JP6162544B2 - Throw-away tip, throw-away cutting tool, and method of manufacturing cut workpiece - Google Patents

Description

  The present invention relates to a throw-away tip, a throw-away cutting tool, and a method for manufacturing a cut product, which are used for cutting such as grooving and threading.

  Conventionally, as a throw-away cutting tool used for grooving or threading, a shape in which a substantially triangular throw-away tip is fixed to a holder is known (for example, see Patent Document 1 below). The generally triangular throw-away tip has three cutting edges, and when one cutting edge is worn, it can be reattached to the holder so that another cutting edge can be used. The generally triangular throw-away tip generally has a constraining surface for constraining to a holder on the side surfaces of three sides.

  However, since the generally triangular throw-away tip has only three cutting edges, the cost performance is poor as compared to a substantially square-shaped throw-away tip (see, for example, Patent Document 2 below).

JP-A-10-113802 JP 7-501751 gazette

  The surface of the throwaway tip that has a substantially rectangular shape is superior in cost performance to the throwaway tip that has a substantially triangular shape, but the chips generated when the work material is shaved are not restrained by the holder. It becomes easy to hit the constraining surface in a state where is exposed. And there exists a possibility that chips may hit the constraining surface whose surface is exposed, and the chips may adhere to the constraining surface. If you want to use another cutting blade with chips fixed to the constraining surface with exposed surface, fix the constraining surface with the chips fixed to the holder in the desired state. I can't.

  The present invention has been made in view of the above problems, and provides a throw-away tip, a throw-away cutting tool, and a method for manufacturing a cut workpiece that can suppress chips from adhering to a constraining surface. There is.

A throw-away tip according to an aspect of the present invention includes a first main surface having four corner portions in plan view, and a second main surface having an outer edge that matches the first main surface in plan view, A throw-away tip comprising a side surface connecting outer edges of the first main surface and the second main surface, wherein the side surface includes the four corner portions adjacent to one of the four corner portions. A cutting edge, a rake face and a restraint surface are provided in order until one of the two, and the restraint surface is provided between each of the four corner portions, and the restraint surface in plan view. A first virtual extension line along the second constraining surface is formed at an angle perpendicular to the second virtual extension line along the adjacent constraining surface, and outwardly so as to separate both surfaces between the rake surface and the constraining surface toward the convex portion is provided that protrudes, in plan view, before Against fifth virtual extended line connecting the far end from the projecting portion of the cutting edge and the restraint surface, a top portion of the convex portion is characterized by being located within 1 mm.

  A throw-away cutting tool according to an aspect of the present invention is mounted on the insert pocket such that a holder having an insert pocket on the tip side and one of the plurality of cutting blades protrudes outward from the tip side of the holder. The throwaway tip is provided.

  The manufacturing method of the cut material based on one mode of the present invention includes a step of rotating a work material, a step of bringing the cutting blade of the throw-away cutting tool into contact with the rotating work material, A step of separating the cutting edge of the throw-away cutting tool from the work material is provided.

  According to the present invention, it is possible to provide a throw-away tip, a throw-away cutting tool, and a method for manufacturing a cut workpiece that can suppress chips from adhering to the constraining surface.

It is an appearance perspective view of a throw away tip concerning one embodiment of the present invention. It is the external appearance perspective view which expanded a part of throw-away tip shown in FIG. FIG. 2 is a top view of the throw-away tip shown in FIG. 1. FIG. 4 is an enlarged top view of a part of the throw-away tip shown in FIG. 3. It is a side view of the throw away tip shown in FIG. FIG. 2 is a bottom view of the throw-away tip shown in FIG. 1. 1 is an external perspective view of a throw-away cutting tool according to an embodiment of the present invention. It is the external appearance perspective view which showed the holder of the state which removed the throw away tip from the throw away type cutting tool shown in FIG. It is a side view which shows the front-end | tip part of the throw away type cutting tool shown in FIG. FIG. 10 is an enlarged side view of a part of a throw-away tip of the throw-away cutting tool shown in FIG. 9. It is a perspective view which shows 1 process of the manufacturing method of the cut workpiece of one Embodiment of this invention. It is a perspective view which shows 1 process of the manufacturing method of the cut workpiece of one Embodiment of this invention. It is a perspective view which shows 1 process of the manufacturing method of the cut workpiece of one Embodiment of this invention.

<Throw away tip>
Hereinafter, a throw-away tip 1 according to an embodiment will be described with reference to FIGS. 4 is a top view obtained by cutting out and enlarging a part of the throw-away tip 1 in FIG. 3, and FIG. 4 shows an edge from which a part of FIG. As shown in FIGS. 1 to 6, the throw-away tip 1 of the present embodiment has a first main surface 2 having four cutting portions A (corner portions) in a top view and a first main surface in a top view. A second main surface 3 whose outer edges coincide with the surface 2 and a side surface 4 that connects the outer edges of the first main surface 2 and the second main surface 3 are provided. The throw-away tip 1 has a cutting edge 5, a rake face 6, and a constraining face 7 in order from one of the four cutting parts A to one of the four adjacent cutting parts A on the side face 4. Is provided. In addition, the restraint surface 7 is provided between each of the four cutting parts A. When viewed from above, the first virtual extension line L1 along the restraint surface 7 is a second virtual line along the adjacent restraint surface 7. A convex portion 8 is formed between the rake face 6 and the restraining face 7 and projecting outward so as to separate both faces. In the present embodiment, the first main surface 2 is the upper surface and the second main surface 3 is the lower surface.

The throw-away tip 1 is a substantially rectangular plate-like body as viewed from above, and has a cutting portion A at the corner.
A is provided. The cutting portion 5 is provided with a cutting edge 5 and a rake face 6. Here, the top view means that the four cutting parts A of the throw-away tip 1 are viewed.

  The first main surface 2 and the second main surface 3 of the throw-away tip 1 have the same outer edge as viewed from above. Further, the throw-away tip 1 is formed with a through hole H penetrating vertically. The through hole H is formed from the central portion of the first main surface 2 to the central portion of the second main surface 3. The through hole H is a hole through which the fixing screw 104 passes, and is used to fix the throw-away tip 1 to the holder 102 by screwing the fixing screw 104 to the holder 102. The through hole H is circular when viewed from above, and has a diameter of 4 to 7 mm, for example.

  Examples of the material of the throw-away tip 1 include cemented carbide or cermet. As the material of the cemented carbide, for example, WC-Co produced by adding cobalt (Co) powder to tungsten carbide (WC) and sintering, and WC-Co obtained by adding titanium carbide (TiC) to WC-Co. There is WC-TiC-TaC-Co in which tantalum carbide (TaC) is added to TiC-Co or WC-TiC-Co. The cermet is a sintered composite material in which a metal is combined with a ceramic component, and specifically includes a titanium compound mainly composed of titanium carbide (TiC) or titanium nitride (TiN).

The surface of the throw-away tip 1 may be coated with a film using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. Examples of the material for the coating include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and alumina (Al ₂ O ₃ ).

  In the throw-away tip 1, the maximum width of the first main surface 2 or the second main surface 3 is 15 to 25 mm. Moreover, the height from the 1st main surface 2 to the 2nd main surface 3 is 2-8 mm. That is, the thickness of the throw-away tip 1 is 2 to 8 mm. In addition, as a shape of the upper surface 3 and the lower surface 2, it is not limited to said form. For example, the shape may be a substantially square shape as a whole, and may be a shape in which the cutting portion A protrudes outward and the cutting portion A is formed with irregularities.

  The side surfaces 4 are formed on the four surfaces of the generally square throw-away tip 1. As shown in FIGS. 1, 2, and 5, the side surface 4 has a cutting edge 5 formed at a location corresponding to the cutting portion A. The four cutting parts A are provided rotationally symmetrically about the through hole H. By being provided in rotational symmetry, the exchange of the cutting blade 5 with respect to the holder 102 can be rotated in one direction. The cutting blade 5 can directly contact the rotating work material 200 to cut the rotating work material 200. The cutting blade 5 is formed in each of the four cutting parts A along the thickness direction from the first main surface 2 to the second main surface 3. The cutting edge 5 is formed on each of the intersecting portions where the two surfaces intersect each other on the side surface 4 of the generally square throw-away tip 1. And each of the four cutting blades 5 inclines with respect to the 1st main surface 2 and the 2nd main surface 3, as shown in FIG. In addition, the angle | corner which the cutting blade 5 and the 1st main surface 2 make is set to the angle of 1-3 degrees. In the state where the throw-away tip 1 is attached to the holder 102, the cutting edge 5 is set to be parallel to the bottom surface of the groove formed in the work material 200 when grooving the work material 200. At this time, in order to adjust so that the 1st main surface 2 may leave | separate from the inner wall face in the groove | channel of the workpiece 200, the cutting blade 5 inclines with respect to the 1st main surface. In addition, the cutting blade 5 is formed in 2-8 mm along the thickness direction.

  Further, the intersecting line portion between the four surfaces of the side surface 4 is not a strict line shape due to the intersection of the two surfaces. When the intersecting portions of the four surfaces are sharpened at an acute angle, the durability of the cutting blade 5 is lowered. Therefore, a so-called honing process may be performed in which a portion where the four surfaces intersect each other has a slightly curved surface shape.

  A narrow land 9 is provided on the side surface 4 along the cutting edge 5. The land 9 is formed in the thickness direction of the throw-away tip 1 between the first main surface 2 and the second main surface 3. The land 9 is for increasing the strength of the cutting blade 5. The land 9 is formed between the cutting edge 5 and the rake face 6. The land 9 has a length in the thickness direction of 2 to 8 mm. Further, the width of the land is appropriately set depending on the cutting conditions, but is set in a range of 0.05 to 0.5 mm. Although the land 9 is provided in this embodiment, the throw-away chip 1 without the land 9 may be used.

  A rake face 6 is formed on the side face 4 continuously with the land 9. The rake face 6 is a portion continuous with the land 9 and is formed in a direction from the cutting edge 5 toward the land 9. The rake face 6 is a main surface for cutting, and chips of the work material rub on the surface. The rake face 6 is inclined inward from the cutting blade 5 toward the convex portion 8 between the cutting blade 5 and the convex portion 8. That is, the rake face 6 is an inclined face that is provided on the side face 4 and is inclined inward in the direction from the cutting edge 5 toward the convex portion 8. Since the rake face 6 is recessed from the surrounding faces, chips cut by the cutting blade 5 are scooped up by the rake face 6. The rake face 6 is set within a range of 5 to 30 ° with respect to the face on which the cutting edge 5 is provided. The rake face 6 may be constituted by a plurality of regions having different inclination angles, or may have a concave curve shape. In the present embodiment, a breaker protrusion 61 is provided on the rake face 6. The breaker protrusion 61 adjusts the direction in which chips are blown. The breaker protrusion 61 is on the rake face 6 and not on the restraint face 7.

  A flank 10 is formed on the side surface 4 at a location continuous with the cutting edge 5 and in a direction (front) from the land 9 toward the cutting edge 5. The flank 10 is a surface that has been escaped to avoid unnecessary contact with the finished surface of the work material 200. Then, the cutting edge 5 is formed at the intersection of the flank 10 and the rake face 6. The flank 10 is formed between the first main surface 2 and the second main surface 3 so that the length along the thickness direction of the throw-away tip 1 is 2 to 8 mm. The flank 10 has a circumferential length of 1 to 5 mm.

  The restraint surfaces 7 are respectively provided between the four cutting portions A. Four restraint surfaces 7 are provided on the side surface 4. Among the four restraint surfaces 7, one restraint surface 7 and the restraint surface 7 adjacent to the restraint surface 7 are such that the first virtual extension line L <b> 1 along the one restraint surface 7 is the second along the restraint surface 7 adjacent thereto. It is formed at an angle orthogonal to the virtual extension line L2. Therefore, each constraining surface 7 is shifted by 90 °, and the shape connecting the virtual lines along each constraining surface 7 is a regular tetragon. Therefore, the throw-away tip 1 according to this embodiment can be moved rotationally symmetrically to the attachment location of the holder 102 and the cutting blade 5 can be replaced.

  The throw-away tip 1 applies a force from the work material 200 to the throw-away tip 1 when the work material 200 is cut. The throw-away tip 1 is applied with a force to rotate around the through hole H. When the throw-away tip 1 is attached to the holder 102, two of the four restraining surfaces 7 are brought into contact with the holder 102, whereby the throw-away tip 1 can be stably fixed to the holder 102. . That is, in the throw-away tip 1, the restraint surface 7 is formed in a flat surface, so that the restraint surface 7 is brought into surface contact with the holder 102 as compared with the restraint surface formed in a concave curved surface. Can do. As a result, the throw-away tip 1 can be stably fixed to the holder 102.

The restraining surface 7 is provided so as to be spaced from the rake surface 6 of the side surface 4. If the constraining surface is provided continuously with the rake surface, chips scooped up by the rake surface are likely to hit the constraining surface. The chips are obtained by cutting the work material 200 at a high speed with a cutting blade, and heat is generated by friction, so that there is a high possibility that the heated chips adhere to the restraint surface. If the chips adhere to the restraint surface, it is difficult to remove the chips from the restraint surface, and it becomes difficult to attach the restraint surface to which the chips are stuck to the holder even if it is attempted to replace the cutting blade. The away tip cannot be attached to the holder, and the workpiece 200 cannot be cut under desired conditions. As a result, the cutting edge is worn more than necessary, and the replacement work of the throw-away tip with respect to the holder 102 increases, and the production efficiency decreases. Alternatively, there is a high possibility that the chip hits the restraint surface and wears the restraint surface. Therefore, the throw-away tip 1 according to the present embodiment can make it difficult for chips to adhere to the restraint surface 7 by separating the restraint surface 7 from the rake face 6. The constraining surface 7 is formed between the first main surface 2 and the second main surface 3 so that the length along the thickness direction of the throw-away tip 1 is 2 to 8 mm. The restraint surface 7 is straight when viewed from above, and the length of the side surface 4 in the circumferential direction is 5 to 15 mm.

  The convex portion 8 is provided between the rake face 6 and the restraint face 7 in the side face 4. The convex portion 8 protrudes outward, which is a direction away from the through hole H when viewed from above. The convex part 8 blocks the chips so that the chips scooped up on the rake face 6 do not fly toward the restraint surface 7.

As shown in FIG. 4, the convex portion 8 has a cutting edge 5 of the convex portion 8 with respect to the third virtual extension line L <b> 3 connecting the cutting edge 5 to the root of the convex portion 8 near the cutting edge 5 as viewed from above. From the base of the side 8P of the convex portion 8P
The angle formed by the fourth virtual extension line L4 connecting the above is set to 50 to 60 °. Even if the chips scooped up on the rake face 6 fly toward the restraint surface 7, the convex portion 8 is easily cut at an angle of 50 to 60 ° with respect to the face having the face 6 on the rake face. It is possible to prevent chips from flying directly from the surface 6 toward the restraint surface 7. As a result, it is possible to suppress chips from adhering to the restraint surface 7.

  The top portion 8P of the convex portion 8 is located outward in a plan view from the root of the convex portion 8 near the cutting edge 5 in the direction perpendicular to the first virtual extension line L1. If the top 8P is located inward of the base of the convex portion 8 near the cutting edge 5 in the vertical direction, the chips scooped up by the rake face 6 are not blocked by the convex portion 8. It becomes easy to reach the restraint surface 7 along the surface of the convex portion 8. Therefore, the throw-away tip 1 according to this embodiment can make it difficult for the chips to reach the restraint surface 7 by positioning the top 8P of the convex portion 8 outward, and the chips adhere to the restraint surface 7. Can be suppressed. The top 8P has a vertical length of 0.5 to 1.5 mm with respect to the first virtual extension line L1 in the direction perpendicular to the first virtual extension line L1.

  As shown in FIG. 4, the top portion 8P of the convex portion 8 is viewed from above, with respect to the fifth virtual extension line L5 that connects the cutting blade 5 and the end portion away from the convex portion 8 of the restraint surface 7, It is located at a location that is within a range of 1 mm. Furthermore, the top 8P of the convex portion 8 may coincide with the fifth virtual extension line L5. The rake face 6 is set to be positioned in the imaginary line connecting the cutting edge 5 and the top 8P by positioning the top 8P of the convex part 8 so as to overlap the fifth virtual extension line L5. And even if chips are scooped up on the rake face 6, the chips can easily hit the convex portion 8 </ b> P, so that the chips can be prevented from flying to the restraint surface 7. The breaker protrusion 61 makes it easier to apply chips to the convex portion 8 and makes it difficult to fly to the restraint surface 7.

As shown in FIG. 6, a base 11 is provided on the second main surface 3. A part of the base 11 abuts against the holder 102 to fix the throw-away tip 1 when attached to the holder 102. The base 11 is provided on the second main surface 3 located on the lower surface of the throw-away tip 1, and has a size that fits on the outer edge of the throw-away tip 1 when viewed from the bottom. As shown in FIG. 6, the base portion 11 has a substantially rectangular shape and has a hole that matches the through hole H. The base 11 has an outer edge that is curved so as to be recessed inward from one restraint surface 7 to the restraint surface 7 adjacent thereto when viewed from the bottom. The length of the base 11 along the thickness direction of the throw-away tip 1 is 2 to 8 mm. And the place where the base 11 exists is
The thickness of the throw-away tip 1 is the thickest part. That is, since the thickness of the cut portion is increased, the durability of the throw-away tip 1 can be improved.

  Moreover, the cutting part A is provided only in the thin part, and even if the cutting edge 5 is broken and a crack occurs in the cutting part A, the crack only occurs in the part where the thickness of the throw-away tip 1 is thin. It is possible to prevent the crack from progressing at a portion where the throwaway tip 1 does not enter and overlaps with the thick base 11. As a result, a new cutting blade 5 different from the damaged cutting blade 5 can be maintained in a usable state.

  Further, the base 11 can function as a constraining surface by a continuous surface along the side surface 4. In other words, since a part of the restraint surface 7 spreads in the width direction, a wide restraint area can be secured and the holder 102 can be stably fixed. Moreover, since the base 11 has a curved outer edge inside the throw-away tip 1 when viewed from the bottom, the strength of the base of the cutting part A can be increased.

  The throw-away tip 1 according to the present embodiment has four cutting portions A, and a constraining surface 7 is provided between the cutting portions A. Adjacent restraining surfaces 7 are formed at an angle perpendicular to each other, and a convex portion 8 projecting outward is provided between the rake face 6 and the restraining surface 7 so as to separate both surfaces. . With this configuration, the chips cut by the cutting blade 5 flow along the rake face 6, collide with the convex portion 8, and do not easily reach the constraining face 8 positioned above the ridge face 8. It is possible to prevent chips from adhering to the restraining surface 8.

  In addition, this invention is not limited to the above-mentioned form, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.

<Throwaway cutting tool>
A throw-away cutting tool 100 according to an embodiment of the present invention will be described with reference to FIGS. FIG. 7 is an external perspective view showing a state where the throw-away tip 1 of the throw-away cutting tool 100 is attached. FIG. 8 is an external perspective view showing a state in which the throw-away tip 1 of the throw-away cutting tool 100 is removed. FIG. 9 is an enlarged side view in which the tip side to which the throw-away tip 1 is attached in the throw-away cutting tool 100 is enlarged. FIG. 10 is an enlarged side view in which a part of the throw-away tip 1 of the throw-away cutting tool 100 of FIG. 9 is enlarged.

  As shown in FIG. 7, the throw-away cutting tool 100 according to this embodiment includes a holder 102 having an insert pocket 101 on the tip side, and one of the plurality of cutting blades 5 protruding outward from the tip side of the holder 102. As shown, a throw-away tip 1 mounted in the insert pocket 101 is provided.

  The holder 102 has an elongated bar shape. One insert pocket 101 is provided on the tip side of the holder 102. The insert pocket 101 is a portion to which the throw-away tip 1 is attached, and is open to the front end surface and the side surface of the holder 102. At this time, since the insert pocket 101 is also open to the side surface of the holder 102, the throw-away tip 1 can be easily attached.

As shown in FIG. 9, the insert pocket 101 has an abutting surface 103 cut out in the outer shape of the side surface 4 of the throw-away tip 1 at the tip of the holder 102. Then, the restraining surface 7 of the side surface 4 of the throw-away tip 1 comes into contact with the contact surface 103 of the insert pocket 101, and the throw-away tip 1 is attached to the holder 102. The throw-away tip 1 is mounted so that one of the plurality of cutting blades 5 protrudes toward the distal end side of the holder 102.

  In this embodiment, the throw-away tip 1 is attached to the holder 102 by a fixing screw 104. That is, by inserting the fixing screw 104 into the through-hole H of the throw-away tip 1 and inserting the tip of the fixing screw 104 into the screw hole formed in the insert pocket 101 and screwing the screw portions together, The chip 1 is mounted on the holder 102. As the holder 102, steel, cast iron, or the like can be used. In particular, it is preferable to use steel having high toughness among these members.

  As shown in FIG. 9, the throw-away cutting tool 100 according to the present embodiment is attached to a holder 102, and in a state of being attached to the holder 102, a convex portion 8 above the rake face 6 of the throw-away tip 1. Is located. And as shown in FIG. 10, the convex part 8 is located between the 6th virtual extension line L6 which tied the lower end of the scoop surface 6 and the upper end of the restraint surface 7. FIG. As a result, the chips scooped up by the scooping surface 6 can collide with the convex portion 8 and can hardly reach the exposed restraint surface 7, and can prevent the chips from adhering to the restraint surface 7. .

<Manufacturing method of cut product>
Next, the manufacturing method of the cut workpiece of one Embodiment of this invention is demonstrated using FIGS. The cut workpiece is produced by cutting the workpiece 200. The manufacturing method of the cut workpiece in the present embodiment includes the following steps. That is,
(1) rotating the work material 200;
(2) contacting one of the plurality of cutting blades 5 in the throw-away cutting tool 100 represented by the above embodiment with the rotating work material 200;
(3) a step of separating the throw-away cutting tool 100 from the work material 200;
It has.

  More specifically, first, as shown in FIG. 11, the work material 200 is rotated around the axis Y, and the throwaway cutting tool 100 is relatively brought closer to the work material 200. Next, as shown in FIG. 12, one of the plurality of cutting edges 5 in the throw-away cutting tool 100 is brought into contact with the work material 200 to cut the work material 200. Then, as shown in FIG. 13, the throw-away cutting tool 100 is relatively moved away from the work material 200.

  In the present embodiment, the throw-away cutting tool 100 is brought close to the shaft Y while the workpiece 200 is rotated. In FIG. 12, the workpiece 200 is cut by bringing one of the plurality of cutting edges 11 in the throw-away tip 1 into contact with the rotating workpiece 200. In FIG. 13, the throw-away cutting tool 100 is moved away while the work material 200 is rotated.

  In the cutting in the manufacturing method of the present embodiment, the throw-away cutting tool 100 is brought into contact with the work material 200 by moving the throw-away cutting tool 100 in each step, or the throw-away cutting tool 100 is moved. Is separated from the work material 200, but it is of course not limited to such a form. For example, in the step (1), the work material 200 may be brought close to the throw-away cutting tool 100. Similarly, in the step (3), the work material 200 may be moved away from the throw-away cutting tool 100. When continuing the cutting process, maintaining the state where the throw-away cutting tool 100 is rotated and bringing one of the plurality of cutting blades 11 in the throw-away tip 1 into contact with a different part of the work material 200 Can be repeated. As typical examples of the material of the work material 200, carbon steel, alloy steel, stainless steel, cast iron, non-ferrous metal, or the like can be used.

DESCRIPTION OF SYMBOLS 1 Throw away tip 2 1st main surface 3 2nd main surface 4 Side surface 5 Cutting edge 6 Rake surface 61 Breaker protrusion 7 Constrained surface 8 Convex part 8P Top part 9 Land 10 Relief surface 11 Base part 100 Throw away type cutting tool 101 Insert pocket 102 Holder 103 Contact surface 104 Fixing screw 200 Work material A Corner portion L1 First virtual extension line L2 Second virtual extension line L3 Third virtual extension line L4 Fourth virtual extension line L5 Fifth virtual extension line L6 Sixth virtual extension Line H Through hole

Claims (8)

In plan view, a first main surface having four corner portions;
A second main surface having an outer edge that coincides with the first main surface in plan view;
A throw-away tip comprising a side surface connecting outer edges of the first main surface and the second main surface,
The side surface is provided with a cutting edge, a rake face and a constraining surface in order from one of the four corner portions to one of the four corner portions adjacent to each other.
The constraining surfaces are respectively provided between the four corner portions,
In plan view, the first virtual extension line along the constraint surface is formed at an angle orthogonal to the second virtual extension line along the adjacent constraint surface,
Between the rake face and the constraining face, a convex portion protruding outward is provided so as to separate both faces ,
The top of the convex portion is located within 1 mm with respect to a fifth virtual extension line connecting the cutting edge and the end portion of the restraining surface away from the convex portion in plan view. And throw away chips. The throw-away tip according to claim 1,
The throw-away tip, wherein the cutting edge is formed in each of the four corner portions along a thickness direction from the first main surface to the second main surface. The throw-away tip according to claim 1 or 2,
The throw-away tip, wherein the rake face is inclined inward from the cutting edge toward the convex part between the cutting edge and the convex part. In plan view, a first main surface having four corner portions;
A second main surface having an outer edge that coincides with the first main surface in plan view;
A throw-away tip comprising a side surface connecting outer edges of the first main surface and the second main surface,
The side surface is provided with a cutting edge, a rake face and a constraining surface in order from one of the four corner portions to one of the four corner portions adjacent to each other.
The constraining surfaces are respectively provided between the four corner portions,
In plan view, the first virtual extension line along the constraint surface is formed at an angle orthogonal to the second virtual extension line along the adjacent constraint surface,
Between the rake face and the constraining face, there is a convex part protruding outward so as to separate both faces.
Provided,
In plan view, the third virtual extension line connecting the cutting edge to the root of the convex portion near the cutting edge is connected to the top of the convex portion from the root of the convex portion near the cutting edge. The throw-away tip, characterized in that the angle formed by the fourth virtual extension line is set to 50 to 60 ° . The throw-away tip according to claim 1 ,
A throw-away tip, wherein a top portion of the convex portion is located on the fifth virtual extension line. The throw-away tip according to any one of claims 1 to 5 ,
The throw-away tip, wherein the four corner portions are provided rotationally symmetrically. A holder having an insert pocket on the tip side;
The throwaway tip according to any one of claims 1 to 6 , wherein one of the plurality of cutting blades is attached to the insert pocket so as to protrude outward from a front end side of the holder. Characteristic throw-away cutting tool. A step of rotating the work material;
Contacting the cutting edge of the throw-away cutting tool according to claim 7 with the rotating work material;
A method for manufacturing a cut product, comprising a step of separating the cutting edge of the throw-away cutting tool from the work material.

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