TOOL FOR MACHINING

Description

[0001] The present invention relates to a tool for machining according to the preamble of claim 1 and a method for fastening a cutting insert to a seat of a base body of such a tool.

[0002] When machining metallic materials in particular, and increasingly also composite materials, tools are often used in which the cutting edges that engage with the material to be machined are formed on replaceable cutting inserts made of a hard, wear-resistant material and arranged in seats provided for this purpose on a base body made of a tougher material, such as tool steel, for example. The replaceable cutting inserts are often designed as so-called indexable cutting inserts or cutting inserts that have a plurality of cutting edges that can be brought into an active cutting position on the base body one after the other when the preceding cutting edge is worn. The cutting inserts can typically be made of cemented carbide, cermet or a cutting ceramic.

[0003] In tools designed for machining by milling, the base body has a rotation axis around which the base body rotates during operation of the tool.

[0004] The base body, for example, may have only one seat for accommodating an interchangeable cutting insert. Typically, however, several such seats are provided, distributed around the circumference of the base body of the tool. To increase productivity when machining with such tools, there is a trend toward operating the tools at increasingly higher speeds for suitable materials and designing them as so-called high-speed milling cutters or high-speed cutters, where the speeds often reach several tens of thousands of revolutions per minute.

[0005] When such tools are operated at very high speeds, in addition to the typically occurring cutting forces acting mainly in the tangential and axial directions, the centrifugal forces acting on the cutting inserts due to the high speeds also pose a problem. Where the terms radial, axial and tangential are used in the following description, these refer to the axis of rotation of the base body of the tool, unless the specific context indicates otherwise.

[0006] The high centrifugal forces can, for example, in the case where the cutting insert is attached to the seat by a fastening screw, cause the position of the cutting inserts in their seats on the base body to change. In extreme cases, this can even lead to a failure of the fastening screw, causing the cutting insert to detach from the seat. If this occurs during machining, it can lead to damage to the workpiece being machined and also poses a safety risk.

[0007] US 10,286,459 B2 describes a tool according to the preamble of claim 1.

[0008] US 3,805,351 A describes a method for reversibly securing a cutting insert in a recess on the circumference of a rotating tool body by means of a threaded clamping element adapted to clamp the cutting insert flat against a seating surface and firmly against edge positioning surfaces when the clamping element is screwed into the tool body.

[0009] EP 1 083 017 A1 describes a cutting tool for high-speed machining, in which the seat for receiving an interchangeable cutting insert is provided with a shape which interacts to a certain extent in a form-fitting manner with the underside of the cutting insert.

[0010] It is an object of the present invention to provide an improved tool for machining at high rotational speeds, an improved use of a cutting insert and an improved method for fastening a cutting insert, in which a cutting insert is reliably supported against acting centrifugal forces in a manner insensitive to manufacturing tolerances and the clamping force with which the cutting insert is clamped in a seat can be specified within a narrower range.

[0011] The object is achieved by a tool for machining according to claim 1. Advantageous further developments are specified in the dependent claims.

[0012] The tool has a base body which has an axis of rotation around which the tool rotates during operation, at least one seat formed on the base body for receiving an interchangeable cutting insert, a fastening screw for fastening the cutting insert to the seat, and a cutting insert fastened to the seat. The seat has a base surface for supporting an underside of the cutting insert, a first lateral contact surface for contacting a first side surface of the cutting insert, which first lateral contact surface supports the cutting insert radially inward, and a second lateral contact surface for contacting a second side surface of the cutting insert, which second lateral contact surface supports the cutting insert axially and radially outward. A bore for receiving the fastening screw is formed in the base surface.The bore has a threaded bore spaced from the base surface and an unthreaded bore portion closer to the base surface. The fastening screw has a threaded portion for engaging with the threaded bore, a head portion for supporting in a through hole of the cutting insert, and an unthreaded shank portion between the threaded portion and the head portion. This unthreaded shank portion has a smaller cross-section than the unthreaded bore portion.The cutting insert is fastened to the seat in such a way that the head section of the fastening screw is supported on the through hole of the cutting insert, the threaded section of the fastening screw cooperates with the threaded bore and the head section of the fastening screw is elastically deflected in such a way that the thread-free shank section is supported on the thread-free bore section in a radially outer and axially towards a free end of the tool second quadrant when viewed perpendicular to the base surface.

[0013] Viewed perpendicular to the base surface, the bore has four quadrants, two of which (a third quadrant and a fourth quadrant) are located radially inward, i.e., closer to the rotational axis of the base body, and two (a first quadrant and a second quadrant) are located radially outward, i.e., farther from the rotational axis of the base body. One of the radially inward quadrants, the third quadrant, and one of the radially outward quadrants of the bore, the second quadrant, are each located axially toward the free end of the tool, which is also referred to below as the "axial front." The other of the radially inward quadrants, the fourth quadrant, and the radially outward quadrant, the first quadrant, are each located away from the free end of the tool, i.e., toward the clamping end of the tool, which is also referred to below as the "axial rear."Thus, viewed clockwise, there is a radially outer first quadrant axially facing away from the free end, a radially outer second quadrant axially facing towards the free end, a radially inner third quadrant axially facing towards the free end, and a radially inner fourth quadrant axially facing away from the free end.

[0014] Since the second lateral contact surface is provided for contacting a second side surface of the cutting insert, which supports the cutting insert axially and radially outwards, and in addition the fastening screw is elastically deflected in such a way that the thread-free shaft section is supported on the thread-free bore section in the second quadrant located radially outer and axially in the direction of the free end of the tool, the cutting insert is supported against centrifugal force in a form-fitting manner at two spatially spaced-apart positions, so that migration of the cutting insert from the seat is reliably prevented even at high speeds of the tool.Since the support of the unthreaded shank section on the unthreaded bore section is achieved through an elastic deflection of the head section and the unthreaded bore section of the fastening screw, manufacturing tolerances of the first and second lateral contact surfaces, the bore, and the fastening screw can be reliably compensated for by the elastic deformation of the fastening screw. Furthermore, the clamping force with which the cutting insert is clamped to the seat can be specified by the elastic properties of the clamping screw.

[0015] According to a further development, the unthreaded shaft section is spaced from the unthreaded bore section in a fourth quadrant located radially inside and facing away from the free end of the tool. The unthreaded bore section therefore has a corresponding oversize compared to the unthreaded shaft section of the fastening screw, so that the latter can be elastically deflected without hindrance until the unthreaded shaft section rests against the unthreaded bore section in the quadrant located radially outside and towards the free end of the tool. In this way, tolerances of the cutting insert and the lateral contact surfaces can be compensated particularly well. Preferably, the unthreaded shaft section is also spaced from the unthreaded bore section in the first quadrant and in the third quadrant.

[0016] If the head section of the fastening screw is elastically deflected radially outwards and axially towards the free end of the tool, the cutting insert is clamped particularly reliably against both the first lateral contact surface and the second lateral contact surface.

[0017] According to a further development, the first lateral contact surface and the second lateral contact surface form an angle of <75° with each other in a viewing direction perpendicular to the base surface. In this case, the cutting insert is enclosed in a particularly reliable form-fitting manner and thus protected against acting centrifugal forces. The angle can preferably be <65°. The angle enclosed by the first lateral contact surface and the second lateral contact surface is preferably >35°, more preferably >40°, in order to ensure reliable enclosing of the cutting insert at the seat.

[0018] According to a further development, the head section of the fastening screw has a largest cross-section perpendicular to an axis of the fastening screw that is larger than the smallest cross-section of the through hole. In other words, in this case, the head section of the fastening screw cannot be passed through the through hole of the cutting insert. In this case, the cutting insert is particularly reliably secured to the seat with a positive fit.

[0019] According to a further development, a longitudinal axis of the threaded bore is offset from the longitudinal axis of the bore in a plane of contact between the head portion of the fastening screw and the through hole of the cutting insert in the direction of the first lateral contact surface and in the direction of the second lateral contact surface. In this case, the cutting insert is reliably clamped in the direction of the first lateral contact surface and in the direction of the second lateral contact surface, and the unthreaded shank portion of the fastening screw is reliably brought into contact with the unthreaded bore portion by elastic deflection.

[0020] If a surface normal of the first lateral contact surface has a radially outward directional component as its main component, then the first lateral contact surface supports the cutting insert particularly reliably against radially inward forces. In addition to the radially outward directional component, the surface normal can also have smaller directional components in the axial and / or tangential directions.

[0021] According to a further development, a surface normal of the second lateral contact surface has an axial directional component and a radially inward directional component. In this case, the cutting insert is reliably supported by the second lateral contact surface against axial forces and centrifugal forces. The surface normal of the second lateral contact surface can also have a smaller tangential directional component.

[0022] According to a further development, a surface normal of the base surface has a tangential directional component as its main component. In this case, the cutting insert is supported particularly reliably at the seat against the cutting forces acting primarily in the tangential direction. The surface normal of the base surface can also have smaller directional components in the radial and / or axial directions.

[0023] According to a further development, the wall of the unthreaded bore section is concavely curved in the circumferential direction on the bore side, at least in the second quadrant of the bore located radially outward and axially toward the free end of the tool. In this case, tolerances in the region of the first lateral contact surface and the second lateral contact surface, as well as the cutting insert interacting with them, are compensated particularly reliably by allowing the contact area of ​​the unthreaded shank section on the unthreaded bore section to adjust within a larger angular range in the second quadrant upon elastic deflection of the head section.

[0024] According to a further development, the threadless bore section has a substantially circular cross-section. In this case, the threadless bore section can be formed particularly simply and cost-effectively. However, it is also possible to form the threadless bore section with a cross-sectional shape that deviates from a circular cross-section.

[0025] According to a further development, the threadless bore section is formed parallel to the threaded bore. This enables particularly simple and cost-effective production of both the bore and the fastening screw accommodated therein. Preferably, the threadless bore section is formed coaxially with the threaded bore.

[0026] According to a further development, the tool is a high-speed milling cutter designed for machining at speeds exceeding 10,000 revolutions per minute. Reliable protection against centrifugal forces is particularly important for tools designed for machining at high speeds.

[0027] The object is also achieved by a method for fastening a cutting insert according to claim 14.

[0028] The method achieves the advantages described above with reference to the tool. The advantageous developments described with reference to the tool can also be advantageously applied to the method.

[0029] Further advantages and benefits of the invention will become apparent from the following description of an embodiment with reference to the accompanying figures. From the figures show

[0030] Fig. 1: a perspective view of a tool according to an embodiment; Fig. 2: an enlarged view of the seat with the cutting insert arranged thereon in the circled area B of Fig. 1 , but without fastening screw; Fig. 3: a Fig. 2 corresponding representation, but additionally without cutting insert; Fig. 4: a schematic representation of the fastening screw in the embodiment; Fig. 5: a schematic sectional representation in a plane containing the longitudinal axis of the threaded bore, in the area of ​​the seat with the cutting insert arranged thereon, but without fastening screw; Fig. 6: a schematic perspective representation of the cutting insert in the embodiment; Fig. 7: a Fig. 5 corresponding sectional view with fastening screw in a non-tightened state of the fastening screw; Fig. 8: a Fig. 7 corresponding sectional view, but with the fastening screw in a tightened state; Fig. 9: a schematic sectional view in a direction perpendicular to a longitudinal axis of the bore in the region of the thread-free bore section with the fastening screw in a non-tightened state; and Fig. 10: a Fig. 9 corresponding schematic sectional view, but with the fastening screw in a tightened state. EMBODIMENT

[0031] An embodiment is described in more detail below with reference to the figures.

[0032] In the concretely illustrated embodiment, the tool 100 for machining is designed as a milling tool, in particular as a high-speed milling cutter designed for machining at a speed of up to several tens of thousands of revolutions per minute.

[0033] The tool 100 has a base body 1, which can be made, for example, from a tool steel, tungsten heavy metal such as Densimet®, or a hard metal. The base body 1 has a first end 11, which is provided with an interface for indirect or direct connection to a drive spindle of a processing machine (not shown), and a free end 12 facing away from the first end 11. The base body 1 has a rotational axis R, about which the tool 100 rotates during operation, i.e., during machining.

[0034] As in Fig. 1 As can be seen, in the area of ​​the free end 12 in the base body 1, a plurality of seats 2 for receiving replaceable cutting inserts 3 are provided. The seats 2 are arranged distributed over the circumference of the base body 1. Although in the specifically illustrated embodiment, a base body 1 is shown which has a total of four seats 2 for receiving replaceable cutting inserts 3, fewer such seats 2, but at least one, or more than four seats 2 can be provided. The seats 2 are arranged in such a way that a cutting insert 3 arranged in them protrudes axially with a secondary cutting edge 31 beyond the free end 12 of the base body 1 and protrudes radially with a main cutting edge 32 beyond the base body 1.The seats 2 are designed for so-called radial clamping of the cutting inserts 3, in which the main extension plane of the cutting insert 3 fastened to the respective seat 2 runs essentially radially and the longitudinal axis of the fastening screw 5, with which the cutting insert 3 is fastened to the seat, extends predominantly in the tangential direction. Since the seats 2 are essentially identical to one another and the cutting inserts 3 arranged on them are also at least essentially identical to one another, only one seat 2 and the fastening of a cutting insert 3 to it will be explained in more detail below.

[0035] The cutting insert 3 has a substantially polygonal basic shape with a bottom side 33 and an upper side 34 opposite the bottom side 33, which is designed as a chip surface, as shown in particular in Fig. 6 can be seen. The underside 33 and the upper side 34 are connected to each other via side surfaces. A through-hole 36 extends from the upper side 34 to the underside 33 through the cutting insert 3. The secondary cutting edge 31 and the main cutting edge 32 are formed along the transition from the upper side 34 to the side surfaces and are connected to each other via a cutting corner 35. In the specifically illustrated embodiment, the cutting insert 3 has a two-fold rotational symmetry with respect to the longitudinal axis of the through-hole 36, so that two cutting edge sections are provided, each having a main cutting edge 32 and a secondary cutting edge 31 connected to the main cutting edge via a cutting corner 35. As in Fig. 1 As can be seen, in the mounted state of the cutting insert 3 on the base body 1, one of the two cutting edge sections is in an active position in which the main cutting edge 32 protrudes radially beyond the base body 1 and the secondary cutting edge 31 protrudes axially beyond the base body 1, the other of the two cutting edge sections is in an inactive position.

[0036] Although in the concretely illustrated embodiment, a cutting insert 3 is shown in which cutting edge sections are provided only at the transition from the upper side 34 to the side surfaces, in a modification a double-sided design of the cutting insert is also possible in which cutting edge sections are also provided at the transition from the lower side 33 to the side surfaces.

[0037] The cutting insert 3 has a first side surface 37, with which the cutting insert 3 is supported radially inwardly against the seat 2. The first side surface 37 is formed on the side of the cutting insert 3 opposite the main cutting edge 32 in the active position. Due to the described two-fold rotational symmetry, a further first side surface 37 is also located below the main flank surface of the active main cutting edge 32, which is associated with the opposite inactive main cutting edge 32.

[0038] The cutting insert 3 further has a second side surface 38, with which the cutting insert 3 is supported axially and radially outwardly on the seat 2. The second side surface 38 is formed on the side of the cutting insert 3 opposite the secondary cutting edge 31 in the active position. Due to the described two-fold rotational symmetry, a further second side surface 38 is also located on the side of the active secondary cutting edge 31, which is associated with the opposite inactive secondary cutting edge 31.

[0039] In the following, the seat 2 in which the cutting insert 3 is held is described with reference to Fig. 3 described in more detail.

[0040] The seat 2 has a base surface 21 for supporting the underside 33 of the cutting insert 3, a first lateral contact surface 22 for supporting the first side surface 37 of the cutting insert 3 and a second lateral contact surface 23 for supporting the second side surface 38 of the cutting insert 3.

[0041] A surface normal of the base surface 21 has a tangential directional component as its main component. In addition, the surface normal of the base surface 21 can also have smaller axial and / or radial directional components.

[0042] The first lateral contact surface 22 supports the cutting insert 3 radially inward. The first lateral contact surface 22 can, for example, be formed as a continuous surface. However, it is also possible, for example, for the first lateral contact surface 22 to have a plurality of separate partial surfaces for radially inward support, as is the case, for example, in Fig. 3 can be seen. To achieve radially inward support, the surface normal of the first lateral contact surface 22 has a radially outward directional component as its main component. The surface normal of the first lateral contact surface 22 can, for example, have only a radially outward directional component or also additionally have smaller tangential and / or axial directional components.

[0043] The second lateral contact surface 23 supports the cutting insert 3 on its side facing away from the free end 12 of the base body 1, both in the axial direction and radially outward. To achieve this, the surface normal of the second lateral contact surface 23 has both an axial directional component in the direction of the free end 12 of the base body 1 and a radially inward directional component. In addition, the surface normal of the second lateral contact surface 23 can also have a slight tangential directional component, as is the case, for example, with the Fig. 3 shown second lateral contact surface 23 is the case.

[0044] As in Fig. 3 As can be seen, the first lateral contact surface 22 and the second lateral contact surface 23 enclose an interior angle α with each other in a viewing direction perpendicular to the base surface 21, which interior angle α is less than 75°, preferably less than 65°. In the specifically illustrated embodiment, the interior angle α is approximately 60°. The first lateral contact surface 22 encloses an interior angle ≥ 90° with the base surface 21. Likewise, the second lateral contact surface 23 encloses an interior angle ≥ 90° with the base surface. In the specifically illustrated embodiment, the interior angle between the base surface 21 and the first lateral contact surface 22 is somewhat greater than 90°, for example, and can be approximately 100°. Likewise, the interior angle between the base surface 21 and the second lateral contact surface 22 is somewhat greater than 90° and can be approximately 100°, for example.In the case of a double-sided design of the cutting insert 3, in which cutting edge sections are also formed at the transition from the underside 33 to the side surfaces, the internal angles between the base surface 21 and the lateral contact surfaces 22, 23 can preferably each be 90°.

[0045] As in the Fig. 3 and Fig. 5 As can be seen, a bore 4 is formed in the base surface 21 of the seat 2. The bore 4 extends from the base surface 21 into the material of the base body 1 and, in an area spaced from the base surface 21, has a threaded bore 41 with an internal thread for interacting with a corresponding external thread of the fastening screw 5, as will be described in more detail. Between the threaded bore 41 and the opening of the bore 4 in the base surface 21, an unthreaded bore section 42 is formed. In the specifically illustrated embodiment, the unthreaded bore section 42 has a circular cross-section and extends coaxially to the threaded bore 41. However, it is also possible for the unthreaded bore section 42 to have a different cross-sectional shape.

[0046] As in Fig. 4 As can be seen, the fastening screw 5 has a threaded portion 51 designed to cooperate with the threaded bore 41, a head portion 53, and a thread-free shaft portion 52 arranged between the head portion 53 and the threaded portion 51. In the specifically illustrated embodiment, a taper is provided between the threaded portion 51 and the thread-free shaft portion 52, which taper promotes a relative elastic deflection of the head portion 53 relative to the threaded portion 51 in a direction perpendicular to a longitudinal axis of the fastening screw 5. The head portion 53 of the fastening screw 5 is designed to cooperate with the through-hole 36 in the cutting insert 3. The head portion 53 has a largest cross-section that is larger than the smallest internal cross-section of the through-hole 36, so that the head portion 53 cannot pass completely through the through-hole 36.The head portion 53 is adapted to the shape of the through-hole 36 such that the head portion 53 can bear against the through-hole 36, particularly preferably in a ring-shaped manner. The unthreaded shaft portion 52 of the fastening screw 5 has a cross-section that is significantly smaller than the cross-section of the unthreaded bore portion 42 of the bore 4. In other words, the unthreaded bore portion 42 has an oversize all around compared to the unthreaded shaft portion 52, which is significantly larger than the usual tolerances for precision manufacturing.

[0047] As particularly in Fig. 3 As shown, the unthreaded bore section 42 has four quadrants Q1, Q2, Q3 and Q4, which are numbered clockwise in the present case. A first quadrant Q1 of the unthreaded bore section 42 is located on the radially outer side of the unthreaded bore section 42 facing away from the free end 12 of the base body 1. A second quadrant Q2 is located on the side of the free end 12 and radially outward. A third quadrant Q3 is also located on the side of the free end 12, but radially inward. A fourth quadrant Q4 is located radially inward on the side facing away from the free end 12.In other words, the first quadrant Q1 is located in a range between "12 o'clock and 3 o'clock" from a direction parallel to the rotation axis R, the second quadrant Q2 is located in a range between "3 o'clock and 6 o'clock", the third quadrant Q3 is located in a range between "6 o'clock and 9 o'clock" and the fourth quadrant Q4 is located in a range between "9 o'clock and 12 o'clock".

[0048] In the following, with reference to the Fig. 7 bis Fig. 10 described in more detail how the cutting insert 3 is held to the seat 2 by means of the fastening screw 5.

[0049] First, with reference to the Fig. 7 and Fig. 9 The situation is described when the cutting insert 3 is arranged on the seat 2 and the fastening screw 5 with its threaded portion 51 is guided through the through hole 36 of the cutting insert 3, so that the threaded portion 51 engages with the threaded bore 41 and the unthreaded shank portion 52 is arranged in the unthreaded bore portion 42, but the fastening screw 5 is not yet tightened. In this state, the unthreaded shank portion 52 is spaced on all sides from the oversized unthreaded bore portion 42, as shown in particular in Fig. 9 can be seen. In other words, the thread-free shank section 52 in this state is spaced apart from the thread-free bore section 42 in the first quadrant Q1, as well as in the second quadrant Q2, in the third quadrant Q3 and in the fourth quadrant Q4. The longitudinal axis Z of the threaded bore 41 is slightly offset from the longitudinal axis W of the through hole 36 in the cutting insert 3 both in the direction of the first lateral contact surface 23 and in the direction of the second lateral contact surface 23, as shown, for example, in Fig. 5 can be seen. In Fig. 2 An arrow P schematically shows (not to scale) the direction in which the longitudinal axis Z of the threaded bore 41 is offset relative to the longitudinal axis W of the through hole 36. It can be seen that this direction is inclined at an angle β relative to the axial direction, so that the direction has a radially inwardly directed directional component and an axially rearward directional component, toward the first end 11 of the base body 1. In the specific example shown, the angle β is, for example, between 50° and 70°.

[0050] When the fastening screw 5 is tightened, the threaded portion 51 is screwed deeper into the threaded bore, so that the head portion 53 of the fastening screw 5 comes into contact with the through-hole 36 of the cutting insert 3. Due to the described offset between the longitudinal axis W of the through-hole 36 and the longitudinal axis Z of the threaded bore 41, the head portion 53 first comes into contact in the area of ​​the through-hole 36 on the side between the first lateral contact surface 22 and the second lateral contact surface 23 of the seat 2. As a result, the cutting insert 3 is pressed in the direction between the first lateral contact surface 22 and the second lateral contact surface 23.By engaging the through-hole 36, the head section 53 and with it the unthreaded shaft section 52 of the fastening screw 5 are elastically deflected radially outwards and in the direction of the free end 12 of the base body 1, so that the unthreaded shaft section 52 is deflected into the second quadrant Q2 of the unthreaded bore section 42. The elastic deflection continues until the unthreaded shaft section 52 rests against the unthreaded bore section 42 in the second quadrant Q2 of the unthreaded bore section 42. This state is shown in FIGS. Fig. 8 and Fig. 10 shown. In Fig. 10 the resulting offset of the longitudinal axis Y of the fastening screw 5 in the area of ​​the unthreaded shaft section 52 relative to the longitudinal axis Z of the threaded bore 41 is shown schematically. In addition to being secured radially outward via the second lateral contact surface 23, the cutting insert 3 is secured in a form-fitting manner radially outward at a further position via the interaction of the unthreaded shaft section 52 with the unthreaded bore section 42, so that the cutting insert 3 is secured particularly reliably against centrifugal forces acting during machining.Since the support takes place in the unthreaded shaft section 52, the shear forces on the fastening screw 5 caused by centrifugal forces do not act on the weaker threaded section 51 of the fastening screw 5, but rather on the significantly more stable unthreaded shaft section 52, thereby reducing the risk of material failure of the fastening screw 5. Due to elastic deformation of the fastening screw 5, the head section 53 of the fastening screw 5 engages the through-hole 36 in a form-fitting manner. The interaction of the larger head section 53 of the fastening screw 5 with the smaller through-hole 36 of the cutting insert 3 reliably clamps the cutting insert 3 toward the base surface 21 and secures the cutting insert 3 in a form-fitting manner against lifting off the base surface 21.

[0051] In the first quadrant Q1, the third quadrant Q3 and the fourth quadrant 4 of the thread-free bore section 42, the thread-free shaft section 52 of the fastening screw 5 does not bear against the thread-free bore section 42 due to the oversize of the thread-free bore section 42 when the fastening screw 5 is tightened, as shown in particular in Fig. 10can be seen. Manufacturing tolerances of the cutting insert 3 as well as of the first lateral contact surface 22 and the second lateral contact surface 23 can be easily compensated over a relatively large range via the elastic deformation of the fastening screw 5 until the unthreaded shank section 52 comes into contact with the unthreaded bore section 42. Tolerances in the position and alignment of the first lateral contact surface 22 and the second lateral contact surface 23 relative to one another are compensated for by the unthreaded shank section 52 coming into contact in the second quadrant Q2 of the unthreaded bore section 42 either further in the direction of the free end 12 or further radially outward. The circumferentially concave shape of the wall of the unthreaded bore section 42 in the second quadrant Q2 on the bore side enables the unthreaded shank section 52 to be easily aligned in this direction.Although in the illustrated embodiment a circular cross-sectional shape of the thread-free bore section 42 is shown, which is particularly simple and cost-effective to produce, the cross-sectional shape of the thread-free bore section 42 is not limited to such a circular shape, but other cross-sectional shapes are also possible, however, the wall of the thread-free bore section 42 should preferably be concavely curved in the circumferential direction, at least in the second quadrant.

Claims

1. Tool (100) for cutting processing having a base member (1) which has a rotation axis (R) about which the tool rotates during operation, at least one seat (2) which is formed on the base member (1) for receiving a replaceable cutting insert (3), a securing screw (5) for securing the cutting insert (3) to the seat (2), and a cutting insert (3) which is secured to the seat (2), wherein the seat (2) has a base face (21) for supporting a lower side (33) of the cutting insert (3), and a first lateral abutment face (22) for abutting against a first lateral face (37) of the cutting insert (3), which first lateral abutment face (22) supports the cutting insert (3) in a radially inward direction, and a hole (4) for receiving the securing screw (5) is formed in the base face (21), wherein the hole (4) has with spacing from the base face (21) a threaded hole (41) and closer in the direction of the base face (21) a thread-free hole portion (42), wherein the securing screw (5) has a threaded portion (51) for cooperating with the threaded hole (41), a head portion (53) for supporting in a through-hole (36) of the cutting insert (3) and between the threaded portion (51) and the head portion (53) a thread-free shaft portion (52), which thread-free shaft portion (52) has a smaller cross section than the thread-free hole portion (42), wherein the cutting insert (3) is secured to the seat (2) in such a manner that the head portion (53) of the securing screw (5) is supported on the through-hole (36) of the cutting insert (3), the threaded portion (51) of the securing screw (5) cooperates with the threaded hole (41) and the head portion (53) of the securing screw (3) is resiliently deflected characterized in that the seat (2) has a second lateral abutment face (23) for abutting against a second lateral face (38) of the cutting insert (3), which second lateral abutment face (23) supports the cutting insert (3) axially and in a radially outward direction and that the head portion (53) of the securing screw (3) is resiliently deflected in such a manner that the thread-free shaft portion (52) is supported when viewed in a direction perpendicular to the base face (21) in a second quadrant (Q2) which is located in a radially outward direction and axially in the direction of a free end (12) of the tool on the thread-free hole portion (42).

2. Tool according to claim 1, wherein the thread-free shaft portion (52) in a fourth quadrant (Q4) which is located in a radially inward direction and faces away from the free end (21) of the tool is spaced apart from the thread-free hole portion (42).

3. Tool according to claim 1 or 2, wherein the head portion (53) of the securing screw (5) is deflected resiliently in a radially outward direction and axially in the direction of the free end (12) of the tool.

4. Tool according to any one of the preceding claims, wherein the first lateral abutment face (22) and the second lateral abutment face (23) enclose in a viewing direction perpendicular to the base face (21) an angle (α) < 75° with each other, preferably < 65°.

5. Tool according to any one of the preceding claims, wherein the head portion (53) of the securing screw (5) has a largest cross section perpendicularly to an axis of the securing screw (5) which is greater than a smallest cross section of the through-hole (36).

6. Tool according to any one of the preceding claims, wherein a longitudinal axis (Z) of the threaded hole (4) is offset in a plane of the contact between the head portion (53) of the securing screw (5) and the through-hole (36) of the cutting insert (3) with respect to the longitudinal axis (W) of the through-hole (36) in the direction towards the first lateral abutment face (22) and in the direction towards the second lateral abutment face (23).

7. Tool according to any one of the preceding claims, wherein a surface normal of the first lateral abutment face (22) has a radially outwardly directed direction component as a main component.

8. Tool according to any one of the preceding claims, wherein a surface normal of the second lateral abutment face (23) has an axial direction component and a radially inwardly directed direction component.

9. Tool according to any one of the preceding claims, wherein a surface normal of the base face (21) has a tangential direction component as a main component.

10. Tool according to any one of the preceding claims, wherein the wall of the thread-free hole portion (42) at least in the second quadrant (Q2), which is located in a radially outward direction and axially in the direction of the free end (12) of the tool, of the hole (4) is constructed to be curved in a concave manner at the hole side in the circumferential direction.

11. Tool according to any one of the preceding claims, wherein the thread-free hole portion (42) has a substantially circular cross section.

12. Tool according to any one of the preceding claims, wherein the thread-free hole portion (42) is constructed parallel with the threaded hole (41).

13. Tool according to any one of the preceding claims, wherein the tool (100) is a high-speed milling cutter which is configured for a cutting processing operation at speeds of more than 10,000 revolutions per minute.

14. Method for securing a cutting insert (3) to a seat (2) of a base member (1) of a tool (100) according to any one of the preceding claims, wherein the method has the following steps: - placing the cutting insert (3) on the seat (2) so that the lower side (33) thereof is supported on the base face (21), a first lateral face (37) is supported on the first lateral abutment face (22) and a second lateral face (38) is supported on the second lateral abutment face (23), - guiding a threaded portion (51) of a securing screw (5) through a through-hole (36) in the cutting insert (3) and into the hole (4) so that the threaded portion (51) moves into engagement with the threaded hole (41) and a thread-free shaft portion (52) which is arranged between the threaded portion (51) and a head portion (53) of the securing screw (5) comes to rest with spacing all around in the thread-free hole portion (42), and - screwing in the securing screw (5) so that the head portion (53) initially moves into abutment with the through-hole (36) at a radially inner side facing away from a free end (12) of the base member (1) and subsequently the head portion (53) and the thread-free shaft portion (52) are resiliently deflected in a radially outward direction and in the direction of the free end (12) of the base member (1) until the thread-free shaft portion (52) moves into abutment with a second quadrant (Q2), which is located in a radially outward direction and axially in the direction of the free end (12), of the thread-free hole portion (42).