Milling and / or grinding tool and turning system

Abstract

Milling and / or grinding tool, in particular dental milling or dental grinding tool (10, 100), comprising a shank (12, 120, 140) and a working part (14, 140), wherein the working part (14, 140) has at least one partially spherical end region (20, 200) and a section (18, 180) tapering towards the end region (20, 200), in particular a conical section, wherein the end region (20, 200) comprises geometrically defined and / or geometrically undefined cutting edges (80a, 80b, 91) and wherein the working part (14, 140), in particular the tapered section (18, 180), has a first region (18a, 180a) with geometrically defined and / or geometrically undefined cutting edges (80a, 80b, 91) and at least one second, non-cutting area (18b, 180b)) comprises the tapered section (18, 180) being designed to remove a first time chip volume (ZSV1), with the front area (20, 200) being designedthat it can remove a second time volume (ZSV2) and wherein the first time volume (ZSV1) is removed at the same rotational speed (n, F ) of the milling and / or grinding tool is greater than the second material removal volume (ZSV2).

Description

[0001] The present invention relates to a milling and / or grinding tool and a turning system. In particular, the invention relates to a milling and / or grinding tool or a turning system, each for the manufacture of components for use inside or near the human body, for example for the manufacture of elements for prosthetic dental restorations, such as abutments or crowns, otoplasty, such as hearing protection or hearing aids, or other medical devices or components.

[0002] The publication EP 1 810 637 A1 describes a dental milling cutter with a milling head attached to a shaft, which is essentially conical and equipped with several cutting edges.

[0003] Publication WO 2013 / 164068 A1 describes a dental milling cutter and a milling process for manufacturing dental prostheses. The dental milling cutter comprises a hemispherically rounded ball-head section that transitions into an axial cutting section with a constant diameter.

[0004] DE 10 2005 001 600 B4 discloses a method for material removal machining of workpieces, in which the workpiece is machined by the engagement of a rotating milling tool that is at least partially cylindrical and / or frustoconical, and in which the rotating milling tool is engaged with the workpiece both on the face and on the side of the body.

[0005] EP 3 332 737 B1 discloses a method for producing a dental restoration part using a dental machining machine comprising a multi-axis workpiece arm and at least one tool spindle. During machining, the tool remains in continuous contact with the workpiece, essentially machining the entire outer profile of the workpiece in a spiral motion. The dental machining machine is designed as a 5 / 0-axis milling machine, i.e., with five axes for the multi-axis workpiece arm and zero axes for the machining tool.

[0006] The object of the invention is to improve the manufacture of precision engineering or precision mechanical components, in particular for use within or near the human body and especially for prosthetic dental care, otoplasty or for other medical technology products and in particular the manufacture of abutments or dental crowns.

[0007] The problem is solved according to the invention by a milling and / or grinding tool, in particular a dental milling or dental grinding tool, comprising a shank and a working part, wherein the working part has at least a partially spherically shaped end region and a section tapering towards the end region, in particular a conically shaped section, wherein the end region comprises geometrically defined and / or geometrically undefined cutting edges, and wherein the working part, in particular the tapered section, comprises a first region with geometrically defined and / or geometrically undefined cutting edges and at least a second, cutting-less region, wherein the tapered section is designed in such a way that it can remove a first material volume, and wherein the end region is designed in such a way thatthat it can remove a second material volume, and where the first material volume is greater than the second material volume at the same rotational speed of the milling and / or grinding tool.

[0008] With a milling and / or grinding tool according to the invention, an advantageous manufacturing process for producing components for use inside or near the human body, and especially elements for prosthetic dental restorations, and particularly abutments, becomes possible. The shaping of the working part with a section tapering towards the end face increases the stiffness of the milling and / or grinding tool to such an extent that a turning process becomes possible in which roughing and finishing can be performed in a single operation with the same tool. In other words, both the tapered section and the end face can engage the workpiece blank in a chip-removing manner.The tapered section is designed for roughing operations with a relatively large chip volume, while the end section is designed for finishing or fine finishing operations with a relatively small chip volume. This allows for simultaneous roughing and finishing of a workpiece. The tapered section increases the stiffness of the milling and / or grinding tool to such an extent that it can withstand the high loads during simultaneous roughing and finishing operations. Geometrically defined cutting edges are defined as those whose geometry and number are known. Geometrically defined cutting edges can be advantageously produced using a laser machining process.Geometrically indeterminate cutting edges are defined as cutting edges where neither the geometry of the cutting edges nor their number is known.

[0009] An advantageous embodiment comprises a partial region of the tapered section extending over a first axial length being designed in such a way that it can remove the first material removal volume, and wherein the end region extending over a second axial length is designed in such a way that it can remove the second material removal volume, wherein the first axial length and the second axial length are of the same length.

[0010] The tapered section and the end face are thus designed such that the tapered section can remove a higher material volume over a first axial length or extension than the end face over a second axial length or extension that is the same length as the first axial length or extension. This can be achieved, for example, by having fewer cutting edges in the end face over the second axial length than in the tapered section over the first axial length, or by having lower cutting edges in the end face over the second axial length than in the tapered section over the first axial length.

[0011] In a further advantageous embodiment, it is provided that the first area has geometrically defined cutting edges which are spirally shaped around a longitudinal axis of the milling and / or grinding tool, and in particular continuously, preferably without transverse cuts. and / or that the end face comprises geometrically defined cutting edges. The geometrically defined cutting edges of the end face can be helical around a longitudinal axis of the milling and / or grinding tool, and in particular continuous, preferably without cross-cuts. Alternatively, the geometrically defined cutting edges of the end face can also extend radially away from the tool axis, for example, in a straight line or in a curved path.

[0012] In this way, an advantageously designed milling cutter can be created that meets high requirements for stiffness during operation.

[0013] Furthermore, it can be advantageous if the first area comprises exclusively geometrically undefined cutting edges, and / or that the forehead area comprises exclusively geometrically undefined cutting edges.

[0014] In this way, an advantageously designed grinding tool, especially in the form of a grinding pin, can be designed that meets the high requirements for rigidity in operation.

[0015] It can also be advantageous to provide a combined milling and grinding tool in which either the tapered section or the end face has geometrically defined cutting edges, and the corresponding section has other geometrically undefined cutting edges. It is also possible for both geometrically defined and geometrically undefined cutting edges to be provided in the tapered section and / or the end face.

[0016] Furthermore, it can be advantageous if the tapered section includes the second, non-cutting area.

[0017] Providing a non-cutting area within the tapered section can contribute to a further increase in tool stiffness.

[0018] In an advantageous embodiment, the end face has a number N1 of cutting edges and the tapered section has a number N2 of cutting edges, wherein the number N1 of cutting edges of the end face is less than the number N2 of cutting edges of the tapered section.

[0019] The larger number of cutting edges allows for a large chip volume to be removed per unit of time with the tapered section, which is desirable for roughing operations. In particular, this enables high cutting speeds. Due to the fewer number of cutting edges on the face, this area can only remove a smaller chip volume per unit of time. The maximum achievable chip thickness is also reduced. Therefore, the partially spherical face is advantageously designed for finishing operations, such as surface finishing or fine finishing.

[0020] Furthermore, it may be advantageous if the tapered section is a conically shaped section and has a cone angle of 2° to 7°, in particular 3° to 6°, preferably 5°, relative to the longitudinal axis of the milling and / or grinding tool.

[0021] Cone angles of 2° to 7°, in particular of 3° to 6°, preferably of 5°, are particularly advantageous when the specified angles enable both an advantageous radius of the partially spherical end region and an advantageous cutting edge length, or an advantageous ratio of free neck length to cutting edge length of the milling and / or grinding tool for the cutting edges on the conical area.

[0022] As an alternative to a conical shape, the tapered section can be concave or convex, or taper in a stepped or wavy manner, or have a mixture of these shapes.

[0023] Alternatively or additionally, it is possible that the tapered section, in particular immediately, transitions into the partially spherical forehead area in such a way that a forehead area that is essentially exactly hemispherical is provided, or that the tapered section transitions into the partially spherical forehead area in such a way that a forehead area that is essentially more than hemispherical is provided, or that the tapered section transitions into the partially spherical forehead area in such a way that a forehead area that is essentially less than hemispherical is provided.

[0024] Additionally, the conically shaped section can have a cone base diameter of 2.3mm to 3.8mm, in particular 2.8mm to 3.3mm, preferably 3.0mm or 3.033mm.

[0025] With a cone base diameter within the specified values, particularly good stiffness of the milling tool can be achieved.

[0026] Another advantageous embodiment is defined in that the partially spherical end face has a sphere radius of 0.5mm to 1.2mm, in particular of 0.6mm to 0.9mm, preferably of 0.7mm.

[0027] With a radius of the specified values, very fine contours with high tolerance requirements can be produced. Such a radius is particularly advantageous in combination with a favorable taper angle and / or a favorable cutting edge length, or with a favorable ratio of free neck length to cutting edge length of the milling and / or grinding tool.

[0028] Furthermore, it may be advantageous if a ratio of free neck length of the milling and / or grinding tool to cutting edge length of the milling and / or grinding tool of 2:1 to 1, in particular of 3:2, 4:3, 5:4, 6:5 or 7:6, is provided.

[0029] An advantageous ratio of free neck length to cutting edge length provides high rigidity of the working area, so that bending of the end mill is prevented or at least reduced, especially when a force acts radially on the working area during operation. Such a ratio is particularly advantageous in combination with a favorable taper angle and / or radius of the partially spherical end face.

[0030] Another advantageous embodiment is defined in that at least a limited surface area of ​​the milling and / or grinding tool, in particular a limited surface area of ​​the face, preferably a partial area of ​​a face cutting edge or a rake face of the face or a clearance face of the face or a rake face or a clearance face of the tapered section, has a mean roughness value R a exhibits a thickness of less than 0.4µm or less than 0.35µm, and / or that at least a limited surface area of ​​the milling and / or grinding tool, in particular a limited surface area of ​​the face area, preferably a partial area of ​​a face cutting edge or a rake face of the face area or a clearance face of the face area or a rake face or a clearance face of the tapered section, has an average roughness depth Rz of less than 3.0µm, preferably less than 2.5µm or 2.4µm.

[0031] Milling and / or grinding tools designed in this way can be used to produce workpieces with very high surface quality.

[0032] The object of the invention is further achieved by a turning system, in particular a turning and milling system, comprising a turning spindle and a milling spindle with a milling and / or grinding tool according to the invention.

[0033] Such a turning system, in particular a mill-turning system, enables a turning process, in particular a mill-turning process, for the production of elements for prosthetic dental care, for otoplasty or for medical technology products with a milling and / or grinding tool according to the invention, in particular a dental milling cutter designed and configured for use in a mill-turning process.

[0034] With such a turning system, in particular a milling turning system, it is possible to manufacture precision engineering or precision mechanical components, especially for use inside or near the human body and especially for prosthetic dental care, for otoplasty or for other medical technology products and especially dental prostheses, economically and in high quality.

[0035] The problem is further solved by a turning system comprising at least one turning spindle, at least one milling spindle and at least one milling and / or grinding tool, as well as a control device for controlling the turning spindle and the milling spindle such that the following steps are carried out: - Rotating a workpiece blank around a workpiece rotation axis; - Rotation of the milling and / or grinding tool around a tool rotation axis; - Insertion of the rotating milling and / or grinding tool into the rotating workpiece blank for the machining removal of workpiece material; - Machining the rotating workpiece blank in one machining step by removing workpiece material in a first machining operation and in a second machining operation, wherein the workpiece blank is machined in the first machining operation to the extent of a first material removal volume and in the second machining operation to the extent of a second material removal volume, wherein the first material removal volume is greater than the second material removal volume and wherein the first machining operation and the second machining operation take place at least partially, in particular predominantly, preferably substantially completely, simultaneously; - Retraction of the rotating dental milling cutter from the rotating workpiece.

[0036] With this turning system, it is possible to produce a finished workpiece, for example, a dental prosthesis, from a workpiece blank in a single, continuous machining step without interrupting the milling process. This machining step, i.e., milling and / or grinding step, includes a first machining operation in which the workpiece blank is roughed and a second machining operation in which finishing is performed. The milling and / or grinding tool is inserted into the workpiece blank to remove material. The workpiece blank is machined with a section of the milling and / or grinding tool capable of removing the first volume of material and, preferably simultaneously, with another section of the milling and / or grinding tool capable of removing the second volume of material.The area removing the first material volume can be the section of the milling and / or grinding tool, in particular according to the invention, which tapers towards the end face and is in particular conically shaped, and the area removing the second material volume can be the end face of the milling and / or grinding tool, in particular according to the invention.

[0037] The first and second machining operations can thus be performed simultaneously, which significantly reduces the overall machining time of the workpiece. Furthermore, it is possible for the milling and / or grinding tool to remain in machining engagement with the workpiece blank throughout the entire machining step.

[0038] One embodiment of the turning system further includes the fact that the first machining operation is carried out, in particular exclusively, by the tapered section, and / or that the second machining operation is carried out, in particular exclusively, by the partially spherically shaped end area of ​​the milling and / or grinding tool.

[0039] Thus, in the first machining operation, roughing is performed using a section of the tool specifically designed for this task, namely the tapered, particularly conical, section, and in the second machining operation, finishing is performed using a different section of the tool specifically designed for finishing. In this embodiment of the method, the milling and / or grinding tool can remain in machining engagement with the workpiece blank throughout the entire machining step.

[0040] Furthermore, it may be provided that when the rotating milling and / or grinding tool enters the rotating workpiece blank, the first machining operation begins first and, in particular, the second machining operation begins immediately afterwards. and / or that the first machining operation ends before or during the exit from the rotating workpiece and, in particular, the second machining operation ends immediately afterwards.

[0041] This can be achieved, for example, by not positioning the tool towards the workpiece along its longitudinal axis, but rather laterally. In this way, during entry, the tapered section of the tool can engage with the workpiece before the end face and perform a roughing operation ahead of the end face.

[0042] Furthermore, it may be possible to design the turning system in such a way that the tool axis intersects the workpiece axis when entering the workpiece blank and / or when machining the workpiece blank and / or when exiting the workpiece. or that the tool rotation axis is oriented offset relative to the workpiece rotation axis when entering the workpiece blank and / or when machining the workpiece blank and / or when exiting the workpiece, or that the tool rotation axis is moved offset relative to the workpiece rotation axis during a first insertion phase when entering the workpiece blank and / or during machining of the workpiece blank, and is moved in a cutting orientation with the workpiece rotation axis in a second insertion phase, and / or that during the withdrawal from the workpiece, the tool rotation axis is oriented in a cutting orientation with the workpiece rotation axis in a first withdrawal phase, and in a second withdrawal phase the tool rotation axis is moved into an orientation offset relative to the workpiece rotation axis.

[0043] The way in which the milling and / or grinding tool, and especially a dental milling cutter, is brought into contact with or moved away from the workpiece blank is crucial for machining quality. Advantageous entry and exit strategies avoid high, sudden impact loads on the milling and / or grinding tool upon initial contact with the workpiece blank, thus increasing quality and simultaneously reducing stress on the milling and / or grinding tool, which in turn extends its tool life.

[0044] Furthermore, it may be provided that the tool rotation axis is arranged perpendicular to the workpiece rotation axis when entering the workpiece blank and / or when machining the workpiece blank and / or when exiting the workpiece; or that the tool rotation axis is arranged at a leading angle, in particular relative to the workpiece rotation axis, when entering the workpiece blank and / or when exiting the workpiece and / or during machining of the workpiece blank.

[0045] A tool axis perpendicular to the workpiece axis of rotation during tool entry allows for efficient transfer of the cutting force into the workpiece blank. Setting the tool at a lead angle increases the cutting performance.

[0046] Furthermore, it may be stipulated that the workpiece is rotated at a speed of 10 min⁻¹. -1 up to 200 min -1 rotates, in particular at a speed n of 100 min -1 up to 160 min -1 , preferably at a speed of 120 min -1 .

[0047] In this way, a favorable ratio of workpiece rotation speed to the cutting speed of the tool on the workpiece blank can be achieved.

[0048] Furthermore, it may be provided that at least a limited surface area of ​​the workpiece has a mean roughness value R after the rotating milling and / or grinding tool has been withdrawn from the rotating workpiece. a of less than 0.3µm, in particular less than 0.2µm, preferably less than 0.18µm or 0.1µm.

[0049] In this way, a workpiece with very low surface roughness can be produced in a single machining step. It is also possible to further process the workpiece after the machining process is complete, for example, by polishing or milling with a cutter that has a partially spherical end face with a smaller radius.

[0050] Advantageous embodiments and further developments according to the invention result from the respective dependent patent claims and also from the following description.

[0051] An advantageous embodiment is defined in that the rotary spindle, the milling spindle and the control device are encompassed by a multi-axis CNC machine.

[0052] The invention will be further explained below with reference to exemplary embodiments and the drawings. The drawings show, in schematic representation: Fig. Figure 1 shows a side view of a dental milling cutter according to an embodiment of the invention; Fig. Figure 2 shows a side view of a dental grinding pin according to an alternative embodiment of the invention; Fig. Figure 3 shows a perspective view of a turning system for the manufacture of dental prostheses; Fig. Figure 4 shows a side view of the turning machining system of the Fig. 3; Fig. 5 shows a perspective view of a dental milling cutter according to an embodiment of the invention; Fig. Figure 6 shows a perspective view of an abutment that can be produced with the tool according to the invention;

[0053] The Fig. 5 and Fig. Figure 6 shows schematic illustrations that are not suitable for determining sizes or dimensions by measurement.

[0054] Fig. Figure 1 shows, as a preferred embodiment of a milling and / or grinding tool, a dental milling cutter 10 designed as an end mill, comprising a shank 12 and a working part 14. The working part 14 has a conically shaped section 18, which has a partially spherical end face 20 at a front end. More precisely, the conical shape of the conically shaped section transitions directly into a partially spherical shape, thereby forming the end face of the dental milling cutter 10, which thus has a partially spherical end face 20. In the embodiments shown, Fig. 1 and Fig. 2 the conically shaped section 18 transitions into the partially spherical frontal area 20 in such a way that a frontal area that is essentially less than hemispherical is provided.

[0055] Alternative embodiments are possible in which, instead of the depicted conically shaped section 18, a differently tapered section is formed in which there is no conical shape, or at least not an exclusively conical shape. In such embodiments, it is possible that the tapered section transitions into the partially spherical end face 20 in such a way that an essentially exactly hemispherical end face 20 is provided, or that the tapered section transitions into the partially spherical end face 20 in such a way that an essentially more than hemispherical end face 20 is provided.

[0056] The conically shaped section 18 has a region 18a with helical cutting edges rotating around a longitudinal tool axis WL of the dental milling cutter 10. The cutting edges are continuous or uninterrupted, meaning they have no breaks or notches and, in particular, no cross-cuts. The cutting edges have a cutting length L2 of, for example, 8 mm.

[0057] The cutting area 18a of the conical section is immediately followed by a cutting-free area 18b. The total length of the conical section, the so-called free neck length L3, includes the cutting length L2 as well as the length of the cutting-free area 18b and can, for example, be 10 mm.

[0058] The front area of ​​the end mill 10, which adjoins the shank 12, has a shank connection length L4, which can be, for example, 15mm.

[0059] The free neck length L3 to the cutting edge length L2 can have a ratio of 2:1 to 1, in particular 3:2, 4:3, 5:4, 6:5 or 7:6. In particular, the cutting edge length L2 can be 8 mm.

[0060] The end face 20 has a number N1 of cutting edges, and the conically shaped section 18 has a number N2 of cutting edges. The number N1 of cutting edges in the end face 20 can be the same as the number N2 of cutting edges in the section 18, or the end face 20 can have fewer N1 of cutting edges than the section 18. For example, the end face 20 can have 2 to 4 cutting edges, and the section 18 can have 3 to 6 cutting edges. For some applications, a number N1 of 2 and a number N2 of 4, as shown in the illustrated embodiment, is advantageous.

[0061] The cutting edges of the conically shaped section 18 are spirally helixed around the longitudinal axis WL of the dental milling cutter and are continuous. In the illustrated embodiment, the helix angle of the cutting edges is 45°. The helix direction is to the right, and the dental milling cutter is accordingly designed for a cutting direction to the right.

[0062] Furthermore, the cutting edges are equally spaced, meaning the distance between the cutting edges in the circumferential direction of the tool is always the same.

[0063] The shank of the dental milling cutter may comprise or be made of carbide, the working part 14 and / or the cutting edges may be provided with a TiAlN (titanium aluminum nitride) coating.

[0064] Furthermore, the conically shaped section 18 can have a cone angle α of 2° to 7°, in particular 3° to 6°, relative to the longitudinal axis WL of the dental milling cutter. In the illustrated embodiment, the conically shaped section 18 has a cone angle of 5°. Additionally, the conically shaped section 18 can have a cone base diameter D2 of 2.3 mm to 3.8 mm, in particular 2.8 mm to 3.3 mm, preferably 3.0 mm. In the illustrated embodiment, the cone base diameter D2 is 3.033 mm.

[0065] The partially spherical end face 20 can have a sphere radius r of 0.5 mm to 1.2 mm, in particular of 0.6 mm to 0.9 mm. The illustrated embodiment has a sphere radius r of 0.7 mm.

[0066] The shank 12 has a shank diameter D1 of 6 mm and a shank length of 25 mm. The overall length of the dental milling cutter 10 can, for example, be 50 mm. To simplify automatic tool changes, a stop ring 16 is provided on the dental milling cutter.

[0067] Fig. Figure 2 shows an alternative embodiment with a grinding tool designed as a shank tool, more precisely a grinding pin 100. The grinding pin 100 has essentially the same shape and dimensions as the dental milling cutter 10. However, instead of geometrically defined, helical cutting edges, the grinding pin 100 has abrasive elements in the cutting area 180a and in the end face 200 that have or represent geometrically undefined cutting edges, for example in the form of diamond grains, which are connected to the working part 14 of the grinding pin via a carrier matrix or in another suitable manner. Embodiments not shown include a combined milling and grinding tool which, for example, has geometrically defined cutting edges spirally helical around the longitudinal axis WL of the dental milling cutter in the cutting area 18a, 180a, and grinding elements with a defined grit size, i.e., geometrically undefined cutting edges, in the end area 20, 200. It is also conceivable that grinding elements are provided in the cutting area 18a, 180a and geometrically defined cutting edges in the end area 20, 200.

[0068] Furthermore, in the Fig. 1 and Fig. 2. It is apparent that a sub-area of ​​the conically shaped section 18 extends over a first axial length AL. K This section is designed to allow the removal of an initial material volume ZSV1. Furthermore, the end face 20 extends over a second axial length AL. S , which is the same length as the first axial length AL KThe end face 20 is designed to remove a second material removal volume ZSV2. When the aforementioned section of the conically shaped portion 18 and the end face 20 are simultaneously engaged in machining the workpiece, both areas rotate at the same speed n. F The section of the conically shaped part 18 removes a higher chip volume in the same period than the face area 20. This allows the conically shaped area 18 to perform roughing operations while the face area 20 can perform finishing operations.

[0069] The Fig. 3 and Fig. Figure 4 shows a perspective view and a side view of a turning system, in particular a mill-turn system, for the manufacture of dental prostheses. The one shown in the Fig. 3 and Fig. The milling cutter 60 shown in section 4 corresponds to an exemplary milling cutter. The described rotary milling system can also advantageously be equipped with a dental milling cutter according to the invention, so that the milling cutter 60 can be replaced by a dental milling cutter 10 or a grinding pin 100.

[0070] The mill-turn system comprises a milling spindle 40 and a turning spindle 50, which are arranged orthogonally to each other. A workpiece 30 in the form of a blank is clamped in the turning spindle 50, so that the workpiece 30 can be rotated by the turning spindle 50 about a workpiece rotation axis RWS. A workpiece 30 with predefined final dimensions, more precisely a so-called abutment, is to be produced from the workpiece blank. Abutments are typically defined as connecting elements between a dental implant, for example, a tooth root substitute, and the prosthetic restoration, for example, the visible dental crowns. Abutments are usually made of titanium, aluminum oxide ceramic, or zirconium dioxide ceramic.

[0071] The milling cutter 60 is mounted in the milling spindle 40, so that the milling cutter has a tool rotation axis R of 10µm. WZ It is rotatable. The directions of rotation of workpiece 30 and milling cutter 10 can be opposite.

[0072] For example, when using the milling cutter 10 from Fig. Since the milling spindle 40 has a clockwise rotation as its predetermined cutting direction, the turning spindle 50 is operated clockwise, while the turning spindle 50 is operated counterclockwise. In this way, the workpiece blank is rotated "into" the rotating milling cutter 10, thus performing a counter-rotating machining operation.

[0073] The workpiece rotation axis Rws is oriented parallel to a y-axis of a Cartesian coordinate system or slopes downwards, as in the diagram shown in the Fig. 3 and Fig. In the situation shown in Figure 4, the tool rotation axis Rwz is parallel to a z-axis of the Cartesian coordinate system or, as in the figure shown in the Fig. 3 and Fig. 4. Situation shown, together with the z-axis.

[0074] Workpiece rotation axis R WS and tool rotation axis R WZThe two components are shown arranged orthogonally to each other, with the milling spindle 40 additionally pivotable about two rotary axes A and B around the z-axis and the milling spindle 40 itself being rotatable around the y-axis. The rotary spindle 50 also enables the workpiece 30 to be fed in along the y-axis.

[0075] The turn-milling system designed in this way enables turn-milling in which a workpiece blank rotates around the workpiece axis Rws, similar to a turning process. The rotating workpiece blank 30 is machined by the milling cutter 60, which rotates around its tool axis Rwz. For this purpose, the rotating milling cutter 60 enters the rotating workpiece blank 30 along a defined entry path to remove workpiece material.

[0076] In the illustrated embodiment, the workpiece rotation axis R intersects the workpiece blank 30 when entering it or when exiting it. WSthe tool rotation axis R WZ the workpiece rotation axis R WS More precisely, for this purpose, the milling cutter 10, 60 is arranged such that the tool rotation axis Rwz intersects the workpiece rotation axis Rws. In this arrangement, the milling cutter 10, 60 can rotate along the workpiece rotation axis R WS , or, along the y-axis into the workpiece 30.

[0077] Alternatively, the rotary milling system can be used to adjust the tool rotation axis Rwz relative to the workpiece rotation axis R when entering the workpiece blank and / or when exiting the workpiece. WS be oriented in a displaced manner.

[0078] Likewise, a variable setting is possible, so that the tool rotation axis Rwz is offset relative to the workpiece rotation axis Rws in a first insertion phase when entering the workpiece blank, and in a second insertion phase in a cutting orientation with the workpiece rotation axis R WSis driven, or that the tool rotation axis Rwz, when extending from the workpiece in a first extension phase, intersects the workpiece rotation axis R WS The workpiece is driven in a cutting direction and, in a second extension phase, moves into a position relative to the workpiece rotation axis R. WS A staggered orientation is used.

[0079] Due to the special design of the milling cutter 10 or the grinding pin 100, it is possible for the conically shaped section 18 to machine the rotating workpiece blank 30 with a first material removal rate ZSV1 in a first machining operation, and for the end face 20 to machine the rotating workpiece blank 30 with a second material removal rate ZSV2 in a second machining operation. The first and second machining operations can be performed simultaneously due to the special design of the milling cutter 10 or the grinding pin 100.

[0080] Furthermore, in the Fig. 3 and Fig. In the illustrated embodiment 4, the tool rotation axis R WZ The tool rotation axis Rws is arranged perpendicular to the workpiece rotation axis Rws when entering the workpiece blank 30 or exiting the finished workpiece. Alternatively, the tool rotation axis Rwz can be arranged at a lead angle, particularly relative to the workpiece rotation axis Rws, when entering the workpiece blank 30, exiting the workpiece, or during machining of the workpiece blank 30. The lead angle is defined as the angle by which the milling cutter 10, 60 is inclined in the direction of travel. The lead angle can be less than 90°. More precisely, the lead angle is the angle between the surface normal of the machined surface and the tool orientation, in the direction of the tangent of the tool's travel path.

[0081] The lead angle serves to orient the tool at a fixed angle to the machining plane. This increases the cutting efficiency. For example, when a ball end mill is oriented vertically, its tip touches the surface being machined. At this point on the cutter, however, the rotational speed, and therefore the cutting speed, is zero.

[0082] The workpiece 30 is rotated by the spindle 50 at a speed n of 10 min⁻¹ -1 up to 200 min -1 rotates, in particular at a speed n of 100 min -1 up to 160 min -1 , preferably at a speed of 120 min -1 .

[0083] With the described turning system in general, and specifically with turn-milling, workpieces, such as abutments, with diameters typically ranging from 2 mm to 10 mm can be machined. When machining non-circular workpieces, the milling and / or grinding tool can be adjusted in the z-direction, for example, so that roughing is performed by the tapered section 18, 180 leading the machining operation, and finishing is performed by the end face 20, 200 trailing the machining operation. Alternatively or additionally, the milling and / or grinding tool can be positioned or guided at an angle to the workpiece surface such that roughing is performed by the tapered section 18, 180 and finishing by the end face 20, 200.

[0084] Fig. Figure 5 shows a perspective view of the dental milling cutter 10 with a partially spherical end face 20, which has two end cutting edges 80a, 80b. In the view shown, a rake face 70b associated with end cutting edge 80b and a clearance face 95a associated with end cutting edge 80a are visible. On the side of the end face 20 facing away from the viewer, there is one further rake face and one further clearance face. Chip spaces 90 are defined in the spiral grooves between the cutting edges 91 of the conically shaped section 18.

[0085] It can be advantageous if at least a limited surface area of ​​the milling and / or grinding tool, in particular a limited surface area of ​​the face region 20, preferably a partial area of ​​a face cutting edge 80a, 80b or a rake face 70b of the face region 20 or a clearance face 95a of the face region 20, also a rake face or clearance face of the tapered section 18, has a mean roughness value R a has a thickness of less than 0.4µm or less than 0.35µm.

[0086] Likewise, it can be advantageous if at least a limited surface area of ​​the milling and / or grinding tool, in particular a limited surface area of ​​the face region 20, preferably a partial area of ​​a face cutting edge 80a, 80b or a rake face 70b of the face region 20 or a clearance face 95a of the face region 20, also a rake face or clearance face of the tapered section 18, has an average roughness depth Rz of less than 3.0µm, preferably of less than 2.5µm or 2.4µm.

[0087] Fig. Figure 6 shows a perspective view of an abutment 300 that can be produced with the tool according to the invention.

[0088] It can be advantageous if at least a limited surface area of ​​the workpiece, for example a limited area or a complete handling area, such as a polygonal surface for anti-rotation protection 310, a front surface 320 or a side surface 330 of the abutment 300, has an arithmetic mean roughness value R after the rotating milling and / or grinding tool has been withdrawn from the rotating workpiece. a of less than 0.3µm, in particular less than 0.2µm, preferably less than 0.18µm or 0.1µm.

[0089] Likewise, it can be advantageous if at least a limited surface area of ​​the workpiece, for example a limited area or a complete handling area, such as an anti-rotation surface 310, a front surface 320 or a side surface 330 of the abutment 300, has an average roughness depth Rz of less than 1µm, in particular less than 0.9µm, preferably less than 0.7µm or 0.6µm or 0.5µm, after the rotating milling and / or grinding tool has been extended from the rotating workpiece.

[0090] In this way, a workpiece with very low surface roughness can be produced in a single machining step. It is also possible to further process the workpiece after the machining process is complete, for example, by polishing or milling with a cutter that has a partially spherical end face with a smaller radius. Reference symbol list 10 dental burs 100 dental grinding tools 12, 120 shaft 14, 140 Working part 16, 160 stop ring 18, 180 conical section 18a, 180a Cutting area 18b, 180b non-cutting area 20, 200 forehead area 30, 300 workpiece 40 milling spindle 50 Turning spindle 60 milling cutters 70b chip surface 80a, 80b Forehead cutting 90 Chip space 91 Cutting the conical section 95a Open space 300 workpieces 310 Area for anti-rotation protection 320 front surface area 330 side area L1 Total length L2 cutting length L3 free neck length L4 shaft connection length L5 shaft length D1 shaft diameter D2 cone base diameter r sphere radius WL tool longitudinal axis α Cone angle Rwz Rotary axis of the tool R WS axis of rotation of the workpiece Red indicates the direction of rotation of the tool. n F Milling cutter speed x,y,z linear axes A, B rotational axes R a arithmetic mean roughness Rz average roughness depth AL K first axial length AL S second axial length QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 1 810 637 A1

[0002] WO 2013 / 164068 A1

[0003] DE 10 2005 001 600 B4 EP 3 332 737 B1

[0005]

Claims

[1] Milling and / or grinding tool, in particular dental milling or dental grinding tool (10, 100), comprising a shank (12, 120, 140) and a working part (14, 140), wherein the working part (14, 140) has at least a partially spherical end region (20, 200) and a section (18, 180) tapering towards the end region (20, 200), in particular a conical section, wherein the end region (20, 200) comprises geometrically defined and / or geometrically undefined cutting edges (80a, 80b, 91) and wherein the working part (14, 140), in particular the tapered section (18, 180), has a first region (18a, 180a) with geometrically defined and / or geometrically undefined cutting edges (80a, 80b, 91) and comprises at least a second, non-cutting area (18b, 180b)), wherein the tapered section (18, 180) is designed to remove a first time-scale volume (ZSV1), wherein the end face (20, 200) is designedthat it can remove a second time volume (ZSV2) and wherein the first time volume (ZSV1) is removed at the same rotational speed (n, F ) of the milling and / or grinding tool is greater than the second material removal volume (ZSV2). [2] Milling and / or grinding tool according to claim 1, wherein a milling and / or grinding tool extends over a first axial length (AL) K ) extending sub-area of ​​the tapered section (18, 180) is designed such that it can remove the first time-scale volume (ZSV1), and wherein the extending over a second axial length (AL S ) extending frontal region (20, 200) is designed such that it can remove the second time chip volume (ZSV2), wherein the first axial length (AL) K ) and the second axial length (AL) S are the same length. [3] Milling and / or grinding tool according to one of the preceding claims, wherein the first area (18a, 180a) comprises geometrically defined cutting edges (91) which are helically formed circumferentially and in particular continuously around a longitudinal axis (WL) of the milling and / or grinding tool, preferably without transverse cuts, and / or that the end face (20) comprises geometrically defined cutting edges (80a, 80b), in particular wherein the geometrically defined cutting edges (80a, 80b) are helically formed around a longitudinal axis (WL) of the milling and / or grinding tool, and in particular continuously, preferably without cross-cutting. [4] Milling and / or grinding tool according to any of the preceding claims, wherein the first area (18a, 180a) comprises exclusively geometrically undefined cutting edges, and / or that the forehead area (20, 200) comprises exclusively geometrically undefined cutting edges. [5] Milling and / or grinding tool according to any of the preceding claims, wherein the tapered section (18, 180) comprises the second, non-cutting, area (18b, 180b). [6] Milling and / or grinding tool according to one of the preceding claims, wherein the end region (20, 200) has a number N1 cutting edges and the tapered section (18, 180) has a number N2 cutting edges, wherein the number N1 of cutting edges of the end region (20, 200) is less than the number N2 of cutting edges of the tapered section (18, 180). [7] Milling and / or grinding tool according to one of the preceding claims, wherein the tapered section (18, 180) is a conically shaped section (18, 180) and has a cone angle (α) of 2° to 7°, in particular of 3° to 6°, preferably of 5°, relative to the longitudinal axis (WL) of the milling and / or grinding tool. [8] Milling and / or grinding tool according to claim 7, wherein the conically shaped section (18, 180) has a cone base diameter (D2) of 2.3mm to 3.8mm, in particular of 2.8mm to 3.3mm, preferably of 3.0mm or 3.033mm. [9] Milling and / or grinding tool according to one of the preceding claims, wherein the partially spherical end face (20, 200) has a sphere radius (r) of 0.5mm to 1.2mm, in particular of 0.6mm to 0.9mm, preferably of 0.7mm. [10] Milling and / or grinding tool according to one of the preceding claims, wherein a ratio of a free neck length (L3) of the milling and / or grinding tool to a cutting edge length (L2) of the milling and / or grinding tool of 2:1 to 1, in particular of 3:2, 4:3, 5:4, 6:5 or 7:6, is provided. [11] Milling and / or grinding tool according to one of the preceding claims, wherein at least a limited surface area of ​​the milling and / or grinding tool, in particular a limited surface area of ​​the end face (20, 200), preferably a partial area of ​​an end cutting edge (80a, 80b) or a rake face (70b) of the end face (20, 200) or a clearance face (95a) of the end face (20, 200) or a rake face or a clearance face of the tapered section (18, 180) has a mean roughness value (R a ) of less than 0.4µm or less than 0.35µm, and / or at least a limited surface area of ​​the milling and / or grinding tool, in particular a limited surface area of ​​the end face (20, 200), preferably a partial area of ​​an end cutting edge (80a, 80b) or a rake face (70b) of the end face (20, 200) or a clearance face (95a) of the end face (20, 200) or a rake face or a clearance face of the tapered section (18) an average roughness depth (R z ) of less than 3.0µm, preferably of less than 2.5µm or 2.4µm. [12] Turning system, in particular turn-milling system, comprising at least one turning spindle (50) and at least one milling spindle (40) with a milling and / or grinding tool according to one of claims 1 to 11. [13] Turning system, in particular according to claim 12, comprising at least one turning spindle (50), at least one milling spindle (40) and at least one milling and / or grinding tool (10) as well as a control device for controlling the turning spindle (50) and the milling spindle (40) such that the following steps are carried out: - Rotating a workpiece blank (30, 300) around a workpiece rotation axis (Rws); - Rotation of the milling and / or grinding tool around a tool rotation axis (Rwz); - Insertion of the rotating milling and / or grinding tool into the rotating workpiece blank (30, 300) for machining of workpiece material; - Machining the rotating workpiece blank (30, 300) in a machining step by removing workpiece material in a first machining operation and in a second machining operation, wherein the workpiece blank (30, 300) is machined in the first machining operation to the extent of a first material removal volume (ZSV1) and in the second machining operation to the extent of a second material removal volume (ZSV2), wherein the first material removal volume (ZSV1) is greater than the second material removal volume (ZSV2) and wherein the first machining operation and the second machining operation take place at least partially, in particular predominantly, preferably substantially completely, simultaneously; - Retraction of the rotating milling and / or grinding tool from the rotating workpiece. [14] Turning system according to claim 13, wherein the first machining operation is performed, in particular exclusively, by a tapered section (18, 180) of the milling cutter and / or wherein the second machining operation is performed, in particular exclusively, by the partially spherical end region (20, 200) of the milling and / or grinding tool. [15] Turning system according to one of claims 13 or 14, in which, when the rotating milling and / or grinding tool is inserted into the rotating workpiece blank (30, 300), the first machining operation begins first and, in particular, the second machining operation begins immediately thereafter, and / or that the first machining operation ends before or during the exit from the rotating workpiece and, in particular, the second machining operation ends immediately afterwards. [16] Turning system according to one of claims 13 to 15, wherein the tool rotation axis (Rwz) aligns with the workpiece rotation axis (R) when entering the workpiece blank and / or when machining the workpiece blank and / or when withdrawing from the workpiece WS ) cuts, or that the tool rotation axis (Rwz) is relative to the workpiece rotation axis (R) when entering the workpiece blank and / or when machining the workpiece blank and / or when exiting the workpiece WS ) is oriented in a displaced manner, or that the tool rotation axis (R WZ ) when entering the workpiece blank and / or when machining the workpiece blank, in a first travel phase it is offset relative to the workpiece rotation axis (Rws) and in a second travel phase it is moved into a cutting orientation with the workpiece rotation axis (R WS) is driven and / or that during machining of the workpiece blank and / or during exiting from the workpiece in a third driving phase the tool rotation axis (R) WZ ) to the workpiece rotation axis (R WS ) is oriented in a cutting direction and in a fourth driving phase the tool rotation axis (R WZ ) is moved into an orientation offset relative to the workpiece rotation axis (Rws). [17] Turning system according to one of claims 13 to 15, wherein the tool rotation axis (Rwz) is arranged perpendicular to the workpiece rotation axis (Rws) when entering the workpiece blank (30, 300) and / or when machining the workpiece blank (30, 300) and / or when withdrawing from the workpiece; or that the tool rotation axis (R WZ) when entering the workpiece blank (30, 300) and / or when exiting the workpiece and / or during machining of the workpiece blank (30, 300) at a lead angle, in particular relative to the workpiece rotation axis (R) WS ). [18] Turning system according to one of claims 13 to 17, wherein the workpiece is turned at a speed n of 10 min -1 up to 200 min -1 rotates, in particular at a speed n of 100 min -1 up to 160 min -1 , preferably at a speed of 120 min -1 . [19] Turning system according to one of claims 13 to 18, wherein at least a defined surface area of ​​the workpiece has a mean roughness value (R) after the rotating milling and / or grinding tool has been withdrawn from the rotating workpiece. a ) of less than 0.3µm, in particular less than 0.2µm or less than 0.18µm. [20] Turning system according to one of claims 13 to 19, wherein the turning spindle (50), the milling spindle (40) and the control device are comprised of a multi-axis CNC machine.

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