Milling processes and milling tools

Abstract

Milling method, in particular for milling chamfers, in which straight cutting edges (5) arranged on a rotating conical milling head (4) are moved successively through a workpiece (9) while removing material, wherein at least two of the cutting edges (5) are moved at different angles (α,β) to the generatrix (M) of the milling head (4) running along them, wherein the cutting edges (5) are moved at the different angles (α,β) to the respective generatrix (M) when projected onto a cylindrical surface of the milling head (4) and when projected onto a plane that includes an axis of rotation (R) and the respective generatrix (M) of the milling head (4), characterized in that at least one of the cutting edges (5) is moved such that a cut surface produced by it forms a straight line in cross-section when viewed in the cutting direction, wherein the milling head (4) is rotated by means of a hand-held milling machine.

Description

[0001] The invention relates to a milling method, in particular for milling chamfers, in which straight cutting edges arranged on a rotating conical milling head are moved successively through a workpiece, removing material, wherein at least two of the cutting edges are moved at different angles to the generatrix lines of the milling head running along them, wherein the cutting edges are moved at the different angles to the respective generatrix lines when projected onto a cylindrical surface of the milling head and when projected onto a plane that includes an axis of rotation and the respective generatrix line of the milling head.

[0002] Such a method is shown in DE 37 14 533 A1, which describes a milling method using a milling cutter comprising successive cutting inserts in the circumferential direction, which are inclined at different angles in both the radial and axial directions.

[0003] US 5,899,252 A also describes such a method, wherein a milling head comprising successive cutting inserts in the circumferential direction, which engage a workpiece at different rake and shear angles.

[0004] From JP S63-52911 A a milling method is known using a cylindrical milling head comprising cutting inserts, wherein the cutting inserts arranged successively in the circumferential direction have different rake angles.

[0005] In DE 10 2004 023 743 A1 and DE 202 03 391 U milling processes are described using tools which have cutting inserts whose cutting edges engage at the same angle in a material to be machined.

[0006] Another method is known through use. A rotating milling head, on whose cylindrical surface cutting inserts are arranged one behind the other in the direction of rotation, is moved along a workpiece, so that the cutting inserts penetrate the workpiece one after the other and gradually remove material from the workpiece, forming chips.

[0007] The invention is based on the objective of improving the milling process and the milling tool.

[0008] According to the invention, the problem is solved by moving at least one of the cutting edges in such a way that a cut surface produced by it forms a straight line in cross-section when viewed in the cutting direction, wherein the milling head is rotated by means of a hand-held milling machine.

[0009] If the cutting edges are moved or arranged in such a way that the angles of the cutting edges, viewed in the direction of rotation and preferably aligned, are different from one another, the cutting edges penetrate the material in different ways. This ensures that the cutting edges always penetrate the workpiece first with one side and not simultaneously along their entire length. The material is therefore peeled from the workpiece rather than being knocked out, resulting in a relatively low load on the cutting edges during milling.

[0010] The milling head runs more smoothly in both conventional and climb milling, higher cutting performance can be achieved, and the service life of the cutting edges is increased.

[0011] The milling process proves particularly advantageous in climb milling with a manually operated milling tool, a so-called hand-held milling machine. Since only a relatively small amount of force is available when milling with a hand-held milling machine, which can be applied manually, the arrangement of the cutting edges according to the invention allows for higher cutting performance with the hand-held milling machine.

[0012] Furthermore, it has been shown that the manufacturing of the milling head and cutting edges no longer requires such tight tolerances to produce a functional milling tool. Since the cutting edges alternately engage the milling head first at the top, bottom, or middle of their engagement length, inaccuracies in their arrangement on the milling head still result in a continuous machining process by the successive cutting edges. Without this regular offset, inaccuracies would mean that only the cutting edges protruding due to a tolerance would remove material, while those recessed due to a tolerance would "run in the shadow" of the protruding edges and not participate in the machining process. This simplifies the manufacturing of the milling head and the cutting inserts that form the cutting edges.Furthermore, the cutting inserts no longer need to be positioned as precisely on the milling head as with milling heads known from the prior art.

[0013] Advantageously, the cutting edges, which are preferably straight, have the same shape and are preferably straight, and may optionally be provided with angled or rounded corners or have at least one straight section. If they are arranged obliquely to a generatrix of the milling head and tilted relative to each other on a cylindrical surface of the milling head, the cutting edges, when compared to each other along their edges, have different distances to the axis of rotation of the milling head, so that, in the arrangement according to the invention, the cutting edges arranged one behind the other cut paths of different shapes into the workpiece.

[0014] For example, if one of the straight cutting edges lies with its center on the generatrix of a cylindrical milling head, its ends, depending on the angle of the cutting edge to the generatrix and the length of the cutting edge, are positioned at a greater distance from the axis of rotation than its center. It cuts a convex shape into the workpiece. Another cutting edge, positioned behind the latter at a different angle to the generatrix, cuts a convex path with a different curvature. Similarly, with a conical milling head, different cutting paths are produced depending on the orientation of the cutting edges.

[0015] The individual cutting edges, depending on the feed rate of the milling tool, advantageously cut the workpiece in different sections, thus dividing the cutting work. Milling can be performed with a relatively low contact pressure and a high feed rate.

[0016] In one embodiment of the invention, in addition to the aforementioned tilting on the cylindrical surface, which can also be described by a projection of the cutting edges perpendicular to the axis of rotation, or alternatively, when projecting the cutting edges onto a plane that includes the axis of rotation and the respective generatrix of the milling head, the cutting edges are arranged at different angles to the respective generatrixes, i.e., the cutting edges are arranged tilted to each other in a radial direction with respect to the respective generatrixes.

[0017] While it would be conceivable to tilt the cutting edges only in the latter direction to ensure that each cutting edge only removes half of the material, by combining the tilting in both directions and, in particular, by adjusting the respective angles in the directions to each other, it becomes possible to align the cutting paths of the cutting edges to approximate the resulting cut surface to a plane.

[0018] The mutual adjustment of the angles to one another is particularly important with the conical milling head, where different tilts on the cylindrical surface, due to the changing distance of the cutting edge from the axis of rotation along its length, can result in relatively large deviations in the cutting paths. This can lead to both high stress on the cutting edges and the formation of excessively curved cut surfaces. Tilting in the aforementioned radial direction prevents the cutting edge from protruding too far from the milling head at its ends.

[0019] Advantageously, the angles in the aforementioned two directions are provided such that the ends of the cutting edges are arranged on a straight line in the projection onto the plane that includes the axis of rotation R and the generatrix M.

[0020] In a further embodiment of the invention, the cutting edges, particularly with respect to the cutting edge center, are arranged at different distances from the axis of rotation of the milling head in order to adapt the different shapes of the cutting paths produced by the cutting edges to each other.

[0021] Advantageously, the cutting edges are arranged tilted in the same direction relative to their respective generatrixes, i.e., the angles between the cutting edges and the respective generatrixes have the same sign, and / or are arranged tilted in different directions relative to each other, i.e., the angles have different signs. While in the first case the angles must have different magnitudes to achieve the effects mentioned, in the latter case they can have the same magnitudes.

[0022] Advantageously, at least one of the cutting edges is arranged such that it alone produces a flat cutting surface during milling. For this purpose, the cutting edge can be arranged so that, in projection onto the axis of rotation, it is parallel to the axis of rotation. It separates the material from the workpiece in a straight cutting path and removes material, in particular, from a curved area of ​​the convex cutting path previously formed by a cutting edge arranged at an angle to the generatrix.

[0023] This cutting edge is preferably arranged such that its ends are at the same distance from the axis of rotation as the ends of the cutting edge tilted furthest from the generatrix. As explained above, it is arranged at a different distance from the axis of rotation than the cutting edges that do not form a straight cutting surface.

[0024] In a further embodiment of the invention, the cutting edges are arranged at their respective angles, particularly the angular differences between immediately adjacent cutting edges, as a function of the feed rate of the milling tool and thus as a function of the thickness of the chips produced, in particular the feed per cutting edge, the length of the cutting edges, and the material to be machined. It has been shown that smaller angles can be selected for machining harder materials and larger angles for machining softer materials, since the cutting edges can penetrate softer materials more deeply than harder materials. The angles and feed rates of the milling tools can therefore be coordinated with each other, taking into account the material to be milled.With machine-guided tools, the cutting speed and feed rate are set according to the specific milling head and the resulting angles, as well as the material being milled. With manually guided milling tools, the optimal feed rate is determined automatically, as it is noticeable whether the milling tool runs smoothly and is easy to guide, or whether it jerks, for example.

[0025] To achieve the flattest possible cut surface at the highest possible working speed, the milling head is moved along the workpiece at a cutting speed and feed rate such that each cutting edge removes only a portion of the material to be removed at its respective machining point. The required cutting work is thus distributed among the different cutting edges.

[0026] Advantageously, if the cutting edges are tilted in the same direction as described above, they should be arranged at angles such that the maximum differences in the distances of the cutting edges to the respective generatrix do not exceed twice the desired chip thickness. If the cutting edges are tilted in opposite directions as described above, the maximum differences in the distances correspond at most to the desired chip thickness. Since the chips produced during milling always carry away the majority of the heat generated, it has proven advantageous for the process, particularly for the service life of the cutting edges, to mill with a feed rate such that the chips have a thickness of 0.02 mm to 0.5 mm. For many materials to be milled, such as steel or aluminum, additional cooling is then unnecessary.

[0027] It has proven advantageous to arrange the cutting edges such that the angles between the cutting edges and the respective generatrix lines of the cutting edges, which are arranged directly one behind the other, possibly aligned with each other, and thus successively penetrate the material, differ by less than 4°, preferably by less than 2°. If the cutting edges are tilted in the same direction, the differences are a maximum of 2°, preferably 1.5°. Due to the aforementioned different cutting paths of the individual cutting edges, any irregularities that may form in a resulting cut surface are negligible at these angles. Nevertheless, the aforementioned advantages regarding handling, cutting performance, and cutting edge wear remain.

[0028] To achieve the smoothest possible rotation of the milling head, the differences between the angles of all adjacent cutting edges are preferably equal. The orientation of the cutting edges therefore depends on the number of cutting edges on the milling head. If an even number of cutting edges are aligned in the direction of rotation around the circumference of the milling head, the cutting edges can, for example, be arranged alternately at the same angles to the generatrix.

[0029] In a further embodiment of the invention, the cutting edges are arranged at different distances from each other when viewed in the direction of rotation. This prevents the milling tool from vibrating due to resonance during milling.

[0030] In a further embodiment of the invention, two or more rows of cutting edges are arranged on the milling head, in which the cutting edges are positioned at the same height on the axis of rotation, apart from minor deviations due to their inclination. While it would be conceivable to provide the rows at such a distance from one another that the adjacent ends of the cutting edges of adjacent rows are at the same height, in a preferred embodiment they are arranged such that the cutting edges overlap section by section in the direction of rotation. Burrs in the chamfer to be formed at the interface between the rows, which can occur, for example, due to tolerances in the manufacture of the milling head or the cutting edges, are avoided.

[0031] While it would be conceivable that the cutting edges on the milling head are formed in one piece with the milling head, e.g. if the milling head is made of carbide, in the preferred embodiment the cutting edges are formed on cutting inserts which are provided for arrangement in seats formed on the milling head.

[0032] Advantageously, the seats and / or the cutting inserts are designed such that the cutting edges are arranged at different angles. To this end, the seats on the milling head can be positioned in different locations so that the aforementioned angles are achieved when identical cutting inserts are mounted on the milling head.

[0033] Alternatively, it is also conceivable to achieve the arrangement according to the invention by means of differently shaped cutting inserts. Advantageously, the effects according to the invention could then also be achieved with a conventional milling head.

[0034] In a further embodiment of the invention, the cutting edges are arranged and shaped such that they have a wedge angle of 40 to 75° and each operates on average with a positive rake angle of at least 6° and a clearance angle of at least 6°. The cutting edges penetrate the workpiece relatively sharply. Wedge angles between 60° and 72° have proven particularly advantageous. The highest cutting performance can be achieved with a wedge angle of approximately 66° and clearance and rake angles of 12° each.

[0035] In a further development of the invention, the cutting edges are moved or arranged such that the angles of the cutting edges, viewed in the direction of rotation, differ from one another when moved or arranged side by side and / or offset from one another. This allows the cutting edges, particularly in the case of conical milling heads where the geometric conditions with which the cutting edges penetrate the workpiece change depending on their position on the milling head, to penetrate the workpiece with rake, wedge, and clearance angles as uniform as possible along their length and especially at different points on the milling head. This achieves a uniform load on the cutting edges and consequently reduces wear.

[0036] In a further embodiment of the invention, the milling tool comprises a drive for the milling head, which has a spring-loaded clutch for transmitting the torque, as known, for example, from WO 2008 / 025350. With the milling tool equipped with the spring-loaded clutch, even higher cutting performances are possible, since significantly less vibration occurs during milling and therefore less force is required to hold the milling tool. This proves particularly advantageous for manually guided milling tools, as considerably higher milling speeds can be achieved. Furthermore, a surprising combination effect has been observed: with manually guided milling tools, it is easier to feel at what maximum feed rate a flat chamfer can still be milled.

[0037] In a particularly preferred embodiment of the invention, the coupling is formed by a claw coupling, between whose interlocking claws coil springs are arranged. Advantageously, blind bores are provided in at least one of the coupling parts, into which the coil springs can be inserted at one end each. They are thereby held against the coupling part and can bear against the opposing claw of the other coupling part.

[0038] Advantageously, this arrangement of helical springs according to the invention allows for a dynamic response with high reaction speed to the loads applied to the milling head, and the energy stored by deformation of the springs can be fed back into the milling process.

[0039] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings relating to these embodiments. The drawings show: Fig. 1 a milling head according to the invention in side view and in top view, Fig. 2 a further milling head according to the invention in side view and in top view, Fig. 3 a further milling head according to the invention in side view and in top view, Fig. 4 schematically an arrangement of cutting plates in top view of the cutting plates, Fig. 5 schematically an arrangement of cutting inserts on a milling head in section, Fig. 6 schematic further arrangements of cutting plates, Fig. 7 schematic further arrangements of cutting plates, Fig. 8 schematic further arrangements of cutting plates, Fig. 9 schematic cutting plates when engaging a workpiece, Fig. 10 a further milling head according to the invention, Fig. 11 a further milling head according to the invention, Fig. 12 a cut surface produced on a workpiece, Fig. 13 another cut surface produced on a workpiece, Fig. 14 a milling tool according to the invention, Fig. 15 a part of the milling tool after Fig. 14, and Fig. 16 a detail of the milling tool according to Fig. 14.

[0040] In Fig. Figure 1 shows a conical milling head 4, which has a guide stop or guide roller 7, a projection 10 for connecting the milling head 4 to a drive and is provided with four seats 1, 1', 1'', 1''' for cutting inserts 6.

[0041] The seats 1, 1', 1'', 1''' each comprise a bearing surface for one side of the cutting inserts 6, as well as a threaded bore (not shown) for a screw by means of which the cutting inserts 6 are fastened to the seats 1, 1', 1'', 1''', and a support surface 13 against which the cutting inserts 6 rest for support. On one side of the seats 1, 1', 1'', 1''', where the working cutting edges 5 of the cutting inserts 6 are located, chamfers 11 are provided on the milling head 4 of the seats 1, 1', 1'', 1''' to facilitate the removal of chips formed during milling.

[0042] The cutting inserts 6 intended for seats 1, 1', 1'', 1''' are indexable inserts with a cuboid shape, as known from WO 2004 / 078395 incorporated herein. The two broad sides of the cutting inserts 6 serve as clearance faces and bearing surfaces, respectively. On each of the two longitudinal narrow sides, a groove of uniform cross-section symmetrical to the center plane of the inserts forms two possible rake faces with a rounded transition between them. The intersections of the flat rake faces with the clearance face and the bearing surface 3, which represents a further possible clearance face, result in four possible straight cutting edges. A central bore 8 extending from one broad side to the other has a cylindrical central section on each side, two conical seats for a screw head, and a cylindrical section above them.For the cutting inserts 6, this results in reversibility options by rotating the cutting inserts around the axis of the bore as well as by reversing them, thereby exchanging the previous bearing surface and clearance surface. As in particular... Fig. As can be seen from Figure 9, the ends of the cutting edges of the cutting inserts 6 are rounded and thus extended to the side edges, so that the corners can penetrate directly into a workpiece 9. This ensures that the cutting edges can penetrate the material to a sufficient depth.

[0043] The cutting inserts 6 or the seats 1,1',1'',1''' are designed such that the cutting edges 5 have a wedge angle of 66° at their center point when engaging a workpiece and operate with a positive rake angle of 12° and a clearance angle of 12°.

[0044] Furthermore, the seats 1, 1', 1'', 1''' are provided on the milling head 4 such that the cutting edges 5 of the seats arranged adjacent to each other, e.g. seats 1 and 1', 1' and 1'', as shown by way of example in the Fig. 4 and Fig. 5 shown, are arranged at different angles α,α',β,β' to a generatrix M of the milling head 4 running along the cutting edge 5.

[0045] Fig. Figure 4 shows a tilting of the cutting inserts 6, arranged on seats 1 and 1', relative to their respective generatrix M. Seats 1 and 1' are tilted on the surface relative to the generatrix M and arranged such that the cutting edges 5, 5' are tilted in opposite directions to the generatrix M. The angles α, α' are 1°. In the drawing, the two cutting inserts 6 are superimposed for clarity.

[0046] Fig. Figure 5 schematically shows a tilting to the respective generatrix M in the radial direction of the cutting inserts 6 arranged on the seats 1 and 1' by the angles β,β'.

[0047] By appropriately adjusting the respective angles α and β and, if necessary, selecting a suitable distance of the cutting edges to the generatrix M, the cutting edges can be arranged in such a way that they together produce the flattest possible cutting path during milling. In the present example (see...) Fig. 6a) α and α' are 1.5° and β and β' are 0.3°.

[0048] Possible seating arrangements for the milling head 4 are in Fig. 6 schematically illustrated by means of a representation of the cutting inserts 6. The cutting inserts 6 according to Fig. 6a are alternately in the in Fig. 4 positions shown, so that the cutting plates 6 have the same position in seats 1 and 1'' as well as in seats 1' and 1'''.

[0049] In Fig. Figure 12 illustrates a partially provided cut surface 30 in a workpiece to explain the functioning of the invention. The figure shows a snapshot at a time when, for example, the Fig. The cutting plate 6 shown in Figure 6a, located on seat 1, has already been moved through the workpiece and is subsequently guided through the workpiece by the cutting plate 6 located on seat 1'. The cutting plate 6 on seat 1 initially creates a cutting path 31. The cutting plate 6 on seat 1' then partially follows the already created cutting surface at edge 32, penetrating the workpiece and gradually removing more and more material from the workpiece along a cutting path 33.

[0050] At the in Fig. In the embodiment shown in Figure 6b, the seats 1, 1', 1'', 1''' are arranged such that the cutting inserts 6 mounted on them are tilted in the same direction relative to the respective generatrix M. The cutting inserts 6 in seats 1 and 1'' and in seats 1' and 1''' are arranged in the same positions relative to the generatrix M.

[0051] Are the cutting plates 6, as in Fig. As shown in Figure 6b, the cutting insert 6 arranged in seat 1' is tilted in the same direction to the generatrix M. It is tilted at a larger angle α to the generatrix than the one arranged on seat 1. To prevent the cutting edge of the cutting insert 6 arranged in seat 1' from protruding too far relative to the cutting edge of the cutting insert 6 arranged in seat 1, an angle β' is chosen for seat 1' that is larger than the angle β of seat 1. The cutting insert 6 of seat 1' can thus be countersunk into the cylindrical surface of the milling head on its upper side.

[0052] To mill a chamfer, the milling head 4 is rotated about the axis of rotation R in the direction of rotation r. The cutting inserts 6, arranged on the seats 1, 1', 1'', 1'''', engage the material successively with their cutting edges 5. Due to the differently tilted arrangement of the cutting edges 5 relative to the respective generatrix M running along them, the cutting edges 5 penetrate, as shown in Fig. As shown schematically in Figure 9, instead of impacting the workpiece 9 with the entire cutting edge 5, one side of the cutting edge first engages the workpiece 9. With this guidance of the cutting inserts 6, the material itself is gradually peeled away from the workpiece 9, resulting in a lower load compared to the sudden impact of the entire cutting edge 5.

[0053] Due to the tilting of the cutting edges 5 at different angles, the cutting edges 5 of the cutting inserts 6 arranged on the respective adjacent seats 1, 1', 1'', 1''' are arranged at different radii along their length. This results in cutting paths in the workpiece with differing shapes. Because of the tilting at angles α, β of the straight cutting edges 5, a slightly convex shape is cut into the material, the curvature of which depends on the respective angle to the generatrix M. Depending on the feed rate at which the milling head 4 moves on the workpiece, this can cause the cutting inserts 6, sequentially penetrating the workpiece 9, to divide the areas to be cut among themselves. Furthermore, it is possible to ensure that the cutting edges 5 alternately penetrate the material with different ends first.

[0054] Further options for arranging the seats are in Fig. 7 shown. In the embodiment according to Fig. 7a The cutting insert 6 is arranged on the central seat 1' on the milling head such that its working cutting edge 5 is parallel to the generatrix M and in a plane that includes the generatrix M and the axis of rotation R. The outer seats 1, 1'' are, as above for Fig. As described in 6a, it is tilted in directions opposite to the generatrix M. In the embodiment according to Fig. 7b is the middle seat 1' like the one after Fig. 6a and the outer seats 1.1'', as above for Fig. As described in 6b, it is tilted in the same direction as the generatrix M.

[0055] While the cutting plates 6 are on seats 1 and 1'' according to the arrangements in Fig. 7a and b cut a convex shape into the material as described above, the cutting plates 6 cut on the seats 1' of the Fig. 7a and b create a straight cutting path into the material, so that the milling head can produce overall flat chamfers.

[0056] Fig. Figure 13 shows a cutting path 40 in a workpiece at a time when the cutting inserts of seats 1'' and 1 have already been successively guided through the workpiece and have produced the partial cutting paths 41 and 42. The cutting insert 6 of seat 1' is then guided through the workpiece and, due to the convex cutting path, gradually removes material remaining in the workpiece on the cutting path 43, so that a completely flat cut surface is produced.

[0057] It goes without saying that the arrangements of seats or cutting plates and cutting edges shown can be combined in any way desired. For example, they could also be combined in the Fig. In the 4 illustrated embodiments with four seats 1,1',1'',1''', the individual seats 1,1'1,1'',1''' are arranged such that the cutting edges are arranged parallel to the generatrix M.

[0058] Furthermore, the arrangement of the cutting edges 5 according to the invention ensures that the cutting edges 5 of the adjacent cutting plates 6, as described in Fig. As shown in Figures 9a and b, the cutting edges 5 penetrate the workpiece 9 first from different sides. Due to the different cutting paths, favorable conditions arise when the cutting edges 5 penetrate the material, resulting in increased cutting performance and smooth running of the milling head on the workpiece.

[0059] In the embodiments described below, identical or equivalent parts are designated with the same reference number as in the preceding figures, with the letter a, b, c or d appended to the respective reference number.

[0060] On one in Fig. The conical milling head 4a shown in Figure 2 has two rows x,y of three seats each 1a, 1a', 1a'', 2a, 2a', 2a'', wherein the cutting inserts 6a in the rows x,y can be arranged such that their cutting edges 5a are at the same height of the axis of rotation. The cutting inserts 6a in seats 1a, 1a', 1a'' and those in seats 2a, 2a', 2a'' then machine the same cutting areas during chamfering. The cutting inserts 6a are arranged overlappingly when the cutting edges 5 are projected onto a plane that includes the axis of rotation R and the respective generatrix M, so that no burrs are formed during chamfer milling.

[0061] Schematically, in the Fig. 8a and b show possible arrangements of seats 1a,1a',1a'',2a,2a',2a''.

[0062] At a Fig. Figure 3 shows a further milling head 4b according to the invention, rows x',y' each with four seats 1b, 1b',1b'',1b''',2b,2b',2b'',2b'''. In this embodiment, a larger overlap is provided between the rows x' and y' than in the example according to Figure 3. Fig. 2.

[0063] Possible seating arrangements are shown in the Fig. 8c and d are shown.

[0064] Fig. Figure 10 shows another milling head 4c according to the invention, which has a cylindrical shape. The seats marked 1c, 1c', 1c'', 1c''' and the other seats shown are arranged tilted on the cylindrical surface relative to the respective slant height M, as shown in the Fig. 6a shows, but they can also be arranged as in Fig. 6b or Fig. Figure 7 shows the seats 1c, 1c', 1c'', 1c''' are arranged such that the cutting edges 5c are arranged in planes parallel to the axis of rotation R and thus parallel to the generatrix (β=0°).

[0065] A in Fig. The conical milling head 4d shown in Figure 11 according to the invention differs from the milling heads described above in that the seats 1d, 2d, 3d arranged on the same rows x'', y'', z'' do not differ in their position relative to the respective generatrix, but rather the angles between the seats 1d, 2d, 3d, which are arranged on different rows x'', y'', z'', are different. The seats 1d, 2d, 3d are arranged such that an optimized straight chamfer is formed overall, and the cutting edges 5d of the cutting inserts 6 penetrate the material at the center of the cutting edges 5d with the same wedge, rake, and clearance angles. This ensures that the cutting edges 5d can penetrate the material well along their entire length. The service life of the cutting inserts 6d is thus increased.

[0066] In Fig. Figure 14 shows a cross-section of a hand-held milling machine 10 according to the invention, which moves the milling head 4 according to Fig. 1 carries. How especially Fig. As can be seen from Figure 15, the milling head 4 is arranged on a spindle part 11, which is connected via a spring coupling to a spindle part 12, which is connected to a drive for the milling head 4. Coil springs 16 are arranged between two interlocking coupling parts 13 and 14. For this purpose, blind bores 15 are provided in the coupling part 13, into which the coil springs 16 are loosely inserted. The coil springs 16 are supported in the blind bores 15 on one side and against support struts 17 of the coupling part 14 on the other. To hold the two coupling parts 13 and 14 together axially, a groove 19 is provided on the circumference of both coupling parts 13 and 14, into which a retaining ring 18 is inserted.

[0067] When the milling head 4 is driven via the spindle part 12, the coupling absorbs loads occurring on the cutting inserts 6 of the milling head 4 by twisting the coupling parts 13 and 14 relative to each other, thereby compressing the springs 16. The energy absorbed by the springs 16 is then fed back into the milling process during milling as the springs 16 return to their original position. This prevents vibration of the milling tool 10, particularly when the tool is first engaged with a workpiece, but also during continuous milling, allowing it to be guided manually at high milling speeds.

Claims

[1] Milling method, in particular for milling chamfers, in which straight cutting edges (5) arranged on a rotating conical milling head (4) are moved successively through a workpiece (9) while removing material, wherein at least two of the cutting edges (5) are moved at different angles (α,β) to the generatrix lines (M) of the milling head (4) running along them, wherein the cutting edges (5) are moved at the different angles (α,β) to the respective generatrix lines (M) when projected onto a cylindrical surface of the milling head (4) and when projected onto a plane that includes an axis of rotation (R) and the respective generatrix line (M) of the milling head (4), characterized by , that at least one of the cutting edges (5) is moved in such a way that a cut surface produced by it forms a straight line in cross-section when viewed in the cutting direction, wherein the milling head (4) is rotated by means of a hand milling machine. [2] Milling method according to claim 1, characterized by, that the cutting edges (5) of the cutting edges (5) arranged one behind the other, offset from each other and / or next to each other in the direction of rotation (r) of the milling head (4) are moved at the different angles (α,β). [3] Milling method according to claim 1 or 2, characterized by , that the milling head (4) is moved along the workpiece (9) at such a cutting speed and such a feed rate that each of the cutting edges (5) only removes a part of the material to be removed at the respective machining point. [4] Milling method according to any one of claims 1 to 3, characterized by , that the cutting edges (5) are moved in such a way that a flat cutting surface or a cutting surface approximating a flat surface is formed. [5] Milling method according to any one of claims 1 to 4, characterized by, that the milling head (4) is moved along the workpiece (9) with a feed rate that depends on the rotational speed and the size of the differences between the angles (α,β). [6] Milling tool, in particular for milling chamfers, comprising a rotatable, conical milling head (4) with straight cutting edges (5), wherein at least two of the cutting edges (5) are arranged at different angles (α,β) to generatrix lines (M) of the milling head (4) running along them, wherein the cutting edges (5) are arranged at the different angles (α,β) to the respective generatrix lines (M) when projected onto a cylindrical surface of the milling head (4) and when projected onto a plane that includes an axis of rotation (R) and the respective generatrix line (M) of the milling head (4), characterized by, that at least one of the cutting edges (5) is arranged such that a cut surface produced by it forms a straight line in cross-section when viewed in the cutting direction, wherein the milling tool is a hand milling machine. [7] Milling head for the milling tool according to claim 6, comprising a rotatable milling head (4) with cutting edges (5), wherein at least two of the cutting edges (5) are arranged at different angles (α,β) to generatrix lines (M) of the milling head (4) running along them, wherein the cutting edges (5) are arranged at the different angles (α,β) to the respective generatrix lines (M) when projected onto a cylindrical surface of the milling head (4) and when projected onto a plane that includes an axis of rotation (R) and the respective generatrix line (M) of the milling head (4), characterized by , that at least one of the cutting edges (5) is arranged such that a cut surface produced by it forms a straight line in cross-section when viewed in the cutting direction. [8] Milling tool according to claim 6, or milling head according to claim 7, characterized by , that at least the angles (α,β) of the cutting edges (5) arranged one behind the other, offset from each other and / or next to each other when viewed in a direction of rotation (r) of the milling head (4) are different from each other. [9] Milling tool according to claim 6 or 8, or milling head according to claim 7 or 8, characterized by , that the angles (α,β) in the two directions are adapted to each other to form a planar cutting surface resulting from the cuts of the individual cutting edges (5). [10] Milling tool according to one of claims 6, 8 or 9, or milling head according to one of claims 7 to 9, characterized by , that the angles (α,β) in the two directions are provided such that the ends of the cutting edges (5) are arranged on a straight line in the projection onto the plane that includes the axis of rotation R and the generatrix M. [11] Milling tool according to one of claims 6 or 8 to 10, or milling head according to one of claims 7 to 10, characterized by , that the cutting edges (5), preferably the centers (m) of the cutting edges (5), are arranged at different distances from a rotational axis (R) of the milling head (4). [12] Milling tool according to one of claims 6 or 8 to 11, or milling head according to one of claims 7 to 11, characterized by , that at least one of the cutting edges (1') is arranged parallel to the axis of rotation (R) in projection onto the axis of rotation (R). [13] Milling tool according to one of claims 6 or 8 to 12, or milling head according to one of claims 7 to 12, characterized by , that in which the cutting edges (5) on the milling head (4) are arranged in at least two rows (x,y) in which the cutting edges (5) are arranged at the same height of the axis of rotation (R). [14] Milling tool according to one of claims 6 or 8 to 13, or milling head according to one of claims 7 to 13, characterized by , that the rows (x,y) are arranged at such a distance from each other that the cutting edges (5) overlap section by section when viewed in the direction of rotation (r). [15] Milling tool according to one of claims 6 or 8 to 14, or milling head according to one of claims 7 to 14, characterized by , that the cutting edges (5) are formed on cutting plates (6) which are provided for arrangement in seats (1) provided on the milling head (4), and / or the cutting edges are formed on the milling head, preferably in one piece with the milling head. [16] Milling tool and optionally milling head according to claim 15, characterized by , that the seats (1) and / or the cutting plates (6) are provided such that the cutting edges (5) are arranged at the different angles (α,β). [17] Milling tool according to one of claims 6, or 8 to 16, characterized by a drive for the milling head which has a spring-loaded coupling that transmits the torque. [18] Milling tool according to claim 17, characterized by , that the coupling is formed by a claw coupling, between whose claws (13,17) coil springs (16) are arranged.

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