Cutting insert, method for manufacturing cutting insert, molding die, and method for manufacturing molding die

Abstract

This cutting insert comprises a rake face (32), a flank face (34), and a cutting edge (35) provided on an intersection line between the rake face (32) and the flank face (34). The cutting edge (35) is provided with a cut-out part (36).

Description

Cutting insert, method for manufacturing cutting insert, molding die, and method for manufacturing molding die

[0001] The present invention relates to a cutting insert, a method for manufacturing a cutting insert, a molding die, and a method for manufacturing a molding die.

[0002] As an example of a cutting tool, a cutting insert (see, for example, Patent Document 1) has been devised, which is attached to the tip of a tool body. The cutting insert is required to break down chips generated when cutting a workpiece.

[0003] Japanese Patent Application Laid-Open No. 2004-223648

[0004] The cutting insert according to the first aspect includes a rake face, a flank face, and a cutting edge provided at an intersection line between the rake face and the flank face, and the cutting edge includes a notch portion.

[0005] In the method for manufacturing a cutting insert according to the second aspect, a cutting insert having a rake face, a flank face, and a cutting edge provided at an intersection of the rake face and the flank face is provided with a pulsed light having a pulse width of less than 1 picosecond to form a notch in the cutting edge. Also, the notch in the cutting insert according to the first aspect may be formed by removal processing using a pulsed light having a pulse width of less than 1 picosecond.

[0006] The manufacturing method of a cutting insert according to the third aspect is a manufacturing method of a cutting insert to be attached to the tool body of a cutting tool, wherein the cutting insert comprises a base portion on which a cutting surface having a corner at the tip side is formed, a cutting edge formed on the outer periphery of the corner on the cutting surface to perform cutting, and a groove portion formed near the outer periphery on the cutting surface and extending along the cutting edge, wherein a concave notch portion connected to the groove portion is formed in the cutting edge, and the base portion, the cutting edge, the groove portion and the notch portion are formed by pressurizing and molding a powder material in a molding die and sintering it.

[0007] The molding die of the fourth aspect is a molding die for manufacturing a cutting insert to be attached to the tool body of a cutting tool by pressurizing and sintering a powder material, and the cutting insert comprises a base portion on which a cutting surface having a corner at the tip side is formed, a cutting edge formed on the outer periphery of the corner on the cutting surface to perform cutting, and a groove portion formed near the outer periphery on the cutting surface and extending along the cutting edge, and a concave notch portion connected to the groove portion is formed in the cutting edge, and a transfer surface capable of transferring the shapes of the cutting edge, the groove portion, and the notch portion to the powder material.

[0008] The fifth aspect of the method for manufacturing a molding die is a method for manufacturing a molding die for manufacturing a cutting insert to be attached to the tool body of a cutting tool by pressurizing and sintering a powder material, wherein the cutting insert comprises a base portion on which a cutting surface having a corner at the tip side is formed, a cutting edge formed on the outer periphery of the corner on the cutting surface to perform cutting, and a groove portion formed near the outer periphery on the cutting surface and extending along the cutting edge, wherein a concave notch portion connected to the groove portion is formed in the cutting edge, and a transfer surface is formed using pulsed light having a pulse width of less than 1 picosecond, which can transfer the shapes of the cutting edge, the groove portion, and the notch portion to the powder material.

[0009] 5 is a schematic diagram showing a cutting tool including a cutting insert according to a first embodiment. FIG. 6 is a perspective view of the cutting insert according to the first embodiment. FIG. 7 is a front view showing a cutting edge member. FIG. 8 is a cross-sectional view taken along arrows IV-IV in FIG. 3. FIG. 9 is an enlarged view showing the tip side of the cutting edge member. FIG. 10 is a cross-sectional view taken along arrows VI-VI in FIG. 5. FIG. 11 is a cross-sectional view taken along arrows VII-VII in FIG. 5. FIG. 12 is an enlarged view showing the tip of a cutting insert for machining the outer diameter of a workpiece. FIG. 13 is an enlarged view showing the tip of a cutting insert for machining the end face of a workpiece. FIG. 14 is a front view showing a cutting edge member of a comparative example. FIG. 15 is a flowchart showing a manufacturing method of the cutting insert according to the first embodiment. FIG. 16 is a schematic diagram showing a machining system. FIG. 17 is a block diagram showing the configuration of the machining system. FIG. 18 is a front view showing a first modified example of the cutting edge member. FIG. 19 is a front view showing a second modified example of the cutting edge member. FIG. 19 is a front view showing a third modified example of the cutting edge member. FIG. 19 is a front view showing a fourth modified example of the cutting edge member. FIG. 19 is a cross-sectional view showing a first modified example of the groove portion. FIG. 20 is a cross-sectional view showing a second modified example of the groove portion. FIG. 21 is a cross-sectional view showing a third modified example of the groove portion. FIG. 22 is a schematic diagram showing a cutting tool including the cutting insert according to a second embodiment. FIG. 23 is a perspective view of the cutting insert according to the second embodiment. It is an enlarged front view showing the tip side of the cutting insert related to the second embodiment. It is a flowchart showing a method for manufacturing the cutting insert related to the second embodiment. It is a schematic diagram showing an example of a sintering press. It is a schematic diagram showing a part of the transfer surface of the upper pressing mold. It is a flowchart showing a method for manufacturing the pressing mold.

[0010] A preferred embodiment will be described below. In the following description, the directions indicated by the arrows in each drawing may be referred to as the X direction, Y direction, and Z direction, respectively. The X direction, Y direction, and Z direction are perpendicular to each other. The Z direction is the thickness direction of the cutting insert. The Y direction is the longitudinal direction of the cutting insert. The X direction is the lateral direction of the cutting insert. The thickness of the cutting insert refers to the distance between the top surface (the cutting face) of the cutting insert and the bottom surface (the surface opposite the top surface) of the cutting insert.

[0011] First Embodiment First, a cutting insert according to a first embodiment will be described. As shown in Fig. 1 , a cutting insert 10 according to the first embodiment is detachably attached and fixed to a tip end of a tool body 5 of a cutting tool 1 using a fixing member 3 such as a screw. The cutting insert 10, together with the tool body 5 and the fixing member 3, constitutes the cutting tool 1. The cutting tool 1 is attached to a tool post (not shown) of a lathe and is used for turning (e.g., outer diameter machining and end face machining) by the lathe. Note that Fig. 1 shows only the tip end portion of the tool body 5 in a simplified manner.

[0012] As shown in FIG. 2 , the cutting insert 10 includes a body member 20 and a cutting edge member 30, and is formed into a diamond-shaped block shape as a whole. The body member 20 is formed of a metal material such as cemented carbide, and is shaped like a diamond-shaped block when viewed in the Z direction (thickness direction of the cutting insert 10). A blade joint 21 is formed at the tip end of the body member 20. The blade joint 21 is formed in a recessed pedestal shape that matches the outer periphery of the cutting edge member 30. The cutting edge member 30 is joined to the blade joint 21 by, for example, brazing. A fixing hole 23 penetrating in the Z direction is formed at the center of the body member 20. A fixing member 3 is inserted through the fixing hole 23. Note that a side surface 25 (extending in a direction intersecting the XY plane) at the tip end of the body member 20 is formed to connect to a relief surface 34 (extending in a direction intersecting the XY plane) of the cutting edge member 30. The flank surface 34 is inclined with respect to the cutting direction so as to avoid contact with the new surface (finished surface) of the workpiece created by cutting using the cutting insert 10 .

[0013] The cutting edge member 30 is formed using, for example, a sintered body containing polycrystalline diamond. The cutting edge member 30 may also be formed using a sintered body containing cubic boron nitride. As shown in FIGS. 2 and 3 , the cutting edge member 30 is formed in a substantially isosceles triangular block shape and includes a base portion 31, a cutting edge 35, and a groove portion 38. A substantially isosceles triangular rake face (also referred to as a front surface, upper surface, outer surface, etc.) 32 having a corner 33 on the tip side is formed on the front portion (surface parallel to the XY plane) of the base portion 31. The rake face 32 is a surface against which chips from the workpiece scrape when cutting using the cutting insert 10. A flank 34 is formed on the side portion of the base portion 31, connecting to the tip side outer periphery of the rake face 32 and extending in a direction intersecting the XY plane.

[0014] As shown in FIG. 3 , the cutting edge 35 is formed on the outer periphery of the corner 33 of the rake face 32 (i.e., on the intersection line between the rake face 32 and the flank 34). The cutting edge 35 can cut the side of the workpiece W when performing external diameter machining (see FIG. 8 ) using a lathe (not shown). The cutting edge 35 can also cut the end face of the workpiece W when performing end face machining (see FIG. 9 ) using a lathe. The ridge where the rake face 32 and the flank 34 intersect may also be defined as the cutting edge 35. The tip of the rake face 32 (i.e., the tip of the corner 33) is also referred to as a corner or nose. This corner is rounded, and the radius of this roundness is called the corner radius (nose radius). This corner radius is determined by standards.

[0015] As shown in FIGS. 3 and 4 , the groove 38 is formed near the outer periphery (cutting edge 35) of the corner 33 on the rake face 32. The groove 38 extends in a broken line along the cutting edge 35. For example, the groove 38 is V-shaped or U-shaped in the XY plane. The shape of the groove 38 in the XY plane may be substantially the same as or different from the shape of the cutting edge 35. Furthermore, the groove 38 may be a recess provided near the cutting edge 35. The bottom 38a of the groove 38 is, for example, the thinnest part of the groove 38 in the thickness of the cutting edge member 30 (the thickness of the cutting edge member 30 means the distance between the upper surface (rake face) of the cutting edge member 30 and the bottom surface (the surface opposite the upper surface, which is joined to the blade joint portion 21) of the cutting edge member 30. The length of the cutting insert 10 in the Z direction, or the thickness of the cutting insert 10 in a cross section perpendicular to the extension direction of the groove 38). The bottom 38a of the groove 38 is, for example, approximately the center of the groove 38 in a cross section perpendicular to the extension direction of the groove 38. The groove 38 is curved in a substantially concave shape (any expression similar to a concave shape may be used, such as a valley, depression, dent, groove, or depression) in a cross section perpendicular to the extension direction of the groove 38. The groove 38 has two side surfaces 38b extending from the bottom 38a in a cross section perpendicular to the extension direction of the groove 38. One of the side surfaces 38b is an inclined surface extending from the bottom 38a of the groove 38 toward the cutting edge 35 in a cross section perpendicular to the extension direction of the groove 38. The other side surface 38b is an inclined surface extending from the bottom 38a of the groove 38 toward the opposite side from the cutting edge 35 in a cross section perpendicular to the extension direction of the groove 38. In this embodiment, the thickness of the cutting edge member 30 (or cutting insert 10) in the remaining portion of the rake face 32 (portion other than the cutting edge 35 and the groove 38) is thicker than the thickness of the cutting edge member 30 (or cutting insert 10) at the bottom 38a of the groove 38. However, this is not limiting, and for example, the thickness of the cutting edge member 30 (or cutting insert 10) in the remaining portion of the rake face 32 may be equal to the thickness of the cutting edge member 30 (or cutting insert 10) at the bottom 38a of the groove 38. In this case, in a cross section perpendicular to the extension direction of the groove 38, the side surface 38b extending from the bottom 38a of the groove 38 toward the opposite side to the cutting edge 35 is not an inclined surface but is a surface parallel to the remaining portion of the rake face 32.Furthermore, the thickness of the cutting edge member 30 (or cutting insert 10) at the remaining portion of the rake face 32 may be thinner than the thickness of the cutting edge member 30 (or cutting insert 10) at the bottom 38a of the groove 38. As described above, the bottom 38a of the groove 38 can be said to be the surface (outer surface) of the groove 38 where the cutting edge member 30 (or cutting insert 10) has a thinner thickness.

[0016] As shown in FIG. 5 , a first notch 36 and a second notch 37 are formed near the corner (tip) of the cutting edge 35. The first notch 36 and the second notch 37 are located at the same positions in the Y and Z directions, but are located at different positions in the X direction across the corner of the cutting edge 35. In other words, the first notch 36 and the second notch 37 are located on both sides of the corner of the cutting edge 35. In yet other words, the first notch 36 and the second notch 37 are located in a curved portion of the cutting edge 35 (a curve resulting from the corner radius). The first notch 36 is formed in a concave shape that connects to the groove 38. In other words, the first notch 36 is formed between the flank 34 and the groove 38 of the rake face 32. Alternatively, the boundary between the rake face 32 and the first cutout portion 36 is formed in a groove portion 38 of the rake face 32. As shown in FIG. 6 , the first cutout portion 36 is curved in a generally concave shape in a cross section perpendicular to the extension direction of the first cutout portion 36. Alternatively, the first cutout portion 36 is curved in a generally concave shape in a cross section including two points that are the boundaries between the cutting edge 35 and the first cutout portion 36. Also, as shown in FIG. 7 , the bottom portion 36 a of the first cutout portion 36 is curved in a generally convex shape (any expression similar to a convex shape may be used, such as a mountain, a bulge, a protrusion, or a bump) in a cross section in the extension direction of the first cutout portion 36. Furthermore, the bottom 36a of the first cutout 36 is formed to be curved in a substantially convex shape in a cross section perpendicular to a line connecting two points that are the boundary between the cutting edge 35 and the first cutout 36. The bottom 36a of the first cutout 36 is, for example, approximately the center portion of the first cutout 36 in a cross section perpendicular to the extension direction of the first cutout 36. As shown in FIG. 6 , the side surface 36b of the first cutout 36 is formed as an inclined surface that widens from the bottom 36a of the first cutout 36 in a cross section perpendicular to the extension direction of the first cutout 36. As described above, the bottom 36a of the first cutout 36 can be said to be the thin surface (outer surface) of the cutting edge member 30 (or cutting insert 10) in the first cutout 36.

[0017] As shown in FIG. 5 , the second notch 37, like the first notch 36, is formed as a concave shape connecting to the groove 38. The bottom 37a of the second notch 37 is formed similarly to the bottom 36a of the first notch 36. The side surface 37b of the second notch 37 is formed similarly to the side surface 36b of the first notch 36. The second notch 37 is formed symmetrically to the first notch 36 across the corner of the cutting edge 35. The first notch 36 and the second notch 37 may be expressed in any manner that is similar to a concave shape. Examples include valleys, depressions, dents, grooves, and depressions. The first notch 36 and the second notch 37 may be positioned so as to contact the workpiece W when performing end face machining using a lathe (see FIG. 9 ). Therefore, the positions of the first notch portion 36 and the second notch portion 37 are appropriately designed and modified depending on the end face machining method. In this embodiment, the first notch portion 36 and the second notch portion 37 each divide the cutting edge 35 in a direction perpendicular to the extension direction of the cutting edge 35. In other words, the first notch portion 36 and the second notch portion 37 are each substantially concave portions extending from the cutting edge 35 to the groove portion 38. Furthermore, it can also be said that the first notch portion 36 and the second notch portion 37 each extend from the cutting edge 35 on the rake face 32 in a direction perpendicular to the extension direction of the cutting edge 35. In this embodiment, the first notch portion 36 and the second notch portion 37 have a cutting function and may therefore be treated as part of the cutting edge 35.

[0018] As described above, the cutting insert 10 configured as described above is detachably attached and fixed to the tip of the tool body 5 of the cutting tool 1 using a fixing member 3 such as a screw. The cutting tool 1 is attached to a tool rest (not shown) of a lathe. As shown in FIG. 8 , when performing external diameter machining using a lathe (not shown), the cutting edge 35 including the first notch 36 cuts the side surface of the workpiece W. Chips (not shown) generated when the cutting edge 35 including the first notch 36 cuts the side surface of the workpiece W are tightly wound due to the shape of the first notch 36, resulting in a spiral shape. The spirally wound chips in the first notch 36 are discharged through the groove 38 connected to the first notch 36. The tightly spirally wound chips are swung around widely, becoming brittle, and come into contact with the groove 38, where they are separated from the workpiece W. In other words, the first notch 36 and the groove 38 can break up the chips before they become long. In this way, when performing external diameter machining using a lathe, the first notch 36 and the groove 38 function as chip breakers, and can break up the chips and separate them from the workpiece W.

[0019] As shown in FIG. 9 , when end face machining is performed using a lathe (not shown), the cutting edge 35 including the second notch 37 cuts the end face of the workpiece W. The chips (not shown) generated when the cutting edge 35 including the second notch 37 cuts the end face of the workpiece W are tightly wound into a spiral shape due to the shape of the second notch 37. The spirally wound chips in the second notch 37 are discharged through the groove 38 connected to the second notch 37. The tightly spirally wound chips are swung around widely and become brittle, and are separated from the workpiece W before they come into contact with the groove 38 and become long. In other words, the second notch 37 and the groove 38 allow the chips to be broken down into smaller pieces before they become long. In this way, when the end face is machined using a lathe, the second notch portion 37 and the groove portion 38 function as chip breakers, and chips can be broken down into small pieces and separated from the workpiece W.

[0020] The inventors of the present application used the cutting insert 10 according to the first embodiment to perform outer diameter machining and end face machining of a workpiece W on a lathe (not shown). The cutting conditions were a rotation speed of the lathe's spindle (workpiece W) of 2000 rpm, a cutting depth (depth of the cutting insert 10 into the workpiece W) of 0.05 mm, and a feed rate per revolution of 0.05 mm / rev. When the cutting insert 10 according to the first embodiment was used to perform outer diameter machining of the workpiece W, it was confirmed that chips could be broken down to lengths of approximately 15 to 50 mm. When the cutting insert 10 according to the first embodiment was used to perform end face machining of the workpiece W, it was confirmed that chips could be broken down to lengths of approximately 50 to 70 mm. The workpiece W was made of aluminum. This method is effective for materials with elasticity (toughness) equivalent to or greater than that of aluminum.

[0021] Next, a cutting insert in which the groove portion 38 is not formed will be described as a comparative example. The cutting insert of the comparative example includes a cutting edge member 90 as shown in FIG. 10 instead of the cutting edge member 30 according to the first embodiment. The cutting edge member 90 of the comparative example is formed in the same manner as the cutting edge member 30 according to the first embodiment, except that the groove portion 38 is not formed. That is, the base portion 91 of the cutting edge member 90 of the comparative example is formed with a rake face 32 having a corner portion 33, a flank face (not shown), a cutting edge 35, a first notch portion 36, and a second notch portion 37.

[0022] The inventors of the present application performed outer diameter machining and end face machining of a workpiece W using a lathe (not shown) with a cutting insert of the comparative example. The cutting conditions and the material of the workpiece W were the same as those in the first embodiment described above. As a result of performing outer diameter machining of the workpiece W using the cutting insert of the comparative example, it was confirmed that chips spiraling around the first notch 36 were difficult to discharge due to the absence of the groove 38 and tended to adhere to the first notch 36, making it difficult to break down the chips. Furthermore, as a result of performing end face machining of the workpiece W using the cutting insert of the comparative example, it was confirmed that chips spiraling around the second notch 37 were difficult to discharge due to the absence of the groove 38 and tended to adhere to the second notch 37, making it difficult to break down the chips.

[0023] According to the first embodiment, the cutting edge 35 is formed with a concave first notch 36 connected to the groove 38, so that when performing external diameter machining using a lathe, the first notch 36 and the groove 38 function as chip breakers to break up chips and separate them from the workpiece W. Furthermore, the cutting edge 35 is formed with a concave second notch 37 connected to the groove 38, so that when performing end face machining using a lathe, the second notch 37 and the groove 38 function as chip breakers to break up chips and separate them from the workpiece W. In this way, when performing turning (e.g., external diameter machining or end face machining) using a lathe, it is possible to break up chips generated when cutting the workpiece W into smaller pieces, preventing the chips from becoming long and becoming entangled in the workpiece W.

[0024] In addition, in a cross section taken along the extension direction of the first notch 36, the bottom 36a of the first notch 36 is curved convexly. As a result, chips spiraling around the first notch 36 are easily swung around by the convexly curved bottom 36a of the first notch 36 and become brittle. In addition, in a cross section taken along the extension direction of the second notch 37, the bottom 37a of the second notch 37 is curved convexly. As a result, chips spiraling around the second notch 37 are easily swung around by the convexly curved bottom 37a of the second notch 37 and become brittle. Therefore, when performing turning (e.g., outer diameter machining or end face machining) using a lathe, it is possible to break down chips generated when cutting the workpiece W, preventing the chips from becoming long and becoming entangled in the workpiece W.

[0025] [Method for Manufacturing Cutting Insert] Next, a method for manufacturing the cutting insert 10 according to the first embodiment will be outlined. As shown in Fig. 11, first, powder materials for sintering are mixed (step ST101). At this time, a predetermined binder is added to the powder materials and mixed. As the powder materials, polycrystalline diamond powder or cubic boron nitride powder may be used.

[0026] Next, sintering is performed (step ST102). At this time, an ultra-high pressure and high temperature apparatus (not shown) is used to sinter the powder material mixed in the previous step ST101, and a sintered body 30S (see FIG. 12) having a peripheral shape similar to that of the cutting edge member 30 (specifically, a block shape of an approximately isosceles triangle) is formed. After the powder material is sintered to form a sintered body material (not shown), the sintered body material may be cut using a wire electric discharge machine (not shown) to form the sintered body 30S having a peripheral shape similar to that of the cutting edge member 30.

[0027] Next, brazing is performed (step ST103). At this time, the sintered body 30S formed in the previous step ST102 is brazed to the blade portion joining portion 21 of the main body member 20.

[0028] Next, the sintered body 30S, which has been brazed to the main body member 20 (the blade joint portion 21), is subjected to ablation (step ST104). At this time, a processing system 500 shown in FIG. 12 is used, for example, to irradiate the surface (the surface corresponding to the rake face) of the sintered body 30S with processing light EL to perform ablation. By scattering a portion of the sintered body 30S through ablation, the aforementioned groove portion 38, the first notch portion 36, the second notch portion 37, and the like are formed. By performing ablation, thermal deformation of the sintered body 30S can be prevented. Therefore, the first notch portion 36, the second notch portion 37, and the like, which have minute and complex shapes, can be formed. As a result, the cutting edge member 30 is formed from the sintered body 30S through ablation. At this time, the cutting edge member 30 may be subjected to finishing processing such as grinding using a grinding device (not shown).

[0029] As shown in FIGS. 12 and 13 , the processing system 500 includes a processing device 510, a stage device 530, a control device 540, and a housing 550. The processing device 510 and the stage device 530 are housed inside the housing 550. The processing device 510 irradiates a workpiece (e.g., the sintered body 30S described above or the upper molding die 620 described below) with processing light EL to perform ablation processing on the workpiece. Pulsed light having a pulse width of less than 1 picosecond (e.g., ultrashort pulse laser light also known as a femtosecond laser) is used as the processing light EL. The processing device 510 may also irradiate a measurement light ML on the workpiece to measure the workpiece.

[0030] The machining device 510 includes a machining head 511 and a head drive system 521. The machining head 511 emits machining light EL or measurement light ML toward the workpiece. The head drive system 521 moves the machining head 511. The machining head 511 also includes a machining light source 512, a machining optical system 513, a measurement light source 514, a measurement optical system 515, a combining optical system 516, and a common optical system 517. The machining light source 512 emits the machining light EL toward the machining optical system 513. The machining optical system 513 emits the machining light EL incident on the machining optical system 513 toward the combining optical system 516. The measurement light source 514 emits the measurement light ML toward the measurement optical system 515. The measurement optical system 515 emits the measurement light ML incident on the measurement optical system 515 toward the combining optical system 516. The combining optical system 516 emits the processing light EL or measurement light ML that has entered the combining optical system 516 toward the common optical system 517. The common optical system 517 emits the processing light EL or measurement light ML that has entered the common optical system 517 toward the workpiece.

[0031] The stage device 530 includes a surface plate 531, a stage 532, and a stage drive system 533. The surface plate 531 is disposed on the bottom surface of the housing 550. The stage 532 is disposed on the surface plate 531. A workpiece is placed on the stage 532. The stage drive system 533 moves the stage 532 on the surface plate 531.

[0032] The control device 540 controls the operation of the machining system 500. For example, the control device 540 controls the machining device 510 and the stage device 530 so that the workpiece is machined under preset machining conditions. Also, for example, the control device 540 controls the machining device 510 and the stage device 530 so that the workpiece is measured under preset measurement conditions. The control device 540 may include a CPU (Central Processing Unit) and a memory. The control device 540 functions as a device that controls the operation of the machining system 500 by the CPU executing a computer program.

[0033] After forming the cutting edge member 30 by ablation processing, the cutting insert 10 is inspected (step ST105). In this manner, the cutting insert 10 according to the first embodiment is manufactured. In the above-described manufacturing method, the groove portion 38, the first notch portion 36, and the second notch portion 37 of the cutting insert 10 are formed using pulsed light having a pulse width of less than 1 picosecond. This makes it possible to manufacture the cutting insert 10 that can break down chips into smaller pieces.

[0034] [Modifications] In the first embodiment described above, as shown by the two-dot chain line in FIG. 14, a plurality of recesses 39 may be formed on the central side of the rake face 32, connecting with the grooves 38 and extending in a branch-like manner.

[0035] In the first embodiment described above, one first notch 36 and one second notch 37 are formed near the corner of the cutting edge 35. However, this is not limiting. For example, as shown by the two-dot chain line in FIG. 14 , two or more first notches 36 may be formed side by side on the cutting edge 35. For example, as shown by the two-dot chain line in FIG. 14 , two or more second notches 37 may be formed side by side on the cutting edge 35. For example, as shown in FIG. 15 , a recessed notch 36# connected to the groove 38 may be formed only on the cutting edge 35 located on one side of the outer periphery of the corner 33 of the rake face 32. For example, as shown in FIG. 16 , a recessed notch 36#2 connected to the groove 38 may be formed only on the corner of the cutting edge 35. For example, as shown in FIG. 17 , a structure combining FIGS. 14 and 16 may be used. In other words, a concave notch 36#3 connected to the groove 38 may be formed only at the corner of the cutting edge 35, and multiple recesses 39 connected to the groove 38 and extending in a branch-like manner may be formed on the central side of the cutting face 32.

[0036] In the first embodiment described above, the groove 38 has a bottom 38a formed in a concave curve and a side surface 38b formed in an inclined plane, but this is not limited thereto. For example, the cross section of the groove 41 may be formed in an inverted triangular shape, as in the groove 41 shown in Fig. 18 . Alternatively, the cross section of the groove 42 may be formed in a rectangular shape, as in the groove 42 shown in Fig. 19 . Alternatively, the cross section of the groove 43 may be formed in a semicircular shape, as in the groove 43 shown in Fig. 20 .

[0037] In the first embodiment described above, the cutting insert 10 includes the body member 20 and the cutting edge member 30 and is formed into a diamond-shaped block shape as a whole. However, this is not limited to this. For example, the body member may be formed into a substantially square block shape, and four cutting edge members formed to match the shapes of the four vertices of the body member may be joined to blade portion joints provided at the four vertices of the body member. Alternatively, for example, the body member may be formed into a substantially equilateral triangular block shape, and three cutting edge members formed to match the shapes of the three vertices of the body member may be joined to blade portion joints provided at the three vertices of the body member. In this way, the body member may be formed into a substantially regular polygonal block shape, and multiple cutting edge members formed to match the shapes of the vertices of the body member may be joined to blade portion joints provided at the respective vertices of the body member.

[0038] In the first embodiment described above, the cutting insert 10 is a positive insert having a clearance angle, but the present invention is not limited to this and may be a negative insert having a clearance angle of zero.

[0039] In the first embodiment described above, the cutting insert 10 is removably attached and fixed to the tip of the tool body 5 of the cutting tool 1, but this is not limited to this and the cutting insert 10 may be attached and fixed to the tip of the tool body of the cutting tool by brazing.

[0040] Second Embodiment Next, a cutting insert according to a second embodiment will be described. As shown in FIG. 21 , a cutting insert 110 according to the second embodiment is detachably attached and fixed to a tip end of a tool body 105 of a cutting tool 101 using a fixing member 103 such as a screw. The cutting insert 110, together with the tool body 105 and the fixing member 103, constitutes the cutting tool 101. The cutting tool 101 is attached to a tool post (not shown) of a lathe and is used for turning (e.g., outer diameter machining or end face machining) by the lathe. Note that in FIG. 21 , only the tip end portion of the tool body 105 is shown in a simplified form.

[0041] The cutting insert 110 is formed using cemented carbide. As shown in FIGS. 22 and 23 , the cutting insert 110 is formed in the shape of a diamond-shaped block when viewed from the Z direction (thickness direction of the cutting insert 110), and has a base portion 131, a cutting edge 135, and a groove portion 138. A rake face 132 having a shape of an approximately isosceles triangle and having a corner 133 on the tip side is formed on the front portion of the base portion 131. A flank surface 134 extending and connected to the outer periphery of the tip side of the rake face 132 is formed on the side portion on the tip side of the base portion 131. A fixing hole 123 penetrating in the Z direction is formed in the center of the base portion 131. A fixing member 103 is inserted into the fixing hole 123.

[0042] The cutting edge 135 and the groove 138 are formed in the same manner as the cutting edge 35 and the groove 38 according to the first embodiment, and detailed description thereof will be omitted. Also, a first notch 136 and a second notch 137 are formed near the corner of the cutting edge 135. The first notch 136 and the second notch 137 are formed in the same manner as the first notch 36 and the second notch 37 according to the first embodiment, and detailed description thereof will be omitted.

[0043] As described above, the cutting insert 110 configured as above is detachably attached and fixed to the tip of the tool body 105 of the cutting tool 101 using the fixing member 103 such as a screw. The cutting tool 101 is attached to a tool rest (not shown) of a lathe. As described above, the first notch 136 and the groove 138 are formed in the same manner as the first notch 36 and the groove 38 according to the first embodiment. Therefore, when performing external diameter machining using a lathe (not shown), the first notch 136 and the groove 138 function as chip breakers, similar to the first embodiment, and chips (not shown) generated when the cutting edge 135 cuts the side surface of the workpiece can be broken down and separated from the workpiece.

[0044] Furthermore, the second notch portion 137 and the groove portion 138 are formed in the same manner as the second notch portion 37 and the groove portion 38 according to the first embodiment. Therefore, when performing end face machining using a lathe (not shown), the second notch portion 137 and the groove portion 138 function as chip breakers, similar to the first embodiment, and chips (not shown) generated when the cutting edge 135 cuts the end face portion of the workpiece can be broken down and separated from the workpiece.

[0045] According to the second embodiment, a concave first notch 136 connected to the groove 138 is formed in the cutting edge 135. Therefore, when performing external diameter machining using a lathe, the first notch 136 and the groove 138 function as chip breakers, breaking up chips and separating them from the workpiece. Furthermore, a concave second notch 137 connected to the groove 138 is formed in the cutting edge 135. Therefore, when performing end face machining using a lathe, the second notch 137 and the groove 138 function as chip breakers, breaking up chips and separating them from the workpiece. In this way, when performing turning (e.g., external diameter machining or end face machining) using a lathe, it is possible to break up chips generated when cutting the workpiece, preventing the chips from becoming long and becoming entangled in the workpiece.

[0046] As in the first embodiment, the bottom of the first notch 136 is curved convexly in a cross section taken along the extension direction of the first notch 136. As a result, chips spiraling around the first notch 136 are likely to be swung around by the convexly curved bottom of the first notch 136 and become brittle. Furthermore, the bottom of the second notch 137 is curved convexly in a cross section taken along the extension direction of the second notch 137. As a result, chips spiraling around the second notch 137 are likely to be swung around by the convexly curved bottom of the second notch 137 and become brittle. Therefore, when performing turning (e.g., outer diameter machining or end face machining) using a lathe, chips generated when cutting a workpiece can be broken down into smaller pieces, preventing the chips from becoming long and becoming entangled in the workpiece.

[0047] [Method for Manufacturing Cutting Insert] Next, a method for manufacturing the cutting insert 110 according to the second embodiment will be outlined. As shown in Fig. 24, first, powder materials for sintering are mixed (step ST201). At this time, multiple types of powder materials required for manufacturing a cemented carbide are mixed. As the powder materials, for example, at least two types of metal powders may be used from among iron-containing metal powder, copper-containing metal powder, nickel-containing metal powder, chromium-containing metal powder, tungsten-containing metal powder, and molybdenum-containing metal powder.

[0048] Next, molding is performed (step ST202). At this time, for example, using a sintering press 600 shown in Fig. 25, the powder material M mixed in the previous step ST201 is pressure-molded to form a molded body (not shown) having the same shape as the cutting insert 110.

[0049] As shown in FIG. 25 , the sintering press 600 includes a lower molding die 610 and an upper molding die 620. Powder material M is supplied between the lower molding die 610 and the upper molding die 620. The lower molding die 610 presses the powder material M from below. A lower transfer surface 611 is formed on the upper surface of the lower molding die 610, which can transfer the shape of the back side portion of the cutting insert 110 (the portion opposite the rake face 132) to the powder material M. The upper molding die 620 presses the powder material M from above. A lower transfer surface 621 is formed on the lower surface of the upper molding die 620, which can transfer the shape of the front side portion of the cutting insert 110, more specifically, the shape of the rake face 132 on which the cutting edge 135, the groove 138, the first notch 136, the second notch 137, etc. are formed to the powder material M. As shown in Figure 26, the upper transfer surface 621 has a first convex surface portion 622 that can transfer the shape of the first notch portion 136 to the powder material M, a second convex surface portion 623 that can transfer the shape of the second notch portion 137 to the powder material M, and a third convex surface portion 624 that can transfer the shape of the second notch portion 137 to the powder material M.

[0050] Next, a sintering process is performed (step ST203). At this time, a sintering furnace (not shown) is used to sinter the compact formed in the previous step ST202, thereby forming the cutting insert 110, which is a sintered body. At this time, a grinding device (not shown) or the like may be used to perform finishing processing such as grinding on the cutting insert 110.

[0051] Then, the cutting insert 110 formed by the sintering process is inspected (step ST204). In this manner, the cutting insert 110 according to the second embodiment is manufactured. In the above-described manufacturing method, the powder material M is pressure-molded and sintered using the upper molding die 620 and the lower molding die 610 to form the base portion 131, the cutting edge 135, the groove 138, the first notch 136, and the second notch 137 of the cutting insert 110. In addition, the upper molding die 620 is formed with an upper transfer surface 621 that can transfer the shapes of the cutting edge 135, the groove 138, the first notch 136, the second notch 137, etc. to the powder material M. This makes it possible to manufacture a cutting insert 110 that can break down chips.

[0052] [Method of Manufacturing the Forming Mold] Next, an overview of a method of manufacturing the upper forming mold 620 will be given. As shown in Fig. 27 , rough machining is first performed (step ST301). At this time, using, for example, a machining center (not shown), cutting processes such as milling and drilling are performed on a metal material (base material of the upper forming mold 620) to cut out the main frame portion of the upper forming mold 620.

[0053] Next, detailed machining is performed (step ST302). At this time, for example, a wire electric discharge machine (not shown) is used to perform wire electric discharge machining (wire cutting) on ​​the general frame portion of the upper forming die 620 to form detailed contours of the upper forming die 620. Furthermore, the aforementioned machining system 500 is used to perform ablation machining to form detailed portions of the upper transfer surface 621 of the upper forming die 620. More specifically, the aforementioned machining system 500 is used to perform ablation machining by irradiating the upper transfer surface 621 of the upper forming die 620 with machining light EL to form the first convex surface portion 622, the second convex surface portion 623, the third convex surface portion 624, etc. of the upper transfer surface 621. It should be noted that a small-hole electric discharge machine (not shown) may be used to perform small-hole electric discharge machining on the upper forming die 620 to machine small holes (not shown) in the upper forming die 620. In this manner, the detailed portions of the upper forming die 620 are formed.

[0054] Next, the upper molding die 620 formed in the previous step ST302 is subjected to a finishing process (step ST303). At this time, the surface of the upper molding die 620 is polished using, for example, diamond paste or a ceramic grindstone.

[0055] Then, the upper molding die 620 that has undergone the finishing process is inspected (for example, its operation is confirmed) (step ST304). In this manner, the upper molding die 620 is manufactured. In the manufacturing method of the upper molding die 620 described above, pulsed light having a pulse width of less than 1 picosecond is used to form the upper transfer surface 621 that can transfer the shapes of the cutting edge 135, the groove 138, the first notch 136, the second notch 137, etc. to the powder material M. This makes it possible to manufacture the upper molding die 620 for manufacturing the cutting insert 110 that can break down chips.

[0056] [Modification] In the second embodiment described above, similarly to the first embodiment, a plurality of recesses may be formed on the center side of the rake face 132, which are connected to the groove portion 138 and extend in a branch-like manner.

[0057] In the second embodiment described above, similarly to the first embodiment, two or more first notches 136 may be formed side by side on the cutting edge 135. Also, two or more second notches 137 may be formed side by side on the cutting edge 135. Also, a concave notch connected to the groove 138 may be formed only on the cutting edge 135 located on one side of the outer periphery of the corner 133 of the rake face 132. Also, a concave notch connected to the groove 138 may be formed only on the corner of the cutting edge 135.

[0058] In the second embodiment described above, similarly to the first embodiment, the cross section of the groove portion 138 may be formed in an inverted triangular shape, a rectangular shape, or a semicircular shape.

[0059] In the second embodiment described above, the cutting insert 110 is formed in a diamond-shaped block shape, but is not limited thereto. For example, the cutting insert may be formed in a substantially regular polygonal block shape, and cutting edges, grooves, first notches, and second notches may be formed at each corner of the substantially regular polygonal rake face.

[0060] In the second embodiment described above, the cutting insert 110 is a positive insert having a clearance angle, but is not limited to this and may be a negative insert with a clearance angle of zero.

[0061] In the second embodiment described above, the cutting insert 110 is removably attached and fixed to the tip of the tool body 105 of the cutting tool 101, but this is not limited to this and the cutting insert 110 may be attached and fixed to the tip of the tool body of the cutting tool by brazing.

[0062] In the second embodiment described above, the upper transfer surface 621 of the upper molding die 620 is irradiated with the processing light EL to perform ablation processing, thereby forming the fine details of the upper transfer surface 621 of the upper molding die 620, but this is not limiting. For example, the upper transfer surface 621 of the upper molding die 620 may be irradiated with an ion beam to perform ion beam processing (also called etching processing) to form the fine details of the upper transfer surface 621 of the upper molding die 620.

[0063] In the second embodiment described above, the upper molding die 620 has an upper transfer surface 621 formed on its lower surface, which is capable of transferring the shape of the front side portion of the cutting insert 110 (the shape of the rake surface 132 on which the cutting edge 135, the groove 138, the first notch 136, the second notch 137, etc. are formed) to the powder material M. However, this is not limiting. For example, the upper surface of the lower molding die 610 may have a lower transfer surface formed on its upper surface, which is capable of transferring the shape of the front side portion of the cutting insert 110 to the powder material M, and the lower surface of the upper molding die 620 may have an upper transfer surface formed on its lower surface, which is capable of transferring the shape of the back side portion of the cutting insert 110 (the portion opposite the rake surface 132) to the powder material M. In this case, the lower transfer surface of the lower molding die 610 may be irradiated with processing light EL to perform ablation processing, thereby forming the fine details of the lower transfer surface of the lower molding die 610, or the lower transfer surface of the lower molding die 610 may be irradiated with an ion beam to perform ion beam processing (etching processing), thereby forming the fine details of the lower transfer surface of the lower molding die 610.

[0064] In the second embodiment described above, the upper molding die 620 is used to form the cutting edge 135, the groove 138, the first notch 136, the second notch 137, etc. of the cutting insert 110, but this is not limited thereto. For example, the upper molding die 620 may be used to form a surface corresponding to the rake face of the cutting insert 110 (on which the cutting edge 135, the groove 138, the first notch 136, the second notch 137, etc. are not formed), and the above-described machining system 500 may be used to irradiate the surface corresponding to the rake face with machining light EL to perform ablation machining, thereby forming the cutting edge 135, the groove 138, the first notch 136, the second notch 137, etc.

[0065] REFERENCE SIGNS LIST 1 Cutting tool (first embodiment) 5 Tool body 10 Cutting insert 20 Body member 30 Cutting edge member 31 Base portion 32 Rake face 33 Corner portion 34 Flank face 35 Cutting edge 36 First notch portion (36a bottom portion, 36b side portion) 37 Second notch portion (37a bottom portion, 37b side portion) 38 Groove portion (38a bottom portion, 38b side portion) 101 Cutting tool (second embodiment) 105 Tool body 110 Cutting insert 131 Base portion 132 Rake face 133 Corner portion 134 Flank face 135 Cutting edge 136 First notch portion 137 Second notch portion 138 Groove portion 500 Machining system 600 Sintering press machine 610 Lower forming die 611 Lower transfer surface 620 Upper forming die 621 Upper transfer surface W Work material M Powder material

Claims

1. A cutting insert comprising: a cutting face; a flank; and a cutting edge provided at an intersection line between the cutting face and the flank, the cutting edge having a notch.

2. The cutting insert according to claim 1, wherein the notch is formed to be concavely curved in a cross section including two points that are the boundaries between the cutting edge and the notch.

3. The cutting insert according to claim 2, wherein the bottom of the notch is formed to be convexly curved in a cross section perpendicular to the extension direction of the cutting edge.

4. The cutting insert of claim 1, wherein the rake face is provided with a recess adjacent the cutting edge.

5. The cutting insert according to claim 4, wherein the notch is formed between the flank and the recess of the rake face.

6. The cutting insert according to claim 5, wherein the recess is in the form of a groove.

7. The cutting insert according to claim 1, wherein the rake face has a corner, and the notch is provided in the vicinity of the corner.

8. The cutting insert according to claim 1, wherein the rake face has a corner, the cutting edge has two notches, and the two notches are provided on either side of the corner.

9. The cutting insert according to claim 1, wherein the rake face has a corner, and the notch is provided in a curved portion near the corner.

10. The cutting insert according to claim 1, wherein the rake face has a corner, and the notch is provided in the corner.

11. The cutting insert according to claim 1, wherein the cutting face has a corner, the cutting edge has three notches, and of the three notches, two notches are provided on both sides of the corner and the remaining one is provided at the corner.

12. A method for manufacturing a cutting insert, comprising forming the notch of the cutting insert according to any one of claims 1 to 11 by removal processing using pulsed light having a pulse width of less than 1 picosecond.

13. A method for manufacturing a cutting insert comprising: a cutting face; a clearance face; and a cutting edge provided at the intersection of the cutting face and the clearance face, the method comprising forming a notch in the cutting edge using pulsed light having a pulse width of less than 1 picosecond.

14. A method for manufacturing a cutting insert to be attached to a tool body of a cutting tool, the cutting insert comprising: a base portion having a cutting surface with a corner at its tip side, a cutting edge formed on the outer periphery of the corner of the cutting surface for cutting, and a groove portion formed near the outer periphery of the cutting surface and extending along the cutting edge, the cutting edge having a concave notch portion connected to the groove portion, and the base portion, the cutting edge, the groove portion and the notch portion are formed by pressurizing and molding a powder material in a molding die and sintering it.

15. A molding die for manufacturing a cutting insert to be attached to a tool body of a cutting tool by pressurizing and sintering a powder material, wherein the cutting insert comprises: a base portion having a cutting surface with a corner at the tip side, a cutting edge formed on the outer periphery of the corner of the cutting surface for cutting, and a groove portion formed near the outer periphery of the cutting surface and extending along the cutting edge, wherein a concave notch portion connected to the groove portion is formed in the cutting edge, and the molding die has a transfer surface capable of transferring the shapes of the cutting edge, the groove portion and the notch portion to the powder material.

16. A method for manufacturing a molding die for manufacturing a cutting insert to be attached to a tool body of a cutting tool by pressurizing and sintering a powder material, wherein the cutting insert comprises: a base portion on which a cutting surface having a corner at the tip side is formed; a cutting edge formed on the outer periphery of the corner on the cutting surface for performing cutting; and a groove portion formed near the outer periphery of the cutting surface and extending along the cutting edge, wherein a concave notch portion connected to the groove portion is formed in the cutting edge; and a method for manufacturing a molding die for forming a transfer surface capable of transferring the shapes of the cutting edge, the groove portion and the notch portion to the powder material using pulsed light having a pulse width of less than 1 picosecond.

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