elements are PCD blanks or machined PCD blanks.

[0032] In another exemplary embodiment, the inclination angle of the abutment surfaces between two cutting head blank elements abutting each other in the direction of the rotation axis is at least locally in the range of 75° to 89° relative to the rotation axis.

[0033] The use of a tilt angle avoids continuous joint surfaces that are perpendicular to the axis of rotation. The tilt angle causes joints at the tool cutting edge to overlap other tool cutting edges along a circumference perpendicular to the axis of rotation. The joints are located at different heights of the cutting head blank, measured along the axis of rotation. Thus, the joints of the cutting head blank elements on the tool cutting edge do not all lie in a common plane perpendicular to the axis of rotation.

[0034] The abutment surface can have a continuous inclination angle relative to the rotation axis. Furthermore, the abutment surface can also have areas with different inclination angles relative to the rotation axis. For example, the abutment surface can be formed so that a conical ridge is formed that fits conformally into a conical recess of an adjacent cutting head blank element that is formed as a mating shape. Any shape can be used to produce a form fit between adjacent cutting head blank elements.

[0035] In another exemplary embodiment, the tool shank has a pin protruding from an end face to which the cutting head blank is attached, and a bore or recess is formed in at least one cutting head blank element, and the at least one cutting head blank element is attached in a form-fitting manner to the bore or recess on the pin of the tool shank.

[0036] The pins and the bores or recesses in the cutting head blank elements can be aligned with each other so that they can be positioned on top of each other in a conformal manner. In addition, the bores and pins simplify the positioning of the cutting head blank elements. Preferably, at least one cutting head blank element is attached to the pin using a solder connection. The pins increase strength due to a larger surface area for the solder. Pins can additionally be used in any of the described embodiments. For example, the abutment surface of the cutting head blank element, which is angled for a form-fit connection, can additionally have a bore for the pin, which allows the abutment surface to be connected to the pin in a conformal manner.

[0037] In another exemplary embodiment, the height of the cutting head blank element measured along the axis of rotation is in the range of 0.2 mm to 2 mm, specifically in the range of about 0.5 mm to 1.5 mm, and the length of the cutting head blank element measured in the direction of the axis of rotation is in the range of 0.2 mm to 15 mm, specifically in the range of about 2 mm to 10 mm.

[0038] According to a second aspect of the present invention, the above-mentioned object is solved by a cutting tool, such as an end mill, drill or engraving tool, in which at least one tool cutting edge extending across a plurality of fixedly interconnected cutting head blank elements is produced on a tool blank according to the first aspect of the present invention.

[0039] In such cutting tools, the tool cutting edge is preferably laser machined on the cutting head blank. By using the cutting head blank according to the invention, a long cutting head blank and therefore a long tool cutting edge can be realized. Naturally, such cutting tools exhibit all the advantages of the tool blank according to the invention described above.

[0040] In the context of this disclosure, the term cutting head blank element is used to refer to a cutting head blank element on which a tool cutting edge has not yet been generated, as well as a cutting head blank element on which a tool cutting edge has been generated. A cutting head blank on which a tool cutting edge has been generated is called a cutting head.

[0041] In an exemplary embodiment of the cutting tool, at least one tool cutting edge does not contact an abutment surface between the cutting head blank element of the first stack column and the cutting head blank element of the second stack column.

[0042] One or more tool cutting edges extend from the end of the cutting head connected to the tool shank to the terminal end of the cutting head. The abutment surfaces between the cutting head blank elements of the first stack column and the cutting head blank elements of the second stack column are aligned with the path of the tool cutting edges so that the tool cutting edges do not intersect with such abutment surfaces, thereby avoiding weak points in the tool cutting edges. Therefore, the joints are located in the non-cutting areas of the cutting tool.

[0043] Preferably, the tool cutting edge is arranged to be spaced a distance of at least 0.01 mm from the abutment surface between the cutting head blank element of the first stack column and the cutting head blank element of the second stack column.

[0044] According to a third aspect of the present invention, the above mentioned object is solved by a method for manufacturing a cutting head blank for a cutting tool such as an end mill, drill or engraving tool, the method comprising the steps of providing a plurality of cutting head blank elements, in particular made of a high hardness material such as a PCD blank, and fixedly connecting, preferably soldering, the plurality of cutting head blank elements to a tool shank such that the interconnected cutting head blank elements form a cutting head blank that is fixedly connected to the tool shank.

[0045] The cutting head blank elements can be stacked on top of each other in various stack configurations as already described for the tool blanks. The cutting head blank elements form a cutting head blank that is machined from at least one tool cutting edge. The tool cutting edge is preferably machined into the cutting head blank by a laser. Any shape can be stacked on top of each other in a stack configuration, as long as adjacent cutting head blank elements have a common abutment surface.

[0046] For example, a cylindrical shape or a ring shape can be cut from a PCD blank. Depending on the ring shape selected, a smaller cylinder is cut from a larger cylinder. A ring-shaped cut can be used for a first cutting tool or cutting head blank. A cylindrical cut can be used for a smaller second cutting tool or second cutting head blank.

[0047] In an exemplary embodiment of a method for manufacturing a cutting head blank, the step of fixedly connecting is performed by connecting cutting head blank elements to form a cutting head blank and then connecting the cutting head blank to a tool shank.

[0048] Such a process allows the cutting head blank to be produced spatially separated from the tool shank, with the cutting head blank only being connected to the tool shank once the cutting head blank has been produced.

[0049] In another exemplary embodiment of the method for manufacturing a cutting head blank, the step of fixedly connecting is performed by connecting individual cutting head blank elements one by one to the tool shank or to cutting head blank elements that are already connected to the tool shank.

[0050] This method allows the cutting head blank elements to be individually connected, for example with a precise fit onto pins on the tool shank, using the tool shank as a guide and aid for mounting.

[0051] According to a fourth aspect of the present invention, the above-mentioned object is solved by a method for manufacturing a cutting tool, such as an end mill, drill or engraving tool, comprising the steps of manufacturing a cutting head blank according to the third aspect of the present disclosure, and further comprising the step of generating at least one tool cutting edge on the cutting head blank across a plurality of cutting head blank elements.

[0052] Cutting head blank elements according to the present disclosure can be cut, for example by laser, from the following commercially available circular blanks: Elementsix PCD circular blank, Syndite, R70.0mm / T1.6mm, KT-DP-CMX850 Elementsix PCD round blanks, Syndite, CTB R743-36007CPL010, 180-200-2330-01, and CBN round blank from elementsix, Amborite, DBC50 R574-36008 002, 310-200-0353-01. [Brief explanation of the drawings]

[0053] Exemplary embodiments of the invention are described and explained in more detail below with reference to the accompanying drawings. [Figure 1] 1 shows a side view of a cutting tool according to the present invention; [Figure 2] 2 shows a cross-sectional view of the cutting tool 1 shown in FIG. 1 taken along the section AA shown in FIG. 1. [Figure 3] 1 shows a front view of a tool blank according to the invention, according to a first embodiment; [Figure 4] 4 shows a cross-sectional view of the tool blank shown in FIG. 3 taken along cross section BB shown in FIG. 3. [Figure 5] 3 and 4 taken along the cross section CC shown in FIG. 4. FIG. [Figure 6] Schematic diagram of the four tool cutting edges depicted in Fig. 5 in their developed form, plotted one above the other. [Figure 7] FIG. 6 is a perspective view of the tool blank shown in FIGS. 3 to 5, as viewed obliquely from the front. [Figure 8] 1 shows a front view of a tool blank according to the invention, according to a second embodiment; [Figure 9] 9 shows a cross-sectional view of the tool blank shown in FIG. 8 taken along section DD shown in FIG. 8. [Figure 10] 9A and 9B show two cross-sectional views of the tool blank shown in FIG. 9 along cross sections EE and FF shown in FIG. [Figure 11] 1 shows a cross-sectional view of a cutting tool according to the invention perpendicular to the axis of rotation R. [Figure 12] 10 shows a cross-sectional view of a tool blank according to the invention according to a fourth embodiment. [Figure 13] 10 shows a cross-sectional view of a tool blank according to the invention according to a fifth embodiment. [Figure 14] 10 shows a cross-sectional view of a tool blank according to the invention, according to a sixth embodiment. [Figure 15] 10 shows a cross-sectional view of a tool blank according to the invention according to a seventh embodiment. [Figure 16] 16 shows a cross-sectional view of the tool blank shown in FIG. 15 along cross section GG shown in FIG. 14. [Figure 17] FIG. 10 is a cross-sectional view of a tool blank according to the present invention, according to an eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0054] FIG. 1 shows a side view of a cutting tool 1 according to the present invention, according to a first embodiment. A cutting head 6 is connected to a tool shank 2 at a shank junction 11. During use, the cutting tool 1 rotates about a rotation axis R. The cutting head 6 is manufactured by generating a tool cutting edge 15 on a cutting head blank 3. Therefore, the cutting head blank 3 is no longer visible in FIG. 1 . The cutting head blank 3 is shown having already been further processed into the cutting head 6. The cutting head blank 3 is formed by a plurality of cutting head blank elements 5 stacked on top of each other. The cutting head blank elements 5 are stacked on top of each other in a stack-like structure. Adjacent cutting head blank elements 5 abut each other at abutment surfaces 7. Therefore, the cutting head blank elements 5 are no longer visible in FIG. 1 . The cutting head blank elements 5 are shown having already been further processed. In the present disclosure, the term cutting head blank element is also used to refer to cutting head blank elements on which a tool cutting edge has been generated.

[0055] Cutting head blank elements 5a, 5c, and 5d are exemplarily shown for cutting head blank element 5, and abutment surfaces 7b, 7c, and 7d are exemplarily shown for abutment surface 7. Cutting head blank element 5a abuts cutting head blank element 5c at abutment surface 7b. Furthermore, cutting head blank element 5a abuts cutting head blank element 5d at abutment surface 7c. Cutting head blank element 5c and cutting head blank element 5d abut against each other at abutment surface 7d.

[0056] A plurality of tool cutting edges 15 extend across the plurality of cutting head blank elements 5 . A plurality of cutting head blank elements 5, which are fixedly connected to one another, are arranged in the direction of and around the axis of rotation R.

[0057] The contact surfaces 7b and 7c are not perpendicular to the rotation axis R but are inclined at an angle α with respect to the rotation axis R. Figure 2 shows a cross-sectional view of the cutting tool 1 shown in Figure 1 along the section AA. The cross-sectional plane extends through the abutment surfaces 7b and 7c. The cross-sectional plane is therefore arranged at an angle α to the rotation axis R. The abutment surfaces 7b and 7c abut and are connected to each other at the abutment surface 7a. Two tool cutting edges 15 are generated on both the outer periphery of the cutting head blank element 5a and the outer periphery of the cutting head blank element 5b.

[0058] FIG. 3 shows a front view of a tool blank 30 according to the present invention, according to a first embodiment. The tool cutting edge 15 has not yet been generated on the cutting head blank 3. A pin 9 is arranged on the tool shank 2. Two cutting head blank elements 5e, 5f are arranged one above the other on the pin 9. The cutting head blank elements 5e and 5f abut and are connected together at abutment surfaces 7e and 7f. In addition, the cutting head blank elements 5e, 5f are connected to the pin 9 of the tool shank 2 at a shank junction 11.

[0059] Figure 4 is a cross-sectional view of the tool blank 30 shown in Figure 3 along cross section BB shown in Figure 3. A total of seven cutting head blank elements 5e, 5f, 5g, 5h, 5i, 5j, 5k are arranged on the pin 9 of the tool shank 2. The two cutting head blank elements 5e, 5f arranged to the right of the pin 9 are the cutting head blank elements 5e, 5f shown in Figure 3.

[0060] The cutting head blank elements 5e, 5f, 5g, 5h, 5i, 5j, and 5k abut against and are connected to each other at abutment surfaces 7g, 7h, 7i, 7j, and 7k. The cutting head blank elements 5e, 5f, 5g, 5h, 5i, 5j, and 5k are connected to the tool shank 2 or to pins 9 of the tool shank 2 at shank joints 11. The cutting head blank elements 5e, 5i, 5j, and 5k are stacked on each other in the direction of the rotation axis R in the form of a first stack column 12a, and the cutting head blank elements 5f, 5g, and 5h are stacked on each other in the direction of the rotation axis R in the form of a second stack column 12b. The first stack column 12a and the second stack column 12b are arranged one above the other. The first stack column 12a and the second stack column 12b are arranged parallel to each other.

[0061] The cutting head blank elements 5e, 5i, 5j, 5k of the first stack column 12a and the cutting head blank elements 5f, 5g, 5h of the second stack column 12b are arranged offset from one another in the direction of the rotation axis R. Thus, there is an offset V between the abutment surfaces 7g, 7h, 7i of the first stack column 12a and the abutment surfaces 7j, 7k of the second stack column 12b in the direction of the rotation axis R. For example, FIG. 4 shows the offset V between the abutment surfaces 7j and 7h.

[0062] FIG. 5 is a cross-sectional view of the tool blank 30 shown in FIGS. 3 and 4 along the cross section CC shown in FIG. 4. The cutting head blank element 5g having the shank joint 11 is attached to the pin 9 from below. In the upper half of the pin 9, the cross section extends just through the abutment surface 7h between the cutting head blank element 5j and the cutting head blank element 5k. Thus, the end face of the cutting head blank element 5j is shown. The cutting head blank element 5j and the cutting head blank element 5g abut against each other at the abutment surfaces 7l and 7m and are connected to each other at the abutment surfaces 7l and 7m. Furthermore, four tool cutting edges 15c to 15f are shown. The depiction of the tool cutting edges 15c to 15f corresponds to a front view of the tool blank and not a cross-sectional view along the cross section CC. The tool cutting edges 15c to 15f are shown in FIG. 5 merely as an example. Furthermore, the tool cutting edges 15c to 15f are not shown in FIGS. 3, 4, and 7, which show the first embodiment.

[0063] Figure 6 shows a schematic diagram of the four tool cutting edges 15 shown in Figure 5. The four tool cutting edges 15c to 15f arranged around the rotation axis R of the cutting head blank are shown in a developed form from left to right in Figure 6 and are plotted side by side. The tool cutting length L shown in Figure 6 S are the lengths of the tool cutting edges 15c to 15f from the end of the cutting head 6 connected to the tool shank 2 to the terminal end of the cutting head 6. The tool cutting lengths L of the four tool cutting edges 15c to 15f S are of equal length.

[0064] Furthermore, FIG. 6 shows, for each of the four tool cutting edges 15c-15f depicted in expanded form, the abutment surface 7 along the length of the tool cutting edge 15c-15f, i.e., the point / length to which the tool cutting edge extends from one cutting head blank element 5 to another. The abutment surface 5 of tool cutting edge 15c and the abutment surface 5 of tool cutting edge 15e are located at equal lengths. The abutment surfaces 5 of tool cutting edges 15d and 15f are located at equal lengths. However, the abutment surfaces 5 of tool cutting edges 15c and 15e are located at different lengths along the tool cutting edge compared to tool cutting edges 15d and 15f. Therefore, the abutment surfaces 5 of tool cutting edges 15c and 15e are offset from the abutment surfaces 5 of tool cutting edges 15d and 15f.

[0065] FIG. 7 is a perspective view of the tool blank 30 shown in FIGS. 3 to 5, seen from an oblique front. The cutting head blank elements 5e, 5i, 5j, and 5k extend in the first stack column 12a in the direction of the rotation axis R, parallel to the second stack column 12b formed by the cutting head blank elements 5f, 5g, and 5h. The cutting head blank elements 5e, 5f, 5g, 5h, 5i, 5j, and 5k are stacked on top of each other in the form of a stack structure 6. They abut each other at abutment surfaces 7, of which abutment surfaces 7g, 7h, and 7j are exemplarily shown. Furthermore, the abutment surfaces of the cutting head blank elements abutting each other in a direction perpendicular to the rotation axis R are exemplarily shown as abutment surfaces 7e and 7f.

[0066] Due to the cutting head blank elements 5e, 5f, 5g, 5h, 5i, 5j, 5k being arranged offset from one another in the direction of the rotation axis R, for example the abutment surface 7j is not in direct contact with the abutment surfaces 7g or 7h.

[0067] FIG. 8 shows a front view of a tool blank 30 according to the invention, according to a second embodiment. A pin 9 is attached to the tool shank 2. Two cutting head blank elements 5l, 5m are arranged one above the other on the pin 9. The cutting head blank elements 5l and 5m abut and are connected together at abutment surfaces 7n and 7o. Furthermore, the cutting head blank elements 5l and 5m are connected to the pin 9 of the tool shank 2 at a shank junction 11.

[0068] 9 is a cross-sectional view of the tool blank 30 shown in FIG. 8 along the cross section DD shown in FIG. 8. The pin 9 of the tool shank 2 extends in the direction of the rotation axis R into a bore 8 that passes through the six cutting head blank elements 5l, 5m, 5n, 5o, 5p, 5q. The cutting head blank elements 5l, 5m, 5n, 5o, 5p, 5q abut against each other at abutment surfaces 7, of which abutment surfaces 7p, 7q are exemplarily shown in FIG. 9. At a shank junction 11, the cutting head blank elements 5l, 5m, 5n, 5o, 5p, 5q are connected to the tool shank 2 or to the pin 9 of the tool shank 2. The cutting head blank elements 5l, 5m, 5n, 5o, 5p, 5q are arranged in the direction of the rotation axis R without an offset V.

[0069] Figure 10 shows two cross-sectional views of the tool blank 30 shown in Figure 9, taken along cross sections EE and FF shown in Figure 9. Cross section EE shows the end faces of cutting head blank elements 5o, 5p. Cross section EE shows the end faces of cutting head blank elements 5n, 5q.

[0070] In cross section EE shown on the left, the abutment surfaces 7r and 7s between the two cutting head blank elements 5o and 5p can be seen. Additionally, the abutment surfaces 7t and 7u between the two cutting head blank elements 5n and 5q are shown in dashed lines, as shown in cross section FF shown on the right. Conversely, in cross section FF shown on the right, the abutment surfaces 7r and 7s shown in cross section EE are shown in dashed lines. The abutment surfaces 7r and 7s are arranged at a rotational offset angle β relative to the abutment surfaces 7t and 7u.

[0071] FIG. 11 is a cross-sectional view of another exemplary embodiment of a cutting tool perpendicular to the rotation axis R. Two cutting head blank elements 5 are connected to each other at two abutment surfaces 7v, 7w. Furthermore, the cutting head blank elements 5 are connected to a pin 9 of the tool shank 2 at a pin joint 11. Two tool cutting edges 15 are arranged on the outer periphery of each cutting head blank element 5, of which tool cutting edges 15a and 15b are shown by way of example. The abutment surface 7v extends between the tool cutting edges 15a and 15b. In addition, an area B is shown between the tool cutting edges 15a and 15b and spaced apart from the tool cutting edges 15a and 15b. This area identifies the area in which the abutment surface 7v is arranged. The same applies to the areas between the other tool cutting edges not shown in FIG. 11. Therefore, the joints in these areas are also arranged at a certain distance from the tool cutting edges.

[0072] 12 to 17 show further exemplary embodiments of tool blanks according to the present invention. 12 shows a cross-sectional view of the fourth exemplary embodiment. In FIG. 12, the cutting head blank 3 is formed by a stack structure of three cutting head blank elements 5. The cutting head blank elements 5 have a height x1 measured in the direction of the rotation axis R. The cutting head blank 3 has a length x2 measured in the direction of the rotation axis R.

[0073] Fig. 13 shows a cross-sectional view of a fifth exemplary embodiment. In Fig. 13, the cutting head blank 3 is formed by a stack structure of ten cutting head blank elements 5. Nine cutting head blank elements 5 are attached to pins 9 of the tool shank 2 from above and below, respectively, and the joints 7 of these nine cutting head blank elements 5 have an offset V in the direction of the rotation axis R. At the right end, an additional cutting head blank element 5 is attached as a terminal end to the end face of the pin 9. Such an embodiment is particularly suitable for end cut tools and forming tools.

[0074] 14 shows a cross-sectional view of the sixth exemplary embodiment. In FIG. 14, the cutting head blank 3 is formed by a stack structure of six cutting head blank elements 5. The abutment surfaces 7 between the cutting head blank elements 5 are not perpendicular to the rotation axis R, but are arranged at an angle α to the rotation axis R.

[0075] 15 shows a cross-sectional view of an exemplary seventh embodiment having five cutting head blank elements 5 arranged on a pin 9. The abutment surface 7x between the cutting head blank element 5r and the cutting head blank element 5s is not perpendicular to the rotation axis R.

[0076] FIG. 16 shows a cross-sectional view of the tool blank shown in FIG. 15 along section GG shown in FIG. Figure 17 is a cross-sectional view of a tool blank according to the invention, according to an eighth embodiment. In Figure 17, the cutting head blank 3 is formed by a stack of six cutting head blank elements 5. The abutment surfaces 7 between the cutting head blank elements 5 are not perpendicular to the rotation axis R, but are arranged at an angle α obliquely to the rotation axis R. In contrast to the embodiment shown in Figure 14, the abutment surfaces are additionally angled so that they extend symmetrically outward relative to the rotation axis R, as seen in the cross-sectional view from the rotation axis R. The abutment surfaces 7 therefore form tips in the region of the rotation axis R that are form-fittingly connected with opposing recesses of adjacent cutting head blank elements 5.

[0077] Additionally, pins and bores may be provided in the cutting head blank element 5, as shown in Figure 15. Such pins and bores are not shown in Figure 17. [Industrial Applicability]

[0078] The cutting tool according to the present invention makes it possible to produce relatively large cutting head blanks or large cutting heads with long tool cutting edges from small cutting head blank elements. Such large cutting tools do not incur a disproportionate increase in cost with volume, as is known for example for PCD blanks. Therefore, cutting tools with high wear resistance, excellent processing reliability, and long tool life, as well as cutting tools with large cutting heads, can be produced at lower cost using the present invention.

[0079] 7 and 1, the manufacturing process for the cutting tool will now be described in detail. The cutting head blank elements 5 are attached one after another to the pins 9 of the tool shank 2 shown in FIG. 7 . For this purpose, for example, the cutting head blank element 5i is first attached to the pin 9 so that it is connected to the tool shank 2 at the shank joint 11. The shank joint 11 refers to both the connection to the cross section of the tool shank 2 extending perpendicular to the rotation axis and the connection to the pin 9. Next, other cutting head blank elements 5 are attached to the pin 9. The cutting head blank elements 5 are connected to each other at their abutment surfaces 7, for example, by solder connections. In this way, the cutting head blank 3 is produced as shown in FIG. 7 . The cutting head blank is made up of a total of seven cutting head blank elements 5. At least one tool cutting edge 15 is then produced on this cutting head blank 3. This produces a cutting head 6, such as the one depicted in FIG. 1 . The tool cutting edge 15 extends across multiple cutting head blank elements 5. [Explanation of symbols]

[0080] 1 cutting tools 2 Tool shank 3 Cutting head blank 5, 5a~5q Cutting head blank elements 6 Cutting head 7, 7a~7u contact surface 8 bore, through hole 9-pin 11 Shank joint 12, 12a, 12b Stack Column 15 Tool cutting edge 30 Tool Blanks R rotation axis A Tilt angle β rotation offset angle V Offset x1 Cutting head blank height x2 Cutting head length L1 Height of element cylinder, height of element semi-cylinder L2 Height of blank cylinder

Claims

1. A tool blank (30) having an axis of rotation (R) for a cutting tool (1), such as an end mill, a drill or a carving tool, a tool shank (2) configured to be received in a rotary tool holder of a processing machine; a cutting head blank (3) fixedly connected to the tool shank (2), The cutting head blank (3) comprises a plurality of cutting head blank elements (5), the cutting head blank elements (5) being fixedly connected to each other by being soldered to each other and made of a high hardness material; A tool blank (30) in which a plurality of the cutting head blank elements (5) are stacked on one another in the form of a plurality of stack columns (12) extending in the direction of the rotation axis (R) of the tool blank (30) and arranged adjacent to one another in the circumferential direction of the rotation axis (R).

2. 2. The tool blank (30) according to claim 1, wherein a first cutting head blank element (5) in one stack column (12a) is arranged offset in the direction of the rotation axis (R) relative to an adjacent second cutting head blank element (5) in another stack column (12b).

3. 3. The tool blank (30) according to claim 2, wherein the offset (V) is in the range of 20% to 80% of the height of the first cutting head blank element (5) or the second cutting head blank element (5) measured in the direction of the rotation axis.

4. 4. The tool blank (30) according to claim 1, wherein a third cutting head blank element (5) in any stack column (12a) is arranged at a rotational offset angle (β) about the rotation axis (R) relative to an adjacent fourth cutting head blank element (5) in the same stack column (12a).

5. The tool blank (30) of claim 4, wherein the rotational offset angle (β) is in the range of 10° to 80°.

6. A tool blank (30) having an axis of rotation (R) for a cutting tool (1), such as an end mill, a drill or a carving tool, a tool shank (2) configured to be received in a rotary tool holder of a processing machine; a cutting head blank (3) fixedly connected to the tool shank (2), The cutting head blank (3) comprises a plurality of cutting head blank elements (5), the cutting head blank elements (5) being fixedly connected to each other by being soldered to each other and made of a high hardness material; At least one abutment surface (7) between two cutting head blank elements (5) abutting each other in the direction of the rotation axis (R) has an inclination angle (α) relative to the rotation axis (R) at least locally in the range of 75° to 89°.

7. The tool blank (30) according to any one of claims 1 to 6, wherein the tool blank (30) has two stack columns, and the plurality of cutting head blank elements (5) have a semi-cylindrical shape and are arranged so that the cutting head blank (3) forms a cylindrical shape.

8. a plurality of said cutting head blank elements (5) are arranged in the form of a single stack column (12) and have a cylindrical shape; 7. The tool blank (30) according to claim 6, wherein adjacent cutting head blank elements (5) in the stack column (12) abut against each other at abutment surfaces (7) and are connected to each other at the abutment surfaces (7).

9. 9. A tool blank (30) according to any one of claims 1 to 8, wherein the tool shank (2) has a pin (9) protruding from an end face to which the cutting head blank (3) is attached, and at least one of the cutting head blank elements (5) is formed with a bore (8) or a recess, whereby the at least one cutting head blank element (5) having the bore or recess is attached in a form-fitting manner to the pin (9) of the tool shank.

10. said cutting head blank element (5) having a height (x1), measured in the direction of said rotation axis, in the range of 0.2 mm to 2 mm; The tool blank (30) according to any one of the preceding claims, wherein the cutting head blank (3) has a length (x2), measured in the direction of the rotation axis, in the range of 0.2 mm to 15 mm.

11. A tool blank (30) according to any one of claims 1 to 10, wherein the hard material is polycrystalline diamond.

12. A cutting tool (1), such as an end mill, drill or engraving tool, in which at least one tool cutting edge (15) extending across a plurality of fixedly interconnected cutting head blank elements (5) is produced on a tool blank (30) according to any one of claims 1 to 11.

13. 13. Cutting tool (1) according to claim 12, wherein at least one tool cutting edge (15) does not contact an abutment surface (7) between cutting head blank elements (5) of different stack columns (7).

14. A method for manufacturing a cutting head blank (30) having an axis of rotation (R) for a cutting tool (1), such as an end mill, a drill or a carving tool, comprising at least the steps of: providing a plurality of prefabricated cutting head blank elements (5) made of a high hardness material; and fixedly connecting a plurality of said cutting head blank elements (5) to each other and to said tool shank (2) by soldering, such that said interconnected cutting head blank elements (5) form a cutting head blank (3) that is fixedly connected to said tool shank (2); The cutting head blank elements (5) are stacked on one another in the form of a plurality of stack columns (12) extending in the direction of the rotation axis (R) of the cutting head blank (30) and arranged adjacent to one another in the circumferential direction of the rotation axis (R).

15. A method for manufacturing a cutting head blank (30) having an axis of rotation (R) for a cutting tool (1), such as an end mill, a drill or a carving tool, comprising at least the steps of: providing a plurality of prefabricated cutting head blank elements (5) made of a high hardness material; and fixedly connecting a plurality of said cutting head blank elements (5) to each other and to said tool shank (2) by soldering, such that said interconnected cutting head blank elements (5) form a cutting head blank (3) that is fixedly connected to said tool shank (2); wherein at least one abutment surface (7) between two cutting head blank elements (5) abutting each other in the direction of said rotation axis (R) has an inclination angle (α) relative to said rotation axis (R) at least locally in the range of 75° to 89°.

16. 16. The method according to claim 14 or 15, wherein the step of fixedly connecting is performed by connecting the cutting head blank elements (5) to form the cutting head blank (3) and then connecting the cutting head blank (3) to the tool shank (2).

17. 16. The method according to claim 14 or 15, wherein the step of fixedly connecting is performed by connecting the individual cutting head blank elements (5) one by one to the tool shank (2) or to cutting head blank elements (5) already connected to the tool shank (2).

18. A method for manufacturing a cutting tool (1), such as an end mill, drill or engraving tool, comprising at least the steps of: Providing a cutting head blank (3) according to any one of claims 14 to 17; generating at least one tool cutting edge (15) in said cutting head blank (3) across a plurality of cutting head blank elements (5).

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