WO2014021250A1

WO2014021250A1 - Cutting insert, cutting tool, and method for producing cut workpiece

Info

Publication number: WO2014021250A1
Application number: PCT/JP2013/070444
Authority: WO
Inventors: 雅大山本
Original assignee: 京セラ株式会社
Priority date: 2012-07-31
Filing date: 2013-07-29
Publication date: 2014-02-06
Also published as: JPWO2014021250A1; JP5905965B2

Abstract

A cutting insert (1) is provided with a lower surface (5), an upper surface (3), a side surface (7) connected to the lower surface (5) and the upper surface (3), and an upper cutting blade (9) located at an intersection line section between the upper surface (3) and side surface (7). The side surface (7) has a groove (31) that extends toward the direction orthogonal to an axis of rotation passing through the center of the lower surface (5) and the center of the upper surface (3) when viewed from the side. In a cross-section that includes the groove (31) and the axis of rotation and passes through the groove (31), the groove (31) is provided with a first inclined part (33) at which the inner surface is inclined toward the axis of rotation and a second inclined part (35) which is positioned closer to the side of opening of the groove (31) than the first inclined part (33) and at which the inner surface is inclined toward the axis of rotation. In a cross-section that includes the axis of rotation and passes through the groove (31), the angle of incline of the first inclined part (33) is greater than the angle of incline of the second inclined part (35), and the width of the second inclined part (35) in the direction orthogonal to the axis of rotation is greater than the width of the first inclined part (33) in the direction orthogonal to the axis of rotation.

Description

Cutting insert, cutting tool, and method of manufacturing cut workpiece

The present invention relates to a cutting insert, a cutting tool, and a manufacturing method of a cut workpiece.

Conventionally, a cutting element described in Patent Document 1 is known as a cutting insert used for cutting a work material. Specifically, the cutting element (cutting insert) described in Patent Document 1 is used for a turning process such as face milling or end milling. The cutting insert described in Patent Document 1 includes a contact surface having a V-shaped cross section formed by two inclined cutting surfaces. The cutting insert is fixed to the holder with the contact surface in contact with the carrier body (holder).

In the cutting insert described in Patent Document 1, the cutting insert is fixed to the holder by bringing the V-shaped contact surface into contact with the holder. However, at the time of cutting, the force accompanying the cutting force is transmitted from the cutting insert to the holder. As an example, a back component force is applied from the contact surface to the holder. At this time, since the contact surface has a V-shaped cross section, the back component force concentrates on the bottom of the V shape, and the cutting insert may be cracked.

This invention is made | formed in view of said subject, and is providing the manufacturing method of a cutting insert with good durability, a cutting tool, and a cut workpiece.
Special table 2007-515303 gazette

The cutting insert based on 1 aspect of this invention is equipped with the lower surface, the upper surface, the side surface connected to each of the said lower surface and the said upper surface, and the upper cutting blade located in the intersection part of the said upper surface and the said side surface ing. Further, the side surface has a groove portion extending in a direction orthogonal to a rotation axis passing through the center of the lower surface and the center of the upper surface when viewed from the side. In the cross section including the rotating shaft and passing through the groove portion, the groove portion is located on the opening side of the groove portion with respect to the first inclined portion with the inner surface inclined with respect to the rotating shaft, A second inclined portion having an inner surface inclined with respect to the rotation axis. In this cross section, an inclination angle of the first inclined portion is larger than an inclination angle of the second inclined portion, and a width of the second inclined portion in a direction orthogonal to the rotation axis is the first angle. It is larger than the width of the inclined portion in the direction orthogonal to the rotation axis.

It is a perspective view which shows the cutting insert of one Embodiment of this invention. It is a top view of the cutting insert shown in FIG. It is a side view of the cutting insert shown in FIG. FIG. 3 is a cross-sectional view of a D1-D1 cross section in the cutting insert shown in FIG. 2. FIG. 3 is a cross-sectional view of a D2-D2 cross section in the cutting insert shown in FIG. 2. FIG. 3 is a cross-sectional view of a D3-D3 cross section in the cutting insert shown in FIG. 2. It is the expanded sectional view which expanded the area | region A in the cutting insert shown in FIG. It is an expanded sectional view which shows the 1st modification of the cutting insert shown in FIG. It is an expanded sectional view which shows the 2nd modification of the cutting insert shown in FIG. It is an expanded sectional view which shows the 3rd modification of the cutting insert shown in FIG. It is a perspective view which shows the cutting tool of one Embodiment of this invention. It is a side view of the cutting tool shown in FIG. It is an expanded sectional view of the cutting tool shown in FIG. It is an expanded sectional view which shows the 1st modification of the cutting tool shown in FIG. 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.

<Cutting insert>
Hereinafter, the cutting insert 1 of one Embodiment is demonstrated in detail using drawing. However, in the drawings referred to below, for convenience of explanation, among the constituent members of the embodiment, only the main members necessary for explaining the present invention are shown in a simplified manner. Therefore, the cutting insert of the present invention may include any member not shown in the drawings to which the present specification refers. Moreover, the dimension of the member in each figure does not represent the dimension of an actual structural member, the dimension ratio of each member, etc. faithfully.

As shown in FIGS. 1 to 7, the cutting insert 1 of the present embodiment has an upper surface 3, a lower surface 5, and a side surface 7. The side surface 7 is connected to the upper surface 3 and the lower surface 5 respectively. An upper cutting edge 9 is formed at the intersection of the upper surface 3 and the side surface 7. A lower cutting edge 25 is formed at the intersection of the lower surface 5 and the side surface 7. Each of the upper surface 3 and the lower surface 5 has a substantially circular shape when viewed in plan, and has substantially the same shape. Specifically, the outer periphery of the upper surface 3 has four arc-shaped curved portions. The four curved portions are connected by portions that are linear when viewed in plan. Moreover, the cutting insert 1 of this embodiment has the rotating shaft X which passes along the center of the lower surface 5, and the center of the upper surface 3, as shown in FIG.

When the upper surface of the cutting insert has a polygonal shape having a plurality of corners, a large load is easily applied to the corners from the work material during cutting. However, when the upper surface 3 has a substantially circular shape as in the cutting insert 1 of the present embodiment, excessive concentration of force on a specific portion of the upper surface 3 can be avoided. Durability can be increased.

Examples of the material of the cutting insert 1 include cemented carbide or cermet. The composition of the cemented carbide is, for example, WC—Co produced by adding cobalt (Co) powder to tungsten carbide (WC) and sintering, and WC—coating WC—Co with titanium carbide (TiC). There is WC—TiC—TaC—Co in which tantalum carbide (TaC) is added to TiC—Co or WC—TiC—Co. A cermet is a sintered composite material in which a metal is combined with a ceramic component. Specific examples of the cermet include a titanium compound mainly composed of titanium carbide (TiC) or titanium nitride (TiN).

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

The maximum width of the upper surface 3 and the lower surface 5 in the cutting insert 1 of the present embodiment is 5 to 20 mm, respectively. The height from the lower surface 5 to the upper surface 3 is 2 to 8 mm. Here, the height from the lower surface 5 to the upper surface 3 means a width in a direction parallel to the rotation axis X between the upper end of the upper surface 3 and the lower end of the lower surface 5.

As shown in FIG. 4, a through hole 11 is formed from the central portion of the upper surface 3 to the central portion of the lower surface 5. Therefore, the penetration direction of the through hole 11 is parallel to the rotation axis X. The through hole 11 is provided for inserting a screw when the cutting insert 1 is fixed to the holder of the cutting tool with a screw.

1 and 2, the upper surface 3 has a land surface 13, a rake surface 15, a breaker surface 17, and a main surface 19. The land surface 13 is located on the outer periphery of the upper surface 3 and is connected to the upper cutting edge 9. The rake face 15 is located closer to the center of the upper surface 3 than the land surface 13. The rake face 15 is an inclined surface whose height decreases as it goes to the center of the upper surface 3. The breaker surface 17 is located closer to the center of the upper surface 3 than the rake surface 15. The breaker surface 17 is an inclined surface that increases in height toward the center of the upper surface 3. The main surface 19 is located closer to the center of the upper surface 3 than the breaker surface 17. The main surface 19 is a flat surface perpendicular to the rotation axis X.

The land surface 13 is formed so as to be substantially parallel to the lower surface 5 or an inclined surface whose height decreases toward the center of the upper surface 3. Note that “substantially parallel” does not mean strictly parallel, but may mean that the surface may be slightly inclined about ± 5 ° with respect to the lower surface 5. When it is difficult to evaluate whether the lower surface 5 is not flat but parallel to the lower surface 5, it may be compared with the rotation axis X instead of the lower surface 5. That is, the land surface 13 may be evaluated based on whether or not it is perpendicular to the rotation axis X.

As shown in FIGS. 1 and 3, an upper cutting edge 9 is formed at the intersection of the land surface 13 and the side surface 7. The land surface 13 is provided to increase the strength of the upper cutting edge 9. When the land surface 13 is not provided, the upper cutting edge 9 is formed at the intersection of the rake surface 15 and the side surface 7. The rake face 15 located inside the land surface 13 is an inclined surface whose height decreases as it goes toward the center of the upper surface 3 as described above. Therefore, the internal angle formed by the rake face 15 and the side face 7 is small. However, the internal angle formed by the land surface 13 and the side surface 7 is larger than the internal angle formed by the rake surface 15 and the side surface 7. Therefore, the strength of the upper cutting edge 9 can be increased by having the land surface 13.

In addition, if it aims at improving the machinability of the upper cutting edge 9, it is good also as a structure by which the upper cutting edge 9 was formed in the intersection of the scoop surface 15 and the side surface 7. FIG. This is because the upper cutting edge 9 has a sharp shape. The width of the land surface 13 is indicated by the distance between the outer periphery of the upper surface 3 and the outer periphery of the rake surface 15. The width of the land surface 13 is appropriately set depending on the cutting conditions, but is set in the range of 0.05 to 0.2 mm, for example.

As shown in FIGS. 1 and 2, the rake face 15 is located inside the land face 13. The rake face 15 plays a role of scooping off chips cut by the upper cutting edge 9. Therefore, chips of the work material flow so as to travel along the surface of the rake face 15. The scooping surface 15 is an inclined surface whose height decreases toward the center of the upper surface 3 in order to scoop off chips well. The inclination angle indicated by the angle formed between the lower surface 5 and the rake face 15 in the cross section perpendicular to the rake face 15 may be set in the range of 10 ° to 50 °, for example.

The rake face 15 only needs to decrease in height toward the center of the upper face 3. Therefore, as shown in FIG. 4, when viewed in cross-section, it may be configured by a plurality of regions having different inclination angles, or may have a concave curve shape.

1 and 2, the breaker surface 17 is located inside the rake surface 15. The breaker surface 17 serves to curl the chips flowing on the rake surface 15 in a spiral shape. When the chips are deformed in a spiral shape, the cutting insert 1 can exhibit excellent chip discharging performance. Therefore, the height of the region close to the main surface 19 on the breaker surface 17 increases as the distance from the outer periphery increases. Specifically, the breaker surface 17 is an inclined surface whose height on the center side of the upper surface 3 is higher than that on the outer peripheral side. An inclination angle indicated by an angle formed between the lower surface 5 and the breaker surface 17 in a cross section perpendicular to the breaker surface 17 is set in a range of, for example, 5 ° to 45 °.

As shown in FIGS. 1 and 3, an upper cutting edge 9 is formed at the intersection of the upper surface 3 and the side surface 7. The upper cutting edge 9 has a first main cutting edge 21 having a convex curve shape and a first sub cutting edge 23 having a linear shape when viewed in plan. The cutting insert 1 of the present embodiment has four arc-shaped portions as the first main cutting edge 21. In addition, linear first auxiliary cutting edges 23 are located between the four first main cutting edges 21. That is, the four first main cutting edges 21 are connected by the four first sub cutting edges 23, respectively. Each first main cutting edge 21 is longer than each first sub-cutting edge 23.

The cutting insert 1 of the present embodiment has four first main cutting edges 21 and four first sub cutting edges 23, but the first main cutting edge 21 and the first sub cutting edge. The number of blades 23 is not limited to four. For example, there is no problem even if there are two, three, five, or six or more.

In the cutting tool shown in FIG. 11 using the cutting insert 1 of the present embodiment, one of the four first main cutting edges is used as a main cutting edge for cutting a work material. At this time, the first sub cutting edge adjacent to the first main cutting edge used for the cutting process is used as the “sieving edge” for the cutting process. It is preferable that the first auxiliary cutting edge used as the wiping edge is arranged on the holder so as to be parallel to the upper surface 3 of the work material.

When one of the four first main cutting edges 21 used as the main cutting edge deteriorates due to long-time cutting, the cutting insert 1 is temporarily removed from the holder, and then the cutting insert 1 is set to the rotation axis X. It is only necessary to rotate it 90 ° and attach it to the holder again. Another one of the four first main cutting edges 21 can be used as a main cutting edge for cutting a work material.

At this time, the intersection line between the upper surface 3 and the side surface 7 is not a strict line shape due to the intersection of the two surfaces. If the intersection line between the upper surface 3 and the side surface 7 is sharpened at an acute angle, the durability of the upper cutting edge 9 is lowered. Therefore, a so-called honing process may be applied to the intersection line between the upper surface 3 and the side surface 7 so that a portion where the upper surface 3 and the side surface 7 intersect each other has a slightly curved shape.

Further, as shown in FIG. 1 and FIG. 3, the upper cutting edge 9 is not a linear shape when viewed from the side, but has a curved shape undulating. In particular, the concave portion is formed so as to be positioned on the first main cutting edge 21. When the upper cutting edge 9 has such a shape, the upper cutting edge 9 is inclined to contact with the work material as compared with the case where the upper cutting edge 9 has a linear shape parallel to the upper surface 3. It becomes easy to let. Therefore, since cutting force can be made small, a work material can be processed satisfactorily.

Further, as shown in FIGS. 1 and 3, the cutting insert 1 of the present embodiment includes an upper cutting edge 9 formed at the intersection of the upper surface 3 and the side surface 7, and a lower surface 5 and a side surface 7. The lower cutting edge 25 formed in the intersection part is provided. When the cutting insert 1 is mounted on the holder, the lower cutting edge 25 can function in the same manner as the upper cutting edge 9 by mounting the cutting insert 1 upside down. Therefore, in the cutting insert 1 of this embodiment, the lower surface 5 has the same configuration as the upper surface 3. Specifically, similarly to the upper surface 3, the lower surface 5 has a land surface, a rake surface, a breaker surface, and a main surface.

In addition, since the lower cutting edge 25 has the same function as the upper cutting edge 9, the lower cutting edge 25 is a second main body having a convex curve shape on the outside when viewed from below, as shown in FIGS. It has the cutting edge 27 and the 2nd sub cutting edge 29 which is a linear shape. The cutting insert 1 of the present embodiment has four arc-shaped portions as the second main cutting edge 27. Further, between the four second main cutting edges 27, linear second auxiliary cutting edges 29 are positioned. That is, the four second main cutting edges 27 are connected by the four second auxiliary cutting edges 29. Each second main cutting edge 27 has a longer configuration than each second sub-cutting edge 29.

As shown in FIGS. 1 and 3, a side surface 7 is formed between the upper surface 3 and the lower surface 5. The side surface 7 is connected to each of the upper surface 3 and the lower surface 5. Specifically, the side surface 7 includes a curved portion on the outer peripheral edge of the upper surface 3, that is, a curved portion connected to the first main cutting edge 21, and a straight portion on the outer peripheral edge of the upper surface 3, that is, the first auxiliary cutting edge. 23 having a planar shape connected to 23.

When performing cutting using the cutting insert 1, when the cutting insert 1 is fixed to the holder or when performing cutting, a force is applied in the rotational direction with respect to the rotation axis X of the cutting insert 1. This is because, for example, a back force is applied to the cutting insert 1 during cutting.

When the upper surface 3 of the cutting insert 1 has an arc-shaped portion as in the case of a substantially circular shape, the portion of the side surface 7 connected to the arc-shaped portion has a curved surface shape. Therefore, when the cutting insert 1 is fixed to the holder or when cutting is performed, the cutting insert 1 is likely to be displaced in the rotational direction with respect to the rotation axis X of the cutting insert 1.

The cutting insert 1 of the present embodiment has a groove portion 31 in which the side surface 7 extends in a direction orthogonal to the rotation axis X when viewed from the side as shown in FIG. The groove 31 functions as a constraining surface to the holder when the cutting insert 1 is attached to the holder and used. In other words, it can be said that the side surface 7 has a plurality of concave constraining surfaces. By bringing the inner surface of the groove portion 31 into contact with the holder, the cutting insert 1 is suppressed from rotating.

Furthermore, in the cutting insert 1 of the present embodiment, as shown in FIG. 7, the groove portion 31 includes a first inclined portion 33 and a second inclined portion 35 in a cross section including the rotation axis X and passing through the groove portion 31. Yes. The first inclined portion 33 is located on the bottom side of the groove portion 31 with respect to the second inclined portion 35. In other words, the second inclined portion 35 is located closer to the opening side of the groove portion 31 than the first inclined portion 33. The inner surfaces of the first inclined portion 33 and the second inclined portion 35 are inclined with respect to the rotation axis X, respectively.

At this time, the width of the second inclined portion 35 in the direction orthogonal to the rotation axis is larger than the width of the first inclined portion 33 in the direction orthogonal to the rotation axis. That is, when constraining the cutting insert 1 to the holder, the second inclined portion 35 mainly functions as a constraining surface rather than the first inclined portion 33. Since the cutting insert 1 is restrained by the holder in the second inclined portion 35 that is larger than the first inclined portion 33, the cutting insert 1 is stably fixed to the holder in the second inclined portion 35.

Furthermore, as shown in FIG. 7, the inclination angle θ <b> 1 of the first inclination part 33 is larger than the inclination angle θ <b> 2 of the second inclination part 35. Therefore, when the cutting insert 1 is mounted and fixed to the holder, the inner surface of the groove 31 can be brought into contact with the holder, while the possibility that the bottom of the groove 31 comes into contact with the holder is reduced. While the inner surface of the second inclined portion 35 is in contact with the holder, the cutting insert 1 of the present embodiment is attached to the holder while the inner surface of the first inclined portion 33 is not in contact with the holder and is separated from the holder. Therefore, since the possibility that the force from the holder due to the contact of the holder concentrates on the bottom of the groove 31 is reduced, the durability of the cutting insert 1 is improved.

In order to stably fix the inner surface of the groove portion 31 to the holder, the second inclined portion 35 is preferably larger than the first inclined portion 33. In the cutting insert 1 of the present embodiment, the width W3 in the direction parallel to the rotation axis X of the second inclined portion 35 in the cross section including the rotation axis X and passing through the groove portion 31 is the rotation axis X of the first inclined portion 33. Is larger than the width W4 in the direction parallel to.

The second inclined portion 35 in the present embodiment has a flat surface shape. Since the second inclined portion 35 has such a shape, the second inclined portion 35 can be stably brought into contact with the holder and the rotation of the cutting insert 1 is stably suppressed. The

Although the groove part 31 in this embodiment is comprised only by the 1st inclination part 33 and the 2nd inclination part 35, as a shape of the groove part 31, it is not limited to such a form. For example, as shown in FIG. 8, the shape may include a bottom surface 37 in addition to the first inclined portion 33 and the second inclined portion 35. Although the bottom part of the groove part 31 shown in FIG. 7 is V-shaped, since the bottom part of the groove part 31 shown in FIG. 8 is surface shape, the force added to the cutting insert 1 from a holder concentrates too much on the specific location of a bottom part. This can be suppressed. FIG. 8 is an enlarged cross-sectional view in the same cross section as the region shown in FIG.

On the contrary, in the case of the groove part 31 shown in FIG. 7, the space | interval between the upper surface 3 and the inner surface of the 1st inclination part 33 can be enlarged compared with the groove part 31 shown in FIG. That is, since the thickness of the cutting insert 1 between the upper surface 3 and the inner surface of the first inclined portion 33 can be increased, the depth of the groove portion 31 is ensured, and at the same time, the cutting material is added to the cutting insert 1 during the cutting process. The durability against force can be increased. In addition, the depth of the groove part 31 means the width | variety of the direction orthogonal to the rotating shaft between the bottom part of the groove part 31, and an opening part in the cross section shown in FIG.

In the cutting insert 1 of the present embodiment, as shown in FIG. 4, the deepest position in the groove 31 is located below the first sub-cutting edge 23 that is a wiping edge. Although the groove part 31 functions as a restraint surface to the holder, since the thickness in the direction parallel to the rotation axis X becomes small in the part where such a groove part 31 is formed, the durability becomes relatively small. On the other hand, the force applied to the first sub cutting edge 23 from the work material during cutting is smaller than the force applied to the first main cutting edge 21.

In the cutting insert 1 of the present embodiment, the deepest position in the groove 31 which is the portion where the durability is relatively the smallest is the workpiece to be cut during cutting as shown in FIGS. It is located below the first auxiliary cutting edge 23, which is a position where the force applied from the material is relatively small. Therefore, it is possible to obtain the cutting insert 1 having good durability while having the groove portion 31 on the side surface 7.

In the modification shown in FIG. 9, the groove part 31 is provided with the bottom surface 37 similarly to the groove part 31 shown in FIG. 7 and 8, the first inclined portion 33 has a flat surface shape. However, in the groove portion 31 shown in FIG. 9, the first inclined portion 33 has a curved surface shape. Therefore, the bottom portion of the groove portion 31 has a curved shape formed by the first inclined portion 33, so that the durability of the bottom portion is improved. When a force is applied from the holder to the inner surface of the groove 31, this force may travel along the inner surface of the groove 31 and collect at the bottom of the groove 31. Even in such a case, the bottom may crack. Becomes smaller.

In addition, what is necessary is just to let the inclination | tilt angle in a flat part be inclination | tilt angle (theta) 1 of the 1st inclination part 33, when a part of 1st inclination part 33 is a curved surface shape. Further, when the entire first inclined portion 33 has a curved surface shape, the inclination angle closest to the opening in the first inclined portion 33 may be the inclination angle θ1 of the first inclined portion 33.

In the modification shown in FIG. 10, the groove 31 further includes a curved surface portion 39 between the first inclined portion 33 and the second inclined portion 35. When the flat 1st inclination part 33 and the flat 2nd inclination part 35 are directly connected, it becomes a shape where the boundary of these inclination parts bent. On the other hand, when the curved surface part 39 is formed between the 1st inclination part 33 and the 2nd inclination part 35 like the groove part 31 in this embodiment, the 1st inclination part 33 and the 2nd inclination part 35, Are smoothly connected through the curved surface portion 39. Therefore, when attaching the cutting insert 1 to the holder, the holder can be brought into smooth contact with the inner surface of the groove 31. As a result, the possibility of damage to the cutting insert 1 or the holder is reduced.

In the first embodiment, the first inclined portion 33 and the second inclined portion 35 of the groove portion 31 each have a flat inner surface. In particular, since the inner surface of the second inclined portion 35 that contacts the holder has a flat surface shape, the cutting insert 1 can be stably attached to the holder.

As shown in FIG. 3, when the groove 31 is viewed from the opening side, the width W5 in the direction perpendicular to the rotation axis X on the upper end side and the lower end side of the groove 31 is the rotation axis X on the center side of the groove 31. It is smaller than the width W6 in the orthogonal direction.

Since the second inclined portion 35 is inclined, the upper surface 3 and the groove portion 31 on the opening side of the second inclined portion 35 are larger than the thickness between the upper surface 3 and the groove portion 31 on the bottom side of the second inclined portion 35. The thickness between them is small. Therefore, the durability tends to be relatively smaller on the opening side of the second inclined portion 35 than on the bottom side of the second inclined portion 35. However, since the width W5 in the direction orthogonal to the rotation axis X on the upper end side and the lower end side of the groove portion 31 is smaller than the width W6 in the direction orthogonal to the rotation axis X on the center side of the groove portion 31, it is relatively durable. The cutting insert 1 can be brought into contact with the holder within a large range on the bottom side of the large second inclined portion 35.

In addition, as shown in FIG. 3, when the groove 31 is viewed from the opening side, the maximum width W7 of the first inclined portion 33 in the direction orthogonal to the rotation axis X is the rotation axis of the second inclined portion 35. It is larger than the maximum value W8 of the width in the direction orthogonal to X.

Even when the force accompanying the cutting force is transmitted from the second inclined portion 35 to the first inclined portion 33, the above-mentioned force is distributed over a wide range because the maximum value W7 of the width is larger than W8. Can be made. Therefore, compared with the case where the maximum value of the width W7 is smaller than or equal to the width W8, the possibility that the force accompanying the cutting force is concentrated on a specific region at the bottom of the groove 31 is reduced.

<Cutting tools>
Next, a cutting tool 101 according to an embodiment of the present invention will be described with reference to the drawings. 13 is an enlarged cross-sectional view in which a portion where the groove 31 of the cutting insert 1 is attached to the holder 103 is enlarged.

The cutting tool 101 of this embodiment includes a holder 103 having a rotation center axis Y and a plurality of the cutting inserts 1 as shown in FIGS. The holder 103 has a plurality of insert pockets 107 on the outer peripheral surface on the distal end side. The plurality of cutting inserts 1 are mounted in the insert pockets 107, respectively.

The holder 103 has a substantially rotating body shape around the rotation center axis Y. A plurality of insert pockets 107 are provided at equal intervals on the outer peripheral surface on the tip side of the holder 103. The insert pocket 107 is a part to which the cutting insert 1 is mounted, and is open on the outer peripheral surface and the front end surface of the holder 103. Specifically, the insert pocket 107 has a seating surface that opposes the rotation direction, and a plurality of constraining side surfaces that are positioned in a direction intersecting the seating surface. A convex portion 109 is formed on each constraining side surface. The convex portion 109 is formed so that the surface thereof contacts the second inclined portion 35 in the groove portion 31 of the cutting insert 1 when the cutting insert 1 is mounted on the holder 103.

Then, the cutting inserts 1 are mounted in a plurality of insert pockets 107 provided in the holder 103, respectively. The plurality of cutting inserts 1 are mounted such that the upper cutting edge 9 protrudes outward from the outer peripheral surface, that is, to the side of the holder 103. Specifically, the plurality of cutting inserts 1 are attached to the holder 103 such that the arcuate curved portion of the upper cutting edge 9 protrudes from the outer peripheral surface of the holder 103. As a result, the curved portion of the upper cutting edge 9 is constrained to the position most protruding from the outer peripheral surface of the holder 103 during cutting.

When the cutting insert 1 has not only the upper cutting edge 9 but also the lower cutting edge, the cutting insert 1 is turned upside down so that the lower cutting edge protrudes to the side of the holder 103 from the outer peripheral surface. 1 may be mounted in the insert pocket 107.

In the cutting tool 101 of this embodiment, as shown in FIG. 13, the second inclined portion 35 in the groove portion 31 of the cutting insert 1 is in contact with the convex portion 109 of the insert pocket 107. On the other hand, the first inclined portion 33 in the groove portion 31 is not in contact with the convex portion 109. Therefore, the bottom of the groove 31 of the cutting insert 1 is not in contact with the insert pocket 107 of the holder 103. Thereby, since it is suppressed that the bottom part of the groove part 31 is damaged, the cutting process by the cutting insert 1 can be performed stably. Moreover, it is suppressed that the convex part 109 of the insert pocket 107 is damaged. Therefore, even when the cutting insert 1 is replaced a plurality of times, the cutting insert 1 can be satisfactorily attached to the holder 103.

Further, in the cutting tool 101 of the present embodiment, each of the second inclined portions 35 positioned on the upper side and the lower side with the first inclined portion 33 interposed therebetween is in contact with the convex portion 109 of the insert pocket 107. The cutting insert 1 is fixed to the holder 103 by this contact, but the convex portion 109 of the insert pocket 107 may be in contact with only one of the upper and lower second inclined portions 35.

In such a case, the first inclined portion 33 is separated from the convex portion which is the holder restraining surface. Therefore, even when the position of the constraining surface by the convex portion 109 is slightly shifted, interference between the bottom portion of the groove portion 31 and the convex portion 109 of the insert pocket 107 is suppressed. That is, the restraining surface of the holder 103 can be widened.

In the present embodiment, the cutting insert 1 is attached to the insert pocket 107 with a screw 105. That is, the screw 105 is inserted into the through hole of the cutting insert 1, the tip of the screw 105 is inserted into a screw hole (not shown) formed in the insert pocket 107, and the screw parts are screwed together, thereby cutting the cutting insert. 1 is mounted on the holder 103.

In this embodiment, the cutting insert 1 is mounted on the holder 103 so that the upper cutting edge 9 protruding outward from the outer peripheral surface has a negative axial rake angle and a negative radial rake angle. .

As the holder 103, steel, cast iron or the like can be used. In the cutting tool 101 of this embodiment, steel with high toughness is used among these members.

The cutting insert 1 is attached to the insert pocket 107 with a screw 105. At this time, if only one of the upper and lower second inclined portions 35 is brought into contact with the convex portion 109 of the insert pocket 107, it is not necessary to accurately match the shape of the convex portion 109 to the shape of the groove portion 31. Therefore, it can be easily manufactured.

When the upper second inclined portion 35 is in contact with the insert pocket 107, the cutting insert 1 is formed by the screw 105 and the portion of the insert pocket 107 that contacts the upper second inclined portion 35. It becomes the structure pinched | interposed. Since the groove portion 31 can be reliably brought into contact with the insert pocket 107, the cutting insert 1 can be stably fixed to the holder 103.

Therefore, as shown in FIG. 14, among the second inclined portions 35 located on the upper side and the lower side with the first inclined portion 33 interposed therebetween, the upper second inclined portion 35 contacts the insert pocket 107. It is particularly preferable that the lower second inclined portion 35 is separated from the insert pocket 107.

In the case where each of the plurality of grooves 31 included in the cutting insert 1 is in contact with the convex portion 109 of the insert pocket 107, at least one of the plurality of grooves 31 is in contact with the insert pocket 107 as described above. The cutting insert 1 can be stably fixed to the holder 103. However, in order to more stably fix the cutting insert 1 to the holder 103, the upper second inclined portion 35 in each of the plurality of groove portions 31 contacts the insert pocket 107 and the lower second inclined portion 35. Is preferably away from the insert pocket 107.

<Manufacturing method of cut product>
Next, the manufacturing method of the cut workpiece of one Embodiment of this invention is demonstrated using drawing.

The cut workpiece is produced by cutting a work material. The manufacturing method according to the present embodiment includes the following steps as shown in FIGS. That is,
(1) a step of rotating the cutting tool 101 represented by the above embodiment;
(2) contacting the work material 201 with the upper cutting edge 9 or the lower cutting edge of the rotating cutting tool 101;
(3) a step of separating the cutting tool 101 from the work material 201;
It has.

More specifically, first, the cutting tool 101 is rotated relatively close to the work material 201. Next, as shown in FIGS. 15 and 16, the upper cutting edge 9 of the cutting tool 101 is brought into contact with the work material 201 to cut the work material 201. Then, as shown in FIG. 17, the cutting tool 101 is relatively moved away from the work material 201.

In the present embodiment, the work material 201 is fixed and the cutting tool 101 is approached. 15 and 16, the work material 201 is fixed and the cutting tool 101 is rotated about the rotation center axis Y. In FIG. 17, the work material 201 is fixed and the cutting tool 101 is moved away. Note that, in the cutting in the manufacturing method of the present embodiment, the work material 201 is fixed and the cutting tool 101 is moved in each step, but it is naturally not limited to such a form.

For example, the work material 201 may be brought close to the cutting tool 101 in the step (1). Similarly, in the step (3), the work material 201 may be moved away from the cutting tool 101. When continuing the cutting process, the state where the cutting tool 101 is rotated around the rotation center axis Y is maintained, and the upper cutting edge 9 or the lower cutting edge of the cutting insert 1 is brought into contact with a different part of the work material 201. What is necessary is just to repeat the process to make. When the used upper cutting edge 9 or lower cutting edge is worn, the cutting insert 1 is rotated 90 degrees with respect to the rotation axis X of the through hole, and the unused upper cutting edge 9 or lower cutting edge is used. Good.

Note that representative examples of the material of the work material 201 include carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metal.

DESCRIPTION OF SYMBOLS 1 ... Cutting insert 3 ... Upper surface 5 ... Lower surface 7 ... Side surface 9 ... Upper cutting edge 11 ... Through-hole 13 ... Land surface 15 ... Rake surface 17 ... Breaker surface 19 ... main surface 21 ... first main cutting edge 23 ... first sub cutting edge 25 ... lower cutting edge 27 ... second main cutting edge 29 ... second Sub-cutting blade 31 ... groove 33 ... first inclined portion 35 ... second inclined portion 37 ... bottom surface 39 ... curved surface portion 101 ... cutting tool 103 ... holder 105 ... -Screw 107 ... Insert pocket 109 ... Projection 201 ... Work material

Claims

The bottom surface,
The top surface;
A side surface connected to each of the lower surface and the upper surface;
A cutting insert provided with an upper cutting edge located at the intersection of the upper surface and the side surface,
The side surface has a groove extending in a direction orthogonal to a rotation axis passing through the center of the lower surface and the center of the upper surface when viewed from the side,
In the cross section including the rotating shaft and passing through the groove portion, the groove portion is located on the opening side of the groove portion with respect to the first inclined portion with the inner surface inclined with respect to the rotating shaft, A second inclined portion having an inner surface inclined with respect to the rotation axis;
In a cross-section including the rotation axis and passing through the groove portion, the inclination angle of the first inclination portion is larger than the inclination angle of the second inclination portion and is orthogonal to the rotation axis of the second inclination portion. The cutting insert is characterized in that the width of the first inclined portion is larger than the width in the direction orthogonal to the rotation axis of the first inclined portion.
The cutting insert according to claim 1, wherein the second inclined portion has a flat inner surface.
The cutting insert according to claim 1 or 2, wherein the groove has a curved bottom.
In a cross section including the rotating shaft and passing through the groove, the width of the second inclined portion in the direction parallel to the rotating shaft is larger than the width of the first inclined portion in the direction parallel to the rotating shaft. The cutting insert according to any one of claims 1 to 3, characterized in that:
In a side view from the opening side of the groove portion, the width of the first inclined portion in the direction orthogonal to the rotation axis is larger than the width of the second inclined portion in the direction orthogonal to the rotation axis. The cutting insert according to any one of claims 1 to 4.
The groove portion further includes a curved surface portion between the first inclined portion and the second inclined portion,
The cutting insert according to any one of claims 1 to 5, wherein the first inclined portion and the second inclined portion are smoothly connected via the curved surface portion.
A holder having a plurality of insert pockets having convex portions on the tip side;
The cutting insert according to any one of claims 1 to 6, wherein the cutting portion is attached to the insert pocket so that the groove portion contacts the convex portion and an upper cutting edge protrudes to the side of the holder. Cutting tool.
The cutting tool according to claim 7, wherein only the portion of the second inclined portion closer to the upper surface than the first inclined portion is in contact with the convex portion.
Rotating the cutting tool according to claim 7;
Contacting the work piece with the upper cutting edge in the rotating cutting tool;
The manufacturing method of the cut workpiece provided with the process of separating the said cutting tool from the said workpiece.