Drilling and milling tool

Abstract

The invention relates to a drill-mill tool, in particular with exactly one drill head (9), in particular for producing workpiece holes (57, 59) with different diameters (D1, D2), the drill head having a drill longitudinal cutting edge (11) and a drill end cutting edge (13) extending transversely at the drill tip (16), the drill end cutting edge converging with the drill longitudinal cutting edge (11) at a radially outer drill nose (19), the drill tool further having a milling head (21) which is preferably configured in a circumferential distribution in front of and behind the drill back (17), a cutting force (F1) acting on the transversely extending drill end cutting edge (13) during drilling. According to the invention, for stabilizing the drilling process, the tool has at least one support head (14) which generates a support force (F2). The length (l2) of the support head (14) is designed in such a way that, as a result of the corresponding forces (F1, F2), a tendency of the tool to vibrate is prevented.

Description

Technical Field

[0001] The present invention relates to a drilling and milling tool for producing workpiece holes of different diameters. Background Technology

[0002] In principle, this type of drilling and milling tool is implemented in the form of a so-called single-flute drill bit, which is constructed with exactly one drill bit. This drill bit has a longitudinal drilling cutting edge extending along the tool rotation axis, at which the chip venting surface of the drill chip vent transitions into the peripheral drill back. Furthermore, the drill bit has a transversely extending drill tip cutting edge at the drill tip. This drill tip cutting edge merges with the longitudinal drilling cutting edge at the radially outer drill tip. In addition, the drilling and milling tool also has milling cutters, which are preferably constructed sequentially on the drill back in a circumferentially distributed manner.

[0003] During drilling, the drill bit of a milling tool is loaded with a cutting force. This cutting force attempts to move the tool translationally, causing the tool to bend. The tool bends to such an extent that sufficient preload is generated, at which point the tool temporarily returns to its initial state. This process repeats very rapidly, causing tool vibration during drilling. Summary of the Invention

[0004] The purpose of this invention is to provide a drilling and milling tool that enables drilling processes with minimal tool vibration associated with cutting forces.

[0005] According to one aspect of the invention, in order to suppress or reduce tool vibration associated with the cutting force, the drilling tool has a support head at which a support force opposite to the cutting force acts. By the opposing action of the support force and the cutting force, tool vibration during the drilling process is reduced or prevented, thereby achieving a tool rotation that is as vibration-free as possible.

[0006] In one technical implementation, the support cutter head can have a support-end cutting edge extending laterally at the top of the borehole. This support-end cutting edge can converge with the support-longitudinal edge at the radially outer support-tip.

[0007] Preferably, the length of the laterally extending support-end cutting edge is designed such that the drilling process can proceed stably (vibration-free). However, on the other hand, the support-end cutting edge must be as short as possible. An excessively long support-end cutting edge requires a correspondingly large support-chip flute, which may compromise tool stability. In such cases, the milling process may become unstable, or milling may have to be performed with a very small feed rate.

[0008] Therefore, the length of the support cutter head is crucial to the functionality of the drilling and milling tool. Preferably, the length of the laterally extending support-end cutting edge is reduced compared to the length of the laterally extending drill-end cutting edge. In this way, the chip evacuation groove cross-section, groove depth, and / or groove length of the support-chip evacuation groove can be designed to be smaller than in the drill-chip evacuation groove. Thus, the drilling and milling tool has an additional tool-material, thereby improving tool stability during drilling / milling.

[0009] During drilling, the support tip primarily serves a supporting function to prevent tool vibration. In this context, it is preferable that the radially outer support tip is located on a tool diameter smaller than the radially outer drill tip. Therefore, during drilling, the drill tip and the laterally extending support end-cutting edge engage in a cutting contact, while the support longitudinal edge of the support tip is unloaded, i.e., not engaged in a cutting contact.

[0010] In drilling processes without tool vibration, achieving the most complete possible force balance between cutting and support forces is crucial. In this context, it is preferable that the drill bit and support bit are arranged on opposite tool sides with reference to the tool-rotation axis. In this case, the laterally extending drill-end cutting edge and the laterally extending support-end cutting edge can be extended at approximately 180° in the circumferential direction.

[0011] In a specific implementation, the drilling and milling tool may have two drill-ribs extending along the axis of rotation. These drill-ribs define a drill-chip removal groove and a support-chip removal groove in the circumferential direction.

[0012] The drilling and milling tool according to the invention is particularly designed for a process route described below, in which, during the drilling stroke, a rotating drilling and milling tool is pushed into the workpiece along the drilling-feed direction until the theoretical drilling depth is reached, resulting in a small-diameter hole. After the drilling stroke ends, a reverse stroke can be performed, in which the drilling and milling tool is guided out of the small-diameter hole. A milling stroke is then performed. To prepare for the milling stroke, the radial offset of the guided drilling and milling tool relative to the drilling axis is controlled. During the milling stroke, the drilling and milling tool enlarges the small-diameter hole into a large-diameter hole along the milling-feed direction, which is the same as the drilling-feed direction. The milling stroke is performed by means of the circumferential movement of the drilling and milling tool along a circular trajectory about the drilling axis and while the tool is rotating.

[0013] During the drilling stroke, only the drill bit and the support bit engage with the workpiece material, while the milling cutter remains unengaged. Conversely, during the milling stroke, both the drill bit and the milling cutter engage with the workpiece material, while the support bit remains unengaged. In this context, the drilling and milling tool can have a tool geometry where the milling cutter is positioned at the same axial drilling-milling tool height. Furthermore, the milling cutter can have the same cutter geometry, in which it has a milling longitudinal cutting edge extending along the tool rotation axis, terminating at the drill tip and ending at the end-side milling tip. The milling cutter, particularly the end-side milling tip, can be axially offset relative to the drilling end-cutting edge to ensure that the milling cutter remains unloaded during the drilling stroke. Particularly preferred is that the axial displacement corresponds at least to the drilling feed rate per revolution during the drilling stroke (e.g., 0.2 mm per revolution).

[0014] In terms of stable process control, it is important to prevent lateral deflection of the drilling and milling tool during the drilling stroke. In this context, the drilling and milling tool can have a circumferentially distributed support chamfer (rounded chamfer) on the drill bit back. This support chamfer extends along the tool rotation axis. Regarding this support chamfer, the following describes the support chamfer on the drill bit side: the support surface of this support chamfer can meet the chip groove surface of the drill-longitudinal cutting edge.

[0015] For reliable chip removal during the milling stroke, a milling chip vent can be arranged before each milling head in the tool rotation direction. The chip vent surface of the milling chip vent can transition from the longitudinal cutting edge of the milling cutter into the support surface of the support chamfer (round grinding chamfer) on the side of the milling head.

[0016] To further enhance process safety, it is preferable that the support surface of the corresponding support chamfer on the drilling or milling cutter side transitions into the free surface opposite to the tool rotation direction. This free surface bends from the support surface at a free angle and therefore does not contact the hole-wall during the drilling stroke. In the continuing stroke (viewed circumferentially), a milling-chip evacuation groove or a drilling-chip evacuation groove is connected to the free surface. Similarly, a free surface is constructed on the end face at the drill tip, which does not engage with the workpiece material during drilling.

[0017] During the drilling stroke, all support chamfers contact the hole wall. Conversely, during the milling stroke, all support chamfers serve as free surfaces that do not contact the hole wall.

[0018] Furthermore, it should be emphasized that, preferably, the drilling longitudinal cutting edge, the milling longitudinal cutting edge, and the support surface of all support chamfers are located on the same tool diameter.

[0019] For safe chip removal, it is preferable to connect the drilling and milling tool to a cooling medium and / or lubricant system. For this purpose, at least one cooling medium and / or lubricant channel can extend within the drilling and milling tool. Cooling medium and / or lubricant can be supplied to the drill tip via a channel outlet on the end side of the cooling medium and / or lubricant channel, i.e., assisting chip removal outward via the drill-chip evacuation groove during the drilling stroke and / or milling stroke. Preferably, both the milling-chip evacuation groove and the drilling-chip evacuation groove are open on the end side at the drill tip. Furthermore, it is preferable that the groove depth of each milling-chip evacuation groove decreases along its length until it reaches zero in the direction of the clamping shank. Thus, the milling-chip evacuation groove is configured in a blade shape, thereby ensuring that during the milling stroke, the generated chips move towards the bottom of the produced hole and are discharged outward via the flow of cooling medium and / or lubricant along the drill-chip evacuation groove. For this reason, it is also advantageous that the groove length and / or groove depth of the milling-chip removal groove are significantly smaller than the groove length and / or groove depth of the drilling-chip removal groove.

[0020] The drilling and milling tool, along with its drilling head, its support head, and its milling head, is preferably made of a solid material, for example, by grinding. In this case, related to the manufacturing technology, only drilling and milling tools with minimal component taper / reduction (e.g., 1 to 2 μm for a component length of 100 mm) can be manufactured. In this context, the following cutting edge geometry is advantageous: that is, the drilling-longitudinal cutting edge and the milling-longitudinal cutting edge are separated, specifically divided into end-side edge sections that extend the edge length from the respective tool tip toward the clamping shank. Preferably, to avoid feed marks, the end-side edge sections have a smaller component taper compared to the edge sections further away from the end side. Preferably, the edge length of the end-side edge sections corresponds at least to the milling-feed amount per revolution in the milling stroke, for example, 1 mm per revolution.

[0021] For a successful milling operation following the drilling stroke, the key is to use as many milling heads as possible, such as five. In this context, the cross-section of the drill-chip flute and / or the supporting chip flute can be reduced towards the drill tip, specifically, by simultaneously increasing the rib width of the corresponding drill rib in the circumferential direction. In this way, the available structural space for the milling heads at the drill tip is increased, thereby allowing for the construction of a greater number of milling heads.

[0022] Drilling and milling tools may have a chamfering cutter at the transition between the drill body and the clamping shank. During the drilling stroke, the chamfering cutter creates a hole-bevel.

[0023] The following describes the special drill tip geometry of the milling tool: Accordingly, the milling tool has a flattened end face at the drill tip. This end face can surround a centrally formed tapered drill tip protrusion, which extends axially from the flattened end face. The drilling end cutting edge (and the support end cutting edge) can extend almost to the tapered tip of the drill tip protrusion.

[0024] In one variant, all milling cutters, especially the end-side milling tips, can be repositioned relative to the drilling cutter by the same axial offset (Δx1). In this case, all milling cutters can be arranged at the same axial height. Alternatively, to ensure that the milling cutters are unloaded, the axial offset (Δx1) can correspond at least to the maximum drilling feed per revolution (vfu) (e.g., 0.3 mm) plus a safety margin (S).

[0025] Accordingly, to achieve a more uniform cut-load distribution, all drilling and milling cutters can be axially offset from each other by an axial displacement (Δx2). To ensure no load on the milling cutter, each axial displacement / pitch (Δx2) can correspond to the maximum feed rate per revolution (v). fz (e.g., 0.05mm) plus a safety margin (S). Applicable to: v fz = , in, v fz = Feed rate per tooth revolution v fu = Drill feed rate per revolution z = Number of blades S = safety margin.

[0026] To prevent lateral deflection during the drilling stroke, drilling and milling tools may have circumferentially distributed support chamfers (round chamfers) on the back of the drill bit that extend along the tool rotation axis.

[0027] A milling-chip evacuation groove can be arranged before each milling cutter head in the tool rotation direction. The chip evacuation groove surface transitions into the support chamfer (round chamfer) on the side of the milling cutter head at the milling longitudinal cutting edge. This support chamfer can transition into the free surface in the opposite direction of the tool rotation direction.

[0028] During the drilling stroke, all support chamfers can contact the hole wall. Furthermore, during the milling stroke, the support surfaces of all support chamfers can be used as free surfaces that do not contact the hole wall. The drilling longitudinal cutting edges and the milling longitudinal cutting edges can be located on the same tool diameter.

[0029] Milling-chip evacuation grooves, drilling-chip evacuation grooves, and support-chip evacuation grooves may be open at the end side of the drill tip, and in particular, towards the clamping shank, the groove depth of each milling-chip evacuation groove decreases along its length until it becomes zero. The groove length and / or groove depth of the milling-chip evacuation groove may be significantly smaller than the groove length and / or groove depth of the drilling-chip evacuation groove or the support-chip evacuation groove.

[0030] Drilling and milling tools can be made from a solid material by grinding, in which the drill bit, support bit, and milling bit are made of the same material and integrally integrated into the drill body. After grinding, a wear-resistant material layer can be applied to the tool area to improve the tool's durability.

[0031] Due to manufacturing limitations, drilling and milling tools cannot be entirely cylindrical; instead, they can only be produced with minimal component taper / reduction (e.g., 0.1 mm over a 100 mm component length). In this case, the drilling-longitudinal cutting edge and the milling-longitudinal cutting edge can be separately divided into end-side edge segments and edge segments away from the end-side edge segments. The end-side edge segments can extend their edge length from the corresponding tool tip towards the clamping shank and transition into the edge segments away from the end-side edge segments. Furthermore, to avoid feed marks during the milling stroke, the end-side edge segments can have a smaller component taper compared to the edge segments away from the end-side edge segments. For example, the edge length can correspond at least to the feed per revolution, e.g., 1 mm.

[0032] The cross-section of the chip removal groove in the drilled hole or support chip removal groove can widen towards the clamping shank. This widening of the chip removal groove's cross-section facilitates chip removal.

[0033] To reduce the cross-section of the chip removal groove, the drilling chip removal groove can have a groove sidewall that has an end wall section that is inclined toward the groove cavity.

[0034] At the tapered transition between the drill body and the clamping shank, at least one chamfering cutter can be constructed, which creates a hole-chamfer at small-diameter holes. Drill-chip flutes and / or support-chip flutes can extend beyond the tapered transition, specifically in the case of the chamfering cutter.

[0035] Drilling and milling tools may have a flattened end face at the drill tip, which surrounds a centrally formed tapered drill tip protrusion. The drilling end-cutting edge and / or the support end-cutting edge may extend almost to the tapered tip of the drill tip protrusion. Attached Figure Description

[0036] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0037] As shown in the attached figure: Figures 1 to 3 4a and 4b show different views of the drilling and milling tool according to the present invention; Figure 5 a through 5f show views illustrating process routes that can be performed using drilling and milling tools; Figures 6 to 8 Other views of the drilling and milling tool according to the invention are shown; and Figure 9 and 10 The sides of the milling / drilling tools are shown in an unfolded manner. Detailed Implementation

[0038] exist Figure 1 The drilling and milling tool according to the invention is shown in different views in sections 4 to 4. Thus, the drilling and milling tool includes a clamping shank 1, the clamping shank having a drill body 3 connected thereon. The drill body 3 is configured to have two drill-ribs 5 and 6 (…). Figure 7 The drill bit ribs extend along the tool-rotation axis and also define the drill-chip removal groove 7 and the support-chip removal groove 8 in the tool-circumferential direction.

[0039] The drilling and milling tool according to the invention includes exactly one drill bit 9, which consists of a drilling longitudinal cutting edge 11 and a drilling end cutting edge 13. At the drilling longitudinal cutting edge 11, the chip removal groove surface 15 of the drilling chip removal groove 7 transitions into the drill bit back 17. The drilling end cutting edge 13 extends laterally at the drill bit tip 16. Furthermore, the drilling end cutting edge 13 merges with the drilling longitudinal cutting edge 11 at the radially outer drilling tip 19.

[0040] As from Figure 2 The drilling and milling tool has an additional support head 14 on its tool side, diagonally opposite the drill bit 9 relative to the axis of rotation. The support head 14 has a support-end cutting edge 18 extending laterally at the drill tip 16. The support-end cutting edge transitions into a support-longitudinal edge 22 at the radially outer support-tip 20. In the rotational direction, a support-chip evacuation groove 8 is arranged before the support head 14. The chip evacuation groove surface 24 of the support-chip evacuation groove transitions into the peripheral drill back 17 at the laterally extending support-end cutting edge 18.

[0041] As from Figure 3 It was also found that the length l1 of the laterally extending support-end cutting edge 18 is much shorter than the length l2 of the laterally extending drill-end cutting edge 13. In this way, the chip groove cross-section of the support-chip groove 8 can be designed to be smaller than that in the drill-chip groove 7 to ensure reliable chip removal. Figure 3In this configuration, the radially outer support-tip 20 is positioned on a tool diameter smaller than that of the radially outer drill-tip 18. Therefore, during drilling, the drill bit 9 and the laterally extending support-end cutting edge 18 engage in a cutting contact, while the support-longitudinal edge 22 is unloaded, meaning it does not engage in a cutting contact.

[0042] exist Figure 3 The diagram illustrates a cutting force F1 that acts on the laterally extending drill-end cutting edge 13 during drilling. To prevent tool vibration associated with the cutting force during drilling, a support head 14 is provided according to the invention. A support force F2, opposite to the cutting force F1, acts on the support head 14. Through the two opposing forces F1 and F2, force compensation is provided at least partially, thereby preventing tool vibration during drilling.

[0043] The design of the laterally extended support-end cutting edge 18 ensures that the drilling process proceeds stably (vibration-free). However, the support-end cutting edge 18 must be as short as possible. A long support-end cutting edge 18 (due to more chip generation) requires a correspondingly large support-chip groove 8, which could compromise tool stability. In such cases, the milling process may become unstable or require very small feed rates.

[0044] As from Figure 2 It is also found that a total of five milling cutter heads 21 are constructed sequentially in a circumferentially distributed manner at the drill bit back 17. All milling cutter heads 21 are positioned at the same axial tool height. Furthermore, all milling cutter heads 21 have the same cutter head geometry. Accordingly, each milling cutter head 21 is configured to have a milling longitudinal cutting edge 23 extending linearly along the tool rotation axis, with the milling longitudinal cutting edge at the drill bit tip 16 at the end-side milling tip 25 (…). Figure 4a End at )

[0045] As from Figure 1 , 4a As obtained in 4b, the milling tip 25 of the end face of the milling cutter head 21 is axially displaced by an amount Δx relative to the drilling end cutting edge 13. In the simplified diagram shown in Figure 4, only the important contour lines are highlighted, which show the drilling cutter head 9 and the milling cutter head 21 with the relatively displaced axial displacement Δx. This axial displacement Δx causes the drilling stroke B (described later) to... Figure 5 In this process, only the drilling head 9 engages with the workpiece material for cutting, while the milling head 21 does not. The axial displacement Δx corresponds at least to the drilling feed rate f per revolution in the drilling stroke B, which will be described later. B (e.g., 0.2mm) to ensure that the milling cutter head 21 is unloaded.

[0046] To prevent lateral deflection during the drilling stroke B, the milling tool has multiple circumferentially distributed support chamfers 27, 28 at the drill bit back 17. Figure 3 The support chamfer extends along the tool's rotation axis. Next, regarding support chamfers 27 and 28, the support chamfer 27 on the drill bit side will be described first. Figure 2 and 3 The support chamfer merges with the chip removal groove surface 15 of the drill-longitudinal cutting edge 11 at the drill-chip removal groove 7.

[0047] As from Figure 2 and 3 It is also found that, in the tool-rotation direction, a milling-chip removal groove 29 is arranged before each milling cutter head 21. The discharge groove surface of the milling-chip removal groove transitions at the milling-longitudinal cutting edge 23 into the support surface of the support chamfer (round grinding chamfer 28) on the side of the milling cutter head, which in Figure 3 As shown in the image.

[0048] exist Figure 3 In the middle, the support surfaces of the corresponding support chamfers 27 and 28 transition into the free surface 33 in the opposite direction to the tool-rotation direction in the continuing direction, and the free surface bends from the support surface at a free angle. In the continuing direction in the circumferential direction, the milling-chip groove 29 or the drilling-chip groove 7 connects to the corresponding free surface 33.

[0049] Both the drilling longitudinal cutting edge 11 and the milling longitudinal cutting edge 23 are located on the same tool diameter.

[0050] In addition, the drilling and milling tool has a cooling medium and / or lubricant channel, which has a channel outlet 36 on the end side for supplying cooling medium and / or lubricant to the drill tip 16. Figure 3 During the drilling stroke B and / or milling stroke F, the cooling medium and / or lubricant assists in the outward discharge of chips through the chip removal grooves 7, 8, and 29.

[0051] Not only the milling-chip removal groove 29, but also the drilling-chip removal groove 7 is open on the end side at the drill tip 16. In the direction of the clamping shank 1, the groove depth of each milling-chip removal groove 39 is within the groove length l. F Decrease upwards until it reaches zero. For example, from... Figure 1 The groove length l of the milling-chip removal groove 39 is obtained from this. F And / or the groove depth is significantly less than the groove length l of the drill-chip removal groove 7 or the support-chip removal groove 8. B And / or groove depth.

[0052] The geometry of the drill tip 16 is described below: The drill tip 16 thus has a flattened end face 37 surrounding a centrally shaped tapered drill tip protrusion 39. The bore-end cutting edge 13 extends almost to the tapered tip 41 of the drill tip protrusion 39. Correspondingly, the support-end cutting edge 18 also extends almost to the tapered tip 41 of the drill tip protrusion 39.

[0053] The milling tool has a chamfering cutter 49 at the transition between the drill body 3 and the clamping shank 1. Figure 1 The chamfering tool creates a hole-chamfer 51 at the small-diameter hole 57. Figure 5 c).

[0054] Next, according to Figure 5 The preferred process route is described, which can be performed using the drilling and milling tool according to the invention: accordingly, during the drilling stroke B, the rotating drilling and milling tool is pushed into the workpiece 55 along the drilling-feed direction until the theoretical drilling depth t is reached. S ( Figure 5 c), specifically, in the case of forming a small-diameter hole 57. After the drilling stroke B ends, a reverse stroke R is performed, during which the drilling and milling tool is guided out of the small-diameter hole 57. Immediately afterwards, in preparation for the milling stroke F, the guided drilling and milling tool is controlled to deflect radially by an amount Δr. Along the milling-feed direction, which is the same as the drilling-feed direction, the radially deflected drilling and milling tool is reintroduced into the small-diameter hole 57, thereby enlarging the small-diameter hole into a large-diameter hole 59. Figure 5 f). The milling stroke F is performed by means of a drilling and milling tool moving in a circular path around the axis of the drill hole and rotating the tool.

[0055] The drilling and milling tool according to the invention is made of a solid material, for example, by grinding. Related to the manufacturing technology, the drilling and milling tool necessarily possesses [specific characteristics]. Figure 6 The minimum component taper is shown in an exaggerated manner, for example, 0.1 mm over a structural length of 100 mm.

[0056] In this context, to avoid feed marks, the following tool geometry is advantageous: that is, according to Figure 6 The drilling-longitudinal cutting edge 11 and the milling-longitudinal cutting edge 23 are each divided into edge segments 67 on the end sides, which extend from the corresponding tool tips 25 and 19 by an edge length x. K And it transitions to edge segment 69, which is the edge segment furthest from the end. Edge segment 67 on the end side has a smaller member taper than edge segment 69, which is the edge segment furthest from the end. Here, the edge length x K At least corresponding to the feed rate f per revolution in the milling stroke F. F(For example, 1 mm), so that the process can reliably avoid feed marks when producing large-diameter holes 59. Figure 6 In the text, for the sake of simpler understanding, the taper of the component is pointed out in an exaggerated way.

[0057] Furthermore, preferably, the cross-section of the chip removal groove 7 (and, if necessary, the support chip removal groove 8) decreases towards the drill tip 16, specifically, while simultaneously increasing the rib width of the corresponding drill rib 5 in the circumferential direction. In this way, the structural space available for the milling cutter head 21 at the drill tip 16 is increased. To reduce the chip removal groove cross-section, in Figure 7 In the drill-chip removal groove 7, the groove-sidewall 71 has an end-side wall section 75 that is inclined toward the groove cavity.

[0058] exist Figure 9 The side of the drilling and milling tool is shown in an unfolded manner. Accordingly, the distribution intervals t1 to t6 between the drilling head 9 and the milling head 21 are constant in the circumferential direction. Furthermore, in Figure 9 In this configuration, all milling cutter heads 21 are arranged at the same axial height. To ensure that the milling cutter heads 21 are unloaded during drilling, the milling cutter heads 21 are axially offset relative to the drilling cutter head 9 by an amount Δx1. Figure 9 In this context, the axial displacement Δx1 corresponds to the maximum drilling feed rate v per revolution. fu (For example, 0.3mm) plus a safety margin S.

[0059] exist Figure 10 Alternative implementation variations are shown. Accordingly, the milling cutter heads 21 are not arranged at the same axial height. Instead, in Figure 10 In this configuration, all drilling and milling cutters 9 and 21 are spaced apart by the same axial offset Δx2. To ensure that the milling cutter 21 is unloaded, each axial offset Δx2 corresponds to the maximum feed rate v per revolution. fz (For example, 0.05mm) plus a safety margin S. Applicable to: Δx2 = v fz + S = , in, v fz = Feed rate per tooth revolution v fu = Drill feed rate per revolution z = the number of knives 9 and 21 S = safety margin.

[0060] For example, the drilling feed rate v per revolution is 0.3 mm. fuWhen a total of six cutters are used (9, 21), a tooth feed rate v of 0.05 mm is obtained. fz In addition, there is a safety margin S.

[0061] List of reference numerals

[0062] 1 clamping handle

[0063] 3 drill bit body

[0064] 5, 6 drill bits - ribs

[0065] 7 Drilling - Chip Removal Groove

[0066] 8-Support Chip Removal Groove

[0067] 9-point drilling tool

[0068] 11 Drilling - Longitudinal Cutting Edge

[0069] 13 Drilling - End Cutting Edge

[0070] 14 Supporting Cutting Head

[0071] 15 chip face

[0072] 16 drill bit tip

[0073] 17-bit drill bit - back

[0074] 18 Supports - End Cutting Edges

[0075] 19 Drilling - Cutting Edge

[0076] 20 Supports - Blade Tip

[0077] 21 Milling cutter head

[0078] 22 Supports - Longitudinal Edges

[0079] 23 Milling - Longitudinal Cutting Edge

[0080] 24 chip removal groove surface

[0081] 25-inch end mill tip

[0082] 27, 28 Support chamfer

[0083] 29 Milling - Chip Removal Groove

[0084] 33 Free Sides

[0085] Entrance to Channel 36

[0086] 37 Free surface on the end side

[0087] 39. Tapered drill bit tip - protrusion

[0088] 41 Conical apex

[0089] 49, 50 chamfering tools

[0090] 51-hole chamfer

[0091] 55 workpieces

[0092] 57 Small diameter holes

[0093] 59 large diameter holes

[0094] 67 End side edge-section

[0095] 69 Edges and sections furthest from the end

[0096] 71, 72 slots - sidewalls

[0097] 73 slot bottom

[0098] 75 groove - end wall section of the side wall

[0099] x K Edge length

[0100] B drilling stroke

[0101] F Milling stroke

[0102] R reverse travel

[0103] t S Theoretical hole depth

[0104] l F l B l S Chip removal groove length

[0105] v fu Drilling feed rate

[0106] v fz Tooth feed rate

[0107] n B Drilling speed

[0108] f F feed rate

[0109] n F Milling speed

[0110] D1 and D2 have different hole diameters.

[0111] F1 Cutting Force

[0112] F2 support force

[0113] l1 Support - Length of the end cutting edge

[0114] L2 Drilling - Length of the End Cutting Edge

[0115] Distribution interval from t1 to t6

[0116] The quantity of z-knife 9, 21

[0117] S safety margin

[0118] Δr radial offset

[0119] Axial displacement of Δx1 and Δx2

[0120] v fz Feed rate per revolution

[0121] v fu Drill feed rate per revolution

Claims

1. A drilling and milling tool having a drill bit (9) having a drilling-longitudinal cutting edge (11) and a drilling-end cutting edge (13) extending laterally at the drill tip (16), the drilling-end cutting edge converging with the drilling-longitudinal cutting edge (11) at a radially external drilling-tip (19), wherein, The drilling tool also has a milling head (21) constructed on the drill bit back (17), wherein during drilling, a cutting force (F1) acts on the laterally extending drill end cutting edge (13), wherein, to stabilize the drilling process, the drilling and milling tool has at least one support head (14) that generates a support force (F2), the length (l1) of which is designed to prevent the tool from vibrating due to the corresponding forces (F1, F2), wherein the support head (14) has a position at the drill tip (16). The laterally extending support-end cutting edge (18) merges with the support-longitudinal edge (22) at the radially outer support-tool tip (20). It is characterized in that the length (l1) of the laterally extending support-end cutting edge (18) is reduced compared to the length (l2) of the laterally extending drilling-end cutting edge (13). As a result, the chip groove cross-section, groove depth and / or groove length of the support-chip groove (8) can be designed to be smaller than that in the drilling-chip groove (7), thereby improving tool stability during drilling / milling.

2. The drilling and milling tool according to claim 1, characterized in that, The radially outer support-tip (20) is located on a smaller tool diameter than the radially outer drill-tip (19), so that during drilling, the drill head (9) and the laterally extending support-end cutting edge (18) cut into each other, while the support-longitudinal edge (22) is unloaded, that is, uncut into each other.

3. The drilling and milling tool according to any one of the preceding claims, characterized in that, The drill bit (9) and the support bit (14) are arranged on opposite tool sides with reference to the tool-rotation axis, and / or the laterally extending drill-end cutting edge (13) and the laterally extending support-end cutting edge (18) are extended at an angle of approximately 180° in the circumferential direction.

4. The drilling and milling tool according to claim 1 or 2, characterized in that, The drilling and milling tool has two drill-ribs (5, 6) extending along the axis of rotation, which define a drill-chip removal groove (7) and a support-chip removal groove (8) in the circumferential direction.

5. The drilling and milling tool according to claim 1 or 2, characterized in that, The drilling and milling tool is designed for a process in which, during the drilling stroke (B), a rotating drilling and milling tool is pushed into the workpiece (55) along the drilling-feed direction until the theoretical drilling depth (ts) is reached, specifically in the case of forming a small diameter hole (57), wherein, in order to prepare for the milling stroke (F), the drilling and milling tool is controlled to deflect a radial offset (Δr), and then, during the milling stroke (F), the drilling and milling tool enlarges the small diameter hole (57) into a large diameter hole (59) along a milling-feed direction that is the same as or opposite to the drilling-feed direction, specifically in the case of circular motion along a circular trajectory about the drilling axis and in the case of tool rotation.

6. The drilling and milling tool according to claim 5, characterized in that, During the drilling stroke (B), a small-diameter hole (57) with a hole-chamfer (51) is created. After the drilling stroke (B) ends, a reverse stroke (R) is performed. During the reverse stroke, the drilling tool is guided out of the small-diameter hole (57). The radial offset (Δr) of the guided drilling tool is controlled. Then, the milling stroke (F) begins. During the milling stroke, the drilling tool is pushed into the small-diameter hole (57) by a helical motion.

7. The drilling and milling tool according to claim 1 or 2, characterized in that, The milling cutter heads (21) have the same cutter head geometry, in which each milling cutter head (21) has a milling longitudinal cutting edge (23) extending along the tool-rotation axis, the milling longitudinal cutting edge ending at the milling tip (25) on the end side at the drill tip (16).

8. The drilling and milling tool according to claim 1 or 2, characterized in that, The distribution interval between the drilling head (9) and the milling head (21) is constant in the circumferential direction.

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