JPH0839308A - Throwaway tip - Google Patents

Abstract

PURPOSE:To suppress the chip elongation in a low cut depth and the chip clogging in a high cut depth to enhance chip treating property, and enhance the strength of a sub-cutting edge. CONSTITUTION:Main cutting edges 13 are provided on three sides of the upper surface of a throwaway tip 10 and a sub-cutting edge 14 and a round part 14a on each corner part. A substantially triangular pressing surface 15 is provided on the center, and a recessed part 17 is formed between the cutting edge 13 and the pressing surface 15. In each corner part, a protruding part 23 extended from the wide land part 17a of the sub-cutting edge 14 to the pressing surface 15 is formed. The recessed part 18 is formed in the minimum same groove width and connected to the peripheral side surface 21 of the pressing surface 15 on the low cut depth side, and extended to the adjacent protruding part 23 and connected to its gently inclined second boundary surface 23b on the high cut depth side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away tip used for cutting tools such as face mills, cutters and end mills.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
An example of a throw-away tip provided with the proposed tip breaker is shown in FIGS. 12 and 13 (A), (B).
This will be described below. In FIG. 12, the throw-away tip 1 has a substantially quadrangular plate shape, and linear main cutting edges 3 constituting each side are formed at four peripheral edges of an upper surface 2 facing a lower surface which is a seating surface, and adjacent to each other. Sub cutting edges 4 are formed at the corners between the main cutting edges 3. A pressing surface 5 for attaching to a holder such as a face milling cutter or a cutter is provided at the center of the upper surface 2 of the chip 1, and the cutting edges 3 and 4 at the four peripheral edges are provided.
A narrow land portion 6 and a concave portion 7 forming a chip breaker groove are formed on the rake surface between the pressing surface 5 and the pressing surface 5. The concave portion 7 is between the cutting blades 3 and 4 and the pressing surface 5,
A steep slope and a gentle slope are formed symmetrically across the valley line 7a from both end sides, respectively, and have a downward slope and an upward slope across the valley line 7a (FIG. 12A). (See the sectional view taken along the line AA and the sectional view taken along the line BB shown in FIG.

In the chip 1 having such a structure, since the concave portion 7 is formed around the entire inner circumference of the cutting blades 3 and 4, chipping, chipping or the like is likely to occur particularly in the sub cutting edge 4 by cutting, and the sub cutting edge There is a defect that the strength of 4 is weak. Further, since the concave portion 7 has the same width as a whole in the region of the main cutting edge 3, there is a drawback that the chips are extended and the chip disposability is poor when light cutting with a low depth of cut is attempted. Further, at the time of high cutting, the generated chips are curled at the rising surface of the boundary between the concave portion 7 and the pressing surface 5 and return to the machining surface direction of the work material, so that the chip discharge performance is poor and chip clogging occurs. It also had the drawback of being easy.

As another example of the throw-away tip, the entire circumference is formed in a plane parallel to the lower surface in the rake face side direction from the ridge line of the main cutting edge and the sub cutting edge without forming the above-mentioned concave portion on the upper surface. In some cases, the chip breaker is formed by raising the pressing surface of the central portion from the rake surface. In this case, depending on the throw-away tip, there is also one in which a tapered protrusion having the same height as the pressing surface is formed to project from the corner portion of the pressing surface toward the sub cutting edge direction of the tip corner portion. With such a structure, since the breaker groove is not provided, the strength of the auxiliary cutting edge is high, and the chip treatability becomes good in cutting with a low depth of cut, but in heavy cutting with a high depth of cut, this protrusion is It has the disadvantage of being clogged because it is considerably higher than the cutting edge. Further, since the rake angle is not formed on the breaker, there is a drawback that the cutting resistance is high and the vibration is likely to occur.

In view of the above-mentioned problems, the present invention is intended to increase the strength of the auxiliary cutting edge and reduce the cutting resistance so that the chip disposability from a low depth of cut to a high depth of cut can be favorably maintained. The purpose is to provide away chips.

[0006]

A throw-away tip according to the present invention is a substantially flat plate-like throw-away tip having a main cutting edge and a sub-cutting edge formed on a peripheral edge thereof, and an upper surface facing a lower surface forming a seating surface. Has a concave portion formed inside the main cutting edge, and the groove width of the concave portion gradually increases in the direction away from the sub cutting edge along the main cutting edge, and cuts in the central portion of the upper surface substantially parallel to the lower surface. A pressing surface having the same height as or slightly higher than that of the blade is formed, and a protrusion having a height substantially the same as the auxiliary cutting edge is provided from the vicinity of the auxiliary cutting edge toward the pressing surface. It is a thing.

One boundary surface of the protrusion is characterized in that it is formed as a gently inclined surface which rises from the recess at a position farthest from the auxiliary cutting edge along the main cutting edge in the recess. Further, the other boundary surface of the protrusion is characterized in that it is formed so as to rise from the recess at a position close to the sub cutting edge in the recess. The concave portion is formed with the same groove width from the end on the side of the secondary cutting edge to the region where the protrusion is connected to the pressing surface, and the groove width is from that region to one boundary surface of another adjacent protrusion. It is characterized in that it is formed so as to gradually increase. Alternatively, the concave portion is characterized in that the groove width is gradually increased from the end portion on the side of the secondary cutting edge to one boundary surface of another adjacent protrusion. The protrusion may be connected to extend from the vicinity of the sub cutting edge to the pressing surface, and the width thereof may be gradually increased from the side of the sub cutting edge toward the pressing surface. Further, the protrusion may extend from the land portion of the auxiliary cutting edge in the pressing surface direction and may be separated from the pressing surface.

The throw-away tip according to the present invention is characterized in that it is provided with an R portion or a chamfer on one side between the auxiliary cutting edge and the main cutting edge so that it is self-supporting. or,
Lands are formed on the upper surface so as to be connected to the main cutting edge and the sub cutting edge and extend over the entire circumference, and the land width of the sub cutting edge is set to be larger than the land width of the main cutting edge. When viewed from the main cutting edge in the pressing surface direction, the concave portion has a downwardly sloping steep surface and a gently sloping surface, and an upwardly sloping gentle slope and a steeply sloping surface. On the recess,
There may be formed a plurality of recessed groove portions whose width increases in the direction away from the main cutting edge.

[0009]

When the cutting depth is low, the chips generated by cutting with the cutting edge during the cutting run in the region of the recess having a relatively narrow groove width and collide with the rising surface of the projecting region to be curled. In the case of high depth of cut, the chips are ejected after being suppressed from extending, and in the case of a high depth of cut, they travel in a relatively wide area of the recess and collide with the rising surface of the pressing surface area to be curled away from the machined surface. Will be discharged by being guided to, and chip clogging can be eliminated, stable chip disposal can be performed regardless of the direction of the generated chips, and the strength of the auxiliary cutting edge is high due to the protrusion.

At the time of high cutting, the chips are guided by the concave portion, curled at the rising surface of the pressing surface region, and curled again at one boundary surface of the adjacent protrusions, so that the chip disposability at the time of high cutting is improved. improves. When the depth of cut is low, the chips are guided by the recesses and collide with the other boundary surface of the protrusion rising from the recesses to be curled, and the extension of the chips is suppressed. Since the recesses have the same groove width which is relatively small in the low-cut area, it suppresses the extension of chips and facilitates curling,
In the high-cut area, the groove width gradually increases, so that the chip discharge direction can be controlled to prevent chip clogging. The groove width of the recess is
By gradually increasing from the end on the side of the secondary cutting edge to another adjacent protrusion, it is possible to prevent the chip clogging by controlling the chip discharge direction from the low cutting to the high cutting. Since the width of the protrusion gradually increases from the side of the secondary cutting edge toward the pressing surface, it facilitates the second curl of the chips during high cutting. Since the protrusion is separated from the pressing surface, the cutting resistance in this region is small and the chip discharge property is good.

The R portion or the chamfer is provided on one side between the sub cutting edge and the main cutting edge, and the cutting edge strength is high because it is arbitrary. Since the land width of the sub cutting edge is larger than the land width of the main cutting edge, the strength of the sub cutting edge is higher. Due to the concave curved surface shape of the concave portion, the contact area of the guided chips becomes small, so that the heat generation of the chip is small and the chip life is long. By forming the plurality of concave groove portions on the concave portion, the contact area of the chips is further reduced, and the heat generation of the chip is further suppressed.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 7 show a first embodiment of the present invention. FIG. 1 is a plan view of a throw-away tip, FIG. 2 is a side view of FIG. 1, and FIG. 3 is a sectional view taken along line CC of FIG. Figure, Figure 4
Is a sectional view taken along line D-D, FIG. 5 is a sectional view taken along line E-E, and FIG.
FIG. 7 is a cross-sectional view taken along line F-G and taken along line F-G. 1 and 2
In, the throw-away tip 10 has a substantially polygonal plate shape,
For example, it is a positive throw-away tip having a substantially equilateral triangular plate shape. A linear main cutting edge 13 forming each side is formed on a substantially parallel upper surface 12 facing the chip lower surface 11 forming a seating surface, and the adjacent main cutting edge 1 is formed.
A straight sub-cutting edge 14 and an arcuate R-shaped portion 14a (cutting edge) connected to one of the straight sub-cutting edge 14 are formed at each corner between 3 and 13, respectively, and are right-handed (or left-handed) Is configured.

At the center of the upper surface of the chip 10, a pressing surface 15 for attaching to a holder or the like, which is slightly larger in height than each of the cutting edges 13 and 14 (or has the same height) and which has a substantially triangular shape in a plan view.
Are provided, and a small flat land portion 17 following the main cutting edge 13 and a concave portion 18 forming a chip breaker groove are formed on the rake face between each main cutting edge 13 and the pressing surface 15. . The land portion 17 includes the sub cutting edge 14 and the R portion 14a.
The area is a wide land portion 17a having a width larger than that of the area of the main cutting edge 13. Each of the recesses 18 extends along the main cutting edge 13 and is formed to have substantially the same groove width from the end of the main cutting edge 13 on the side of the sub cutting edge 14 to the vicinity of the tip corner 15a of the pressing surface 15 near the tip. Further, the groove width is gradually increased from the position to the other tip corner portion 15a adjacent thereto (and the other end portion of the main cutting edge 13) toward the pressing surface 15 side. Therefore, the pressing surface 15 having a substantially triangular shape in a plan view forms a substantially "V" -shaped peripheral side surface 21 having a bent portion 20 that bends inward near the tip corner portion 15a of each side. It is inclined and rises from the concave portion 18 to the pressing surface 15 (see the sectional view taken along the line D-D in FIG. 1 shown in FIG. 4).

The concave portion 18 has a main cutting edge 13 and a pressing surface 15.
Between the main cutting edge 13 side, a steeply inclined surface 18a and a gently inclined surface 18b having a downward slope, and a gently inclined surface 18c and a steeply inclined surface 18d having an upward slope are formed with a valley line 19 interposed therebetween, and a concave curved surface shape. (See FIG. 4). Then, in the region of the pressing surface 15, the flat surface portion 18 is provided after the steeply sloping surface 18d having an upward slope.
e is formed, and is connected to the peripheral side surface 21 that rises on the pressing surface 15 with a steeper slope. Therefore, the recess 18 is
With the same groove width from the wide land portion 14a of the auxiliary cutting edge 14 to the vicinity of the tip corner portion 15a of the pressing surface 15, it is possible to prevent chip clogging and chip extension at the time of low cutting. Further, this tip corner portion 15a
The tip corner portion 15a adjacent to the region (the bent portion 2 of the peripheral side surface 21)
The width gradually increases up to the vicinity of 0), and it is possible to prevent clogging of chips at high cutting depth. Also, each recess 1
In FIG. 8, a concave groove portion 22 having a substantially triangular shape in plan view, the width of which gradually widens from the main cutting edge 13 side toward the pressing surface 15 across the steep descending surface 18a of the descending slope 18d.
Are formed in plural (4 in the figure). As shown in FIG. 5 (cross section taken along the line EE of FIG. 1), the groove inner shape of the concave groove portion 22 is
It has a concave shape. Moreover, the concave groove portions 22 are separated from each other and arranged in a direction parallel to the main cutting edge 13.

At the corners between the adjacent recesses 18 and 18, from the vicinity of the boundary between the wide land portion 17a of the auxiliary cutting edge 14 and the land portion 17 of the main cutting edge 13 to the tip corner portion 15a of the pressing surface 15. A planar projecting portion 23 that is connected to and extends up to the sub-cutting edge 14 is formed at substantially the same height as the sub-cutting edge 14 (see the sectional view taken along the line CC in FIGS. 1 and 3). The width of the protrusion 23 is
It is the smallest at the end portion on the side of the wide land portion 17a, and the width is gradually (linearly) gradually widened from this area in the direction of the pressing surface 15 and is connected to the tip corner portion 15a of the pressing surface 15 via a step. Is made. A first boundary surface 23a (another boundary surface) and a second boundary surface 23b (one boundary surface) that are inclined from the two adjacent recesses 18 and are inclined to each other are formed on both side surfaces of the protrusion 23. . The first boundary surface 23a constitutes a small-width, steeply-inclined rising wall that curls or bends the chips when the main cutting edge 13 is cut low. Further, the second boundary surface 23b provided on the high cutting side of the other adjacent main cutting edge 13 is formed as a wide and gentle slope, and the chips are divided into two parts, the peripheral side surface 21 and the second boundary surface 23b. It can be curled on the surface.

Since this embodiment is constructed as described above, when cutting is performed with the throw-away tip 10, first, the tip 10 is firmly fixed to the holder such as a face mill or a cutter by the pressing surface 15. Install.
When cutting with a low depth of cut after mounting the chip, the sub-cutting edge 14 and the R portion 14a make a cut into the work material, and while feeding in the lateral direction, the main cutting edge 13 near the R portion 14a cuts the work material. Make a cut. Then, the chips generated by the main cutting edge 13 are guided and run on the recesses 18, and the protrusions 2
The third first boundary surface 23a collides and is curled. In particular, in the case of the present embodiment, since the recess 18 has a recessed surface structure composed of four divided surfaces from the steeply descending surface 18a to the steeply descending surface 18d, the contact with the recess 18 of the chips is made in the low-cut area. The area is small, heat generation of the chip 10 due to friction with chips and cutting resistance are suppressed, and chip flow becomes good. In the region of the concave groove portion 22, the contact area with the chips is further reduced, and the heat generation of the chip can be further suppressed. Moreover, in the low cutting area,
Since the recess 18 is formed to have the same minimum groove width up to the tip corner portion 15a of the pressing surface 15, as compared with the conventional chip breaker groove, the chip extension at the time of low cutting is suppressed and the first boundary surface is formed. At 23a, the chips are curled to a small diameter and discharged, so that the chip discharge property is improved.

Further, when cutting with a high cutting depth, chips collide with the peripheral side surface 21 of the pressing surface 15, but the recess 18 gradually widens in the direction away from the auxiliary cutting edge 14, so that the pressing surface 15 The peripheral side surface 21 is arranged at an approximately predetermined angle with respect to the main cutting edge 13, and the generated chips collide with the peripheral side surface 21 and are curled, and the adjacent side is the side opposite to the auxiliary cutting edge 14. The protrusion 23 is guided in the direction of the second boundary surface 23b and discharged in a direction away from the machined surface of the work material. In this case, the bent portion 20 is formed at the end of the peripheral side surface 21 in the region farthest from the sub cutting edge 14 of the recess 18, and the breaker groove width is maximized here, and the breaker groove is adjacent to the bent portion 21. Since it is configured to be connected to the second boundary surface 23b of the protrusion 23, the chips curled on the peripheral side surface 21 of the pressing surface 15 at the time of a high cutting depth are adjacent to the protrusion 23.
Is guided toward the second boundary surface 23b, curled again at the second boundary surface 23b, and discharged.

Therefore, at the time of high cutting, even if the traveling direction of the discharged chips is different, regardless of this, the chips are guided toward the second boundary surface 23b by the peripheral side surface 21 and are curled by these two surfaces. Then, it is discharged in a predetermined direction. Therefore, stable chip disposal can be realized without causing chip clogging. Further, when the chips travel in the concave portion 18, the contact area with the concave portion 18 is small and the concave groove portion 22 is provided in the concave portion 18, so that the contact area is further reduced and the heat generation of the chip is further suppressed. This helps improve the life of the insert and reduce cutting resistance.

As described above, in this embodiment, the auxiliary cutting edge 14 is used.
The protruding portion 2 connected to the wide land portion 17a and the pressing surface 15
Since 3 is provided as the reinforcing portion, it is possible to suppress the chipping and chipping of the auxiliary cutting edge 14 and increase the strength of the cutting edge, and to improve the life of the tip 10. Further, the contact surface area of the chips is reduced due to the concave shape of the concave portion 18, and the contact surface area with the chips is further reduced by the concave groove portion 22 of the concave portion 18 while suppressing the decrease in the cutting edge strength of the main cutting edge 13. As a result, the contact area with chips is reduced as a whole, heat generation can be suppressed, and it is useful for improving the chip life and cutting resistance. Further, the concave portion 18 has a shape in which the groove width is the smallest in the low-cut area and gradually increases in the high-cut area from the side of the sub cutting edge 14 toward the second boundary surface 23b of the projection 23. Since the width of the chip breaker is relatively narrow at the time of low cutting, the chip extension can be suppressed, the curl of the chip can be promoted, and the chip can be discharged well. Further, the width of the chip breaker groove becomes gradually wider at the time of high cutting, and the generated chips are curled in the predetermined direction on the peripheral side surface 21 of the pressing surface 15 regardless of the traveling direction thereof, and further curled again at the second boundary surface 23b. Therefore, chips can be discharged in a fixed direction, and good and stable chip processing characteristics can be realized.

Next, FIG. 8 shows a second embodiment of the present invention and is a partial plan view of a corner portion of the throw-away tip 10. In the figure, the protrusion 26 is the auxiliary cutting edge 14
From the vicinity of the boundary between the wide land portion 17a of the main cutting edge 13 and the land portion 17 of the adjacent main cutting edge 13 in the direction of the tip corner portion 15a of the pressing surface 15 and at a distance from the tip corner portion 15a of the pressing surface 15. It is formed into a substantially trapezoidal shape in plan view, which is partitioned at positions. Therefore, the protrusion 26 has the maximum width at the end portion on the pressing surface 15 side, and the first boundary surface 26a and the second boundary surface 26b are similarly partitioned on the way, and especially the second boundary surface 26b is also divided. The end portion on the pressing surface 15 side has the maximum width. The partition surface 26c on the pressing surface 15 side is formed substantially parallel to the auxiliary cutting edge 14. Therefore, the two adjacent recesses 18, 18 are formed by the partition surface 26b and the tip corner portion 1 of the pressing surface 15.
It has a structure in which it communicates with a gap 27 between it and 5a.
The shape of the protrusion 26 does not necessarily have to be formed in a substantially trapezoidal shape in plan view, and an appropriate shape such as a triangle can be adopted.

In this embodiment, since the protrusion 26 is separated from the pressing surface 15, the strength of the auxiliary cutting edge 14 is slightly small, but the provision of the gap 27 results in a cutting resistance. It has a further advantage that the chip clogging at a high cutting depth can be reduced and the chip disposability is high.

Next, FIG. 9 shows a third embodiment of the present invention. In the figure, a chamfer 28 is chamfered between the sub cutting edge 14 and the main cutting edge 13 at each corner of the chip upper surface 12 instead of the R portion 14a in each of the above-described examples.
Are formed respectively. In the case of the present embodiment, the chamfer 28 is applied to increase the strength of the cutting edge. As a modified example, as shown in FIG. 10, a configuration in which a chamfer 28 is provided instead of the R portion 14a may be adopted in the configuration of the second embodiment of FIG.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 11 is a plan view of the throw-away tip according to the fourth embodiment. The same parts as those in the above-mentioned first embodiment are designated by the same reference numerals, and the description thereof will be omitted. In the figure, the throw-away tip 30 has a substantially square plate shape, and the CC line cross section, the DD line cross section, and the EE line cross section are respectively FIG. 3, FIG. 4, and FIG. It has the same structure as that shown in FIG. On the substantially square upper surface 31 of the throw-away tip 30 shown in the drawing, the central pressing surface 32 has a substantially square shape, and is formed in a state of being rotated by a predetermined angle with respect to the main cutting edge 13 forming each of the four sides of the upper surface 31. ing. At each corner of the tip 30, the wide land 17a of the auxiliary cutting edge 14 and the land 1 of the main cutting edge 13 are provided.
The projecting portion 33 connecting the boundary area of 7 and the pressing surface 32 further surrounds the entire circumference of the pressing surface 32 and is connected to the pressing surface 32 with a step. The first boundary surface 33a of the protrusion 33 is an inclined surface (even if it is a curved surface or a curved surface) that linearly extends from the boundary with the wide land portion 17a to the second boundary surface 29b of the adjacent protrusion 29 located on the high cut side. Good) and the main cutting edge 13
Is formed at a substantially predetermined angle with respect to. The second boundary surface 33b is a wide gently inclined surface similarly to the second boundary surface 23b of the first embodiment.

In this embodiment, the recess 1 of the first embodiment is used.
A configuration in which a concave portion 34 having a chip breaker groove having a bottom surface configuration similar to that of 8 has a groove width (linearly) gradually increasing as a whole from the sub cutting edge 14 side to the second boundary surface 33b of the adjacent protrusion 33. Therefore, in addition to the effect of the first embodiment, even at the time of a low depth of cut, the generated chips pass through the concave portion 34 and collide with the first boundary surface 33a to be curled, and the adjacent protrusions 33 are It is possible to discharge in the direction of the second boundary surface 33b, and it is possible to obtain an advantage that stable chip disposal can be realized regardless of the direction of the chips that are running even when the depth of cut is low.

In the first embodiment described above, the groove width of the recess 18 is gradually increased even in the region of the first boundary surface 23a,
It may be connected to the region of the peripheral side surface 21 of the pressing surface 15. Alternatively, the configuration of the recesses 18, 34 having the groove width in the first embodiment or the fourth embodiment may be adopted in the fourth embodiment or the first embodiment. Moreover, you may employ | adopt the protrusion part shape and chamfer shape shown in 2nd Example, 3rd Example, and its modification to 4th Example. Further, in the above-mentioned embodiment, the pressing surface 15 is slightly higher than the cutting blades 13 and 14, but it goes without saying that they may have the same height. In each of the above-described embodiments, the throw-away tip has a substantially triangular or square plan view, but it goes without saying that it can be applied to other appropriate shapes. The chip of the present invention is not limited to the positive type, but may be the negative type. In this case, if the height of the pressing surface 15 is the same as that of the cutting blade, the structure of the present invention can be provided on both upper and lower surfaces.

[0026]

As described above, in the throw-away tip according to the present invention, the concave portion is formed inside the main cutting edge on the upper surface, and the groove width of this concave portion is along the main cutting edge in the direction away from the sub cutting edge. The pressing surface is formed at the same height as the cutting edge or slightly higher than the cutting edge in the center of the upper surface. Since the protrusion is provided, it is possible to suppress chipping or chipping of the auxiliary cutting edge and increase the strength of the cutting edge, thereby improving the life of the tip. Further, the concave portion reduces the contact area with the chips and suppresses the generation of heat, which is useful for improving the chip life and cutting resistance. Furthermore, since the groove width of the recess gradually increases in the direction away from the auxiliary cutting edge, at low cutting depth,
Suppressing the chip extension and chip clogging to promote the curl of the chip for better discharge, it is possible to curl the chip in a certain direction regardless of the traveling direction of the generated chip at a high depth of cut, and the chip is fixed in a certain direction. It is possible to discharge chips to achieve good and stable chip disposal characteristics. Further, since one boundary surface of the protrusion is formed as a gently inclined surface which rises from the recess along the main cutting edge at the position farthest from the sub-cutting edge, chips are guided by the recess during high cutting. After being curled at the rising surface of the pressing surface region, it is further curled at one boundary surface of the protrusions, so that the chip disposability at the time of high cutting is improved. Further, since the other boundary surface of the protrusion is formed so as to stand up from the concave portion at a position close to the sub cutting edge, the chips are guided by the concave portion and collide with the other boundary surface to be curled at a low cutting depth. The extension of chips is suppressed. The recess is formed with the same groove width from the end on the side of the secondary cutting edge to the area where the projection is connected to the pressing surface, and the groove is formed from that area to one boundary surface of another adjacent projection. Since the width is gradually increased, it is possible to suppress the extension of the chips at the time of the low cutting to facilitate the curling, and to prevent the chips from clogging by controlling the discharge direction of the chips at the high cutting. Further, since the concave portion is formed such that the groove width gradually increases from the end portion on the side of the secondary cutting edge to the boundary surface of one of the other adjacent protrusions, from the time of low cutting to the time of high cutting The discharge direction can be controlled to prevent chip clogging. Further, since the protrusion extends from the vicinity of the sub cutting edge to the pressing surface and is connected, and the width thereof is formed so as to gradually increase from the side of the sub cutting edge toward the pressing surface, the chips at the time of high cutting It is easy to cause the second curl. Further, since the protrusion is separated from the pressing surface, the cutting resistance is reduced and the chip discharging property is improved. Further, since the R portion or the chamfer is provided on one side between the sub cutting edge and the main cutting edge and it is arbitrary, the cutting edge strength is high. Further, since the land width of the sub cutting edge is set larger than the land width of the main cutting edge, the strength of the sub cutting edge is increased. Further, since the concave portion has a steep slope surface and a gentle slope surface having a downward slope and a gentle slope surface and a steep slope surface having an upward slope, the contact area with the traveling chip is reduced, the heat generation of the chip is small, and the chip life is short. long.
Further, since a plurality of concave groove portions are formed in the concave portion, the contact area of the chips is further reduced, and the heat generation of the chip is further suppressed.

[Brief description of drawings]

FIG. 1 is a plan view of a throw-away tip according to a first embodiment of the present invention.

FIG. 2 is a side view of the throw-away tip of FIG.

FIG. 3 is a sectional view taken along line CC of the throw-away tip of FIG.

FIG. 4 is a sectional view taken along the line DD of FIG.

5 is a cross-sectional view taken along the line EE of FIG.

FIG. 6 is a sectional view taken along line FF of FIG. 1;

7 is a cross-sectional view taken along the line GG of FIG.

FIG. 8 is a partial plan view of a corner portion of the throw-away tip according to the second embodiment of the present invention.

FIG. 9 is a partial plan view of a corner portion of the throw-away tip according to the third embodiment of the present invention.

FIG. 10 is a view similar to FIG. 8 showing a modification of the second embodiment.

FIG. 11 is a plan view of a throw-away tip showing a fourth embodiment of the present invention.

FIG. 12 is a plan view of a conventional throw-away tip.

13A is a sectional view taken along line AA of FIG. 12, and FIG. 13B is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 10 Throw-away tip 13 Main cutting edge 14 Sub cutting edge 14a R part 15,32 Pressing surface 15a Tip corner part 17 Land part 17a Wide land part 18,34 Recessed part 22 Recessed groove part 23,26,33 Projection part 23a, 26a, 33a , First boundary surface 23b, 26b, 33b, second boundary surface 28 chamfer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenji Sugawara 1511 Furumagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture Mitsubishi Materials Corporation Tsukuba Plant (72) Atsushi Oki 1511 Furumagi, Ishishita-machi, Yuki-gun, Ibaraki Prefecture Mitsubishi Materials Corporation Tsukuba Works

Claims (11)

[Claims] 1. A substantially flat plate throw-away tip having a main cutting edge and a sub cutting edge formed on a peripheral edge thereof, wherein a recess is formed inside the main cutting edge on an upper surface facing a lower surface forming a seating surface. The groove width of the recess gradually increases along the main cutting edge in the direction away from the sub cutting edge, and a pressing surface having the same height as or slightly higher than the cutting edge is formed in the central portion of the upper surface. The throw-away tip is characterized in that a protrusion having substantially the same height as the sub-cutting edge is provided from the vicinity of the sub-cutting edge toward the pressing surface direction. 2. A boundary surface of one of the projections is formed as a gently inclined surface which rises from the recess at a position farthest from the sub cutting edge along the main cutting edge in the recess. The throw-away tip according to claim 1. 3. The throw according to claim 1, wherein the other boundary surface of the protrusion is formed so as to rise from the recess at a position close to the sub cutting edge in the recess. Away tip. 4. The recess is formed to have the same groove width from an end on the side of the sub cutting edge to a region where the protrusion is connected to the pressing surface, and the protrusion of another adjacent protrusion from that region. The throw-away tip according to claim 2 or 3, wherein the groove width is formed so as to gradually increase to one boundary surface. 5. The groove is formed so that the groove width gradually increases from the end on the side of the secondary cutting edge to the one boundary surface of another adjacent protrusion. The throw-away tip described in 2 or 3. 6. The projection is connected to extend from the vicinity of the sub cutting edge to the pressing surface, and its width is gradually increased from the side of the sub cutting edge toward the pressing surface. The throw-away tip according to any one of claims 1 to 5. 7. The throw-away tip according to claim 1, wherein the protrusion extends from the land portion of the auxiliary cutting edge in the pressing surface direction and is separated from the pressing surface. 8. The throw according to any one of claims 1 to 7, wherein an R portion or a chamfer is provided on one side between the sub cutting edge and the main cutting edge, and is provided with an arbitrary hand. Away tip. 9. A land extending over the entire circumference is formed on the upper surface so as to be connected to the main cutting edge and the sub cutting edge, and the land width of the sub cutting edge is set to be larger than the land width of the main cutting edge. The throw-away tip according to any one of claims 1 to 8. 10. The recessed portion has a downwardly sloping steep surface and a gently sloping surface, and an upwardly sloping gently sloped surface and a steeply sloping surface when viewed in the pressing surface direction from the main cutting edge. The throw-away tip according to any one of claims 1 to 9. 11. The throw-away tip according to any one of claims 1 to 10, wherein a plurality of concave groove portions are formed on the concave portion, the concave groove portions having a width that widens in the direction away from the main cutting edge. .