Reversible cutting inserts for drilling tools

Abstract

Cutting plate (10), comprising: a surface (12); a floor area (14) with a smaller area than the surface (12); four side surfaces (16) adjacent to the surface (12) and the bottom surface (14); four cutting edges (20) at the intersection of each of the side faces (16) and the surface (12), defining the four corner edge sections (40) at intersections between adjacent cutting edges (20), each of the cutting edges (20) comprising: a first cutting edge segment (22) extending from a first of the corner edge sections (40) arranged radially outside a central longitudinal axis of rotation (54) of a drill body (50) when the cutting insert (10) is mounted in the drill body (50); a second cutting edge segment (24) extending from the first cutting edge (20) at a second cutting edge angle (δ) with respect to the first cutting edge segment (22); and a linear stripping edge (30) which is arranged radially inwards from the central longitudinal axis of rotation (54) of the drill body (50) with respect to the first cutting edge segment (22) at a stripping edge angle (β) with respect to the first cutting edge segment (22) to a second of the corner edge sections (40), wherein the stripping edge angle (β) is a negative angle with respect to the first cutting edge segment (22) in the range of 0.5 to 10 degrees.

Description

[0001] The present invention relates to cutting tools with cutting inserts and drill bodies. In particular, the present invention relates to reversible and replaceable cutting inserts and drill bodies configured to engage and secure the reversible and replaceable cutting inserts.

[0002] Drilling tools are used to bore cylindrical holes in metallic workpieces. The cutting or drilling action of the drilling tools can be achieved by an elongated, essentially cylindrical tool, such as a combination of a tool holder and a cutting insert selectively attached to it. Such an arrangement can then be used in an application where one end of the tool holder is fixed in a drive device that rotates the holder about its longitudinal axis. At the opposite end of the elongated tool holder, the cutting insert engages the material to be cut. Alternatively, the workpiece can be rotated relative to the holder and cutting insert, as, for example, when positioning the holder in the end shank of a lathe or similar device. Furthermore, the tool and workpiece can be rotated relative to each other.The use of cutting inserts allows for quick replacement of the cutting insert when the cutting surfaces wear out, instead of the entire tool, and allows one tool to be used for different hole-making applications by simply replacing the cutting insert rather than the entire drill assembly.

[0003] Indexable inserts allow all sides of a cutting insert to be used for cutting sequentially. Furthermore, the use of indexable inserts reduces manufacturing lead time and assembly time.

[0004] Conventional square indexable inserts have four rectangular cutting edges for cutting the workpiece. The use of rectangular cutting edges generally causes the drill to be pulled away from its center due to the forces acting across the drill body rather than precisely in the middle. Furthermore, this drill drift creates a thin wall, which is impractical in real-world applications. Conventional indexable inserts also rub against the surface of the bore if the bore diameter is smaller than the desired target size.

[0005] Conventional cutting inserts and drill bodies generally require that both the central cutting insert and the peripheral cutting inserts be moved either radially inwards and / or outwards or axially forwards and / or backwards in order to effectively achieve a range of cutting circle diameters.

[0006] Cutting inserts are known from DE 10 2013 105 347 A1 and AT 12 700 U1.

[0007] The object of the invention is to provide an improved cutting plate.

[0008] The problem is solved by a cutting plate according to claim 1.

[0009] The inserts feature four cutting edges and drill bodies. Each of the four cutting edges can comprise a multitude of cutting edge segments and a stripper edge. The multiple cutting edge segments and the stripper edge are arranged at various angles relative to a reference plane of the insert to ensure effective chip breaking and a stronger cutting edge at the insert's corners. Furthermore, the inserts' side surfaces allow them to be held more securely in a recess of the drill body. The inserts can be used in a peripheral recess of a drill body. According to experts in the field, these inserts can also be referred to as outboard inserts.

[0010] One aspect of the present invention is the provision of a cutting plate comprising a surface, a bottom surface with a smaller surface area than the surface, four side surfaces adjacent to the surface and the bottom surface, four cutting edges at the intersection of each of the side surfaces and the surface, defining four corner edge sections at intersections between adjacent cutting edges, wherein each of the cutting edges comprises a first cutting edge segment extending radially outward from a first of the corner edge sections from a central longitudinal axis of rotation of a drill body when the cutting plate is mounted in the drill body at a first cutting edge angle with respect to a reference plane perpendicular to the surface of the cutting plate and parallel to an axis of rotation of the cutting plate, and a second cutting edge segment.which extends from the first cutting edge at a second cutting edge angle with respect to the reference plane, and a stripping edge which is arranged radially inwards from the central longitudinal axis of rotation of the drill body with respect to the first cutting edge segment at a stripping edge angle with respect to the reference plane to a second of the corner sections.

[0011] These and other aspects of the present invention will become more apparent from the following description. Fig. Figure 1 is an isometric view of a cutting plate according to an embodiment of the present invention. Fig. Figure 2 is an isometric bottom view of the cutting plate of Fig. 1. Fig. 3A is a top view of the cutting plate of Fig. 1. Fig. 3B is an enlarged section of the cutting plate of Fig. 3A. Fig. 3C is a top view of the cutting plate of Fig. 1. Fig. Figure 4 is a side view of the cutting plate of Fig. 1. Fig. Figure 5 is an isometric view of a drill body with a peripheral cutting plate in a peripheral recess of the drill body and a cutting plate in a central recess of the drill body according to an embodiment of the present invention. Fig. 6 and Fig. Figure 7 shows side views of a drill body with a peripheral cutting plate in a peripheral recess of the drill body and a cutting plate in a central recess of the drill body according to an embodiment of the present invention. Fig. Figure 8 is an isometric view of a drill body according to an embodiment of the present invention. Fig. Figure 9 is a partially schematic side view of a peripheral cutting plate in a peripheral recess of the drill body and a cutting plate in a central recess of the drill body according to an embodiment of the present invention. Fig. Figure 10 is a partially schematic side view of a peripheral cutting plate and a central cutting plate according to an embodiment of the present invention. Fig. Figure 11 is a partially schematic side view of the position of a peripheral cutting plate compared to a central cutting plate according to an embodiment of the present invention. Fig. Figure 12 is a partially schematic side view of the position of a peripheral cutting plate compared to a central cutting plate according to a further embodiment of the present invention.

[0012] Fig. 1 and Fig. Figure 2 illustrates isometric top and bottom views of a peripheral indexable insert 10 according to an embodiment of the present invention. The insert 10 comprises a surface 12, a bottom surface 14, and a side surface 16 that abuts the top and bottom surfaces 12 and 14. According to one embodiment of the present invention, the body of the insert is structured and arranged such that the side surfaces 16 are generally inclined from the surface 12 to the bottom surface 14 or are inclined inwards, so that the bottom surface 14 can have a smaller surface area than the surface 12, in order to, as shown in Figure 2, Fig. Figures 5-7 show a positive cutting geometry between the cutting insert 10 and a recess 60 in a drill body 50. The surface 12 is cut by the side surface 16 to form a cutting edge 20 on each side of the cutting insert 10.

[0013] As in Fig. 1 and Fig. As shown in Figure 2, the indexable insert 10 includes a mounting through-hole 18 extending from the surface 12 to the bottom surface 14. A central axis 19 of the mounting through-hole 18 runs perpendicular to the surface 12 and bottom surface 14. The central axis 19 defines a rotation axis of the cutting insert 10. The mounting through-hole 18 is structured and arranged to receive an insert screw 90.

[0014] According to one embodiment of the present invention, each cutting edge 20 can be formed by a plurality of cutting edge segments and a stripping edge. As in Fig. 1, Fig. 2, Fig. 3 to Fig. As shown in Figure 4, each cutting edge 20 is formed by a first cutting edge segment 22 and a second cutting edge segment 24. According to one embodiment of the present invention, the cutting plate 10 is mounted in the drill body 50, which has a generally cylindrical body 52 with a central longitudinal axis of rotation 54. In certain embodiments, when the cutting plate 10 is mounted in the drill body 50, the first cutting edge segment 22 is positioned radially outward from the central longitudinal axis of rotation 54 relative to the second cutting edge segment 24 and the stripping edge 30. According to one embodiment of the present invention, each cutting edge 20 can be formed by identical cutting edge segments. According to one embodiment of the present invention, the first and second cutting edge segments 22 and 24 are essentially linear.According to one embodiment of the present invention, the orientation and length of the plurality of cutting edge segments 22 and 24 provide stronger corner edge sections that prevent a drill body 50 from drifting away from its center and can align the cutting forces more effectively, as described below.

[0015] As in Fig. 6, Fig. 7, Fig. 9 and Fig. As shown in Figure 10, the width and position of the peripheral cutting plate 10 and the central cutting plate 100 are selected such that the operational cutting areas of the cutting plates overlap during the rotation of the drill body 50. According to one embodiment of the present invention, the orientation and length of the plurality of cutting edge segments 22 and 24 of the peripheral cutting plate 10 are selected to enable the peripheral cutting plate 10 and the central cutting plate 100 to perform a substantially identical cutting action, as described below.

[0016] As in Fig. As shown in Figures 1 and 3A-3C, each cutting edge 20 of the cutting plate 10 has a transition cutting edge segment 32 that connects the second cutting edge segment 24 with a stripping edge 30. In certain embodiments, the transition cutting edge segment 32 forms a concave curve 32A with the second cutting edge segment 24 and a convex curve 32B with the stripping edge 30. According to one embodiment of the present invention, the stripping edge 30 is arranged at intervals, not continuously with and / or not adjacent to the first cutting edge segment 22. In the illustrated embodiment, the transition cutting edge segment 32 can include a linear section 32C between the concave curve 32A formed with the second cutting edge segment 24 and the convex curve 32B formed with the stripping edge 30.According to one embodiment of the present invention, the scraper edge 30 of the cutting plate 10 can provide a stable cutting process and support against bending and the surface of the bore with an improved surface finish.

[0017] According to one embodiment of the present invention, the indexable insert comprises 10 corner edge sections 40 formed between adjacent cutting edges 20. As in Fig. As shown in Figure 3, each corner edge section 40 is formed as a rounded segment with a radius that allows a connection between adjacent cutting edges 20. For example, the corner edge section 40 can connect the stripping edge 30 of a cutting edge 20 with a first cutting edge segment 22 of a subsequent cutting edge 20. In certain embodiments, the radius of the corner edge sections 40 can be determined by the height of the cutting plate 10 and the diameter D of an imaginary marking circle 38. The radius of the corner edge sections 40 can be, as shown in Fig. As shown in Figure 3A, a smaller imaginary labeling circle 39 is formed. For example, the radius of each corner edge segment 40 can be in the range of 0.1 to 1.6 mm, or 0.2 to 1.2 mm, or 0.3 to 0.8 mm. In a particular embodiment, the radius of each corner edge segment 40 can be 0.4 mm.

[0018] As in Fig. As shown in Figure 3A, the first cutting edge segment 22 extends essentially from a first corner edge section 40, which is directed radially outwards from the central longitudinal axis of rotation 54 to form a main section of the cutting edge 20.

[0019] As in Fig. As shown in Figure 3A, the second cutting edge segment 24 extends radially inwards relative to the first cutting edge segment 22 at a second cutting edge angle δ, which in the illustrated embodiment is a negative angle. According to one embodiment of the present invention, the second cutting edge angle δ causes the second cutting edge segment 24 to form a convex curve 25 with the first cutting edge segment 22. For example, the second cutting edge angle δ can typically be in the range of 2.5 to 75 degrees, or 5 to 45 degrees, or 10 to 30 degrees. In a particular embodiment, the second cutting edge angle δ can be approximately 15 degrees.

[0020] As in Fig. As shown in Figure 3A, the linear section 32C of the transition cutting edge 32 extends radially inward toward the central longitudinal axis of rotation 54 from a second cutting edge segment 24 at a transition cutting edge angle α with respect to the first cutting edge segment 22 to a stripping edge 30. In the illustrated embodiment, the transition cutting edge angle α is not the negative angle of the second cutting edge segment 24, but a positive angle. The transition cutting edge angle α can form the concave curve 32A with the second cutting edge segment 24 and the convex curve 32B with the stripping edge 30. For example, the transition cutting edge angle α can typically be in the range of 2.5 to 75 degrees, or 10 to 60 degrees, or 15 to 45 degrees. In a particular embodiment, the transition cutting edge angle α can be approximately 18 degrees.

[0021] As in Fig. 3A and Fig. As shown in Figure 3B, the stripping edge 30 extends radially inward from the transition cutting edge at a stripping edge angle β with respect to the first cutting edge segment 22 to a second corner edge section 40, towards the central longitudinal axis of rotation 54. In the illustrated embodiment, the stripping edge angle β is negative and forms a convex curve 32B between the stripping edge 30 and the transition cutting edge segment 32. For example, the stripping edge angle β can typically be in the range of 0.5 to 10 degrees, or 0.5 to 7 degrees, or 0.5 to 3 degrees. In a particular embodiment, the stripping edge angle β can be approximately 2 degrees. According to one embodiment of the present invention, the stripping edge angle β can be selected such that the radially outermost stripping edge 30, as shown in Figure 3B, is located at the transition cutting edge segment 32. Fig. Figure 9 shows the stripping edge 30 parallel to the central longitudinal axis of rotation 54 of the drill body 50. According to one embodiment of the present invention, the stripping edge 30 can be linear or curved. In the illustrated embodiment, the stripping edge angle β is selected such that the stripping edge 30 does not run parallel to the first cutting edge segment 22.

[0022] According to one embodiment of the present invention, the second cutting edge angle δ and the transition cutting edge angle α can form a notch between the first cutting edge segment 22 and the stripper edge 30. When the cutting insert 10 is mounted in the drill body 50, the notch allows only the stripper edge 30 of the radially outer cutting edge 20 to be the sole portion of the cutting edge 20 in contact with the workpiece surface. The notch formed by the second cutting edge 24 and the transition cutting edge 32 separates the stripper edge 30 from the first cutting edge segment 22. According to one embodiment of the present invention, the transition cutting edge segment 32 may not come into contact with the workpiece, while the axially forward-facing second cutting edge 24 may perform the cutting operation. The stripper edge 30 can form the borehole as a smooth cylinder and provide a desired surface finish.

[0023] As in Fig. As shown in Figure 3C, the first cutting edge segment 22 has a length L1, the second cutting edge segment 24 has a length L2, the transition cutting edge segment 32 has a length L3, and the stripping edge 30 has a length L4. The lengths of the cutting edge segments are selected such that the desired cutting force direction and the rigid clamping of the cutting insert 10 in a recess are achieved. According to one embodiment of the present invention, the length L1 of the first cutting edge segment 22 can typically be in the range of 40 to 90 percent of the diameter D, or 55 to 80 percent of the diameter D, or 65 to 75 percent of the diameter D. The length L2 of the second cutting edge segment 24 can typically be in the range of 5 to 25 percent of the diameter D, or 7 to 20 percent of the diameter D, or 10 to 15 percent of the diameter D.The length L3 of the transition cutting edge segment 32 can typically be in the range of 5 to 25 percent of the diameter D, or 7 to 20 percent of the diameter D, or 10 to 15 percent of the diameter D. The length L4 of the stripping edge 30 can typically be in the range of 1 to 15 percent of the diameter D, or 1 to 10 percent of the diameter D, or 1 to 5 percent of the diameter D.

[0024] According to one embodiment of the present invention, the length of the first cutting edge segment L1 can be greater than the sum of the lengths of the second cutting edge segment L2, the transition cutting edge segment L3, and the stripping edge L4. In certain embodiments, the length of the transition cutting edge segment L3 is shorter than the length of the second cutting edge segment L2 and longer than the stripping edge L4. In certain embodiments, the length of the stripping edge L4 is shorter than the lengths of the first cutting edge segment L1, the second cutting edge segment L2, and the transition cutting edge segment L3. The length of the second cutting edge segment L2 is determined according to the overall cutting circle diameter D. C of the drill body 50 selected to allow the peripheral cutting plate 10 and the central cutting plate 100 to have essentially the same active cutting edges.

[0025] According to one embodiment of the present invention, the length of the second cutting edge segment 24 L2 can be equal to L C * (D CL - D CS ) be. In certain embodiments, L C a constant in the range of 0.25 to 0.85, D CL corresponds to the largest cutting circle diameter with which the cutting insert 10 is used, and D CS corresponds to the smallest cutting circle diameter with which the cutting insert 10 is used. According to one embodiment of the present invention, the cutting circle diameter D C by a cutting edge 20 of the peripheral cutting plate 10 and a cutting edge 120 of the central cutting plate 100, as in Fig. 10 is shown and provided. According to one embodiment of the present invention, L C a constant based on the smallest intersection circle diameter D CS , the largest intersection circle diameter D CL, the transition cutting angle α of the transition cutting edge segment 32, the second cutting edge angle δ and the radius of the corner edge section 40. In a specific embodiment, the largest cutting circle diameter D can be determined CL 19 millimeters and the smallest cutting circle diameter D CS 16.5 millimeters. According to one embodiment of the present invention, the length of the second cutting edge segment 24 L2, which is a function of L, allows C * [(D CL - D CS )] is that the peripheral cutting plate 10 and the central cutting plate 100 perform an essentially equal number of cutting operations.

[0026] According to one embodiment of the present invention, the lengths of the cutting edge segments 22 and 24, the transition cutting edge segment 32, and the stripping edge 30 can be varied depending on the overall size of the cutting plate 10. For example, if the diameter D of an imaginary marking circle 38, as in Fig. As shown in Figure 3C, enlarged, the lengths of the cutting edge segments 22 and 24, the transition cutting edge segment 32, and the stripping edge 30 increase proportionally. If, on the other hand, the diameter D of the Fig. If the imaginary labeling circle 38 shown in 3 is reduced, then the lengths of the cutting edge segments 22 and 24, the transition cutting edge segment 32 and the stripping edge 30 decrease proportionally.

[0027] As in Fig. As shown in Figure 4, each side surface 16 has a first free space area 42 extending from the surface 12 and a second free space area 44 extending from the first free space area 42 to the base surface 14. As shown in Fig. As shown in Figure 4, the first clearance surface 42 extends from the surface 12 at a first clearance angle γ1 with respect to the axis of rotation 19 of the cutting insert 10 towards the bottom surface 14. For example, the first clearance angle γ1 can be at least 1 degree, for example from 2.5 to 20 degrees, or from 5 to 15 degrees, or from 5 to 12 degrees. In a particular embodiment, the first clearance angle γ1 can be approximately 7 degrees. The first clearance angle γ1 can prevent the first clearance surface 42 from rubbing against machined surfaces by providing a clearance between the cutting insert 10 and the machined surface of the workpiece. As shown in Figure 4, the first clearance angle γ1 can prevent the first clearance surface 42 from rubbing against machined surfaces by providing a gap between the cutting insert 10 and the machined surface of the workpiece. Fig. As shown in Figure 4, the second clearance area 44 extends from the first clearance area 42 at a second clearance angle γ2 with respect to the axis of rotation 19 of the cutting insert 10 towards the base surface 14. For example, the second clearance angle γ2 can be at least 1 degree, for example from 5 to 40 degrees, or from 7.5 to 30 degrees, or from 10 to 20 degrees. In a particular embodiment, the second clearance angle γ2 can be approximately 15 degrees. The second clearance angle γ2 allows the cutting insert 10 to be easily inserted and removed from the recess 60 of the drill body 50. According to one embodiment of the present invention, the first clearance angle γ1 and the second clearance angle γ2 allow the surface area 12 to be larger than the base surface 14.The first clearance angle γ1 and the second clearance angle γ2 further provide the first and second clearance surfaces 42 and 44 in orientations that allow the cutting insert to be rigidly fixed in the recess 60 of the drill body 50. In the illustrated embodiment, the second clearance angle γ2 is larger than the first clearance angle γ1; however, any other suitable arrangement can be used, e.g., the second clearance angle γ2 can be less than or equal to the first clearance angle γ1.

[0028] As in Fig. As shown in Figure 4, the first clearance area 42 has a height H1 and the second clearance area 44 has a height H2. According to one embodiment of the present invention, the height of the second clearance area H2 can be greater than or equal to the height of the first clearance area H1, e.g., up to 75 percent higher. For example, the height of the second clearance area H2 can be at least 25 percent, at least 35 percent, or at least 50 percent greater than the height of the first clearance area H1. In certain embodiments, the height of the second clearance area H2 is at least 50 percent of the total height of the cutting plate 10, e.g., at least 60 percent of the total height of the cutting plate. The heights of the first clearance area H1 and the second clearance area H2 are selected such that the cutting plate 10 can be rigidly fixed in a recess 60 of the drill body 50.The ratio of the height H1 of the first clearance surface 40 to the height H2 of the second clearance surface 42 can typically be in the range of 1:1 to 1:10, for example from 1:1.2 to 1:5 or from 1.5:2 to 1:3. According to one embodiment of the present invention, the second clearance surface 44 can provide a contact surface that engages in the recess 60, and the first clearance surface 42 provides a clearance to prevent the cutting plate from contacting the side walls of the drill body recess.

[0029] The cutting inserts 10 can be made of any suitable material, such as tool steels, cemented carbides, and superhard materials like cubic boron nitride (CBN), polycrystalline cubic boron nitride (PCBN), polycrystalline diamond (PCD), tungsten carbide (WC), cermet, ceramics, and the like. The cutting inserts 10 of the present invention can be manufactured by any suitable technique, such as cemented carbide powder pressing, grinding, or additive manufacturing, to provide the plurality of cutting edge segments and the wiper edge.

[0030] Fig. 5, Fig. 6 to Fig. Figure 7 illustrates a drilling tool system 5 according to an embodiment of the present invention. The drilling tool system 5 comprises a drill body 50, a peripheral cutting insert 10, and a central cutting insert 100 installed in the drill body 50. The drill body 50 has a generally cylindrical body 52 with an axis of rotation 54. According to an embodiment of the present invention, the body 52 of the drill body 50 comprises a front drilling surface 56, a rear mounting end 58, and a plurality of helical grooves 59. The front drilling surface 56 comprises a peripheral recess 60 structured and arranged to accommodate a peripheral cutting insert 10, and a central recess 102 structured and arranged to accommodate a central cutting insert 100.In the illustrated embodiment, the body 52 of the drill body 10 includes two grooves 59, but any other suitable number of grooves can be used. For example, there can be one, three, four, five or more grooves.

[0031] As in Fig. As shown in Figure 8, the peripheral cutting insert recess 60 comprises a rear surface 62 and a first side wall section 64, which generally extends perpendicularly forward from the rear surface 62. While a generally square cutting insert recess 60 is shown in this embodiment, any other suitable shape of cutting insert recess can be used, e.g., rectangular, triangular, or the like. As shown in Fig. As shown in Figure 8, the rear surface 62 can be configured to engage with a first side surface of the cutting plate 10, and the first side wall section 64 can be configured to receive a second side surface 16 of the cutting plate 10. As used herein, the terms “engage,” “engages,” and “engaging” and “engaging” mean that two or more features interact with each other to constrain the relative movement between the cutting plate 10 and the cutting plate recess 60. In certain embodiments, the cutting plate recess 60 can include a lower seat surface 68 perpendicular to the rear surface 62 and the first side wall section 64. The lower seat surface 68 can be configured to engage with the bottom surface 14 of the cutting plate 14. As shown in Fig. As shown in Figure 8, the lower seat surface 68 includes a threaded mounting hole 70 which can be configured to accommodate a mechanical fastener 90 to secure the cutting insert 10 in the cutting insert recess.

[0032] As in Fig. As shown in Figure 8, the rear surface 62 and the first side wall section 64 each comprise a first and a second surface 76 and 78, respectively, which are structured and arranged to accommodate the first and second clearance surfaces 42 and 44 of the cutting plate 10. According to one embodiment of the present invention, the first surface 76 can be a clearance surface, and the second surface 78 can engage with the second clearance surface 44 of the cutting plate 10. The first and second engagement surfaces 76 and 78 of the rear surface 62, as well as the first side wall section 64, enable the cutting plate to be mounted more rigidly in the recess 60.

[0033] As in Fig. As shown in Figure 8, the recess 60 can include a recessed channel 72 in the corner between the back surface 62 and the first side wall section 64. The recessed channel 72 provides a clearance for the cutting insert recess 60 to accommodate the cutting insert 10. The side surface 16, which abuts the back surface 62, can experience the greatest force during a drilling operation. According to one embodiment of the present invention, any suitable size or shape of the cutting insert recess 60 can be used to engage any shape or size of the indexable insert 10.

[0034] According to one embodiment of the present invention, the cutting plate recess 60 and the peripheral cutting plate 10 are structured and arranged such that the central cutting plate 100 can make initial contact with a workpiece.

[0035] The drill body 50 can be made of a suitable material, such as steel, aluminum, titanium, or another material with sufficient strength. The drill body 50 of the present invention can be manufactured by any suitable technique, such as machining to provide the cutting insert recesses and grooves.

[0036] As in Fig. 9 and Fig. As shown in Figure 10, the cutting edge 20 of the peripheral cutting plate 10 and the cutting edge 120 of the central cutting plate 100 form a cutting profile 200. Fig. Figure 9 shows in the phantom the positioning of the peripheral cutting plate 10 in relation to the central cutting plate 100 when the drill body 50 is rotated 180 degrees about its central longitudinal axis of rotation 54 according to an embodiment of the present invention. As in Fig. As shown in Figure 10, the cutting edge 20 of the peripheral cutting insert 10 forms an outer section 210 of the cutting profile 200, and the cutting edge 120 of the central cutting insert 100 forms an inner section 205 of the cutting profile 200 relative to the central longitudinal axis of rotation 54. The cutting profile 200, formed by the cutting edge 20 of the peripheral cutting insert 10 and the cutting edge 120 of the central cutting insert 100, is symmetrical about the central longitudinal axis of rotation 54 of the drill body 50. The rotation of the cutting profile 200 about the axis of rotation forms the cutting circle diameter D. C of the drilling tool system 5.

[0037] According to one embodiment of the present invention, the cutting edge 20 of the peripheral cutting plate 10 can overlap with the cutting edge 120 of the central cutting plate 100. According to one embodiment of the present invention, the peripheral cutting plate 10, which overlaps with the central cutting plate 100, can protect the inactive, axially forward and radially inward directed stripping edge 30 and the transition cutting edge segment 32 from contact with the workpiece in order to prevent wear. As in Fig. As shown in Figure 10, an intersection point 220 is formed at the point where the first cutting edge segment 22 overlaps with the cutting edge 120 of the central cutting plate 100. According to one embodiment of the present invention, the intersection point 220 is selected such that the length of the inner section 205 of the cutting profile 200 is substantially equal to the length of the outer section 210 of the cutting profile 200. However, according to another embodiment of the present invention, the length of the inner section 205 may be different from the length of the outer section 210.

[0038] Fig. 9 and Fig. Figure 10 illustrates that the cutting edge 120 of the central cutting plate 100 forms the most axially forward section of the cutting profile 200. This allows the central cutting plate 100 to make initial contact with the workpiece. According to one embodiment of the present invention, a portion of the inner section 205 of the cutting profile 200 extends further axially forward than the outer section 210 of the cutting profile 200.

[0039] As in Fig. Figure 10 shows a horizontal plane 75 perpendicular to the central longitudinal axis of rotation 54 of the drill body 50. In the illustrated embodiment, the first cutting edge segment 22 is inclined at a negative angle with respect to the horizontal plane 75. For example, the first cutting edge segment 22 of the cutting insert 10 can form an angle of 0 to 5 degrees with respect to the horizontal plane 75.

[0040] Fig. 11 and Fig. Figure 12 illustrates the positions of the peripheral cutting insert 10 compared to a central cutting insert 100 according to another embodiment of the present invention. The position of the cutting inserts represents the position of the cutting inserts when mounted in the peripheral recess 60 and the central recess 102 of the drill body 50. According to one embodiment of the present invention, a peripheral cutting insert 10 of identical size and a central cutting insert 100 of identical size can be used for a range of cutting circle diameters D. C can be used. According to one embodiment of the present invention, the different cutting circle diameters D can be used. Cprovided by drill bodies with different overall diameters. The peripheral cutting insert 10 and the central cutting insert 100 are structured and arranged to provide the desired force compensation, cutting performance, and surface finish over a desired range of cutting circle diameters D. C and drill body diameters. The orientation and length of the multitude of cutting edge segments of the peripheral cutting insert 10 and the multitude of cutting edge segments of the central cutting insert 100 are selected such that the peripheral cutting insert 10 and the central cutting insert 100 can perform an essentially identical cutting action.

[0041] According to one embodiment of the present invention, the axial and radial position of the central cutting plate 100 and the central recess 102 of the drill body 50 can be adjusted for a range of cutting circle diameters D. CS -DCL be fixed. In certain embodiments, the central recess 102 is not moved to determine the cutting circle diameter D. C of the drilling tool system 5 for a selected insert size. For example, a rotary axis 119 of a mounting through the bore 118 of the central insert 100 can define the axial and radial position of the central insert 100. As in Fig. As shown in Figure 11, the axis of rotation 119 of the central cutting plate 100 is located at an axial and radial position with respect to the central longitudinal axis 54 for the smallest cutting circle diameter D. CS for a given cutting plate size. As in Fig. As shown in Figure 12, the axis of rotation 119 of the central cutting plate 100 is located at the same axial and radial position with respect to the central longitudinal axis 54 for the largest cutting circle diameter D. CLfor a selected cutting insert size. According to one embodiment of the present invention, a single size of the central cutting insert 100 is structured and arranged such that it can be used at a single position for a range of cutting circle diameters D. CS -D CL is provided while maintaining the desired force direction, force balance and essentially the same active cutting length for the central and peripheral cutting inserts.

[0042] According to one embodiment of the present invention, the peripheral cutting plate 10 and the outer recess 60 of the drill body 50 can be moved axially and / or radially to achieve a range of cutting circle diameters D. CS -D CLTo accommodate, for example, the peripheral cutting insert 10 and the outer recess 60 of the drill body 50 can be moved radially outwards and axially backwards with respect to the central longitudinal axis of rotation 54 to achieve a larger cutting circle diameter D. C to provide. As in Fig. As shown in Figure 11, the axis of rotation 19 of the peripheral cutting plate 10 is located at a first axial position and a first radial position for the smallest cutting circle diameter D. CS for a selected cutting plate size. As in Fig. As shown in Figure 12, the axis of rotation 19 of the peripheral cutting insert 10 is located at a second axial position and a second radial position for the largest cutting circle diameter D. CLfor a selected cutting insert size. According to one embodiment of the present invention, modifying the axial and / or radial position of the peripheral cutting insert 10 and the outer recess 60 of the drill body 50 enables a fixed position of the central cutting insert 100 and the use of the central recess 102 of the drill body 52 for a range of cutting circle diameters D CS -D CL , while maintaining the desired force direction, force balance and essentially the same active cutting length for the central and peripheral cutting inserts.

[0043] In certain embodiments, the plurality of cutting edge segments of the peripheral cutting plate 10 and the plurality of cutting edge segments of the central cutting plate 100 allow the intersection point 220, formed between the cutting edge 20 of the peripheral cutting plate 10 and the cutting edge 120 of the central cutting plate 100, to be formed at a desired position along the cutting profile. As shown in Fig. As shown in Figure 11, the intersection point 220 can be located between the radially outermost cutting edge segment 122 of the central cutting plate 100 and the first cutting edge segment 22 of the peripheral cutting plate 10. As shown in Fig. As shown in Figure 12, the intersection point 220 can be located between the radially outermost cutting edge segment 122 of the central cutting plate 100 and the second cutting edge segment 24 of the peripheral cutting plate 10.

[0044] According to one embodiment of the present invention, the intersection point 220 is located on the radially outermost cutting edge segment 122 of the central cutting plate 100, in order to allow at least a portion of the cutting edge 120 to lie axially in front of the cutting edge 20 of the peripheral cutting plate 10. This enables the central cutting plate 100 to make initial contact with the workpiece. According to another embodiment of the present invention, the radially outermost cutting edge segment 122 of the central cutting plate 100 can be positioned at a negative angle to the horizontal plane 75, in order to allow the intersection point 220 to be located at the desired position on the cutting edge 20 of the peripheral cutting plate 10.

[0045] As in Fig. 11 and Fig.As shown in Figure 12, the axis of rotation 19 of the peripheral cutting plate 10 can be offset from the axis of rotation 119 of the central cutting plate 100 by a radial offset length L. R and an axial offset length L A They must be spaced apart. The radial offset length L R and the axial offset length L A are selected to achieve a desired cutting circle diameter D C and to provide the desired intersection point 220. According to one embodiment of the present invention, the radial offset length L can be R typically range from 2.5 to 25 mm, or from 5 to 20 mm, or from 7.5 to 17.5 mm. For example, the radial offset length L can be R at least 30 percent of the cutting circle diameter D C The axial offset length L can be, for example, at least 40 percent or at least 50 percent. According to one embodiment of the present invention, the axial offset length L can be Atypically range from 0 to 10 mm, or from 0.5 to 7.5 mm, or from 1 to 5 mm. The radial offset length L R and the axial offset length L A are modified by changing the position of the peripheral drill recess 60 relative to the central drill recess 102. According to one embodiment of the present invention, the axis of rotation 19 of the peripheral cutting insert 10, when mounted in the peripheral drill recess 60, can be offset by the axial offset length L. A axially forward or backward from the axis of rotation 119 of the central cutting plate 100 when these are mounted in the central bore recess 102.

[0046] As used herein, “including”, “containing”, and similar terms are understood in the context of this application as synonymous with “comprehensive” and are therefore open-ended and do not exclude the presence of additional undescribed or unspecified elements, materials, phases, or process steps. As used herein, “consisting of” is understood in the context of this application to exclude the presence of any unspecified element, material, phase, or process step. As used herein, “essentially consisting of” is understood in the context of this application to comprehensively include the specified elements, materials, phases, or process steps, where applicable, and also any unspecified elements, materials, phases, or process steps that do not substantially affect the fundamental or novel characteristics of the invention.

[0047] For the purposes of the above description, it is understood that the invention may assume various alternative variants and sequences of steps, unless expressly stated otherwise. Furthermore, all numbers expressing, for example, quantities of components used in the patent specification and the claims are to be understood in all cases as modified by the term "approximately." Accordingly, the numerical parameters given are approximations that may vary depending on the desired properties to be obtained by the present invention, unless otherwise stated. At a minimum, and not as an attempt to limit the application of the doctrine of equivalence, each numerical parameter should be interpreted at least in light of the number of significant figures given and by applying ordinary rounding techniques.

[0048] It is understood that each numerical range listed herein is intended to encompass all subranges summarized therein. For example, a range of "1 to 10" is intended to encompass all subranges between (and including) the listed minimum value of 1 and the listed maximum value of 10, i.e., a range with a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0049] In this application, the use of the singular includes the plural and the plural includes the singular, unless explicitly stated otherwise. Furthermore, in this application, the use of "or" means "and / or," unless explicitly stated otherwise, although "and / or" may be explicitly used in certain cases. In this application, the articles "a," "an," "the," "the," "the," "the," and "the" include multiple referents, unless explicitly and unambiguously limited to one referent.

[0050] Although specific embodiments of this invention have been described above for illustrative purposes, it will be obvious to those skilled in the field that numerous variations of the details of the present invention can be carried out without deviating from the invention defined in the attached claims.

Claims

[1] Cutting plate (10), comprising: a surface (12); a floor area (14) with a smaller area than the surface (12); four side surfaces (16) adjacent to the surface (12) and the bottom surface (14); four cutting edges (20) at the intersection of each of the side faces (16) and the surface (12), defining the four corner edge sections (40) at intersections between adjacent cutting edges (20), each of the cutting edges (20) comprising: a first cutting edge segment (22) extending from a first of the corner edge sections (40) arranged radially outside a central longitudinal axis of rotation (54) of a drill body (50) when the cutting insert (10) is mounted in the drill body (50); a second cutting edge segment (24) extending from the first cutting edge (20) at a second cutting edge angle (δ) with respect to the first cutting edge segment (22); and a linear stripping edge (30) which is arranged radially inwards from the central longitudinal axis of rotation (54) of the drill body (50) with respect to the first cutting edge segment (22) at a stripping edge angle (β) with respect to the first cutting edge segment (22) to a second of the corner edge sections (40), wherein the stripping edge angle (β) is a negative angle with respect to the first cutting edge segment (22) in the range of 0.5 to 10 degrees. [2] Cutting plate (10) according to claim 1, wherein the first cutting edge segment (22) and the second cutting edge segment (24) are linear. [3] Cutting plate (10) according to claim 1 or 2, wherein a radially outermost scraping edge (30) is parallel to the central longitudinal axis of rotation (54) of the drill body (50) when the cutting plate (10) is mounted in the drill body (50). [4] Cutting plate (10) according to one of the preceding claims, wherein the second cutting edge angle (δ) is a negative angle with respect to the first cutting edge segment (22) in the range of 2.5 to 75 degrees. [5] Cutting plate (10) according to one of the preceding claims, wherein the second cutting edge segment (24) and the stripping edge (30) are connected to each other by a transition cutting edge segment (32), wherein the transition cutting edge segment (32) forms a concave curve (32A) with the second cutting edge segment (24) and a convex curve (32B) with the stripping edge (30). [6] Cutting plate (10) according to claim 5, wherein the transition cutting edge segment (32) comprises a linear section (32C). [7] Cutting plate (10) according to claim 6, wherein the linear section (32C) of the transition cutting edge segment (32) extends from the second cutting edge segment (24) at a transition cutting edge angle (α) with respect to the first cutting edge segment (22), wherein the transition cutting edge angle (α) is a positive angle in the range of 5 to 65 degrees. [8] Cutting plate (10) according to claim 7, wherein the transition cutting edge angle (α) is less than or equal to the second cutting edge angle (δ). [9] Cutting plate (10) according to one of the preceding claims, wherein a length (L1) of the first cutting edge segment (22) is greater than a length (L2) of the second cutting edge segment (24) and a length (L4) of the stripping edge (30). [10] Cutting plate (10) according to one of claims 5 to 9, wherein a length (L4) of the stripping edge (30) is less than a length (L1) of the first cutting edge segment (22), a length (L2) of the second cutting edge segment (24) and a length (L3) of the transition cutting edge segment (32). [11] Cutting plate (10) according to one of the preceding claims, wherein each side surface (16) comprises a first free space area (42) extending from the surface (12) and a second free space area (44) extending from the first free space area (42) to the bottom surface (14), and a height (H2) of the second free space area (44) is greater than or equal to the height (H1) of the first free space area (42). [12] Cutting plate (10) according to claim 11, wherein the height (H1) of the first clearance area (42) is less than 50 percent of the total height of the cutting plate (10). [13] Cutting plate (10) according to claim 11 or 12, wherein the first clearance surface (42) forms an angle (γ1) in the range of 2.5 to 20 degrees with respect to an axis of rotation (19) of the cutting plate (10) and the second clearance surface (44) forms an angle (γ2) in the range of 5 to 40 degrees with respect to the axis of rotation (19) of the cutting plate (10). [14] Cutting plate (10) according to one of the preceding claims, wherein the cutting plate (10) is a peripheral cutting plate. [15] Cutting plate (10) according to one of the preceding claims, wherein the stripping edge (30) is not continuous with the first cutting edge segment (22).

Images