Cutting insert

Abstract

The invention relates to a cutting insert (1) having a main body portion (2) and at least one cutting-edge portion (3) projecting from the main body portion (2), by means of which cutting-edge portion a rake face (4) is bordered and which has a front cutting edge (4), two lateral cutting edges (5) and two cutting corners (6), which are interconnected by the front cutting edge (4), wherein the front cutting edge (4) and the two lateral cutting edges (5) are straight, seen in each case in a top view, wherein the rake face (4) has a front face edge region (11) connected to the front cutting edge (4) and an inner region (14) which is connected to the front face edge region (11) and is located above the front cutting edge (4), wherein the front face edge region (11) has at least one chip-forming element (23) for groove-like shaping of a chip which passes off-centre over the front cutting edge (4), said front face edge region sinking on both sides of the chip-forming element (23) to a low point (41) under the front cutting edge (4), wherein the inner region (14) has at least one chip-guiding element (21, 22) for guiding the chip shaped by the chip-forming element (23).

Description

[0001] Stechplate

[0002] The present invention relates to a grooving insert and lies in the technical field of grooving.

[0003] Grooving is a machining process in which a tool, often in the form of a cutting insert, is inserted radially from the outside to the inside of a workpiece rotating relative to the tool to remove material and thus create a groove of a defined width and depth.

[0004] Chip evacuation plays a crucial role in grooving. If the chips are not sufficiently shortened, chip jamming occurs in the groove. This results in poor surface quality and chip jamming. The latter can even lead to tool breakage.

[0005] WO 2021 / 023835 A1 shows an insert that can be used for grooving. The insert shown in WO 2021 / 023835 A1 has a problem with so-called offset grooving, i.e., grooving in which a groove is widened by the insert only partially penetrating the workpiece with respect to its grooving width. This creates the risk of the chip curling up in a helical pattern, which prevents chip-breaking contact with the workpiece or insert as desired. This is all the more true if the workpiece and thus the chip are made of a ductile metal, i.e., with a technical elongation at break of typically more than 20%.

[0006] The object of the present invention is to provide a grooving insert with a better suitability for offset grooving.

[0007] The grooving insert has a shank and at least one cutting edge section protruding from the shank, through which a chip surface is bordered and which has a front cutting edge, two lateral side cutting edges and two cutting corners that are connected to one another by the front cutting edge, wherein the front cutting edge and the two side cutting edges are each straight in plan view, wherein the chip surface has a front edge region connected to the front cutting edge and an inner region connected to the front edge region and located above the front cutting edge, wherein the front edge region has at least one chip forming element for the groove-like chip formation of a chip running off-center over the front cutting edge and is recessed on both sides of the chip forming element to a low point below the front cutting edge,wherein the inner region has at least one chip guide element for guiding the chip deformed by the chip forming element.,

[0008] The grooving insert is suitable for grooving. Therefore, an already created groove can be widened by laterally offsetting the grooving insert. The grooving insert is moved out of the groove and laterally offset by less than the grooving width defined by the cutting edge section, and then cuts into the workpiece radially from the outside inward. With respect to the front cutting edge, only a portion of the cutting edge is used for grooving. The side cutting edges allow the grooving insert to be moved transversely to the groove into the workpiece, cutting into the groove, and thus, alternatively, by so-called longitudinal turning, the groove can be widened, meaning that one of the side cutting edges does the cutting work.

[0009] The chip-forming element is designed to form grooves in the chip flowing off-center over the front cutting edge and is therefore positioned off-center of the front cutting edge. When the chip flows off-center over the front cutting edge in the area of ​​the chip-forming element, the chip-forming element presses into the chip, forming a longitudinal groove in the chip through plastic deformation. This reduces the chip's elongation at break and stiffens it, making it easier to break.

[0010] The chip guide element, which can be designed analogously to the chip forming element, interacts with it in that the chip formed by the chip forming element rises up in the inner area, usually by spiraling, and is guided by the chip guide element. This allows the chip to spiral more easily.

[0011] Because the front edge area and thus the rake face on both sides of the chip-forming element slopes down to a low point below the front cutting edge, the front edge area and thus the rake face are recessed in some areas. The low point can be different on one side of the chip-forming element than on the other.

[0012] The front edge area is defined by the front cutting edge. The rake face may have a chamfer on the front edge area. The rake face typically has a positive rake angle in some areas and may have the chamfer directly adjacent to the front cutting edge.

[0013] Above and below the front cutting edge means a difference in height to the front cutting edge.

[0014] The cutting edge area usually defines a cutting edge plane in which at least one straight section of the front cutting edge and one straight section of one of the side cutting edges extend, so that above and below the front cutting edge usually means above or below with respect to the cutting edge plane.

[0015] The chip forming element and the chip guiding element each refer to a local chip surface elevation.

[0016] Preferably, at least two of the chip-forming elements are provided for the double-groove-like chip formation of the chip running off-center over the front cutting edge; the second chip-forming element can preferably be shaped analogously to the first. A chip-forming chamber is then formed between the two chip-forming elements, which ensures transverse compression of the chip.

[0017] The front cutting edge can be completely straight, meaning it doesn't just appear straight when viewed from above. The two side cutting edges can be completely straight, meaning it doesn't just appear straight when viewed from above.

[0018] Preferably, the two side cutting edges are of equal length to each other when viewed from above and are a maximum of 20% longer or shorter than the front cutting edge.

[0019] The cutting corners are preferably each rounded, preferably with a corner radius that corresponds to 10% more or less of the width of the front edge area measured transversely to the front cutting edge.

[0020] The inner area is located above the front cutting edge and thus above the usually existing cutting edge plane, so that the chip guide element is also located above the front cutting edge and the usually existing cutting edge plane.

[0021] The insert is usually made of cemented carbide, whose hard material particles, usually essentially tungsten carbide particles, form a skeleton structure, with the spaces in the skeleton structure being filled with a

[0022] metal alloy.

[0023] According to a further development, the chip-forming element extends above and below the front cutting edge. Thus, the chip-forming element protrudes in sections beyond the front cutting edge and thus the normally existing cutting edge plane, allowing the chip-forming element to provide the chip running off-center over the front cutting edge with a groove whose depth corresponds at least to the amount by which the chip-forming element protrudes beyond the front cutting edge and thus the normally existing cutting edge plane.

[0024] According to a further development, the chip-forming element is rib-like or dome-like. If the chip-forming element is rib-like, it has a ridge that typically extends transversely to the front cutting edge. If the chip-forming element is dome-like, the chip-forming element is designed as a raised portion that is curved on all sides, without having a specific main direction of extension in plan view.

[0025] According to a further development, the chip deflector element is rib-like or dome-like. If the chip deflector element is rib-like, it has a ridge that typically extends transversely to the front cutting edge. If the chip deflector element is dome-like, the chip deflector element is designed as a raised portion that is curved on all sides, without a specific main direction of extension. Typically, the chip deflector element is more bluntly convexly rounded in a cutting surface parallel to the front cutting edge than the chip deflector element in a cutting surface parallel to the front cutting edge.

[0026] According to a further development, the chip-forming element and the chip-guiding element are aligned in a direction transverse to the front cutting edge, so that the chip-guiding element is aligned to engage in a chip groove created by the chip-guiding element. This provides optimal guidance of the chip formed by the chip-forming element, as the chip-guiding element can engage in the created groove, which further hinders helical curling of the chip.

[0027] According to a further development, the front edge region and the inner region together comprise a chip forming recess for chip forming a chip running centrally over the front cutting edge. The chip forming recess is recessed to a low point below the low point to which the chip surface is recessed on both sides of the chip forming element. The chip forming recess is thus arranged centrally with respect to the front cutting edge, so that the chip generated centrally, as the chip generated during grooving with the entire width of the front cutting edge, is reshaped to facilitate chip breaking. The chip forming recess is part of the front edge region and part of the inner region.

[0028] According to a further development, the chip breaker recess is concavely rounded on one cutting surface parallel to the front cutting edge and on the other cutting surface transverse to the front cutting edge. Due to the concave rounding formed transversely to the front cutting edge, the chip running centrally over the front cutting edge undergoes transverse plastic compression.

[0029] According to a further development, the interior area is designed in the shape of a gable roof with a ridge structure and sloping lateral roof surfaces on both sides, as well as a gable-like front roof surface. The gable-like front roof surface has the chip deflector in the form of a local elevation. Thus, at least one of the lateral roof surfaces is arranged to shape a chip flowing over one of the side cutting edges. The gable-like front roof surface is typically inclined away from the front cutting edge in the direction of the shank, thus being visible in plan view of the chip surface, which would not be the case with a reversed inclination.

[0030] According to a further development, the ridge structure has a frontal high point and a shank-side high point that is lower than the frontal high point. The ridge structure therefore drops from the frontal high point to the shank-side high point. When viewed from the side towards one of the side cutting edges, this then forms a V-shape with the ridge structure, at least in sections, with an apex where the two flanks of the V would meet on the shank side. It has been shown that this ridge structure, shaped in this way, ensures additional chip formation with regard to the chips generated by the side cutting edge and thus improves the application area of ​​the grooving insert with regard to longitudinal turning; during longitudinal turning, the grooving insert remains in the groove to be widened and is moved transversely to the groove with the side cutting edge first into the workpiece with a relative rotation with respect to the workpiece.

[0031] According to a further development, the ridge structure has a cross-sectional area perpendicular to the

[0032] The front cutting edge has at least one concavely rounded area for chip formation of a chip generated by one of the side cutting edges. This ensures transverse compression of the chips flowing over the side cutting edge and rising along the lateral roof surface.

[0033] According to a further development, the front edge region is designed to transition into the inner region at least off-center relative to the front cutting edge, forming a front-side transition edge. The inner region is thus structurally separated from the front edge region at least on the side of the front cutting edge, off-center. The transition edge ensures chip compression of the chip rising off-center beyond the front cutting edge.

[0034] According to a further development, the chip-forming element has a high point located below the transition edge. It has been shown that with this arrangement of the high point, the transition edge and the chip-forming element produce particularly strong plastic deformation of the chip.

[0035] According to a further development, the chip-forming element is arranged at a distance parallel to the front cutting edge from a nearest transition point, wherein the transition point is formed by a transition from one of the side cutting edges to one of the cutting corners, wherein the distance is a maximum of 30%, preferably a maximum of 25%, of a maximum grooving width defined by the cutting edge section on the front side. The chip-forming element is thus arranged in the outer region of the front cutting edge, which has been shown to be preferred for offset grooving.

[0036] According to a further development, the rake face has a corner edge region connected to the inner region and one of the two cutting corners. The corner edge region has at least one chip-forming element in the corner edge region for groove-like chip formation of a chip running over the cutting corner. On both sides of this chip-forming element, it is recessed to a low point below the cutting corner. This chip-forming element is designed in the form of a local rake face elevation. In offset grooving, the cutting edge region also penetrates the workpiece with one of the two cutting corners, i.e., only with the front cutting edge.By having at least one chip-forming element in the corner edge region for groove-like chip formation of the chip running over the cutting corner, i.e., its cutting edge, and by recessing this chip-forming element on both sides to the lowest point below the cutting corner, i.e., its cutting edge, this chip-forming element being designed in the form of a local rake face elevation, the chip running over this cutting corner is advantageously also plastically provided with at least one groove and thus deformed to facilitate chip breaking. The chip-forming element of the corner edge region can be designed analogously to the chip-forming element of the front edge region, for example, rib-like or dome-like.

[0037] According to a further development, the rake face has a lateral edge region connected to the inner region and one of the two side cutting edges, wherein the lateral edge region has at least one lateral chip-forming element for groove-like chip formation of a chip running over the side cutting edge and is recessed on both sides of the lateral chip-forming element to a low point below the side cutting edge, wherein the lateral chip-forming element is designed in the form of a local rake face elevation. In the longitudinal turning process already described, which can be used in combination with offset grooving, the lateral edge region with the lateral chip-forming element has proven advantageous in order to more easily break the chips thus generated laterally. The lateral chip-forming element can be designed analogously to the chip-forming element of the front edge region, for example rib-like or dome-like.

[0038] Preferably, the front edge region, the corner edge region and the side edge region are connected to one another.

[0039] According to a further development, the front cutting edge and at least one of the two side cutting edges extend at least partially in a cutting edge plane, wherein the inner region is located above the front cutting edge, the low point to which the front edge region drops off on both sides of the chip forming element is located below the cutting edge plane, the chip forming element extends above and below the cutting edge plane and transversely to the front cutting edge, wherein the chip forming element is designed as ribs, wherein the chip guide element is designed as ribs or domes and is arranged in alignment with the chip forming element in the direction transverse to the front cutting edge, wherein the front edge region along the front cutting edge ends where the cutting corners are connected to the front cutting edge. The cutting edge plane is the cutting edge plane that is usually present.

[0040] Preferably, the cutting surface is symmetrical in plan view with respect to a longitudinal axis penetrating the cutting edge centrally, at least in the area of ​​the front edge. Further advantages and benefits of the invention will become apparent from the following

[0041] Description of an embodiment with reference to the attached figures.

[0042] From the figures show

[0043] Fig. la: a view of a front section of a grooving plate with

[0044] View of a chip surface;

[0045] Fig. lb: an enlarged detail of Fig. la;

[0046] Fig. 2a: a front view of the grooving plate according to Fig. 1a;

[0047] Fig. 2b: an enlarged detail of Fig. 2a;

[0048] Fig. 3a: a side view of the grooving plate according to Fig. 1a;

[0049] Fig. 3b: an enlarged detail of Fig. 3a;

[0050] Fig. 4a: a representation of a section through the grooving plate according to Fig. la according to the

[0051] Section lines AA;

[0052] Fig. 4b: an enlarged detail of Fig. 4a;

[0053] Fig. 5a: a representation of a section through the grooving plate according to Fig. la according to the

[0054] Section lines BB;

[0055] Fig. 5b: an enlarged detail of Fig. 5a;

[0056] Fig. 5c: another enlarged detail of Fig. 5a;

[0057] Fig. 6a: a representation of a section through the grooving plate according to Fig. la according to the

[0058] Section lines CC;

[0059] Fig. 6b: an enlarged detail of Fig. 6a;

[0060] Fig. 7a: a representation of a section through the grooving plate according to Fig. la according to the

[0061] Section lines DD;

[0062] Fig. 7b: an enlarged detail of Fig. 7a;

[0063] Fig. 8: a perspective view of the grooving plate according to Fig. la.

[0064] Fig. 1a shows a top view of a front section of its grooving plate 1. The grooving plate 1 is designed for offset grooving.

[0065] The grooving insert 1 has a shank 2 and a cutting edge section 3 projecting from the shank 2 longitudinally and transversely thereto. A chip surface 4 is bordered by the cutting edge section 3. The cutting edge section 3, which is viewed in plan view according to Fig. 1a, has a straight front cutting edge 4, two lateral side cutting edges 5 and two cutting corners 6 which are connected to one another by the front cutting edge 4. The front cutting edge 4 and the two side cutting edges 5 extend in a common cutting edge plane 27, which is viewed perpendicularly in Fig. 1a.

[0066] The rake face 4 has a transition edge 7 which extends along the two side cutting edges 5 and in sections along the front cutting edge 4, so that the transition edge 7 is interrupted on both sides of a center point 8 by the front cutting edge 4, specifically by a chip forming recess 9 extending from and in the rake face 4 on both sides of the center point 8 in plan view.

[0067] Between the transition edge 7 and its hypothetical linear extension 10, through which the transition edge 7 in plan view on the side of the front cutting edge 4 would no longer be interrupted, but would also be continuous in the area of ​​the chip recess 9, the chip surface 4 has a front edge area 11 with an extension 12 along the

[0068] Front cutting edge 4 and an extension 13 transverse to the front cutting edge 4, i.e., across the entire width of the front cutting edge 4 and the entire extension of the cutting corners 6, where these are each rounded in plan view. The front edge area 11 is bordered by the front cutting edge 4 and the transition edge 7 and their linear extension 10, the latter only hypothetically.

[0069] The rake face 4 has an inner region 14 within the transition edge 7 and its linear extension 10, which is accordingly connected to the front edge region 11, so that the front edge region 11 is arranged between the front cutting edge 4 and the inner region 14.

[0070] Between the transition edge 7 and the side cutting edge 5 closest to it, the chip surface 4 has a side edge region 15 which is consequently bordered by the transition edge 7 and one of the two side cutting edges 15 and is connected to the inner region 14.

[0071] The chip surface 4 has, with respect to each of the cutting corners 6, a corner edge region 16 which is connected to the front edge region 11 and one of the side edge regions 15 and thus to a transition corner 16a formed by the transition edge 7.

[0072] The inner area 14 is on both sides of the center point 8 on each side of one of the

[0073] Side cutting edges 5 are designed in the shape of a saddle roof, with a cross-section

[0074] A ridge structure 17 extending from the front cutting edge 4 and lateral roof surfaces 18 sloping laterally from this and a gable-like roof surface 19 on the side of the front cutting edge 14; for reasons of clarity, the interior region 14, with regard to its gable roof-shaped design, has been provided with the reference numerals 17, 18 and 19 only on the right-hand side in Fig. 1a.

[0075] On the side of the side cutting edges 5, the inner region 14 has a flat plateau 20 defined by the lateral roof surface 18 and the transition edge 7; for reasons of clarity, the plateau 20 is designated with the reference numeral 20 only on the right side in Fig. 1a. The plateau 20 is triangular and narrows in the direction of the front cutting edge 4.

[0076] The gable-like roof surfaces 19 are inclined in the direction of the shank 2 away from the front cutting edge 4, so that their surface area can be seen accordingly in the plan view according to Fig. 1a. The gable-like roof surfaces 19 each have a rib-like chip deflector element 21 in the form of a local rake face elevation on the side of the chip-forming recess 9, which is divided into a central main recess 9a and, on both sides of the center point 8, into a kidney-shaped secondary recess 9b that is flatter than the main recess 9a, and a dome-like chip deflector element 22 in the form of a local rake face elevation on the side of the cutting corner 6 closest to the gable-like roof surface 19; however, it is also conceivable and possible to omit the dome-like chip deflector element 22, despite its additional supporting effect with regard to chip deflection.

[0077] The front edge region 11 has a rib-like chip forming element 23 in the form of a local rake face elevation, which is aligned with the chip guiding element 21 in the direction transverse to the front cutting edge 4, and a further rib-like chip forming element 23 in the form of a local rake face elevation, which is aligned with the chip guiding element 22 in the direction transverse to the front cutting edge; for reasons of clarity, only the right-hand chip forming elements 23 of the front edge region 11 in Figure 1a are provided with their reference numerals.

[0078] The chip-forming elements 23, which each extend transversely to the front cutting edge 4, are arranged on both sides of the center point 8 within a distance 12a measured parallel to the front cutting edge 4 from a nearest transition point 56, wherein the transition point 56 is formed by a transition from one of the side cutting edges 5 into the cutting corner 6, wherein the distance 12a amounts to a maximum of 30% of a maximum grooving width 24 defined on the front side by the cutting edge section 3. The distances 12a can be selected independently of one another, i.e., different ones can be selected to the right and left of one another with respect to Fig. 1a and the center point 8. The chip-forming recess 9 is located outside the distances 12a. The grooving width 24 is measured between the transition points 56 parallel to the front cutting edge.

[0079] The corner region 16 has a further rib-shaped chip-forming element 23 extending radially inwards with respect to its circular curvature, and the side edge regions 15 each have, by way of example, five further rib-shaped chip-forming elements 23, which each extend transversely to the respective side cutting edge 5.

[0080] The side cutting edges 5, the cutting corners 6 and the front cutting edge 4 each have a chamfer 26, into the area of ​​which the chip forming elements 23 extend.

[0081] Fig. 1b shows an enlarged detail of the cutting edge region 6 in the region of one of the distances 12a, i.e., the region that is cut into the workpiece 38 during offset grooving in the grooving direction 36 radially to a workpiece rotation axis 39 in order to widen a groove 40, only partially shown in Fig. 1b, by the distance 12a or less parallel to the workpiece rotation axis 39; the grooving insert 1 is therefore not cut in the entire area of ​​the front cutting edge 4. The grooving direction 36 is contained in the cutting edge plane 27 and oriented perpendicular to the front cutting edge 4.

[0082] The chip-forming elements 23 of the front edge region 11 extend above and below the cutting edge plane 27 and thus the front cutting edge 4, so that a chip running within the area defined by the distance 12a is deformed in the off-center region of the front cutting edge 4 by the chip-forming elements 23; the grooves, in their projection into the drawing plane of Fig. 1b, run parallel to the piercing direction 36 and roll up spirally, supported by the chip guide elements 21 and 22, which guide the chip and engage in the grooves.

[0083] Fig. 2a shows a front view of the grooving insert 1. In Fig. 2a it can be seen particularly well that the chip forming elements 23 in the front edge area 11 and in the corner edge area 16 are each also extended above the cutting edge plane 27 and thus above the front cutting edge 4 or the cutting corners 6, and that the chip guiding elements 21 and 22, the transition edge 7 and thus the inner area 14 are completely above the

[0084] Cutting edge plane 27 and thus above the front cutting edge 4.

[0085] A chip running off-center over the front cutting edge 8 with respect to the center point 8 of the front cutting edge 4, i.e. a chip generated in the off-center area defined by the distance 12a by the front cutting edge 4 together with the cutting corner 6, can thus be plastically deformed in a groove-like manner on each side of the center point 8 by the chip forming elements 23. The chip forming elements 23 press into the chip generated off-center during offset grooving according to Fig. 1b at least as far as they extend above the cutting edge plane 27 and the front cutting edge 4. The chip guide elements 21 and 22 then engage in grooves in the chip thus generated due to their

[0086] Cutting edge plane 27, which prevents a lateral helical rolling up of the chip, because the chip is guided by the chip guide elements 21 and 22 in a rail-like manner and can thus roll up more easily in a spiral and thus also break more easily; a rolling axis during the spiral rolling up of the chip is oriented parallel to the front cutting edge 4.

[0087] In Fig. 2a, the gable roof-like shape of the interior region 14 on both sides of the center point 8 is particularly clearly visible; note the roof surfaces 18 sloping laterally from the ridge structure 17. The gable-like roof surfaces 19 are arranged above the cutting edge plane 27 and the front cutting edge 4 and serve as supports for the chip deflector elements 21 and 22 and are designed as front flanks; the chip deflector elements 21 and 22 are designed as elevations relative to the gable-like roof surfaces 19.

[0088] In Fig. 2a, it can also be seen that a central axis 28 is oriented perpendicular to the cutting edge plane 27 and virtually penetrates the center point 8. With respect to and parallel to the central axis 27, it is possible to measure how much the chip-forming elements 23 extend above the cutting edge plane 27 and how much the transition edge 7 and thus the inner region 14 are arranged above the cutting edge plane 27. Thus, Fig.2a, that the transition edge 7 is arranged above the front cutting edge 4 and thus the cutting edge plane 27, so that the chip abuts against the transition edge 7, i.e. is thereby deformed in a direction that supports its spiral rolling up, wherein an outer side of the spirally rolled up chip has the grooves formed on the front side by the chip forming elements 23, into which the chip guide elements 21 and 22, due to their arrangement aligned transversely to the front cutting edge, each engage with one of the chip forming elements 23 in the area of ​​the front edge area 11 in a form-fitting manner.

[0089] Fig. 2a further shows that the grooving insert 1 has a front-side flank surface 29 on the side of the front cutting edge 4 and a corner flank surface 30 on the side of the cutting corners 6.

[0090] Fig. 2b shows an enlarged detail of Fig. 2a. Fig. 2b shows particularly clearly that the transition edge 7 and the chip guide elements 21 and 22 are arranged above the cutting edge plane 27 and thus above the front cutting edge 4.

[0091] Fig. 3a shows a side view of the grooving insert 1 viewed parallel to the cutting edge plane 27 and parallel to the front cutting edge 4. It is particularly clearly visible in Fig. 3a that the chip-forming elements 24 of the side edge region 15 also extend above the cutting edge plane 27 and thus also above the side cutting edge 5; the grooving insert 1 looks similar on the other side cutting edge 5.

[0092] In Fig. 3a it can also be seen particularly well that the ridge structure 17 has a front-side high point 17a, i.e. a high point in the area of ​​the ridge structure 17 closest to the front cutting edge 4 above the cutting edge plane 27, and a shaft-side high point 17b, i.e. a high point in the area of ​​the ridge structure 17 closest to the shaft 2 above the cutting edge plane 27. The high point 17a ensures the flank-like rise of the gable-like roof surface 19. The high point 17b is located lower than the high point 17a, so that a linear extrapolation 31 of a linear interpolation 32 with respect to the high points 17a and 17b with a linear extrapolation 33 of the side cutting edge 5 forms a V-shape, the apex 34 of which lies on the shaft 2 side.The ridge structure 17 thus formed ensures strong chip deformation of a chip running over the side cutting edge 5, which is deformed into a groove-like shape by the chip forming element 23 of the side edge region 3, analogous to the front edge region 11, thus being stiffened so that it breaks more easily during spiral winding. This is advantageous for the use of the grooving insert 1 in longitudinal turning, because then one of the two

[0093] Side cutting edges 5 mainly cut the workpiece, for example to alternatively widen a groove that has been widened by offset grooving of the groove with the cutting insert 1. Between the high points 17a and 17b, the ridge structure has a central high point 17c, which is located below the high point 17a and above the high point 17b; the exact position of the high points 17a, 17b and 17c is shown in the cutting surface shown in Fig. 5a, which is oriented perpendicular to the front cutting edge 4 and, in this vertical orientation, centrally with respect to one of the chip guide elements 21. Between the high points 17a and 17c and between the high points 17c and 17b, the ridge structure 17 is concavely rounded in the side view according to Fig. 3a, whereby the chip running over the side cutting edge 5 is transversely compressed, which additionally facilitates chip breaking.

[0094] The high points 17a, 17b and 17c are, as shown in Fig. 3a, defined as the respective centers of plateau-like flattenings 170a, 170b and 170c of the ridge structure 17.

[0095] Fig. 3a further shows that the side cutting edge 5 is assigned a lateral flank 35; the other side cutting edge 5 in Fig. 3a is assigned a similar lateral flank 35.

[0096] Fig. 3b shows an enlarged detail from Fig. 3a in the area of ​​the chip forming elements 23 of the side edge area 15 in order to clarify that these chip forming elements 23 also extend above the cutting edge plane 27 and thus above the side cutting edge 5.

[0097] Fig. 4a shows a representation of a cutting surface according to the section lines AA in Fig. 1a, i.e. perpendicular to the front cutting edge 4 and through the center point 8. Fig. 4a illustrates that the chip forming recess 9 is designed to slope down from the front cutting edge 4 to a low point 37 below the cutting edge plane 27 shown in sections in Fig. 4a and is concavely rounded perpendicular to the front cutting edge 4 in order to support a spiral rolling up of a chip running centrally over the front cutting edge 4.

[0098] Fig. 4b shows an enlarged view of the sectional area according to Fig. 4a in the area of ​​the low point 37.

[0099] Fig. 5a shows a representation of a cutting surface according to the section lines BB in Fig. 1a, i.e. perpendicular to the front cutting edge 4 and in each case centrally through the chip forming element 23 and the chip guide element 22. Fig. 5b shows an enlarged representation of the cutting surface according to Fig. 5b in the area of ​​the chip forming element 23 and the chip guide element 21 which is aligned perpendicular to the front cutting edge 4. In Fig. 5b it can be seen particularly well that the chip forming element 23, as an example for the other chip forming elements 23 of the front edge area 11, the corner edge areas 16 and the side edge areas 15, each has a high point 23a above the cutting edge plane 27 and is concavely rounded between the transition edge 7 and the high point 23a.

[0100] Fig. 5b shows that the high point 23a lies below the transition edge 7, this being exemplary at least for the chip forming elements 23 of the front edge region 11.

[0101] Fig. 5c shows an enlarged view of the cutting surface according to Fig. 5a in the region of the high points 17a, 17b, and 17c, which are defined as the respective centers of plateau-like flattenings 170a, 170b, and 170c of the ridge structure 17. The plateau-like flattenings 170a, 170b, and 170c are each formed extending parallel to the cutting edge plane 27.

[0102] Fig. 6a shows a view of a cutting surface along the section lines CC in Fig. 1a, i.e., parallel to the front cutting edge 4 and through the transition points 56. Fig. 6a shows particularly clearly that the chip-forming recess 9 is also concavely rounded transversely to the front cutting edge 4 in the region of the low point 37, which can cause the chip to undergo transverse compression. Fig. 6b shows an enlarged view of the cutting surface according to Fig. 6a in the region of one of the chip guide elements 21 and 22.

[0103] Fig. 7a shows a representation of a cutting surface according to the section lines DD in Fig. 1a, i.e. perpendicular to the front cutting edge 4 and centrally between the chip-forming elements 23 of the front edge region 11 on the same side with respect to the center point 8. Fig. 7b shows an enlarged representation of the cutting surface according to Fig. 7a in the region of the front cutting edge 4. Fig. 7b shows particularly clearly and as an example for the other chip-forming elements 23 that the front edge region 11 or the side edge regions 15 and the corner edge regions 16 each drop to a low point 41 below the cutting edge plane 27 and thus the front cutting edge 4 or the side cutting edge 5 and the cutting corners 6. The low points 41 can have different distances to the cutting edge plane 27 in the direction perpendicular to the cutting edge plane 27, i.e. can be at different distances from the cutting edge plane 27 on both sides of a chip-forming element.The front edge region 11, the side edge regions 15, and the corner edge regions 16 each slope more gently toward the low point 41 on the side of the front cutting edge 4, the side cutting edges 5, and the cutting corners 6, i.e., on the opposite side connected to the transition edge 7. This shape supports the spiral curling of the chips. In the area of ​​the chamfer 10, the front edge region 11 is connected to the cutting surface in a straight line as shown in Figs. 7a and 7b. The chamfer 10 has a positive rake angle, but can also have a rake angle of 0°. The low point 37 lies below the low points 41 of the front edge region 11.

[0104] Fig. 8 shows a perspective view of the grooving insert 1. Fig. 8 shows that the grooving insert 1 has, by way of example and optionally, a further cutting edge section 42, which is designed analogously to the cutting edge section 3 and is arranged at an opposite end of the shank 2, projecting therefrom. The shank 2 has a V-shaped groove 43, which extends centrally into the inner region 14 and opens into the chip recess 9. Coolant can be transported through the groove 43 in the direction of the respective front cutting edge 4.

[0105] The present invention is not limited to the grooving insert 1 and the design of the cutting edge portion 3 and the chip surface 4.

[0106] For use in offset grooving, it is sufficient that the front area 11 has at least one of the chip forming elements 11 at a distance 12a at least on one side of the center point 8 and that the inner area 14 has at least one chip guiding element 21 or 22 in order to guide a chip deformed in a groove-like manner by the chip forming element 23, preferably in such a way that the chip guiding element 21 or 22 engages in a chip groove, and thus best guides a spiral rolling up of the chip.

[0107] The chip forming recess 9 is optional but advantageous because it contributes to chip formation in particular when the grooving insert 1 cuts into the workpiece 38 in the grooving direction 36 radially to the rotation axis 39 according to the maximum grooving width 24; the kidney-shaped secondary recesses 9b of the chip forming recess 9 cause a groove-like deformation of the chip running centrally over the front cutting edge 4, in that the chip is pressed in more plastically with respect to its original chip thickness between the secondary recesses 9b and less plastically in the area of ​​the main chip recess 9a, which leads to easier chip breakage. However, it is also conceivable and possible to omit the chip forming recess 9, for example by forming the front edge region 11, as it is formed in the area of ​​the distance 12a, analogously in the area of ​​the then omitted chip forming recess 9.The secondary cutting edges 5 are optional but advantageous because they can be used for longitudinal turning, i.e. when the groove 40 is moved by a movement of the grooving insert 1 parallel to the rotation axis 39 under cutting contact with the workpiece 38. The chip forming elements 23 of the side edge regions 15, similar to the chip forming elements 23 of the front edge region 11, cause a groove-like deformation of the chip running over the respective cutting secondary cutting edge 5 during longitudinal turning, so that the chip is also stiffened and thus breaks more easily. The gable roof-shaped inner region 4 with its ridge structure 17 and lateral roof surfaces 18 ensures particularly strong chip deformation of the chip running over the respective cutting secondary cutting edge 5, which facilitates its chip breaking.

Claims

CLAIMS 1. A grooving insert (1) with a shank (2) and at least one cutting edge section (3) projecting from the shank (2), through which a chip surface (4) is located and which has a front cutting edge (4), two lateral side cutting edges (5) and two cutting corners (6) which are connected to one another by the front cutting edge (4), wherein the front cutting edge (4) and the two side cutting edges (5) are each formed straight in plan view, wherein the chip surface (4) has a front edge region (11) connected to the front cutting edge (4) and an inner region (14) connected to the front edge region (11) and located above the front cutting edge (4), wherein the front edge region (11) has at least one chip forming element (23) for the groove-like chip formation of a chip running off-center over the front cutting edge (4) and is tapered on both sides of the chip forming element (23) to a low point (41) below the Front cutting edge (4) is recessed, wherein the inner region (14) has at least one chip guide element (21, 22) for guiding the chip deformed by the chip forming element (23).

2. Grooving insert (1) according to claim 1, wherein the chip forming element (23) extends above and below the front cutting edge (4).

3. Grooving insert (1) according to one of the preceding claims, wherein the chip forming element (23) and / or the chip guiding element (21, 22) is each shaped in a rib-like or dome-like manner.

4. Grooving plate (1) according to one of the preceding claims, wherein the The chip forming element (23) and the chip guiding element (21, 22) are aligned with one another in the direction transverse to the front cutting edge (4), so that the chip guiding element (21, 22) is aligned to engage in a chip groove produced by the chip guiding element (23).

5. Grooving plate (1) according to one of the preceding claims, wherein the The front edge region (11) and the inner region (14) together have a chip forming trough (9) for chip forming a chip running centrally over the front cutting edge (4), wherein the chip forming trough (9) is recessed to a low point (37) below the low point (41) to which the chip surface (4) is recessed on both sides of the chip forming element (23).

6. Grooving insert (1) according to claim 5, wherein the chip forming recess (9) is concavely rounded in a cutting surface parallel to and in a cutting surface transverse to the front cutting edge (4).

7. Grooving plate (1) according to one of the preceding claims, wherein the inner region (14) is designed in the shape of a gable roof with a ridge structure (17) and lateral roof surfaces (18) sloping on both sides thereof and a gable-like frontal roof surface (19), wherein the gable-like frontal roof surface (19) has the chip guide element (21, 22) in the form of a local elevation.

8. Grooving plate (1) according to claim 7, wherein the ridge structure (17) has a frontal high point (17a) and a shaft-side high point (17b) which is located lower than the frontal high point (17a).

9. Grooving insert (1) according to claim 8, wherein the ridge structure (17) has at least one concavely rounded region in a cutting surface transverse to the front cutting edge (4) for chip forming of a chip generated by one of the side cutting edges (5).

10. Grooving insert (1) according to one of the preceding claims, wherein the end edge region (11) is designed to transition into the inner region (14) at least eccentrically with respect to the end cutting edge (4) to form a transition edge (7).

11. Grooving insert (1) according to claim 9 or 10, wherein the chip forming element (23) has a high point (23) located below the transition edge (7).

12. Grooving insert (1) according to one of the preceding claims, wherein the chip-forming element (23) is arranged at a distance (12a) measured parallel to the front cutting edge (4) from a nearest transition point (56), wherein the transition point (56) is formed by a transition from one of the side cutting edges (5) into one of the cutting corners (6), wherein the distance (12) is a maximum of 30% of a maximum grooving width (24) defined by the cutting edge section (3) on the front side.

13. Grooving insert (1) according to one of the preceding claims, wherein the rake face (4) has a corner edge region (16) connected to the inner region (14) and one of the two cutting corners (6), wherein the corner edge region (16) has at least one chip forming element (16) in the corner edge region (16) for groove-like chip forming of a chip running over the cutting corner (6) and is recessed on both sides of this chip forming element (23) to a low point (41) below the cutting corner (6), wherein this chip forming element (23) is designed in the form of a local rake face elevation.

14. Grooving insert (1) according to one of the preceding claims, wherein the rake face (4) has a lateral edge region (15) connected to the inner region (4) and one of the two lateral cutting edges (5), wherein the lateral edge region (15) has at least one lateral chip forming element (23) for groove-like chip forming of a chip running over the lateral cutting edge (5) and is recessed on both sides of the lateral chip forming element (23) to a low point (41) below the lateral cutting edge (5), wherein the lateral chip forming element (23) is designed in the form of a local rake face elevation.

15. Grooving insert according to one of the preceding claims, wherein the front cutting edge (4) and at least one of the two side cutting edges (5) extend at least partially in a cutting edge plane (27), wherein the inner region (14) is located above the front cutting edge (4), the low point (41) to which the front edge region (11) drops off on both sides of the chip forming element (23), is located below the cutting edge plane (27), the chip forming element (23) extends above and below the cutting edge plane (27) and transversely to the front cutting edge (4), wherein the chip forming element (23) is designed in a rib-like manner, wherein the chip guide element (21, 22) is designed in a rib-like or dome-like manner and is arranged in alignment with the chip forming element (23) in the direction transverse to the front cutting edge (4), wherein the front edge region (11) along the front cutting edge (4) ends where the Cutting corners (6) are connected to the front cutting edge (4).

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