MILLING TOOL AND METHOD FOR PRODUCING A CUTTING PART OF A MILLING TOOL

Description

[0001] The present invention relates to a milling tool and a method for manufacturing a cutting part of a milling tool.

[0002] In the machining of materials by milling, milling tools are frequently used in which the cutting edges that engage with the workpiece are formed on inserts made of a particularly hard and wear-resistant material, such as PCD (polycrystalline diamond), CBN (cubic boron nitride), cemented carbide, cermet, or a cutting ceramic. These inserts are arranged on a cutting section of a tool body, which is usually made of a tougher material, such as tool steel. Depending on the material of the inserts and the application of the milling tool, the inserts can be, for example, detachably fastened to seats in the cutting section of the tool body using fastening screws, or they can be bonded to seats in the cutting section of the tool body, for example, by brazing.

[0003] In applications of milling tools where relatively long cutting lengths are required, it is known to use end mills (often also referred to as hedgehog cutters or "porcupine cutters") in which several cutting inserts are arranged one after the other in the axial direction along mostly helical chip flutes, which then together form the usable cutting edge.

[0004] WO 98 / 07541 A1 describes a face mill in which a plurality of cutting inserts are arranged along a plurality of flutes on a cutting portion of a tool holder such that the main cutting edges overlap along the flutes, effectively providing a continuous cutting edge. In the described face mill, the flutes run at a negative helical angle, and the main cutting edges projecting radially from the tool holder each extend at a negative axial rake angle. This design allows the seats for the cutting inserts to be machined even with relatively small diameters of the milling tool, without compromising the overlap of the main cutting edges or reducing the number of flutes distributed around the circumference with the cutting inserts arranged along them.However, this design has the disadvantage that, particularly when milling steps or pockets in the workpiece, where the end cutting edges provided by the end-facing cutting inserts also engage with the workpiece, a smooth cut cannot be achieved and the chips are directed towards the workpiece surface created by the end cutting edges.

[0005] US 7,134,811 B2 discloses a milling tool according to the preamble of claim 1.

[0006] The object of the present invention is to provide an improved milling tool and an improved method for manufacturing a cutting part of a milling tool, which achieve a high number of chip flutes with effectively continuous cutting edges formed along these flutes, even for smaller tool diameters, and at the same time enable a smooth cut for milling steps or pockets, in which the generated chips are reliably removed from the workpiece surface.

[0007] The problem is solved by a milling tool according to claim 1. Advantageous further developments are specified in the dependent claims.

[0008] Since the main cutting edges extend at a positive axial rake angle, a very smooth cut is achieved during milling, which is also very well suited for, for example, aluminum castings. The chips produced are reliably guided away from the surface, even when milling steps or pockets. Because the flutes and seats are additively manufactured, the positive axial rake angles of the main cutting edges can be achieved even with relatively small diameter milling tools, without sacrificing the overlap of the operational main cutting edges or reducing the number of flutes distributed around the circumference with the cutting inserts arranged along them. Furthermore, additive manufacturing allows for efficient internal coolant supply to all cutting inserts, even for milling tools with relatively small diameters.In contrast, conventional machining of the flutes and seats to form seats that provide continuous effective cutting edges with a positive axial rake angle along the flutes and simultaneously have three flat contact surfaces to support three sides of the cutting inserts would require at least a reduction in the number of flutes with cutting inserts arranged along them, due to the necessary spatial accessibility for the machining tools and their cutting geometries, especially with smaller diameter milling tools. Furthermore, conventionally machined milling tools are also geometrically very limited in the design of internal coolant channels.The inventive design of the flutes at a negative helical angle enables the successive additive manufacturing of the flutes and the seats in a build direction towards the end face of the milling tool, without the need to first form additional support structures during additive manufacturing that would then have to be mechanically removed. Furthermore, this method also allows for the direct additive manufacturing of the end-face seats with three flat contact surfaces for the cutting inserts. The flutes can, for example, be uniformly distributed around the circumference of the carrier body, i.e., with uniform angular intervals to each other. However, it is also preferably possible for the flutes, with the cutting inserts arranged along them, to be distributed around the circumference of the carrier body at non-uniform angular intervals, which has a positive effect on the smooth running of the milling tool. The flutes can, for example,All flutes can be formed with the same negative helical angle; however, it is also possible for the flutes to have different negative helical angles relative to each other. The negative helical angle of each flute can, for example, be constant along the axial extent of the flute. It is also possible, for example, for the magnitude of the helical angle to change along the axial extent of the respective flute. The main cutting edges of the inserts can, for example, all have the same positive axial rake angle. However, it is also possible, for example, for the axial rake angle to differ between the main cutting edges assigned to different flutes, or for the main cutting edges of inserts arranged along the same flute to have different positive axial rake angles. Furthermore, the magnitude of the rake angle can also change along a single main cutting edge.The main cutting edges preferably extend along a common cylindrical surface. The flutes and seats can be additively manufactured, for example, using SLS (selective laser sintering) or SLM (selective laser melting) processes, preferably from a metallic starting powder, such as steel powder. The entire milling tool can, for example, be additively manufactured. In this case, the cutting section, on which the flutes and seats are formed, and a mounting section, which has a mounting interface for connecting to a machine-side tool holder, are monolithically additively manufactured. However, it is also possible, for example, that only the cutting section, on which the flutes and seats are formed, is additively manufactured and that this cutting section is connected to a conventionally manufactured mounting section, preferably by a material bond.

[0009] In a milling tool designed for clockwise rotation, as described in the following exemplary embodiments, a negative helix angle corresponds to the direction of a left-handed helix and a positive axial rake angle corresponds to the direction of a right-handed helix. Similarly, in a milling tool designed for counterclockwise rotation, a negative helix angle corresponds to the direction of a right-handed helix and a positive axial rake angle corresponds to the direction of a left-handed helix.

[0010] The tool body incorporates an internal coolant supply system for delivering coolant to the flutes. This system features multiple coolant channels with coolant outlets directed towards the cutting edges. This allows for highly targeted coolant delivery to the cutting edges that engage with the material being machined. Because at least the cutting portion of the milling tool, which includes the flutes and cutting edges, is additively manufactured, the coolant channels can be precisely designed with regard to their path and cross-sectional shape to achieve the desired coolant distribution.

[0011] At least some of the coolant channels have a curved path in a predetermined coolant flow direction. This minimizes pressure drops caused by flow resistance and allows the coolant to be directed more precisely to the cutting inserts. The curved path in the coolant flow direction—that is, the direction in which the coolant flows during operation—is made possible by the additive manufacturing of the cutting element.

[0012] The curved shape of part of the coolant channels causes the coolant to be deflected during operation.

[0013] The coolant channels are of relatively small diameter and extend from coolant distribution cavities, which have a larger diameter.

[0014] According to a further development, several coolant outlets are provided in each of the clamping grooves. This allows for particularly targeted and efficient cooling of the cutting inserts. Separate coolant outlets can be provided for each cutting insert, for example. However, to minimize flow resistance, shared coolant outlets for multiple cutting inserts can also be used.

[0015] According to a further development, the seats along the clamping grooves are arranged such that the cutting circles of the main cutting edges of the cutting inserts located therein overlap in the axial direction. In other words, the main cutting edges, which are arranged at different axial positions along the respective clamping groove, although offset from each other circumferentially, form a continuous, effective cutting edge without gaps due to the axial overlap.

[0016] The main cutting edges are followed by rake faces running at a positive radial rake angle. The implementation of positive radial rake angles also contributes to a smooth cut, and the generated chips are reliably guided away from the workpiece surface machined by the respective main cutting edge. The design of the seats in such a way that positive radial rake angles are possible without having to reduce the number of chip flutes with their corresponding cutting inserts for smaller milling tool diameters is made possible by the additive manufacturing of the cutting edge component.

[0017] According to a further development, the carrier body has a substantially ring-shaped or hollow cylindrical cutting section, on the outer circumference of which the flutes and seats are formed, and a mounting section with a mounting interface for connection to a machine-side tool holder. The cutting section and the mounting section can be additively manufactured monolithically; however, it is preferably possible that only the cutting section is additively manufactured and connected to a conventionally machined mounting section.

[0018] According to further training, the fastening section is manufactured using material removal, and the cutting edge and the fastening section are bonded together by a material bond. In this case, the milling tool as a whole can be manufactured cost-effectively, and high stability is ensured by the material bond.

[0019] According to a further development process, the cutting inserts are bonded to the seats using a material-bonded connection. The cutting inserts can be attached to the seats, in particular, by soldering. In this case, no mechanical machining of the additively manufactured seats is necessary before attaching the cutting inserts. Preferably, at least the cutting edges of the inserts can be made of an ultra-hard material such as PCD (polycrystalline diamond), CBN (cubic boron nitride), or a cutting ceramic. However, it is also possible to manufacture the cutting inserts from, for example, cemented carbide, cermet, or a cutting ceramic. Instead of a material-bonded connection, the cutting inserts can also be attached to the seats using fastening screws.

[0020] If the seats have at least three flat contact surfaces to support the cutting inserts from different sides, the cutting inserts can be positioned and attached to the seats with particular precision.

[0021] The problem is also solved by a method for manufacturing a cutting part of a milling tool according to claim 8. Advantageous embodiments are specified in the dependent claims.

[0022] The described process enables a smooth cut with the milling tool, whereby even with small diameters of the milling tool, the number of clamping grooves with seats arranged along them does not need to be adversely reduced, and continuous effective cutting edges can be maintained along the respective clamping grooves. Furthermore, efficient coolant supply to all seats can be advantageously designed, the assembly can be built without additional support structures, and even end-face seats for cutting inserts can be additively formed with three contact surfaces for three sides of the respective cutting inserts. In this process, for example, only the cutting section, which has the clamping grooves and the seats arranged along them for cutting inserts, can be additively manufactured and then, for example,The conventionally manufactured mounting section, which has a mounting interface for connection to a machine-side tool holder, is joined to the carrier body of the milling tool. Alternatively, it is also possible, for example, to additively manufacture the entire carrier body, i.e., the cutting part and the mounting section.

[0023] According to a further development process, multiple seats for receiving cutting inserts are formed on one end face of the cutting part such that they protrude axially from the end face. The cutting part is then built up successively, layer by layer, from a shank side facing away from the end face towards the end face. In this case, the cutting part can be built up without additional support structures that would subsequently need to be mechanically removed. Furthermore, the seats on the end face of the cutting part can be formed with three flat contact surfaces each for three sides of the cutting inserts during additive manufacturing. The milling tool can then be designed as a cylindrical end mill, which can also be used to machine steps or pockets in the workpiece.

[0024] In the additive manufacturing process, an internal coolant supply system is created to deliver coolant to the flutes. This system features multiple coolant channels with coolant outlets extending towards the seats. By optimizing the shape of the coolant channels during additive manufacturing, flow resistance and pressure losses within the internal coolant supply system can be minimized.

[0025] The coolant channels are designed so that they have a curved path, at least in some areas. This allows the coolant to be directed more precisely towards the cutting insert seats, and flow resistance in the internal coolant supply can be efficiently reduced.

[0026] The coolant channels are further designed in such a way that they have a curved shape, at least in some areas, so that the coolant is deflected during operation.

[0027] Furthermore, coolant distribution cavities are formed, with the coolant channels having relatively small diameters and extending from the coolant distribution cavities, which have a larger diameter.

[0028] According to a further development process, multiple coolant outlets are formed in each of the clamping grooves. This ensures a particularly efficient and targeted supply of coolant to the cutting inserts. Separate coolant outlets can be provided for each seat or the cutting insert attached to it. Alternatively, shared coolant outlets can be provided for several seats. Due to additive manufacturing, the shape of the coolant channels and outlets can be easily designed to optimize coolant distribution.

[0029] According to a further training course, the seats are designed with at least three flat contact surfaces each to support the cutting inserts from three different sides. In this case, the cutting inserts can be positioned on the seats particularly reliably and precisely, without requiring any additional mechanical processing of the seats.

[0030] According to further training, the process includes the step of joining the cutting edge to a separately formed mounting section, which has a mounting interface for connection to a machine-side tool holder. In this case, the mounting section can be manufactured quickly and cost-effectively using a conventional machining process. The milling tool produced by this material-bonded joining exhibits high stability. This material-bonded joining can be achieved, in particular, by welding or brazing.

[0031] Further advantages and expediencies of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying figures.

[0032] The figures show: Fig. 1: a schematic perspective view of a milling tool according to a first embodiment; Fig. 2: a schematic end view of the milling tool made of Fig. 1 Fig. 3: a schematic perspective view of the carrier body of the milling tool; Fig. 4: a schematic perspective view of the cutting part of the milling tool according to the first embodiment; Fig. 5: a schematic exploded view of the milling tool with a view perpendicular to the longitudinal axis of the milling tool; Fig. 6: a schematic sectional view of the cutting part in a plane perpendicular to the longitudinal axis; Fig. 7: an enlarged side view of the cutting part in the area of ​​its end face; Fig. 8: a side view of the milling tool according to the first embodiment; Fig. 9: a schematic perspective view of a milling tool according to a second embodiment; Fig. 10: a schematic perspective view of a milling tool according to a third embodiment according to the invention; Fig. 11: a schematic side view of the milling tool according to the third embodiment; Fig.Fig. 12: a schematic detail view of the internal coolant supply in the milling tool according to the third embodiment; and Fig. 13: a schematic sectional view in a plane perpendicular to the longitudinal axis of the milling tool according to the third embodiment. FIRST VERSION

[0033] A first embodiment of a milling tool 100 is described below with reference to the Fig. 1 bis Fig. 8 described.

[0034] As in Fig. 1 As can be seen, the milling tool 100 according to the first embodiment is designed as a cylindrical end mill or hedgehog cutter with end cutting edges. The illustrated milling tool 100 is designed as a right-hand cutting tool, the predetermined direction of rotation R of which is Fig. 8 is shown schematically.

[0035] The milling tool 100 has a carrier body 1 extending along a longitudinal axis L that corresponds to the axis of rotation of the milling tool 100 during operation. The carrier body 1 can, for example, be made of tool steel. The carrier body 1 has a cutting section 2 on which a plurality of flutes 21 are formed, and a mounting section 3, which is provided with a mounting interface 31 for attachment to a machine-side fixture of a machine tool. Although in the specific embodiment shown, a so-called HSK interface is used as an example ( H ohl s chaft kAlthough the first embodiment (egel interface) is shown as the mounting interface 31, other configurations of the mounting interface 31 are also possible, such as other interfaces for milling tools available on the market. In the first embodiment, the cutting part 2 and the mounting section 3 are separately manufactured components that were subsequently joined together, in particular by a material bond.

[0036] The flutes 21 are formed on the cutting part 2 such that they extend to the end face 20 of the cutting part 2. In the illustrated embodiment, a total of six flutes 21 are formed, distributed around the circumference of the cutting part 2. However, more than six or fewer than six flutes 21 can also be formed on the cutting part 2; in particular, fewer flutes 21 can be provided for smaller tool diameters of the milling tool 100, and more flutes 21 for larger tool diameters of the milling tool 100. The flutes 21 can, for example, be arranged at uniform angular intervals around the circumference of the cutting part 2, i.e., with six flutes, each flute can be offset from the others by 60° (= 360° / 6).Preferably, however, the flutes 21 are arranged unequally around the circumference of the cutting edge 2, i.e., at different angular intervals, in order to reduce vibrations during operation of the milling tool 100. As shown particularly in the end view of . Fig. 2 As can be seen, the clamping grooves 21 in the illustrated embodiment are unevenly distributed around the circumference. The clamping grooves 21 extend between webs 22 and are recessed relative to the outer circumference of the cutting part 2.

[0037] Along the clamping grooves 21, seats 23, 23a are formed, each designed to receive a cutting insert 4, 4a. The seats 23, 23a are, for example, located in the Fig. 3 und Fig. 4 to be seen, in which the carrier body 1 or the cutting part 2 is shown without the cutting inserts 4, 4a arranged on it.

[0038] In the specific embodiment shown, seven seats 23, 23a for cutting inserts 4, 4a are formed along each clamping groove 21, as shown in particular in the Fig. 4 and Fig. 8 as can be seen. Depending on the required axial length of the cutting part 2, however, more than seven or fewer than seven seats 23, 23a can be formed along the clamping grooves 21. The seats 23, 23a are designed such that the cutting inserts 4, 4a arranged on them each project beyond the outer circumference of the cutting part 2 with a main cutting edge 41. In this embodiment, the main cutting edges 41 of the cutting inserts 4 extend along a common enveloping cylindrical surface. The seats 23a formed at the ends are further designed such that the cutting inserts 4a attached to them also each project axially from the cutting part 2 with a front cutting edge 42. The front cutting edges 42 extend essentially in a plane perpendicular to the longitudinal axis L of the cutting part 2. However, the front cutting edges 42 can, for example,The seats 23, and in particular the seats 23a arranged at the end face, are designed to extend slightly towards the fastening section 3 with increasing distance from the associated main cutting edge 41, i.e., to be slightly recessed inwards. The seats 23 are designed such that they each have three flat contact surfaces 30 for supporting three different sides of the cutting inserts 4, 4a, as shown in particular in [reference]. Fig. 4 can be seen.

[0039] Seats 23, 23a are configured such that the cutting inserts 4, 4a are arranged in a so-called radial arrangement on the cutting part 2, i.e., that the principal plane of extension of the cutting inserts 4, 4a extends substantially in a radial direction. However, the cutting inserts 4, 4a are arranged at a slight tilt relative to an orientation exactly in the radial direction, as will be described in more detail below.

[0040] The main cutting edges 41 of the cutting inserts 4, 4a, which are arranged along the same flute 21, are arranged in such a staggered manner that they are offset from each other with respect to the circumferential direction, but overlap with respect to the axial direction of the cutting section 2, so that the main cutting edges 41 arranged along the respective flute 21 together form an effectively functioning continuous circumferential cutting edge. In other words, the cutting circles of the main cutting edges 41 of the cutting inserts 4, 4a, which are arranged along a common flute 21, overlap in the axial direction with respect to the longitudinal axis L.

[0041] In the specific example shown, the cutting inserts 4, 4a are bonded to their respective seats 23, 23a, e.g., by soldering. In this case, the rake faces 43 and the main cutting edges 41 and end cutting edges 42 extending along them of the cutting inserts 4, 4a can be made, for example, of an ultra-hard material, such as PCD or CBN, which can be arranged, for example, on a solderable cutting insert body made of, for example, carbide. In an alternative embodiment, however, the cutting inserts 4, 4a can also be detachably fastened to their respective seats 23, 23a, for example, by means of fastening screws.

[0042] As can be seen in the figures, the clamping grooves 21 extend helically around the longitudinal axis L. The clamping grooves 21 extend at a negative helical angle α (α < 0°) to the longitudinal axis L, as shown in the Fig. 7 and Fig. 8 This can be seen. In the case of the cutting part 2 shown in the figures, which is designed for a right-hand cutting milling tool, this means that the flutes 21 extend according to a left-hand screw.

[0043] The seats 23, 23a and the cutting inserts 4, 4a attached to them are arranged at an angle such that the main cutting edges 41 are each arranged under a positive axial rake angle β (β > 0°), as also shown in the Fig. 7 and Fig. 8 The axial rake angle β is the angle that the main cutting edge 41 forms with the longitudinal axis L when viewed radially from the main cutting edge 41. In other words, the main cutting edges 41 are oriented in such a smooth cutting direction that, when the milling tool 100 is used, the lifted chips are carried away with a directional component in the direction away from the face 20 of the cutting part 2. In this embodiment, the rake faces 43 adjoining the main cutting edges 41 also run at a positive radial rake angle γ, as shown in Fig. 6 The radial rake angle γ is shown schematically. The radial rake angle γ is the angle that the rake faces 43 form with a radial line from the longitudinal axis L to the main cutting edge 41 when cut perpendicular to the longitudinal axis L. In other words, the rake faces 43 are oriented such that when the milling tool is used, 100 chips are carried away with a directional component pointing away from the workpiece surface machined by the main cutting edge 41 in a radial direction.

[0044] As already explained, in the first embodiment, the cutting section 2, on which the clamping grooves 21 and the seats 23, 23a are formed, and the fastening section 3, on which the fastening interface 31 is formed, are designed as separate components that are assembled to form the carrier body 1. This is particularly evident in the schematic exploded view of Fig. 5 shown.

[0045] As especially in the Fig. 4 , Fig. 5 and Fig. 6 As can be seen, in the first embodiment, the cutting part 2 has an annular or essentially hollow cylindrical shape, on the outer circumference of which the clamping grooves 21 and seats 23, 23a are formed. The cutting part 2 is an additively manufactured body, formed layer by layer by cutting off a powdered starting material and selectively solidifying it at the points in each layer that correspond to the contour of the cutting part 2. The cutting part 2 is formed, in particular, from metal powder using an SLS process (selective laser sintering) or a SLM process (selective laser melting). The cutting part 2 can, in particular, be additively built up from steel powder. Due to the layer-by-layer additive construction, the cutting part 2 has a microscopic microstructure that differs from the microstructure of a conventionally manufactured component.

[0046] Due to its ring-shaped form, the cutting part 2 has an inner cavity 27 which extends continuously from the front face 20 to a shaft side 25 of the cutting part 2 facing away from the front face 20.

[0047] The fastening section 3 has a central projection 33, the outer contour of which is adapted to the shape of the cavity 27 in the cutting part 2 such that the central projection 33 can be inserted into the cavity 27 to form the carrier body 1 of the milling tool 100. In the specific embodiment shown in the figures, the projection 33 has a substantially cylindrical outer contour and the cavity 27 has a corresponding hollow cylindrical inner contour. However, other implementations are also possible in which the projection 33 and the cavity 27 have other corresponding geometric shapes.

[0048] In the first embodiment, the fastening section 3 can be formed, for example, using a conventional machining process. The fastening section 3 can, for example, be made of steel. In this way, the volume to be additively built up, i.e., the volume of the cutting element 2, can be kept relatively small, which has a beneficial effect on the manufacturing costs.

[0049] In the first embodiment, an internal coolant supply is formed in the support body 1, in particular in the cutting part 2, through which coolant (or cooling lubricant) can be supplied to the clamping grooves 21. The internal coolant supply has a plurality of coolant channels which have coolant outlets 7 opening into the clamping grooves 21, as shown in particular in Fig. 7 The coolant outlets 7 are oriented such that coolant exiting from them is directed towards the seats 23, 23a and the cutting inserts 4, 4a attached thereto. Several coolant outlets 7 are implemented in each of the individual flutes 21. In this embodiment, the internal coolant supply is formed directly during the additive manufacturing of the cutting part 2 from powdered raw material, so that the coolant channels have a shape that could not be subsequently formed by machining. In particular, at least some of the coolant channels have a curved profile in the predetermined coolant flow direction of the respective coolant channel.

[0050] In a process for manufacturing the cutting part 2, the cutting part 2 is built up layer by layer, starting from the shank side 25 and progressing to the end face 20. Each layer of powdered starting material is applied, and the starting material is solidified at the points in the respective layer that correspond to the cross-section of the cutting part 2 in that layer. The next layer is then applied, and these steps are repeated until the cutting part 2 is completely built up. During this process, the coolant channels inside the cutting part 2 are also built up layer by layer.When building from the shaft side 25 towards the end face 20, the cutting part 2 with the cutting grooves 21 and the seats 23, 23a can be built directly in its final form without the formation of additional support structures due to the previously described structure of the flutes 21 and the seats 23, 23a, and no machining is required.

[0051] The cutting section 2 produced in this way is then connected to the mounting section 3 to form the carrier body 1. The cutting section 2 and the mounting section 3 can be joined together, in particular by a material bond, e.g., by welding. The cutting inserts 4, 4a are then attached to the seats 23, 23a of the carrier body 1, which can be done, in particular, by soldering, to form the milling tool 10. The three flat contact surfaces 30 of the seats 23, 23a ensure particularly precise positioning of the cutting inserts 4, 4a. SECOND VERSION

[0052] A second embodiment of the milling tool is briefly described below with reference to Fig. 9 described.

[0053] To avoid repetition, only the differences compared to the previously described first embodiment are described in more detail, and the same reference numerals are used as in the description of the first embodiment.

[0054] The milling tool 200 according to the second embodiment differs from the milling tool 100 according to the first embodiment only in that the cutting part 2 and the fastening section 3 are not separately manufactured components that are subsequently joined together to form the carrier body 11, but rather the entire carrier body 11, which has the cutting part 2 and the fastening section 3, is additively manufactured in one piece or monolithically.

[0055] In the second embodiment, the fastening section 3 and the cutting part 2 are built up layer by layer from the powdered starting material in the additive manufacturing process. THIRD VERSION

[0056] A third embodiment of the milling tool according to the invention is briefly described below with reference to the Fig. 10 bis Fig. 13 described.

[0057] To avoid repetition, only the differences compared to the previously described embodiments are described in more detail, and the same reference numerals are used.

[0058] In the milling tool 300 according to the third embodiment, the cutting part 2 and the fastening section 3 are additively manufactured in one piece or monolithically, as in the second embodiment.

[0059] The milling tool 300 according to the third embodiment differs from the previously described second embodiment in the design of the mounting section 3 and, in particular, in the design of the mounting interface 31. In the third embodiment, the milling tool 300 is designed as a so-called shell mill and is provided with a corresponding mounting interface 31.

[0060] In the third embodiment, the coolant outlets 7, unlike those described previously, have a non-circular, elongated cross-sectional shape, as shown in particular in Fig. 11 as can be seen. However, it should be noted that the coolant outlets 7 may also have a non-circular cross-sectional shape in the first and / or second embodiment.

[0061] The non-circular cross-sectional shape of the coolant outlets 7 enables a nozzle-like design in which the coolant is directed particularly precisely to the cutting edges.

[0062] Based on the third embodiment and in particular the Fig. 12 und Fig. 13 The internal coolant supply for supplying coolant to the clamping grooves 21 will be described in more detail below. Fig. 12 The diagram is shown with a dashed line. It should be noted that the internal coolant supply can have the same features in both the first and / or second embodiments.

[0063] In Fig. 12 For simplicity, seats 23 and 23a are shown without the cutting inserts attached to them. As in Fig. 12 As can be seen, the coolant channels 7a, which extend to the coolant outlets 7, are curved in the direction of coolant flow, so that the coolant is deflected by the curvature during operation.

[0064] The coolant channels 7a, each extending to the coolant outlets 7 and having a relatively small diameter, extend in particular from coolant distribution cavities 7b, which have a larger cross-section. In this way, a reliable coolant supply to the various coolant outlets 7 is ensured.

Claims

1. Milling tool (100; 200; 300) with: a carrier body (1) which extends along a longitudinal axis (L) and has a plurality of helically extending chip flutes (21) arranged distributed over the circumference of the carrier body (1) and a plurality of seats (23, 23a) which are each formed along the chip flutes (21) and on which cutting inserts (4, 4a) are arranged, which each project radially from the carrier body (1) with a main cutting edge (41), wherein the chip flutes (21) each extend at a negative screw angle (α), wherein the main cutting edges (41) each extend at a positive axial rake angle (β), characterised in that at least one cutting part (2) of the milling tool (100), on which the chip flutes (21) and the seats (23, 23a) are formed, is additively manufactured, that an internal coolant supply is formed in the carrier body (1) for supplying coolant to the chip flutes (21), which has a plurality of coolant channels (7a) with coolant outlets (7) extending in the direction of the seats (23, 23a), in that at least some of the coolant channels (7a) have a course which is curved in a predetermined coolant flow direction, so that the coolant is deflected during operation, that the coolant channels (7a) are relatively small in diameter and extend from coolant distribution cavities (7b) which have a larger diameter, and that the main cutting edges (41) are adjoined by rake faces (43) extending at a positive radial rake angle (γ).

2. Milling tool according to claim 1, wherein a plurality of coolant outlets (7) are formed in the chip flutes (21).

3. Milling tool according to one of the preceding claims, wherein the seats (23, 23a) are each arranged along the chip flutes (21) in such a way that the flight circles of the main cutting edges (41) of the cutting inserts (4, 4a) located thereon overlap in the axial direction.

4. Milling tool according to one of the preceding claims, wherein the carrier body (1) has a substantially annular or hollow-cylindrical cutting part (2), on the outer circumference of which the chip flutes (21) and seats (23, 23a) are formed, and a fastening section (3) with a fastening interface (31) for connection to a machine-side tool holder.

5. Milling tool according to claim 4, wherein the fastening section (3) is manufactured in a material-removing manner and the cutting part (2) and the fastening section (3) are connected to one another in a material-locking manner.

6. Milling tool according to one of the preceding claims, wherein the cutting inserts (4, 4a) are attached to the seats (23, 23a) in a material-locking manner.

7. Milling tool according to one of the preceding claims, wherein the seats (23, 23a) have at least three flat contact surfaces (30) for supporting three different sides of the cutting inserts (4, 4a).

8. Method for manufacturing a cutting part (2) of a milling tool, which cutting part (2) extends along a longitudinal axis (L) and has a plurality of helically extending chip flutes (21) arranged distributed over the circumference of the cutting part (2) and a plurality of seats (23, 23a) for cutting inserts (4, 4a), each formed along the chip flutes, wherein the cutting part (2) is manufactured in an additive manufacturing process by successive layer-by-layer construction of the cutting part (2) in such a way that the chip flutes (21) are constructed extending at a negative screw angle (α) and the seats (23, 23a) for receiving cutting inserts (4, 4a) are formed in such a way that these extend at a positive axial rake angle (β) and that rake faces (43) extending at a positive radial rake angle (γ) adjoin the main cutting edges (41), wherein in the additive manufacturing process an internal coolant supply for supplying coolant to the chip flutes (21) is formed, which has a plurality of coolant channels with coolant outlets (7) extending in the direction of the seats (23, 23a), wherein the coolant channels (7a) are formed in such a way that they have a curved course, at least section-wise, so that the coolant is deflected during operation, wherein coolant distribution cavities (7b) are also formed, wherein the coolant channels (7a) are formed with relatively small diameters and extend from the coolant distribution cavities (7b), which have a larger diameter.

9. Method according to claim 8, wherein a plurality of seats (23a) is formed on an end face (20) of the cutting part (2) for receiving cutting inserts (4a) such that they project axially from the end face (20) of the cutting part (2), and the cutting part (2) is successively built up in layers from a shank side (25) facing away from the end face (20) towards the end face (20).

10. Method according to one of claims 8 or 9, wherein a plurality of coolant outlets (7) are formed in each of the chip flutes (21).

11. Method according to one of claims 8 to 10, wherein the seats (23, 23a) are each formed with at least three flat contact surfaces (30) for supporting three different sides of the cutting inserts (4, 4a).

12. Method according to one of claims 8 to 11, wherein the method further comprises the step of: materially connecting the cutting part (2) to a separately formed fastening section (3), which has a fastening interface (31) for connecting to a tool holder on the machine side.