JP4330933B2 - Throwaway tip - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a throw-away tip (hereinafter referred to as a tip), and more particularly, to a tip with a breaker used for turning.
[0002]
[Prior art]
In the form of cutting of automobile parts and general machine parts, there are many forms of machining in which cutting fluctuations occur and machining directions in which the flow direction of chips such as R machining and copying changes greatly. In terms of the work material, not only materials such as lead free-cutting steel with relatively good machinability but also materials with high ductility such as hot-rolled soft iron and cold-rolled plates are frequently used. For this reason, in the machining of the above parts, troubles in chip disposal are likely to occur. Therefore, there has conventionally been a chip that has been required to reliably curl the chips spirally and discharge them stably. Proposed.
[0003]
As a chip that solves the above problem, there is a chip illustrated in FIG. The tip is formed with a nose cutting edge (10) curved in a nose portion and lateral cutting edges (11) on both sides of the nose cutting edge (10), and a breaker groove ( 21) A breaker projection (12) is formed at a central portion in the inner portion. And the breaker groove (21) directly behind the nose tip cutting edge (10a) at the leading edge of the nose portion is concave with respect to both lateral portions, and the rake angle of the horizontal cutting edge (11) is 5 ° or more, and The horizontal cutting edge (11) is formed at a downward angle of 4 ° to 8 ° in a direction away from the nose tip cutting edge (10a).
[0004]
With such a configuration, in the cutting insert of the present invention, the breaker groove (21) immediately behind the nose tip cutting edge (10a) is concave with respect to both lateral portions. As a result, the chip resistance at the nose tip cutting edge that receives the largest cutting resistance is reduced, the contact area between the chip and the breaker groove surface in this vicinity is reduced, and the cutting resistance from the chip is also reduced. In addition, the rake angle of the side cutting edge (11) is increased to 5 ° or more, and in addition, the side cutting edge (11) is formed at a downward angle of 4 ° to 8 ° in a direction away from the nose tip cutting edge (10a). In the types of machining in which cutting fluctuations are likely to occur, such as R machining and copying machining, there is an effect of reliably curling spirally at the side cutting edge (11) even if the cutting amount is large and the chips are easy to flow. (For example, see Patent Document 1)
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-156608 (2nd to 6th pages, FIG. 1)
[0006]
[Problems to be solved by the invention]
As part of environmental measures, lead free-cutting steel, which has been used extensively in the past, has started to limit the amount of lead used from the viewpoint that lead has an adverse effect on the human body. It has become. Under these circumstances, lead-free materials with extremely low machinability are frequently used for general machine parts and the like, and in the above-described conventional cutting tips, chip processing and deterioration of the cutting edge life become major problems. ing.
[0007]
In addition, in the machining form in which the cutting fluctuation and chip flow direction are likely to change, in order to improve chip processing, it has a corrugated cutting edge like the conventional chip described above, has a large rake angle, and from the chip center What provided the breaker protrusion (12) which protruded toward the corner part has been considered effective. However, in such a tip, the shape of the breaker protrusion (12) provided in the breaker groove (21) of the nose cutting edge (10) or the position of the breaker protrusion (12) and the cutting edge exhibiting a waveform. Depending on the relationship, the chip may not curl because it does not hit the breaker protrusion (12), or conversely, it may be strongly hit against the breaker protrusion (12), and the shape of the breaker protrusion (12) and the position of the cutting edge The relationship was not optimal in chip disposal.
[0008]
Furthermore, the above-mentioned conventional tip is suddenly caused by insufficient cutting edge strength or chip biting in processing that is likely to cause momentary cuts, fluctuations in chip discharge direction, and fluctuations in cutting load, such as R machining and copying. Since chipping and chipping were likely to occur, improvement of the cutting edge life of the chip was desired.
[0009]
The present invention has been made in view of the above-described problems, and its purpose is to cut a work material in which chips are likely to be stretched, a process in which cutting and chip discharge directions are likely to fluctuate, and a fluctuation in cutting load are likely to occur. In processing etc., it is providing the chip | tip which improved the chip processing property and the cutting-blade lifetime.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems and achieve such an object, the chip of the present invention forms a cutting edge at a cross ridge line portion between a rake face and a flank face in a chip body having a polygonal plate shape, When viewed from the direction facing the rake face, the cutting edge is composed of a nose cutting edge forming an arc and lateral cutting edges on both sides thereof, and an inner region on the rake face of the cutting edge is along the cutting edge. A land portion connected to the cutting edge, a breaker groove connected to the land portion, and at least one boss surface in an area inside the breaker groove, and in the breaker groove inside the nose cutting edge. Is a throw-away tip provided with a breaker projection formed of a standing wall continuous with the boss surface while forming a convex shape toward the bisector direction outside of the nose cutting edge,
The cutting edge has a nose tip cutting edge that bisects the nose cutting edge as the highest point, and in the direction along the cutting edge, a crest and a valley are alternately continuous from the nose tip cutting edge toward both sides. The ridges are substantially the same height as the nose tip cutting edge, the rake angle of the lands is gradually reduced from the ridges to the valleys, and the width of the lands is increased. As you gradually increase it,
The rake angle (α1) of the land on the mountain is 0 ° <α1 ≦ 15 °,
The rake angle (α2) of the valley land is 0 ° <α2 ≦ 10 °,
The width (L1) of the land of the mountain portion is 0 mm <L1 ≦ 0.5 mm,
The land width (L2) of the valley is set in a range of 0 mm <L2 ≦ 0.7 mm,
Furthermore, when viewed from the direction facing the rake face, the intersecting ridge line between the rising wall of the breaker projection and the boss surface is concavely curved with respect to the transverse cutting edge, and further, the transverse cutting edge on the intersecting ridge line The distance (F) in the direction along the horizontal cutting edge between the point (A) farthest from the edge and the position (B) of the valley portion closest to the nose tip cutting edge in the cutting edge is less than 0.5 mm. The throw away tip is characterized in that the intersecting ridge line is higher than the nose tip cutting edge and the peak portion.
[0011]
According to the above-described chip, the cutting edge gradually increases in strength as it approaches the valley from the crest, so that chipping or chipping occurs when chip biting or fluctuation in cutting load occurs during cutting. And the life of the cutting edge is improved.
[0012]
The rake angle (α1) of the peak is preferably set in the range of 0 ° <α1 ≦ 15 ° as described above. This is because the cutting resistance increases when the rake angle α1 is 0 ° or less, and the cutting edge strength decreases when the rake angle α1 exceeds 15 °, and chipping and chipping are likely to occur. More preferably, the rake angle (α1) is set in a range of 0 ° <α1 ≦ 10 °. By doing so, the cutting edge strength can be further increased, and chipping and chipping can be prevented even if sudden chipping occurs.
[0013]
The rake angle (α2) of the valley is preferably set in the range of 0 ° <α2 ≦ 10 ° as described above. This is because the cutting resistance increases when the rake angle (α2) is 0 ° or less. When the rake angle (α2) exceeds 10 °, the cutting edge strength decreases, and chipping and chipping are likely to occur due to the biting of the chips. It is to become. More preferably, the rake angle (α2) is set in a range of 0 ° <α2 ≦ 7 °. By doing so, the cutting edge strength can be further increased, and chipping and chipping can be prevented even if sudden chipping occurs.
[0014]
As described above, the land width (L1) at the crest of the cutting edge is preferably set in the range of 0 mm <L1 ≦ 0.5 mm. This is because when the land width is lost, the strength in the cross section perpendicular to the cutting edge is reduced, and the rake angle is not uniformly imparted. When the land width is larger than 0.5 mm, chip disposal is improved. It is because it will fall.
[0015]
As described above, the land width (L2) in the valley portion of the cutting edge is preferably set in the range of 0 mm <L2 ≦ 0.7 mm. This is because when the land width is lost, the strength in the cross section perpendicular to the cutting edge is reduced, and the rake angle is not uniformly applied. When the land width is larger than 0.7 mm, the chip processing property is improved. It is because it will fall.
[0016]
In addition, as described above, the tip according to the present invention provides a positive rake angle to the corrugated cutting edge, thereby reducing cutting resistance and generating a chip and a rake face land from the cutting edge. The contact area decreases and the chip compression rate increases. Therefore, the effect of curling chips is greatly improved.
[0017]
Further, the cutting edge has a downward inclined portion that is gradually lowered from the nose tip cutting edge to a valley portion (hereinafter referred to as a first valley portion) closest to the nose tip cutting edge in a direction along the cutting edge. Is provided. For this reason, even when cutting lead-free materials or highly ductile materials, cutting, or processing that fluctuates in the chip discharge direction, chips generated from the cutting edge are reliably guided to the chip pocket. The outflow direction in the chip pocket is stabilized.
[0018]
Further, since the intersecting ridge line between the rising wall of the breaker protrusion and the boss surface is curved so as to be the farthest from the horizontal cutting edge in the vicinity of the first valley portion of the horizontal cutting edge, chips generated by the cutting edge are generated. On the other hand, since a wide chip pocket is secured, the chips guided to the wide chip pocket are not clogged. Furthermore, since the standing wall of the breaker projection is formed higher than the cutting edge, the chips are surely restrained by the standing wall and are uniformly curled spirally or cut finely. , Chip disposal is greatly improved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a chip according to the present invention will be described with reference to the drawings. 1 to 5 show the chip of this embodiment. FIG. 1A is a plan view of the chip, and FIG. 1B is a lower side view. FIG. 2 is an enlarged plan view of a main part, and FIG. 3 is a perspective view of the main part. FIG. 4 is a view showing a cutting edge shape in a side view of the chip. 5A is a cross-sectional view taken along the line AA in FIG. 1A, and FIG. 5B is a cross-sectional view taken along the line BB in FIG. 1A. FIG. 5 (c) is a cross-sectional view taken along the line CC in FIG. 1 (a).
[0020]
As shown in FIG. 1 (a), FIG. 2, and FIG. 3, this chip has a rhombus shape with an apex angle of 80 °, the upper surface and the lower surface are a rake face (2), and the peripheral surface is a flank (3). A cutting edge is formed at the ridge line where the rake face (2) and the flank face (3) intersect. The cutting edge is formed with an arcuate nose cutting edge (10) at the top and a linear transverse cutting edge (11) on both sides of the nose cutting edge (10). The rake face (2) is provided with a land (20) on the inner side continuously to the nose cutting edge (10) and the side cutting edge (11) along the cutting edge. A breaker groove (21) is continuously formed on the inner side, and an upright wall (12a) of a breaker projection (12) rising obliquely upward inward from the breaker groove (21), and the upright wall (12a) ), A substantially horizontal boss surface (4) is formed. In addition, although this boss | hub surface (4) is formed in several island shape, you may connect continuously so that the center clamp hole (5) may be surrounded.
[0021]
When viewed from the direction facing the flank (3) as shown in FIG. 4, the cutting edge has a nose tip cutting edge (10a) that bisects the nose cutting edge (10) as the highest point. In the direction along the blade, it has a waveform shape in which peaks (11b) and valleys (11c) are alternately and continuously formed from the nose tip cutting edge (10a) toward both sides. And the said peak part (11b) is made into the substantially same height as the said nose tip cutting edge (10a).
[0022]
As shown in FIG. 5, the rake angle of the land (20) formed inward and connected to the cutting edge is maximum at the peak (11b), minimum at the valley (11c), and the land ( The width of 20) is minimum at the peak (11b) and maximum at the valley (11c). The rake angle of the land (20) gradually decreases as the peak (11b) approaches the valley (11c), and the width of the land (20) gradually increases. Here, the rake angle and the width of the land (20) are preferably in the following ranges.
The rake angle (α1) of the land (20) of the peak (11b) is 0 ° <α1 ≦ 15 °,
The rake angle (α2) of the land (20) of the valley (11c) is 0 ° <α2 ≦ 10 °,
The width (L1) of the land (20) of the peak (11b) is 0 mm <L1 ≦ 0.5 mm,
The width (L2) of the land (20) of the valley (11c) is 0 mm <L2 ≦ 0.7 mm,
[0023]
By setting it as such a structure, as this cutting edge approaches a trough part (11c) from a peak part (11b), intensity | strength becomes high gradually and will have the maximum intensity | strength in a trough part (11c). By doing so, chipping and chipping are suppressed when chip biting or fluctuation in cutting load occurs during cutting, and the life of the cutting edge is improved.
[0024]
The rake angle (α1) of the peak (11b) is preferably set in a range of 0 ° <α1 ≦ 15 °. This is because when the rake angle (α1) is 0 ° or less, the cutting resistance increases, and when it exceeds 15 °, the cutting edge strength decreases, and chipping and chipping are likely to occur. More preferably, the rake angle (α1) is set in a range of 0 ° <α1 ≦ 10 °. By doing so, the cutting edge strength can be further increased, and chipping and chipping can be prevented even if sudden chipping occurs.
[0025]
The rake angle (α2) of the valley (11c) is preferably set in the range of 0 ° <α2 ≦ 10 °. This is because the cutting resistance increases when the rake angle (α2) is 0 ° or less. When the rake angle (α2) exceeds 10 °, the cutting edge strength decreases, and chipping and chipping are likely to occur due to the biting of the chips. It is to become. More preferably, the rake angle (α2) is set in a range of 0 ° <α2 ≦ 7 °. By doing so, the cutting edge strength can be further increased, and chipping and chipping can be prevented even if sudden chipping occurs.
[0026]
The land width (L1) at the crest (11b) of the cutting edge is preferably set in a range of 0 mm <L1 ≦ 0.5 mm. This is because, when the land width (L1) is eliminated, the strength in the cross section perpendicular to the cutting edge is reduced, and the rake angle is not uniformly applied. The land width (L1) is less than 0.5 mm. When it becomes large, there is a possibility that the chip disposability is lowered.
[0027]
The land width (L2) in the valley (11c) of the cutting edge is preferably set in the range of 0 mm <L2 ≦ 0.7 mm. This is because, when the land width (L2) is eliminated, the strength in the cross section perpendicular to the cutting edge is reduced, so that the rake angle is not uniformly applied, and the land width (L2) is larger than 0.7 mm. If it becomes, there exists a possibility that chip controllability may fall.
[0028]
In the chip of this embodiment, since a positive rake angle is imparted to the corrugated cutting edge, the cutting resistance is reduced, and the chip generated from the cutting edge and the land (20) of the rake face (2) are reduced. The contact area decreases and the chip compression rate increases. Therefore, the effect of curling chips is greatly improved.
[0029]
Further, the cutting edge is provided with a downwardly inclined portion (11d) that is gradually lowered from the nose tip cutting edge (10a) to the first trough (11a) in a direction along the cutting edge. Therefore, even when cutting lead-free material or highly ductile material, cutting or processing in which the direction of chip discharge tends to fluctuate, chips generated from the cutting edge are reliably guided to the chip pocket (22). As a result, the outflow direction in the chip pocket (22) is stabilized.
[0030]
The intersecting ridge line (12b) between the rising wall (12a) of the breaker projection (12) and the boss surface (4) is farthest from the side cutting edge (11) in the vicinity of the first valley (11a) of the side cutting edge (11). Therefore, a wide chip pocket (22) is secured with respect to the chips generated by the cutting edge. Therefore, the chips are guided to the wide chip pocket (22) and flow toward the breaker protrusion (12). Further, since the highest point of the rising wall (12a) of the breaker projection (12) is formed higher than the cutting edge, the chips are reliably restrained by the rising wall (12a) and are uniformly formed in a spiral shape. It will curl or cut finely, and the chip disposal is greatly improved. The highest point of the upright wall (12a) is connected to the boss surface (4), and this boss surface (4) is formed higher and horizontally than the highest point of the cutting edge, for example, a chip provided with cutting edges on the upper and lower surfaces. Then, it functions as a seating surface when it is attached to the tool holder.
[0031]
The spherical protrusion (13) provided between the breaker protrusion (12) and the nose cutting edge (10) constrains and cuts the chips in a low cut such as cutting in the nose cutting edge (10). There is a function to improve waste disposal. The spherical protrusion (13) has a function of guiding chips to the breaker protrusion (12) located inside the spherical protrusion (13). The highest point of the spherical protrusion (13) is lower than the boss surface (4) and the same height or higher than the nose tip cutting edge (10a). If it does so, it will become possible to restrain a chip reliably, without increasing cutting resistance.
[0032]
In the chip of this embodiment, when viewed from the direction facing the flank (3) in the corrugated shape of the cutting edge, the descending inclined part (11d) and the ascending part sandwiching the first valley part (11a) in the cutting edge. The angle (θ) formed with the inclined portion (11e) is set in a range of 120 ° <θ ≦ 170 °, and the horizontal cutting edge (11) of the descending inclined portion (11d) and the ascending inclined portion (11e) is set. When the horizontal lengths in the horizontal direction are Wa and Wb, respectively, the relationship of 1 <Wa / Wb <2 is set, and the nose tip cutting edge (10a), the crest (11b), and the trough When the difference in height from (11c) is D, it is preferable to set the relationship 5 <Wa / D ≦ 20.
[0033]
When the corrugated cutting edge is formed by the downward inclined portion (11d) and the upward inclined portion (11e) with the first trough portion (11a) in between, a deeper cut than the first trough portion (11a) occurs. In this case, the cross section of the chip is bent into a V shape by the downward inclined portion (11d) and the upward inclined portion (11e), and the chip discharge direction is a direction toward the first valley portion (11a). To stabilize. The reason why the angle (θ) is set in the range of 120 ° <θ ≦ 170 ° is that when the angle (θ) is 120 ° or less, the V-shaped bending tendency in the cross section of the chip becomes strong, and the chip curl This is because if the angle (θ) is larger than 170 °, it is difficult to obtain the effect of stabilizing the chip discharge direction described above.
[0034]
The relationship of 1 <Wa / Wb <2 is set in the lengths Wa and Wb of the downward inclined portion (11d) and the upward inclined portion (11e). This is because the component force of the cutting force in the direction perpendicular to the feed direction, the so-called back component force, becomes high and the workpiece tends to chatter. When Wa / Wb is 2 or more, the downward inclined portion (11d) This is because the length of the upward inclined portion (11e) with respect to is insufficient, and it is difficult to obtain the effect of stabilizing the outflow direction of the chips.
[0035]
When the difference in height between the nose tip cutting edge (10a) and the valley portion (11b) is D, if 5 <Wa / D ≦ 20, the first valley portion from the nose tip cutting edge (10a) The downward inclination part (11d) provided over (11a) will be set to a preferable inclination angle. That is, when Wa / D is 5 or less, the above-mentioned back force is reduced, but the chips tend to flow away in the direction away from the nose tip cutting edge (10a), and therefore may not be guided to the chip pocket (22). . Further, when Wa / D is larger than 20, the above-mentioned back force is increased, or the tendency of chips to flow out toward the nose tip cutting edge (10a) is increased and is not accurately guided to the chip pocket (22). Because there is a fear. In terms of the inclination angle, the downward inclined portion is preferably set in a range of 3 ° to 15 °.
[0036]
When the height difference between the boss surface (4) and the nose tip cutting edge (10a) is t1, and the height difference between the boss surface (4) and the highest point of the spherical protrusion (13) is t2, The relation of 1 ≦ t1 / t2 <2 is set, and the distance in the direction along the rake face (2) between the nose tip cutting edge (10a) and the highest point of the spherical protrusion (13) is defined as Z. Then, the relationship of 0.5 × Wa <Z <0.7 × Wa is set, and the intersecting ridgeline (12b) between the rising wall (12a) of the breaker projection (12) and the boss surface (4) is When viewed from the direction facing the rake face (2), a concave arc shape is formed with respect to the transverse cutting edge (11), and when the radius of curvature of the arc of the intersecting ridge line (12b) is R, 1 × Wa < It is preferable to set a relationship of R <2 × Wa.
[0037]
When the height difference between the boss surface (4) and the nose tip cutting edge (10a) is t1, and the height difference between the boss surface (4) and the highest point of the spherical protrusion (13) is t2, The relationship of 1 ≦ t1 / t2 <2 was set because the chips contacted the spherical protrusions (13) under low cutting conditions such as cutting with only the nose cutting edge (10) when t1 / t2 is less than 1. This is because when t1 / t2 is 2 or more, the chips strongly collide with the spherical protrusions (13), resulting in high cutting resistance or chip clogging. is there.
[0038]
When the distance in the direction along the rake face (2) between the nose tip cutting edge (10a) and the highest point of the spherical protrusion (13) is Z, 0.5 × Wa <Z <0.7 × Wa When Z is 0.5 × Wa or less, the position of the highest point of the spherical protrusion (13) is too close to the nose cutting edge (10), resulting in chip clogging or chipping. This is because the spherical protrusion (13) may be jumped over and extended. Further, when Z is 0.7 × Wa or more, the chips do not contact the spherical protrusion (13) and the chips may be elongated.
[0039]
When the radius of curvature of the arc of the intersecting ridge line (12b) between the standing wall (12a) of the breaker projection (12) and the boss surface (4) is R, the relationship is set to 1 × Wa <R <2 × Wa. If the radius R is 1 × Wa or less, the chip pocket (22) may not be sufficiently wide. If the radius R is 2 × Wa or more, the chip pocket (22) is too wide. This is because the chips do not come into contact with the breaker protrusion (12) and are easy to extend.
[0040]
FIG. 6 and FIG. 7 show the chip shape when cutting the SCr420, which is a material having relatively high ductility, at the cutting speed Vc = 200 m / min using the product of the present invention and the conventional product in the chip shape CNMG120408. As shown in FIG. 8, the tool path was obtained by continuously subjecting a work bar to end face processing, R processing, and outer peripheral surface drawing. In this way, in the machining with a large fluctuation in the chip discharge direction, which is the object of the present invention, the chip according to the present invention has the conditions of cutting ap = 1 to 2 mm and feed f = 0.2 to 0.35 mm / rev. In FIG. 4, a finely cut chip shape or a uniformly curled spiral chip shape is obtained, and it can be seen that effective chip disposal is performed.
[0041]
【The invention's effect】
As described above, the chip according to the present invention has a corrugated cutting edge, a breaker protrusion (12) provided inside the nose cutting edge (10), the nose cutting edge (10) and the breaker protrusion ( 12), and the rake angle and width of the land (20) at the peak (11b) and the valley (11c) provided on the corrugated cutting edge. It was set as the structure which raises the cutting-edge strength of the said trough part (11c) by original setting. By doing so, the effect of suppressing chipping and chipping of the cutting edge with respect to chip biting and large fluctuations in cutting load can be obtained. Furthermore, good chip disposal can be obtained in cutting of a work material in which chips tend to extend, and in cutting and processing in which the direction of chip discharge tends to fluctuate.
[Brief description of the drawings]
FIG. 1A is a plan view of a chip according to an embodiment of the present invention.
FIG. 2B is a lower side view of the chip shown in FIG.
FIG. 2 is an enlarged plan view of a main part of the chip shown in FIG. 1;
FIG. 3 is a perspective view of essential parts of the chip shown in FIG. 1;
4 is a cutting edge shape in a side view of the chip shown in FIG. 1. FIG. 5 (a) is a cross-sectional view taken along line AA in FIG. 1 (a).
(B) is BB sectional drawing in Fig.1 (a).
(C) is CC sectional drawing in Fig.1 (a).
FIG. 6 is a chip shape of a chip according to an embodiment of the present invention.
FIG. 7 is a chip shape of a conventional chip.
FIG. 8 is a diagram showing a processing form.
FIG. 9 is a perspective view of a conventional chip.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tip 2 Rake face 3 Relief face 4 Boss face 5 Clamp hole 10 Nose cutting edge 10a Nose tip cutting edge 11 Side cutting edge 11a First trough part 11b Mountain part 11c Valley part 11d Down sloping part 11e Up sloping part 12 Breaker protrusion 12a Standing Wall 12b Crossing ridge line 13 between standing wall and boss surface 13 Spherical protrusion 20 Land 21 Breaker groove 22 Chip pocket α1 Rake angle α of mountain land Rake angle L1 of valley land L1 Land width L2 of valley width

Claims (4)

A cutting edge is formed at the intersection ridge line portion of the rake face and the flank face on the chip body having a polygonal plate shape, and when viewed from the direction facing the rake face, the cutting edge is a nose cutting edge that forms an arc and its cutting edge. It is composed of lateral cutting edges on both sides, and in the inner region on the rake face of the cutting edge, a land portion connected to the cutting edge along the cutting edge, a breaker groove connected to the land portion, and the breaker groove At least one boss surface in an inner region, and in the breaker groove on the inner side of the nose cutting edge, a convex shape is formed outwardly in the bisector direction of the nose cutting edge and the boss surface In the throw-away tip provided with a breaker projection consisting of a standing wall that continues to
The cutting edge has a nose tip cutting edge that bisects the nose cutting edge as the highest point, and in the direction along the cutting edge, a crest and a valley are alternately continuous from the nose tip cutting edge toward both sides. The ridges are substantially the same height as the nose tip cutting edge, the rake angle of the lands is gradually reduced from the ridges to the valleys, and the width of the lands is increased. As you gradually increase it,
The rake angle (α1) of the land on the mountain is 0 ° <α1 ≦ 15 °,
The rake angle (α2) of the valley land is 0 ° <α2 ≦ 10 °,
The width (L1) of the land of the mountain portion is 0 mm <L1 ≦ 0.5 mm,
The land width (L2) of the valley is set in a range of 0 mm <L2 ≦ 0.7 mm,
Furthermore, when viewed from the direction facing the rake surface, the intersecting ridge line between the rising wall of the breaker projection and the boss surface is concavely curved with respect to the transverse cutting edge, and further, the transverse cutting edge on the intersecting ridge line The distance (F) in the direction along the horizontal cutting edge between the point (A) farthest from the edge and the position (B) of the valley portion closest to the nose tip cutting edge in the cutting edge is less than 0.5 mm. The throw away tip is characterized in that the intersecting ridge line is higher than the nose tip cutting edge and the peak portion. A spherical protrusion that protrudes upward is provided between the breaker protrusion and the nose cutting edge, the highest point of the spherical protrusion is lower than the boss surface, and the same height as the nose tip cutting edge The throw-away tip according to claim 1, wherein the throw-away tip is high or high. In the corrugated shape of the cutting edge, when viewed from the direction facing the flank, the angle θ formed by the descending inclined portion and the ascending inclined portion sandwiching the valley portion closest to the nose tip cutting edge in the cutting blade is 120. Set in the range of ° <θ ≦ 170 °,
Furthermore, when the horizontal lengths of the down slope and the up slope are Wa and Wb, respectively, there is a relationship of 1 <Wa / Wb <2.
Further, the relationship of 5 <Wa / D ≦ 20 is established, where D is a difference in height between the tip of the nose tip and the crest and the trough, according to claim 1 or 2. The throw-away tip described. When the difference in height between the boss surface and the cutting edge of the nose tip is t1, and the difference in height between the boss surface and the highest point of the spherical protrusion is t2, the relationship 1 ≦ t1 / t2 <2 And
Furthermore, when the distance in the direction along the rake face between the nose tip cutting edge and the highest point of the spherical protrusion is Z, there is a relationship of 0.5 × Wa <Z <0.7 × Wa,
Furthermore, when viewed from the direction facing the rake face, the intersecting ridge line between the rising wall of the breaker projection and the boss surface forms a concave arc shape with respect to the transverse cutting edge, and the radius of curvature of the arc of the intersecting ridge line is set. The throw-away tip according to any one of claims 1 to 3, wherein R is 1 x Wa <R <2 x Wa.

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