Throwaway Tip

Abstract

To suppress the generation and progress of thermal cracks in a throw-away tip even at a high-speed working speed.SOLUTION: A throw-away tip comprises a cutting edge 15 shaping a polygonal plate form and formed on an intersection ridgeline of a rake face 10 with a flank 20, a nose part 16 which connects two cutting edges 15 adjacent to each other, a breaker projection 40 protruding upward from the rake face 10 and extending toward the nose part 16. The rake face 10 has a first rake face 11 continuous to the cutting edge 15 and second rake face 12 continuous to the inside of the first rake face 11 and inclining wider than the first rake face 11, has a recess 30 recessing downward from the rake face between the nose part 16 and the breaker projection 40. The recess 30 is continuous to the inside of the first rake face 11 in the nose part 16 and is also continuous to the inside of two second rake faces 12 extending on both sides of the nose part 16, and an inclining plane connected to the first rake face 11 or the second rake face 12 inclines wider than the second rake face 12.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a throw-away tip. [Background technology]

[0002] A throw-away tip is known in which a cutting edge is formed on the intersection ridge between the rake face and the flank (see, for example, Patent Document 1). In the throw-away tip described in Patent Document 1, the rake face is composed of a first rake face and a second rake face, each of which has a different rake angle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4923569 Summary of the Invention [Problem to be solved by the invention]

[0004] In the throw-away tip described in Patent Document 1, the rake face is composed of a first rake face and a second rake face, so that the contact area with the chips during machining is reduced. This reduces the heat generated in the throw-away tip during turning, and suppresses the occurrence and progression of thermal cracks. At normal machining speeds (e.g., cutting speeds of 250 m / min or less), the rake face of Patent Document 1 suppresses the occurrence and progression of thermal cracks, but at high machining speeds (e.g., cutting speeds of 400 m / min or more), the crater wear on the rake face progresses quickly. This causes the first and second rake faces to be smoothed out early, increasing the contact area between the throw-away tip and the chips during turning, which may cause thermal cracks to occur and progress.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to suppress the occurrence and progression of thermal cracks in a throw-away tip even at high machining speeds. [Means for solving the problem]

[0006] The present invention has been made to solve the above-mentioned problems, and can be realized in the following forms.

[0007] (1) According to one embodiment of the present invention, there is provided a throw-away insert having a polygonal plate-like cutting edge formed on an intersecting ridge between a cutting face and a flank, a nose portion connecting two adjacent cutting edges, and a breaker protrusion protruding upward from the cutting face and extending toward the nose portion. In this throw-away insert, the cutting face has a first cutting face connected to the cutting edge and a second cutting face connected to the inside of the first cutting face and inclined more than the first cutting face, and has a recess recessed downward from the cutting face between the nose portion and the breaker protrusion, the recess connected to the inside of the first cutting face at the nose portion and also connected to the inside of the ends of the two second cutting faces extending on both sides of the nose portion, and an inclined surface connected to the first cutting face or the second cutting face is inclined more than the second cutting face.

[0008] When a workpiece is machined using a throw-away tip, the chips come into contact with the recess or the bottom surface of the breaker of the throw-away tip, and heat is generated by the contact. In particular, when the machining speed is high, cutting heat is likely to accumulate in the nose. In contrast, in the throw-away tip of this configuration, the first rake face and the recess are connected in the nose. On both sides of the nose, the recess is connected to the first rake face via the second rake face. Furthermore, the inclined surface of the recess is inclined more than both the first rake face and the second rake face. Therefore, even if the wear of the first rake face progresses, the chips of the workpiece can be received by the nearby second rake face, so that the contact area between the chips of the workpiece and the recess in the nose can be suppressed from increasing. This suppresses the accumulation of cutting heat in the nose, and suppresses the occurrence and progression of thermal cracks in the throw-away tip. On the other hand, on both sides of the nose, the second rake face is formed between the first rake face and the inclined surface of the recess. Therefore, even if the crater wear of the rake face progresses quickly due to high machining speed, the second rake face functions as a cutting edge even if the first rake face wears. As a result, it is possible to suppress the occurrence and progression of thermal cracks in the nose, where cutting heat is likely to accumulate, and to extend the time until the rake face is completely worn down and the chips come into contact with the recess, thereby extending the machining time of the throw-away insert.

[0009] (2) In the throw-away tip of the above aspect, when a portion on the inside of the nose where the first cutting face and the recess are adjacent to each other is defined as a first region, the throw-away tip may further have, in a direction away from the nose, a second region where the first cutting face, the second cutting face, and the recess are adjacent to each other, and a third region where the first cutting face, the second cutting face, and a breaker bottom surface forming a depression shallower than the recess are adjacent to each other. With this configuration, the closer the area is to the nose where cutting heat is likely to accumulate, the closer the distance between the first rake face and the recess, and the farther the area is from the nose, the larger the area where the second rake face is formed. This makes it possible to further suppress the occurrence and progression of thermal cracks in the nose, and further extend the machining time of the throw-away insert.

[0010] The present invention can be realized in various forms, for example, in the form of a throw-away tip, a cutting insert, a processing device, and a system including these. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a front view of the throw-away tip according to the embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of a portion of the throw-away tip. [Diagram 3] FIG. 2 is an explanatory diagram of a cross section of a throw-away tip. [Figure 4] FIG. 2 is an explanatory diagram of a cross section of a throw-away tip. [Diagram 5] FIG. 2 is an explanatory diagram of a cross section of a throw-away tip. [Figure 6] FIG. 2 is an explanatory diagram of a cross section of a throw-away tip. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] <Embodiment> FIG. 1 is a front view of a throw-away chip 100 according to an embodiment of the present invention. FIG. 2 is a perspective view of a portion of the throw-away chip 100. The throw-away chip 100 according to this embodiment is an insert for turning, and is used for high-speed machining, mainly for steel as a work material. Although details will be described later, the throw-away chip 100 includes a rake face 10 having a first rake face 11 and a second rake face 12, and a recess 30 recessed further downward from the rake face 10. Since the recess 30 is inclined more greatly with respect to the second rake face 12, which is inclined more greatly than the first rake face 11, the occurrence and progression of thermal cracks can be suppressed during high-speed machining using the throw-away chip 100.

[0013] 1 and 2, the throw-away tip 100 has a diamond-shaped plate shape. The throw-away tip 100 is made of a hard material such as cemented carbide, cermet, ceramic, or a material in which the surface of the hard material is coated with a PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition) coating film. The throw-away tip 100 includes a rake face 10, a flank face 20 that contacts the outer periphery of the rake face 10, a recess 30 that is recessed downward from the rake face 10, a breaker protrusion 40, a breaker bottom face 50 that forms a recess, a mounting hole 60 that penetrates the center in the thickness direction (Z-axis direction), and a boss 70 that connects the breaker bottom face 50 and the mounting hole 60.

[0014] In this embodiment, a Cartesian coordinate system CS is defined, which corresponds to each of the figures shown in Fig. 1 to Fig. 6. In the Cartesian coordinate system CS, the thickness direction of the throw-away tip 100 is defined as the Z-axis direction, and the X-axis and Y-axis constituting the XY plane perpendicular to the Z-axis direction are defined. The throw-away tip 100 of this embodiment has a symmetrical shape with respect to the ZX plane and the YZ plane passing through the center of the mounting hole 60.

[0015] A part of a tool body such as a cutting tool to which the throw-away tip 100 is attached is inserted into the mounting hole 60. The boss 70 is formed so as to surround the periphery of the mounting hole 60. When the boss 70 is attached to a tip seat (not shown in FIG. 1) provided on the tool body, it functions as a seating surface that comes into contact with the bottom surface of the tip seat.

[0016] As shown in Figs. 1 and 2, the intersection ridge between the rake face 10 and the flank 20 forms a cutting edge 15 that cuts the workpiece. The flank 20 in this embodiment is a so-called negative flank that intersects the upper and lower faces (the faces on the positive and negative sides of the Z axis) at right angles and has a clearance angle of 0°. The throw-away insert 100 has a rhombus shape when viewed from the Z axis direction, and therefore has four linear cutting edges 15 with different inclinations relative to the X axis or Y axis. Two adjacent cutting edges 15 are connected by a nose portion 16 that is arc-shaped in the XY plane.

[0017] In the throw-away tip 100, a rake face 10, a recess 30, a breaker protrusion 40 protruding upward (in the positive direction of the Z axis) from the rake face 10, and a boss 70 are formed in this order from each nose portion 16 toward the center. As shown in FIG. 1, the breaker protrusion 40 extends from the center of the throw-away tip 100 toward the nose portion 16.

[0018] 1 and 2, the rake face 10 has a first rake face 11 continuing to the cutting edge 15, and a second rake face 12 continuing to the inside of the first rake face 11 (toward the center of the throw-away tip 100). The recess 30 continues to the inside of the first rake face 11 at the nose portion 16. Furthermore, the recess 30 continues to the inside of the ends of the two second rake faces 12 extending on the sides of the nose portion 16 that are connected to the cutting edges 15.

[0019] Each of Fig. 3 to Fig. 6 is an explanatory diagram of a cross section of the throw-away tip 100. Each of Fig. 4 to Fig. 6 shows a part of each of cross sections AA, BB, and CC perpendicular to one cutting edge 15 shown in Fig. 3.

[0020] 3, cross section AA is a cross section of nose portion 16 on the positive side of the Y-axis, and is a region (first region) where first rake face 11 and recess 30 are provided adjacent to each other. In this embodiment, the first region is a region on the inside from a cross section perpendicular to cutting edge 15 at the boundary between cutting edges 15 on both sides to which nose portion 16 is connected. In other words, in the first region that is on the inside of the R end of nose portion 16, second rake face 12 does not exist.

[0021] Cross section BB is a cross section of cutting edge 15 in a direction away from nose portion 16 with respect to cross section AA. Cross section BB is a region (second region) on the Y-axis positive direction side where first rake face 11, second rake face 12, and recess 30 are provided adjacent to each other. In other words, in the second region, second rake face 12, which did not exist in the first region, exists between first rake face 11 and recess 30.

[0022] Cross section CC is a cross section of the cutting edge 15 in a direction further away from the nose portion 16 than cross section BB. Cross section CC is a region (third region) in which the first rake face 11, the second rake face 12, and the breaker bottom surface 50 are adjacent to each other on the positive side of the Y axis. In other words, in the third region, the recess 30 that exists in the second region is not formed between the first rake face 11 and the second rake face 12. The second rake face 12 is connected to the breaker bottom surface 50 in a direction from the cutting edge 15 toward the center of the throw-away tip 100.

[0023] As shown in FIG. 4, the recess 30 in the first region includes an inclined surface 31 connected to the first rake face 11, and a bottom portion 32 recessed below the inclined surface 31 and connecting the inclined surface 31 and the breaker protrusion 40. The inclination angle α31 that the inclined surface 31 forms with the XY plane is larger than the rake angle α11 that the first rake face 11 forms with the XY plane, that is, the inclined surface 31 is inclined more than the first rake face 11. In the cross section AA, the first rake face 11 continues to the inclined surface 31 which is further inclined from the nose portion 16 toward the inside. The inclined surface 31 and the breaker protrusion 40 are connected via the bottom portion 32 which is the deepest recess in the recess 30. The bottom portion 32 connected to the inclined surface 31 has a different recess amount from a reference plane (for example, the XY plane including the cutting edge 15) depending on the location.

[0024] As shown in FIG. 5, the rake angle α12 of the second rake face 12 is larger than the rake angle α11 of the first rake face 11 and smaller than the inclination angle α31 of the inclined face 31, based on the XY plane. That is, the second rake face 12 is inclined more than the first rake face 11. The inclined face 31 is inclined more than both the first rake face 11 and the second rake face 12. In the BB cross section, the first rake face 11 is connected to the second rake face 12 toward the inside of the nose portion 16, and the second rake face 12 is connected to the further inclined inclined face 31. The inclined face 31 and the breaker protrusion 40 are connected via the most recessed bottom portion 32 of the recess 30.

[0025] 6, from the inside of the nose portion 16 toward the center of the throw-away tip 100, the first rake face 11 is connected to the second rake face 12, which is connected to the breaker bottom surface 50. The breaker bottom surface 50 is a recess that is shallower in the Z-axis direction than the recess 30, and is connected to the breaker protrusion 40. In other words, in the CC cross section, the first rake face 11, the second rake face 12, and the breaker bottom surface 50, which forms a recess shallower than the recess 30, are provided adjacent to each other.

[0026] As described above, in the throw-away insert 100 of this embodiment, the rake face 10 has the first rake face 11 continuing to the cutting edge 15, and the second rake face 12 continuing to the inside of the first rake face 11 and inclining more than the first rake face 11. Also, as shown in FIG. 1, a recess 30 recessed downward from the rake face 10 is formed between the nose portion 16 and the breaker protrusion 40. The recess 30 continues to the inside of the first rake face 11 in the nose portion 16. Furthermore, the recess 30 continues to the inside of the end of the two second rake faces 12 extending on the side connected to the cutting edge 15 on both sides of the nose portion 16. As shown in FIG. 4, the recess 30 has an inclined surface 31 connected to the first rake face 11 and inclined more than the first rake face 11. When a workpiece is machined using the throw-away tip 100, the chips come into contact with the recess 30 or the breaker bottom surface 50 of the throw-away tip 100, and heat is generated by the contact. In particular, when the machining speed is high, cutting heat is likely to accumulate in the nose portion 16. In contrast, in the throw-away tip 100 of this embodiment, the first rake face 11 and the recess 30 are connected in the nose portion 16. On both sides of the nose portion 16, the recess 30 is connected to the first rake face 11 via the second rake face 12. Furthermore, the inclination angle α31 of the inclined surface 31 of the recess 30 is inclined larger than both the rake angle α11 of the first rake face 11 and the rake angle α12 of the second rake face 12. Therefore, even if the first cutting face 11 wears, the chips of the workpiece can be received by the nearby second cutting face 12, so that the contact area between the chips of the workpiece and the recess 30 in the nose portion 16 can be suppressed from increasing. This suppresses accumulation of cutting heat in the nose portion 16, and suppresses the occurrence and progression of thermal cracks in the throw-away tip 100. On the other hand, on both sides of the nose portion 16, the second cutting faces 12 are formed between the first cutting face 11 and the inclined surface 31 of the recess 30. Therefore, even if the crater wear of the cutting face 10 progresses quickly due to a high machining speed, the second cutting face 12 functions as the cutting edge 15 even if the first cutting face 11 wears.As a result, while suppressing the occurrence and progression of thermal cracks in the nose portion 16 where cutting heat is likely to accumulate, the time until the cutting face 10 is completely worn away and the chips come into contact with the recess 30 can be extended, thereby extending the machining time of the throw-away tip 100.

[0027] In addition, in the throw-away tip 100 of this embodiment, there is a region (first region) in which the first rake face 11 and the recess 30 are adjacent to each other on the inside of the nose portion 16. In the direction away from the nose portion 16 of this region, there is a region (second region) in which the first rake face 11, the second rake face 12, and the recess 30 are adjacent to each other. Furthermore, in the direction away from the nose portion 16 of this region, there is a region (third region) in which the first rake face 11, the second rake face 12, and the breaker bottom surface 50 are adjacent to each other. That is, the closer to the nose portion 16 where cutting heat is likely to accumulate, the closer the distance between the first rake face 11 and the recess 30 is, and the farther from the nose portion 16, the larger the area where the second rake face 12 is formed. This further suppresses the occurrence and progression of thermal cracks in the nose portion 16, and further extends the machining time of the throw-away tip 100.

[0028] <Modifications of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the invention. For example, the following modifications are also possible.

[0029] The throw-away tip 100 of the above embodiment is an example, and the configuration and shape of the throw-away tip 100 can be modified. The throw-away tip 100 having a polygonal plate shape does not have to be rhombic. The flank surface 20 intersects with the upper and lower surfaces at a right angle, but the intersecting angle may be other than 90°.

[0030] A first region where the recess 30 is connected to the first rake face 11 is formed on the nose portion 16 side from the boundary between the nose portion 16 and the cutting edge 15, but the position where the recess 30 is connected to the first rake face 11 can be changed. The first region where the recess 30 is connected to the first rake face 11 only needs to be formed in at least a part of the inside of the nose portion 16, and a second region may be formed outside the first region in the nose portion 16. On the other hand, the first region may be formed in a cross section perpendicular to the cutting edge 15 on the outside of the nose portion 16. In addition, it is not necessary to form both the second region and the third region, and only the first region and the second region may be formed.

[0031] In the above embodiment, the Cartesian coordinate system CS shown in Figures 1 to 6 is defined, but the defined coordinate system can be changed arbitrarily. In the above embodiment, the Z-axis direction parallel to the thickness direction is defined, and Figure 1 is described as the Z-axis positive direction side, but the up and down directions can be expressed correspondingly depending on the defined coordinate system.

[0032] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate. [Explanation of symbols]

[0033] 10…Scooping surface 11…First scooping face 12…Second scooping face 15…Cutting edge 16…Nose section 20…flank 30…Recess 31…Slope surface 32...bottom 40…Breaker protrusion 50…Breaker bottom 60…Mounting hole 70…Boss 100…Throw-away tip CS...Cartesian coordinate system α11…Rake angle of first rake face α12…Rake angle of second rake face α31…Inclination angle of inclined surface

Claims

1. A throw-away insert having a polygonal plate shape, a cutting edge formed on an intersecting ridge between a rake face and a flank, a nose portion connecting two adjacent cutting edges, and a breaker projection protruding upward from the rake face and extending toward the nose portion, The rake face is a first cutting face connected to the cutting edge; a second rake surface that is connected to the inside of the first rake surface and is inclined more than the first rake surface; a recessed portion recessed downward from the rake face between the nose portion and the breaker projection, The recess is the nose portion is connected to the inside of the first rake face and is also connected to the insides of the ends of the two second rake faces extending on both sides of the nose portion; An inclined surface connected to the first rake face or the second rake face is inclined more than the second rake face, A throw-away insert, characterized in that a region extending from the recess to the second rake face has no protrusion.

2. The throw-away tip according to claim 1, When a portion on the inside of the nose portion where the first rake face and the recessed portion are provided adjacent to each other is defined as a first region, the first region is further defined as follows in a direction away from the nose portion: a second region in which the first scooping surface, the second scooping surface, and the recessed portion are provided adjacent to each other; a third region in which the first rake surface, the second rake surface, and a breaker bottom surface that forms a recess shallower than the recessed portion are provided adjacent to each other, A throw-away tip, wherein the second region and the third region are located in this order in a direction away from the nose portion.

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