Tool and cutting plate for this

Abstract

A tool (2) is specified, comprising at least one cutting insert (4) for machining a workpiece having a carrier (6), with an insert seat (8) for the cutting insert (4), wherein the cutting insert (4) has a cutting edge (10) for machining the workpiece, wherein the cutting insert (4) has a cutting corner (12) at which the cutting edge (10) terminates, wherein the cutting insert (4) has a side surface (24) with a contact surface (26) and a clearance surface (28), wherein the contact surface (26) abuts the insert seat (8), wherein the clearance surface (28) is bounded by the cutting edge (10), and wherein the clearance surface (28) projects beyond the contact surface (26) at least at the cutting corner (12). A corresponding cutting insert (4) for such a tool (2) is further specified.

Description

Background of the invention

[0001] The invention relates to a tool and a cutting insert, in particular an indexable cutting insert, for this purpose.

[0002] One or more cutting inserts are typically attached to a tool holder and are therefore replaceable. During operation, the tool, and consequently the cutting inserts, rotate around a rotary axis. In this way, a workpiece can be machined, with chips being removed from the workpiece by the cutting inserts.

[0003] A tool with cutting inserts is shown, for example, in WO 95 07784 A1.

[0004] The cutting insert typically has at least one cutting edge, which is subjected to high stress when machining a workpiece and can easily break off. The design of the cutting edge is of particular importance for cutting performance and stability at shallow axial depths, as well as with regard to potential chatter. Object of the invention

[0005] Against this background, it is an object of the invention to provide an improved cutting plate. The cutting plate should be as stable as possible, especially at the cutting edge. Furthermore, a correspondingly improved tool should be provided. Solution to the task

[0006] The problem is solved according to the invention by a tool with the features of claim 1 and by a cutting insert with the features of claim 12. Advantageous embodiments, further developments and variants are the subject of the dependent claims. The descriptions relating to the tool also apply mutatis mutandis to the cutting insert and vice versa.

[0007] A key concept of the present invention is, in particular, to design a side surface of a cutting insert in such a way that the cutting insert is reinforced specifically in the area of ​​the cutting edge, especially below it, and is therefore particularly stable. The side surface is designed so that as much material as possible is available at the cutting edge, i.e., the cutting insert is designed to be as solid as possible in this area. At the same time, the side surface is also designed in such a way that the cutting insert can be mounted in the predetermined insert seat of a tool. For this purpose, according to the invention, the side surface is divided into several sub-surfaces and is not designed as a simple, flat surface. This results in a high degree of design flexibility, which, especially with a given insert seat, allows for reinforcement of the cutting edge.

[0008] The tool according to the invention comprises at least one cutting insert for machining a workpiece. The cutting insert is also referred to as a cutting insert. Furthermore, the tool comprises a carrier with a pocket for the cutting insert. In the case of multiple cutting inserts, the carrier has, in particular, a separate pocket for each cutting insert. The cutting inserts are attached to the carrier and, for this purpose, are secured in the pockets. For example, the cutting insert has a through-hole through which a screw is passed and then screwed into the pocket, thus securing the cutting insert to the carrier. For the purposes of this description, we assume, without limitation of generality, a tool with multiple cutting inserts, which is also preferred; however, the principles apply equally to tools with only one cutting insert.The cutting plates are distributed regularly or irregularly on the carrier and are attached to it in one or more rows.

[0009] The tool is preferably a rotary tool and rotates during operation around an axis of rotation that corresponds to a longitudinal axis of the tool holder. In a suitable embodiment, the tool is designed as a milling tool, e.g., a 90° shoulder cutter. The insert seats and cutting inserts are arranged radially (perpendicular to the longitudinal axis) from the axis of rotation. While this description assumes such a milling tool without limiting generality, the statements also apply analogously to, for example, drills, lathes, and tools with a cutting insert positioned centrally on the longitudinal axis.

[0010] The cutting plate according to the invention has (at least) one cutting edge for machining the workpiece. The cutting plate also has (at least) one cutting corner at which the cutting edge terminates. Generally, the cutting edge has two ends: the aforementioned cutting corner and another corner of the cutting plate, which is not necessarily also a cutting corner. The cutting corner is preferably rounded or chamfered, or alternatively pointed. The cutting corner and the cutting edge are generally part of a circumferential contour of a front (also: top) surface of the cutting plate.

[0011] The cutting insert generally extends in an x-direction, a y-direction, and a z-direction, which are mutually perpendicular in pairs. The x-direction corresponds specifically to the longitudinal axis and is also referred to as the axial direction. The y-direction corresponds specifically to the radial direction. The z-direction is also referred to as the tangential direction. The cutting insert then has a length in the x-direction, a width in the y-direction, and a height in the z-direction.

[0012] The cutting plate also has a back (also called underside) which faces the front. The back is preferably flat, while this is not mandatory for the front. The height of the cutting plate is the maximum distance between the front and back surfaces, measured in the z-direction. Below the cutting edge, the back surface has a corresponding (rear) corner, which is connected to the cutting edge by an edge. This edge is therefore located below the cutting edge and is also referred to as the cutting edge edge. The cutting plate thus has a cutting edge edge that extends from the cutting edge to the rear corner. Like the cutting edge itself, the cutting edge edge is preferably rounded or chamfered, or alternatively, pointed.The cutting edge extends roughly in the z-direction, but is regularly angled relative to it, so that the cutting plate widens from the back towards the front, i.e., width and length increase.

[0013] The cutting insert also has (at least) one side surface, comprising a contact area and a clearance area. The side surface is thus divided into two sub-areas: the clearance area and the contact area (alternatively, the entire side surface can be considered a clearance area, into which the contact area is integrated, resulting in a contact area and a remaining clearance area). Such a division is not present in the aforementioned WO 95 07784 A1. In this case, the side surface is divided into the clearance area and the contact area by an imaginary dividing line. The clearance area and the contact area are separated by this dividing line in such a way that the clearance area lies on one side of the dividing line and the contact area on the other, both abutting the dividing line.The exact transition from the free surface to the contact surface at the dividing line is described in detail below.

[0014] The contact surface rests against the insert seat, thus serving as a bearing surface for contact with the carrier. Preferably, the contact surface is completely concealed by the insert seat. Typically, the contact surface is angled (i.e., at an angle greater than 0° to the z-direction) so that when the cutting insert is attached, it is drawn into the insert seat. The contact surface is preferably flat, but alternatively curved, e.g., in the case of a round cutting insert (so-called "round insert").

[0015] The clearance surface is bounded by the cutting edge, i.e., it ends there. The clearance surface projects forward and, particularly in the z-direction, extends beyond the insert seat, allowing the cutting edge to engage with the workpiece during operation. Preferably, the clearance surface extends along the entire cutting edge. The clearance surface lies between the cutting edge and the contact surface, so that the latter does not reach the cutting edge.

[0016] According to the invention, the clearance surface projects beyond the contact surface, at least at the cutting edge, particularly when viewed perpendicular to the z-direction. This advantageously reinforces the cutting insert in the region of the cutting edge, especially extending wholly or partially along the cutting edge. The projecting clearance surface results in a thicker cutting insert in this area, i.e., with more material, thus improving stability. This is primarily achieved in the region of the cutting edge, but is also advantageous along the entire cutting edge. In contrast to WO 95 07784 A1 mentioned above, the clearance surface is not simply a continuation of the contact surface towards the cutting edge, but rather the clearance surface is configured differently compared to the contact surface. In other words, the clearance surface is designed independently of the contact surface, namely with the aim of reinforcing the cutting insert, at least in the region of the cutting edge.It is particularly important that the free surface does not merely protrude on its own, e.g., simply in the x and / or y direction and at an angle to the z direction, but that the free surface protrudes relative to (i.e., with respect to) the contact surface. In other words, the contact surface serves as the reference plane, and the free surface projects beyond this reference plane. Two variations are generally possible: firstly, a simple bend in the side surface, so that the free surface and the contact surface run at different angles (angled arrangement of free surface and contact surface); and secondly, a step, so that the free surface is offset from the contact surface (offset arrangement of free surface and contact surface). Both variations are discussed in detail below. Both variations can also be combined.

[0017] The term "at the cutting edge" refers specifically to an area adjacent to and / or in the immediate vicinity of the cutting edge, particularly the portion of the side surface located below the cutting edge, i.e., extending from the cutting edge and between it and the back of the cutting insert, specifically along the cutting edge edge. Laterally, i.e., perpendicular to it, the area in question extends from the cutting edge (or more generally, the cutting edge edge) over a length of, for example, 1% to 50% of the cutting edge's length. More important than the precise designation of the area, however, is the fact that the cutting edge is reinforced by the projecting clearance, and the cutting insert is correspondingly more robust in this area, especially compared to the case of a non-projecting clearance.

[0018] The free surface and the contact surface are separated – as already described – by a dividing line. In a suitable embodiment, this dividing line has an S-shaped or L-shaped profile, generally a kinked profile. In the S-shaped profile, the dividing line descends at a first bend towards the cutting edge, initially in the direction of the back side, and then, at a second bend which is curved in the opposite direction to the first, again runs towards the cutting edge. The dividing line thus kinks twice. In contrast, the dividing line in the L-shaped profile only kinks once, initially running towards the cutting edge and then kinking at a point towards the back side, so that the dividing line has two legs in total: a horizontal leg and a vertical leg.The legs enclose an angle, preferably between 50° and 130°, particularly 90°. Alternatively or additionally, the clearance surface and the contact surface meet at the parting line, which runs along the side surface towards the cutting edge and slopes simply downwards towards the back of the cutting insert. Due to the S- or L-shaped course of the parting line, which generally slopes downwards towards the back, the clearance surface has an increased height towards the cutting edge, and the cutting edge is correspondingly reinforced, since the increased height of the clearance surface in the cutting edge area makes the cutting insert more solid. However, the parting line can also be straight; this too provides advantageous reinforcement at the cutting edge.

[0019] Preferably, the clearance surface and the contact surface are connected via a smooth transition, in particular a groove. The smooth transition has an inner radius. The smooth transition particularly represents a groove or track across the side surface. The smooth transition facilitates the manufacture of the cutting insert, especially when it is produced by die casting or a similar process. The smooth transition makes demolding the cutting insert easier during manufacturing. The smooth transition particularly extends wholly or partially along the parting line and particularly marks the course of the parting line.

[0020] To create a projection of the free surface relative to the contact surface, a suitable first approach involves setting the free surface off from the contact surface by a step. This step runs wholly or partially along the dividing line and thus marks its course. The step's primary effect is that the free surface projects beyond the contact surface. Consequently, depending on its orientation in the x or y direction, the free surface is shifted relative to the contact surface. The step effectively creates a ledge or step in the free surface relative to the contact surface. A free surface projecting due to a step is also referred to as a balcony, as it resembles a building with a balcony. Overall, the step results in a more robust cutting plate than one without a step. This strengthens the cutting edge and makes it particularly stable.The free surface has a clearance angle that is smaller, larger, or equal to the clearance angle of the contact surface.

[0021] In a suitable second embodiment, to design the clearance surface to project beyond the contact surface, the clearance surface has a larger clearance angle (simply referred to as the "angle") than the contact surface. The clearance angle is specifically the angle formed by the side surface and the workpiece during machining. This clearance angle is preferably positive, so that a wedge-shaped gap exists between the workpiece and the side surface during machining. In WO 95 07784 A1 mentioned above, the clearance angle on the side surface is, in particular, constant from the front to the back. In contrast, the clearance angle is varied in the present embodiment, specifically such that it changes from the contact surface to the clearance surface. The clearance angle of the contact surface is, in particular, determined by the plate seating of the carrier. However, the clearance angle can advantageously be varied along the clearance surface.If the same clearance angle is used as on the contact surface, the clearance area is preferably at least offset from the contact surface. However, in the second variant, the option of freely shaping the clearance area is advantageously used to reinforce the cutting insert, at least at the cutting edge. In particular, the clearance angle of the clearance area is larger than the clearance angle of the contact surface, so that, viewed from the back to the front, the cutting insert widens more along the clearance area than along the contact surface. The clearance angle of the contact surface is preferably in the range of 0° to 20°. The clearance angle of the clearance area is preferably in the range of 0° to 35°. If no additional step is present, the different clearance angle results in at least one kink in the side surface. This kink runs wholly or partially along the dividing line and thus marks its course.Starting from the cutting edge and looking towards the back, the clearance angle of the clearance face is either constant or varies along the clearance face. Also viewed along the cutting edge, i.e., depending on the orientation in the x or y direction, the clearance angle is either constant or varies. The clearance angle of the contact surface, however, is preferably constant across the entire contact surface, ensuring that the contact surface is completely flat and thus fits optimally against the insert seat.

[0022] The two variants described above (first and second variant) for the transition at the dividing line can also be combined, so that the free area is then set off from the contact surface by a step and at the same time has a different, in particular larger, free angle.

[0023] Preferably, the clearance area at the cutting edge extends to the back of the cutting plate. In other words, the clearance area stretches along the entire edge of the cutting edge, thus maximizing its reinforcement and stability. This reinforces the cutting plate along its entire edge. Specifically in the case of a step, but also more generally, the clearance area forms a base upon which the cutting edge rests. Depending on the design, this base, specifically the corresponding corner of the back, either projects beyond or rests against the plate seat. While the base can theoretically project below the plate seat, this is preferably avoided.

[0024] The clearance area has a height measured between the cutting edge (i.e., the top surface) and the contact surface (i.e., the parting line). In a practical embodiment, the height varies along the cutting edge, meaning the parting line and the cutting edge are not parallel. This can be achieved in various ways, either alternatively or cumulatively: by having a curved cutting edge, by having a curved parting line (specifically the step or bend), or by having the parting line and the cutting edge be straight but not parallel to each other. Overall, the varying height increases the design freedom for the cutting insert. It also makes it possible to selectively reinforce the cutting edge without making other areas of the cutting insert too thick, thus saving material.

[0025] Similarly, the contact surface also has a height, which is measured from the free surface (i.e., the dividing line) to the back side. The contact surface preferably has a constant height, but this is not mandatory and depends, for example, on the design of the plate seat.

[0026] The cutting insert is advantageously polygonal, with a circumferential contour that borders the front surface and has several edges, one, several, or all of which are designed as cutting edges. For the purposes of this description, without loss of generality, a square cutting insert is assumed, which is rectangular, with four edges and four corners, two of which, opposite each other, are designed as cutting corners. Accordingly, there are also four side surfaces, one for each edge (specifically, the cutting edge). Not every side surface is necessarily divided into a contact surface and a clearance surface, but this is preferred, especially for an indexable insert. In a preferred embodiment, the cutting insert is an indexable insert.An indexable insert has in particular one or more mirror planes (parallel to the z-direction) and / or at least twofold rotational symmetry (around the z-direction) in order to be mounted in different positions in the insert seat and to use different cutting edges and cutting corners when machining the workpiece, depending on the position.

[0027] The preceding descriptions of the cutting edge and the adjacent side surface apply analogously, in particular, to one, several, or all other cutting edges and side surfaces of the cutting plate. In a suitable embodiment, the cutting plate has, in addition to the (first) cutting edge, a further (second) cutting edge, which also terminates at the cutting corner, so that this corner is now enclosed by the two aforementioned cutting edges. The cutting edges are not necessarily of the same length; for example, one of the cutting edges is a short cutting edge and the other a long cutting edge. In the case of a rectangular cutting plate, the cutting edges enclose an angle of preferably 90° (rectangular or square cutting plate); an angle in the range of 50° to 140° is also suitable (rhombic or parallelogram-shaped cutting plate). Triangular and generally polygonal cutting plates are also suitable.Furthermore, in addition to the (first) side surface, the cutting insert has a further (second) side surface with a further (second) contact surface and a further (second) clearance surface. The clearance surface already mentioned is then a first clearance surface, and the contact surface is analogously a first contact surface. The further contact surface also rests against the insert seat. The further clearance surface is bordered by the further cutting edge. Analogous to the first clearance surface, the further clearance surface also projects beyond the further contact surface, at least at the cutting corner. The advantages mentioned so far apply analogously. The side surfaces, and especially the dividing lines, are not necessarily identical or mirror images of each other, but can also be designed independently. In this way, many different and suitable embodiments are possible. Advantageously, the two dividing lines meet at the cutting corner edge.In an advantageous embodiment, the two dividing lines together form a U- or V-shape, with a point facing the rear side, thus reinforcing the cutting edge. Alternatively or additionally, the dividing line of one side surface is straight and the dividing line of the other side surface is S-shaped. Alternatively or additionally, both dividing lines are S- or L-shaped and / or are mirror images of each other. Description of the characters

[0028] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. Each drawing schematically shows: Fig. 1 a tool, Fig. 2 a cutting plate in a perspective view, Fig. 3 the cutting plate made of Fig. 2 in a rear view, Fig. 4 the cutting plate made of Fig. 2 in a side view, Fig. 5 the cutting plate made of Fig. 2 in a different side view, Fig. 6 a variant of the cutting plate, Fig. 7 another variant of the cutting plate, Fig. 8 another variant of the cutting plate, Fig. 9 a side surface with different dividing lines, Fig. 10 a cutting plate with a bend, Fig. 11 a cutting board with a step. Description of the exemplary embodiment

[0029] Fig. Figure 1 shows an embodiment of a tool 2 according to the invention. This tool has at least one, and in this case even six, cutting inserts 4 for machining a workpiece (not shown). Various embodiments of the cutting insert 4 are described in the Fig. Figures 2 to 8 are shown. The tool 2 has a carrier 6 with a plate seat 8 for the cutting insert 4. The respective cutting insert 4 is attached to the carrier 6 and for this purpose is fastened in one of the plate seats 8, in this example by means of a screw.

[0030] The tool 2 is a rotary tool and rotates during operation around an axis of rotation which corresponds to a longitudinal axis L of the carrier 6. The tool 2 shown here is designed as a milling tool, specifically as a 90° shoulder cutter. The insert seats 8 and cutting inserts 4 are arranged radially (perpendicular to the longitudinal axis L) from the axis of rotation. The following explanations also apply analogously to other tools in general.

[0031] Various embodiments for the cutting plate 4 are described in the Fig. 2 to 8 shown, where the Fig. Figures 2 to 5 show the same cutting insert 4 in different views. The cutting insert 4 has at least one cutting edge 10 (here, for example, four cutting edges 10) for machining the workpiece. The cutting insert 4 also has a cutting corner 12 (here, for example, two cutting corners 12) at which the cutting edge 10 terminates. Generally, the cutting edge 10 has two ends: the aforementioned cutting corner 12 and another corner 14, which is not necessarily also a cutting corner 12. The cutting corner 12 is shown here as rounded, but alternatively it can be chamfered or pointed (not shown). The cutting corner 12 and the cutting edge 10 generally form part of a circumferential contour of a front surface 16 (also: top surface) of the cutting insert 4.

[0032] The cutting insert 4 generally extends in an x-direction X, a y-direction Y, and a z-direction Z, which are mutually perpendicular in pairs. The x-direction X corresponds to the direction of the longitudinal axis L and is also referred to as the axial direction. The y-direction corresponds specifically to the radial direction. The z-direction is also referred to as the tangential direction. The cutting insert 4 then has a length in the x-direction X, a width in the y-direction Y, and a height in the z-direction Z.

[0033] The cutting plate 4 also has a back side 18 (also: underside), which is opposite the front side 16. The back side 18 is particularly well suited for Fig. 3. Below the cutting edge 12, the back surface 18 has a corresponding (rear) corner 20, which is connected to the cutting edge 12 via an edge 22. This edge 22 is thus located below the cutting edge 12 and is also referred to as the cutting edge 22. The cutting edge 22 extends from the cutting edge 12 to the rear corner 20. The cutting edge 22 is rounded here, analogous to the cutting edge 12. The cutting edge 22 extends roughly in the z-direction Z, but is regularly angled relative to it, so that the cutting plate 4 widens from the back surface 18 towards the front surface 16, i.e., its width and length increase. This is particularly evident in the side views of the Fig. 4 and Fig. 5. The back side 18 of the cutting plate 4 can be congruent with respect to the x and y directions or rotated relative to the cutting edges 10 or the front side 16. The back side 18 can also be slightly rotated relative to the front side 16.

[0034] The cutting insert 4 also has a side surface 24 with a contact surface 26 and a clearance surface 28, so that the side surface 24 is divided into two sub-surfaces. The side surface 24 is divided by an imaginary dividing line T into the clearance surface 28 on the one hand and the contact surface 26 on the other. The clearance surface 28 lies on one side of the dividing line T and the contact surface 26 on the other side; both abut the dividing line T. Fig. Figure 9 shows three possible dividing lines T for an abstracted side surface 24. These dividing lines T differ in their course and, more specifically, in how they meet the cutting edge 22.

[0035] The contact surface 26 rests against the plate seat 8. Typically, the contact surface 26 is as shown in the Fig. 2 to 8 are recognizably inclined at such an angle (i.e., at an angle greater than 0° to the z-direction Z) that when the cutting insert 4 is attached, it is drawn into the insert seat 8. The contact surface 26 is also planar.

[0036] The clearance surface 28 is bounded by the cutting edge 10, projects forward, and extends beyond the insert seat 8 in the z-direction Z, so that the cutting edge 10 can engage with the workpiece during operation. In the embodiments shown here, the clearance surface 28 extends along the entire length of the cutting edge 10. The clearance surface 28 lies between the cutting edge 10 and the contact surface 26, so that the latter does not reach the cutting edge 10.

[0037] At least at the cutting edge 12, the free surface 28 protrudes beyond the contact surface 26; this is particularly evident in the perspective views of the Fig. 2, Fig. 6, Fig. 7 and Fig. 8. This means that the cutting plate 4 is reinforced in the area of ​​the cutting corner 12, namely starting from the cutting corner 12 either completely along the cutting corner edge 22, as in Fig. 2, or partially along the cutting edge 22, as in the Fig. 6, Fig. 7 and Fig. 8. The clearance surface 28 is designed independently of the contact surface 26, namely with the aim of achieving a reinforcement of the cutting insert 4, at least in the area of ​​the cutting edge 12. It is important that the clearance surface 28 does not merely project in itself, e.g., simply in the x and / or y directions X, Y and at an angle to the z direction Z, but that the clearance surface 28 projects with respect to (i.e., relative to) the contact surface 26. In other words, the contact surface 26 serves as the reference plane, and the clearance surface 28 projects with respect to this reference plane. Basically, two variants are possible: firstly, a simple bend 30 in the side surface 24, so that the free surface 28 and the contact surface 26 run at different angles F1, F2 (angled arrangement of free surface 28 and contact surface 26), and secondly, a step 32, so that the free surface 28 is offset from the contact surface 26 (offset arrangement of free surface 28 and contact surface 26).The variant with bend 30 is in . Fig. Figure 10 illustrates a cross-section of a side surface 24. The variant with level 32 is analogous. Fig. Figure 11 illustrates this, which also shows a cross-section of a side surface 24. In the Fig. Level 32 is also recognizable in levels 2 to 8. Both variants can also be combined.

[0038] The phrase “at the cutting corner 12” refers to an area which borders on and / or is in the immediate vicinity of the cutting corner 12, specifically the part of the side surface 24 which lies below the cutting corner 12, i.e. starting from the cutting corner 12 and between it and the back side 18, specifically along the cutting corner edge 22.

[0039] The course of the dividing line T is formed by the bend 30 or the step 32, therefore the dividing line T is in the Fig. Figures 2 to 8 are not explicitly shown. The dividing line T, for example, has an S-shaped profile (see figure). Fig. 6, Fig. 7, Fig. 8, Fig. 9) or L-shaped course (see Fig. 2, Fig. 9) generally exhibits a kinked profile. In the S-shaped profile, the dividing line T initially descends towards the back side 18 at a first bend in the direction of the cutting edge 22, and then, at a second bend which is curved in the opposite direction to the first, again runs towards the cutting edge 22. In contrast, in the L-shaped profile, the dividing line T only kinks once, initially running towards the cutting edge 22 and then kinking towards the back side 18 at a kink point, so that the dividing line T has a total of two legs, a horizontal leg and a vertical leg. Alternatively or additionally, the clearance surface 28 and the contact surface 26 meet at the dividing line T, which runs along the side surface 24 towards the cutting edge 22 and simply descends towards the back side 18 of the cutting plate 4.Due to the S- or L-shaped course of the dividing line T, which generally leads towards the rear side 18, the clearance surface 28 has an increased height towards the cutting edge 22, and the cutting edge 12 is correspondingly reinforced, since the greater height of the clearance surface 28 in the area of ​​the cutting edge 12 makes the cutting plate 4 more solid. However, the dividing line T can also simply be straight (see 2, 6, 9); this also results in reinforcement at the cutting edge 12.

[0040] In this case, the free surface 28 and the contact surface 26 are connected via a smooth transition, e.g. a cove, i.e. in the Fig. From 2 to 8, stage 32 has a softened transition, so that a transition with an inner radius is realized between the free area 28 and the contact area 26.

[0041] In order to make the free surface 28 project beyond the contact surface 26, in a first variant the free surface 28 is set off from the contact surface 26 by a step 32, as e.g. in the Fig. Figures 2 to 8 and 11 are shown. Step 32 runs wholly or partially along the dividing line T and accordingly marks its course. Step 32 results in the free surface 28 projecting relative to the contact surface 26. Therefore, depending on its orientation in the x or y direction (X, Y), the free surface 28 is shifted relative to the contact surface 26. Due to step 32, the free surface 28 forms a step relative to the contact surface 26. A free surface 28 that projects due to step 32 is also referred to as a balcony, as it creates a similar appearance to a building with a balcony. Overall, step 32 results in the cutting plate 4 being correspondingly more robust due to the offset free surface 28 than it would be without step 32. This reinforces the cutting edge 12.

[0042] In a second variant, to make the free surface 28 project beyond the contact surface 26, the free surface 28 has a larger clearance angle F1, F2 than the contact surface 26, as exemplified in Fig. Figure 10 shows the clearance angle F1, F2. This angle is defined as the angle formed between the side surface 24 and the workpiece during machining. In this case, the clearance angle F1, F2 is positive. Here, the clearance angle F1, F2 is varied such that it changes from the contact surface 26 to the clearance surface 28. The clearance angle F1 of the contact surface 26 is determined by the insert seat 8 of the carrier 6. However, the clearance angle F2 can be varied along the clearance surface 28. In this case, the clearance angle F2 of the clearance surface 28 is larger than the clearance angle F1 of the contact surface 26, so that, viewed from the back 18 to the front 16, the cutting insert 4 widens more along the clearance surface 28 than along the contact surface 26. Starting from the cutting edge 10 and viewed towards the back 18, the clearance angle F2 of the clearance surface 28 is constant (see Figure 10). Fig. 10) or varies along the clearance surface 28 (not shown). Also considered along the cutting edge 10, i.e., depending on the orientation in the x or y direction X, Y, the clearance angle F2 is either constant or varies. The clearance angle F1 of the contact surface 26, on the other hand, is constant across the entire contact surface 26, so that it is planar overall.

[0043] In the exemplary embodiment of the Fig. From 2 to 5, the clearance surface 28 at the cutting edge 12 extends to the back 18 of the cutting plate 4. In other words, the clearance surface 28 extends along the entire cutting edge 22. In this way, the cutting plate 4 is reinforced along the entire cutting edge 22. Specifically at a step 32, but also more generally, the clearance surface 28 then forms a foot 34 on which the cutting edge 12 effectively rests.

[0044] The clearance area 28 has a height H, which is measured between the cutting edge 10 (i.e., the front face 16) and the contact surface 26 (i.e., the dividing line T). In one possible embodiment, the height H varies along the cutting edge 10, for example, by the cutting edge 10 being curved, by the dividing line T being curved, or by the dividing line T and the cutting edge 10 being straight but not parallel to each other.

[0045] The cutting inserts 4 shown here are indexable inserts and are polygonal, specifically rectangular, with a circumferential contour that borders the front face 16 and has four edges, each of which is designed as a cutting edge 10. Of the four corners 12, 14, two opposite each other are designed as cutting corners 12. Correspondingly, there are also four side surfaces 24, one for each cutting edge 10.

[0046] The statements made here regarding cutting edge 10 and side surface 24 also apply analogously to one, several, or all other cutting edges 10 and side surfaces 24 of the cutting plate 4. The cutting edges 10 are not necessarily of the same length, e.g., as in the Fig. Figures 2 to 8 show one of the cutting edges 10 as a short cutting edge and the other cutting edge 10 as a long cutting edge. The various side surfaces 24 and especially the dividing lines T are not necessarily identical or mirror images of each other, but can also be designed independently of each other, as shown in the Fig. Figures 2 to 8 show that many different embodiments are possible in this way. In the embodiments shown here, however, the two dividing lines T of adjacent side surfaces 24 meet at the cutting edge 22. Specifically in Fig. The two dividing lines T are formed by the two steps 32, which together form a U or V shape, with a point facing the rear side 18, so that the cutting corner 12 is specifically reinforced. Alternatively or additionally, as in the Fig. 6 and Fig. Figure 7 shows the dividing line T (step 32) of one side surface 24 as straight, and the dividing line T (step) of the other side surface 24 as S-shaped. Alternatively or additionally, both dividing lines T can be S- or L-shaped, e.g., L-shaped as in Fig. 2 shown. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] WO 95 07784 A1 [0003, 0013, 0016, 0021]

Claims

[1] tool (2), a. which has at least one cutting plate (4) for machining a workpiece, b. which has a carrier (6) with a plate seat (8) for the cutting plate (4), c. wherein the cutting plate (4) has at least one cutting edge (10) for machining the workpiece, d. wherein the cutting plate (4) has at least one cutting corner (12) at which the cutting edge (10) ends, e. wherein the cutting plate (4) has at least one side surface (24) with a contact surface (26) and a free surface (28), f. wherein the contact surface (26) rests against the insert seat (8), g. wherein the free surface (28) is bordered by the cutting edge (10), h. wherein at least at the cutting corner (12) the free surface (28) projects with respect to the contact surface (26). [2] Tool (2) according to claim 1, wherein the free surface (28) and the contact surface (26) are separated by a dividing line (T) which has an S-shaped or L-shaped course. [3] Tool (2) according to claim 1 or 2, wherein the cutting plate (4) has a rear side (18) with a rear corner (20), wherein the cutting plate (4) has a cutting corner edge (22) which extends from the cutting corner (12) to the rear corner (20), wherein the free surface (28) and the contact surface (26) abut at a parting line (T) which runs along the side surface (24) in the direction of the cutting corner edge (22) and thereby drops towards the rear side (18) of the cutting plate (4). [4] Tool (2) according to one of claims 1 to 3, wherein the free surface (28) and the contact surface (26) are connected via a mitigated transition. [5] Tool (2) according to one of claims 1 to 4, wherein the free surface (28) is offset from the contact surface (26) by a step (32). [6] Tool (2) according to one of claims 1 to 5, wherein the clearance surface (28) has a larger clearance angle (F1, F2) than the contact surface (26). [7] Tool (2) according to one of claims 1 to 6, wherein the free surface (28) on the cutting corner (12) extends to the rear side (18) of the cutting plate (4). [8] Tool (2) according to one of claims 1 to 7, wherein the free surface (28) has a height (H) which is measured between the cutting edge (10) and the contact surface (16), wherein the height (H) varies along the cutting edge (10). [9] Tool (2) according to one of claims 1 to 8, wherein the cutting plate (4) has a further cutting edge (10) which ends at the cutting corner (12), wherein the cutting plate (4) has a further side surface (24) with a further contact surface (26) and a further flank surface (28), wherein the further contact surface (26) bears against the plate seat (8), wherein the further free surface (28) is bordered by the further cutting edge (10), wherein at least at the cutting corner (12) the further free surface (28) projects with respect to the further contact surface (26). [10] Tool (2) according to one of claims 1 to 9, wherein the cutting insert (4) is an indexable insert. [11] Tool (2) according to one of claims 1 to 10, wherein it is designed as a milling tool. [12] Cutting plate (4) for a tool (2) according to one of claims 1 to 11.

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