JP4868562B2 - Throwaway tip - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a throw-away tip used for turning, and more particularly to a throw-away tip capable of appropriate chip disposal in a wide range of cutting operations from medium cutting to finish cutting.
[0002]
[Prior art]
In recent parts processing, the near net shape of the material has progressed, and the characteristics required for the throw-away tip are changing accordingly. Specifically, in the processing of the near net shape material, the cutting depth varies greatly depending on the processing site. For this reason, the throw-away tip is required to have a function of appropriately performing chip disposal in a wide area from medium cutting to finish cutting. In order to cope with these demands, throwaway tips having various breaker shapes have already been proposed. For example, in Japanese Patent Application Laid-Open No. 11-48006, an inclined surface that becomes lower as the breaker groove of the nose portion is separated from the nose cutting edge, and an upstanding surface that rises from the bottom toward the protrusion of the boss surface are formed. A throw-away tip that can be applied in a wide range from light cutting to medium cutting by disposing the tip of the protrusion in a concave shape surrounding the nose portion in plan view is disclosed. The publication also discloses that the rising angle of the rising surface is 10 ° to 30 ° and that the pocket of the breaker groove is widened away from the nose portion.
[0003]
Further, as a throw-away tip in which a plurality of breaker protrusions are provided at the nose portion of the breaker groove so that chip disposal in finish cutting, light cutting, and medium cutting can be performed for a general purpose, for example, JP-A-6-55312 According to the publication, a first breaker protrusion and a pair of second breaker protrusions are formed close to each other at the nose portion of the breaker groove, and a third breaker protrusion is formed by a rising wall of the narrower breaker groove portion. way, the Tsu FIG light, the expansion of the processing area of the chip in the middle cutting from finishing cutting. In Japanese Patent Laid-Open No. 2000-17607, a first breaker protrusion having a hemispherical shape at the tip of a boss surface extending to a nose portion is slightly retracted from the first breaker protrusion to sandwich a bisector of the nose portion. A second breaker protrusion is disposed at a target position, and the second breaker protrusion forms a triangular top flat portion surrounded by a side ridge substantially perpendicular to the cutting edge and a side ridge gradually spaced from the cutting edge. Thus, an example having particularly excellent chip disposal with respect to a high ductility steel material is disclosed.
[0004]
[Problems to be solved by the invention]
In the above-mentioned Japanese Patent Application Laid-Open No. 11-48006, since the finish cutting breaker protrusion and the medium cutting breaker protrusion are shared, it is difficult to ensure sufficient chip disposal in both conditions. In the above Japanese Patent Laid-Open No. 6-55312, the chips generated at the time of finish cutting are extremely thin and thus move unstable. Therefore, it is not possible to reliably treat chips generated during finish cutting only by considering only the position of the first breaker protrusion and the rising angle thereof. In the above Japanese Patent Laid-Open No. 2000-17607, the shape and arrangement of the first and second breaker protrusions are improved in order to apply to cutting of a specific material, and cannot be applied to various steel types.
[0005]
The present invention improves the above-described conventional example, and provides two types of breaker projections capable of appropriately performing chip disposal in respective areas of finish cutting and medium cutting of a general steel material. An object of the present invention is to provide a throw-away tip capable of exhibiting chip disposal.
[0006]
[Means for Solving the Problems]
In the present invention, a cutting edge is formed on the ridgeline of the upper and lower surfaces of the throw-away tip having a polygonal flat plate shape, and a breaker groove is formed on the inner side of the land portion formed along the cutting edge, in the central portion of the upper and lower surfaces. Forming a pair of second breaker protrusions at positions that are symmetric with respect to the bisector of the nose part in plan view, and a first breaker protrusion that extends the boss surface toward the nose part; The second breaker projection crosses the bottom of the breaker groove from the inclined surface continuing to the land portion in the vicinity of the nose portion toward the center of the cutting edge, and extends along the lower side of the side surface of the first breaker projection. And again, cross the breaker groove bottom toward the center of the cutting edge, the end of the second breaker projection reaches the inclined surface, and is provided in a curved shape toward the center of the cutting edge. This is a throw-away chip characterized by that.
[0007]
Using the throw-away tip with a corner radius R of 0.8 mm, which is currently most frequently used, when cutting with a cutting depth d = 0.5 mm, which is the final cutting area, results in cutting in the corner radius area. The chip to be cut is wider, thinner and more elastic than the actual depth of cut. This chip becomes unstable also in the outflow direction, and it is difficult to restrain it with a conventional breaker projection. In the present invention, in order to deal with such unstable chips, apart from the first breaker protrusion arranged on the bisector of the nose portion in plan view, the position is symmetrical with respect to the bisector In addition, the pair of second breaker protrusions are raised from the corner R closer to the first breaker protrusion, and are arranged in a curved shape toward the center of the cutting edge. By providing the first and second breaker protrusions in this positional relationship, a concave portion facing the nose portion is formed between the first breaker protrusion and the pair of second breaker protrusions. The concave portion makes it possible to restrain unstable chips generated at the time of finish cutting at a pair of second breaker protrusions, that is, two points, and to curl the chips in the width direction to promote breakage. Further, the second breaker protrusion disposed for finish cutting is formed so as to be lower than the height of the cutting edge, and the height thereof is lowered as the distance from the ridge line as the cutting edge is further increased. Thereby, even when the cutting depth is about 2 mm, the second breaker protrusion can break the chips with the first breaker protrusion without hindering the flow of the chips. Furthermore, in the present invention, the inclination angle of the rising surface in the vicinity where the first breaker protrusion collides with the chip is reduced to reduce the impact at the time of the collision, and the chip moves to the upper part of the rising surface of the first breaker protrusion. Accordingly, in order to increase the restraint force on the chips, the inclination angle of the rising surface is made larger than the vicinity of the collision. Further, by providing the first and second breaker protrusions at appropriate positions, it is possible to perform a wide-area chip treatment from a finish cutting region using the inside of the corner R portion of the nose portion to a medium cutting region having a deep cut.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the embodiments of the present invention will be described with reference to FIG surface. As shown in FIG. 1, a throw-away tip 1 of the present invention is formed by forming a hard material such as cermet or cemented carbide into a polygonal shape, and includes a pair of upper and lower surfaces 2 arranged in the thickness direction, and these upper and lower surfaces 2. Are provided with four side surfaces 3 provided perpendicular to these and a mounting hole 4 penetrating the center of the main body of the throw-away tip 1. The upper and lower surfaces 2 are directed from the cutting edge 6 toward the mounting hole 4 , the land portion 9, the inclined surface 10, the breaker groove bottom portion 11, the rising surface 12 of the first breaker protrusion 13, the first breaker protrusion 13, and a flat boss surface. 5, it consists of. A cutting edge 6 is formed on a ridge line that is an intersection line between the upper and lower surfaces 2 and the side surfaces 3. Further, a nose portion 7 is formed at a corner where adjacent cutting blades 6 intersect. These inclined surface 10, breaker groove bottom 11, and rising surface 12 form a breaker groove. The boss surface 5 protrudes in the direction of the nose portion 7 to form a first breaker protrusion 13. The rising surface 12 projecting in the direction of the nose portion 7 of the first breaker protrusion 13 is formed from the inclined surface 10 disposed on the nose portion 7, preferably from the middle part of the inclined surface 10. The first breaker protrusion 13 is formed to be higher than the cutting edge 6 along the bisector AA line of the nose portion 7. The width of the first breaker protrusion 13 is increased toward the center side of the throw-away tip 1, and the first breaker protrusion 13 continues to the boss surface 5.
As a result, a large seating area can be ensured when attaching to the tool body.
[0009]
FIG. 2 is a cross-sectional view taken along line AA of FIG. 1. The rising surface 12 of the first breaker protrusion 13 has a first inclination angle 14 of 10 ° to 20 ° at a portion lower than the height of the blade edge 6. Relax. And in the part higher than the height of the cutting edge 6, the 2nd inclination angle 15 is set to 20 degrees-30 degrees. Thus, by providing the rising surface 12 with the first inclination angle 14 and the second inclination angle 15 in two stages, the chips first collide with the rising surface 12 having the gentle first inclination angle 14 to reduce the impact. Subsequently, the restraint property after the collision can be enhanced by the rising surface 12 having the second inclination angle 15.
In the present invention, FIG. 3 is a cross-sectional view taken along the line BB in FIG. 1 at a position symmetric with respect to the bisector AA of the nose portion 7, and the cross-sectional shape is semicircular. A pair of second breaker protrusions 16 are provided. The second breaker protrusion 16 is formed from the middle part of the inclined surface 10 in the vicinity of the nose part 7. Further, as shown in FIG. 1, the second breaker projection 16 is provided so as to cross the breaker groove bottom 11 toward the center of the cutting edge 6 and along the lower side of the side surface of the first breaker projection, Again, the breaker groove bottom is traversed toward the center of the cutting edge, and is arranged so as to be curved with respect to the cutting edge 6, and the end thereof reaches the inclined surface 10. Further, the height of the second breaker protrusion 16 is formed to be lower than the height of the cutting edge 6.
By providing the first breaker protrusion 13 and the second breaker protrusion 16, a concave portion 17 that faces the nose portion 7 is formed between the first breaker protrusion 13 and the pair of second breaker protrusions 16. The second breaker protrusion 16 is formed such that the height of the top thereof gradually decreases from the inclined surface 10 of the nose portion 7 toward the first breaker protrusion 13. The difference between the lowest and highest positions of the top of the second breaker protrusion 16 is preferably set to about 0.03 to 0.07 mm. Thus, by providing a height difference at the top of the second breaker protrusion 16, it is possible to suppress the resistance that is generated when the chip passes through the upper part of the second breaker protrusion 16 with respect to the wide chip generated during medium cutting. . Furthermore, it becomes possible to attract the rising surface 12 of the first breaker projection 13 without hindering the outflow of chips.
Further, by making the cross-sectional shape of the second breaker protrusion 16 arcuate or semicircular, stress concentration when chips pass through the second breaker protrusion 16 can be reduced. Thereby, the abrasion resistance of the second breaker protrusion 16 can be improved. If the height of the second breaker protrusion 16 is too low, the chip restraining action by the second breaker protrusion 16 is impaired at the time of low cutting, and conversely, if it is too high, cutting resistance increases due to chip clogging and vibration occurs. The second breaker protrusion 16 is installed from the middle of the inclined surface 10 connected to the cutting edge 6 near the nose portion 7 and is connected to the rising surface 12 of the first breaker protrusion 13. Thereby, the chip | tip produced at the time of middle cutting can be passed through the upper part of the 2nd breaker protrusion 16 without difficulty. The height of the second breaker protrusion 15 is preferably 0.1 to 0.20 mm.
[0010]
The land portion 18 in the nose portion 7 of the present invention is provided with a narrow width portion 19 where the land width is partially narrowed. A narrow portion 19 having a narrow width about one place is provided symmetrically with respect to the bisector AA of the nose portion 7 shown in FIG . The width of the narrow width portion 19 is set so that the width is smoothly reduced with respect to the width of the land portion 18 located on the bisector AA. The width of the narrow portion 19 is preferably about 0.1 mm, and the width of the land portion 18 is preferably about 0.15 mm.
[0011]
The position of the narrow width portion 19 is set approximately between the bisector AA and the land portion 18 which is an end portion of the corner R portion. As shown in FIG. 5 , the land portion 18 located on the bisector AA of the corner R portion is formed as a positive land in order to cope with improved sharpness and low feed cutting. is a 2 ° to 5 °, the positive land width 21 is about 0.15mm as described above, the angle 22 of the inclined surface 10 to 14 ° ~ 16 °. Further, the cross-sectional shape of the land portion at a position within about 2 mm from the end portion of the corner R portion toward the center portion of the cutting edge 6 is a flat land in order to suppress chipping resistance and generation of burrs, as shown in FIG. The land width 23 is 0.17 to 0.23 mm, and the angle 24 of the inclined surface is 14 ° to 16 °. Similarly, the cross-sectional shape of the land portion 9 exceeding 2 mm from the end portion of the corner R portion and within about 3.5 mm is an R-shaped negative land, as shown in FIG. The angle 26 of the inclined surface is set to 14 ° to 16 °. Similarly, the cross-sectional shape of the land portion 9 in a portion exceeding about 3.5 mm from the end portion of the corner R portion is an R-shaped negative land, as shown in FIG. 8 , and the land width 27 is 0.27-0. The angle 28 of the inclined surface is 8 ° to 12 °. The land width at each position of the land portion 9 is desirably an appropriate value within the above range, but in the present invention, the land width is gradually widened as the distance from the nose portion 7 increases. Form and prevent chipping of the cutting edge 6 during medium cutting.
[0012]
At the time of finish cutting, in the region where the cutting depth is around 0.5 mm and the feeding amount is 0.3 mm / rev or less, especially when the cutting depth is smaller than the width of the corner R, chips wider and thinner than the actual cutting depth are generated. . Such chips have an unstable trend due to their thinness, and it is very difficult to restrain and break them with a conventional breaker projection. In the present invention, thin and unstable chips generated by the cutting edge of the nose portion,
1) The first deformation is given by the narrow width portion 19 provided in the land portion in the corner R portion. The chip descends in the direction of the inclined surface 10 by the narrow width portion 19 close to the nose portion, and causes large plastic deformation in the chip.
2) The chips move along the inclined surface 10 and enter the concave portion 17. The chip 17 is deformed by being curved with respect to the width direction at the concave portion 17.
3) The chips are restrained at two points from different directions by the tops of the pair of second breaker protrusions 16 to further promote bending deformation in the width direction.
4) According to 1) to 3), not only the flow of chips generated during finish cutting is reliably controlled, but also the thin and elastic chips are deformed to be curved in the width direction. An apparent thickness thicker than the chip thickness can be formed. With this apparent thickness, the elasticity of the chip can be suppressed, and a large distortion can be given to the inside of the chip, and the chip can be discharged as a breakable chip.
[0013]
In the cutting of medium cutting conditions such as a cutting depth of 2.0 mm or more, the chips that have entered the concave portion 17 come into contact with the rising surface 12 at a position lower than the cutting edge 6. The first inclination angle 14 of the rising surface 12 positioned lower than the cutting edge 6 is formed more gently than the second inclination angle 15 of the rising surface 12 positioned higher than the cutting edge 6. For this reason, the impact and vibration which occur when the cutting edge 6 collides with the rising surface 12 can be reduced. The chips that collide with the rising surface 12 are bent along the rising surface 12. However, if it rises at the same angle up to the top of the rising surface 12, the chips get over the first breaker protrusion 13 and are not broken. Therefore, in the present invention, the first inclination angle 14 and the second inclination angle 15 of the rising surface 12 are set to 14 <15, so that the chips after the collision are reliably bent on the rising surface 12.
[0014]
Next, since the 2nd breaker protrusion 16 is formed higher than the inclined surface 10 continuing from the cutting blade 6, the area where the inclined surface 10 and the breaker groove bottom part 11 contact with a chip can be reduced. Thereby, damage of the inclined surface 10 and the breaker groove bottom part 11 accompanying chip abrasion, so-called crater wear can be reduced. In particular, this effect is significant in the middle cutting region. Further, since the second breaker protrusion 16 is arranged in a curved shape with respect to the cutting edge 6 in plan view, chips are reliably restrained and attracted in the direction of the first breaker protrusion 13 even in cutting with a large cutting width. In addition to the action, the chip is deformed so as to be bent in the width direction to generate a chip that is easily broken. Further, since the second breaker protrusion 16 is provided along the lower side of the side surface of the first breaker protrusion 13, the first breaker protrusion 13 and the second breaker protrusion 16 form a two-step wall. Since the two-stage wall acts to alleviate the impact of the chips on the first breaker projection 13, the life of the throw-away tip can be further improved.
[0015]
【Effect of the invention】
As described above, by applying the present invention, it is possible to provide a throw-away tip capable of reliably cutting chips over a wide range from finish cutting to medium cutting. Especially in finish cutting with low depth of cut, it is a throw-away tip excellent in chip disposal that shows unstable trends, and the second flaker projection can reduce crater wear on the inclined surface following the breaker groove and land, It was possible to provide a long-life throw-away tip with few defects.
[00 16 ]
[Brief description of the drawings]
FIG. 1 shows a top view of the present invention embodiment.
Figure 2 shows a cross-sectional view of line A-A of FIG.
Figure 3 shows a section B-B of FIG.
Figure 4 shows an enlarged view of the nose portion shown in FIG.
Figure 5 shows a cross-sectional view of line A-A of FIG.
Figure 6 shows a cross-sectional view of line C-C in FIG.
Figure 7 shows a cross-sectional view of D-D line in FIG.
Figure 8 shows a cross-sectional view of line E-E in FIG. 4.
[00 17 ]
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Throw away tip 2 A pair of upper and lower surfaces 3 Side surface 4 Mounting hole 5 Boss surface 6 Cutting edge 7 Nose part 9 Land part 10 Inclined surface 11 Breaker groove bottom part 12 Rising surface 13 First breaker protrusion 14 First inclination angle 15 Second inclination corners 16 angle 23 C-C section of the inclined surface 10 of width 22 Pojirando 18 angle 21 positive land 18 of the narrow portion 20 positive land 18 of the second breaker projection 17 recess 18 corner R part positive land 19 positive land 18 in R-shaped negative of the inclined surface 10 of width 24 C-C portion of the flat land angle 25 D-D section of the angle 27 E-E section of the inclined surface 10 of width 26 D-D section of the R-shaped negative land angle of the inclined surface 10 of width 28 E-E section of the land

Claims (7)

A cutting edge is formed on the ridgeline of the upper and lower surfaces of the throwaway tip having a polygonal flat plate shape, a breaker groove is formed on the inner side of the land portion formed along the cutting edge, and a boss surface formed in a central portion of the upper and lower surfaces. And a pair of second breaker protrusions at positions symmetrical with respect to the bisector of the nose part in plan view, the second breaker The protrusion is provided so as to cross the breaker groove bottom from the inclined surface continuing to the land portion in the vicinity of the nose portion toward the center portion of the cutting blade and along the lower side of the side surface of the first breaker protrusion , Again, the breaker groove bottom is traversed toward the center of the cutting edge, the end of the second breaker projection reaches the inclined surface, and is provided in a curved shape toward the center of the cutting edge. And throw away chips.   The throw-away tip according to claim 1, wherein a concave portion facing the cutting edge of the nose portion is formed between the first breaker projection and the pair of second breaker projections.   The throwaway tip according to claim 1, wherein the rising angle of the rising surface of the breaker groove is two steps, and the first inclination angle of the portion lower than the cutting blade height from the breaker groove bottom is the height of the cutting edge. A throw-away tip characterized in that the angle is smaller than the second inclination angle of the higher portion.   4. The throw-away tip according to claim 1, wherein a height of the second breaker protrusion is lower than the cutting edge.   5. The throw-away tip according to claim 1, wherein a top cross-sectional shape of the second breaker projection is a substantially arc shape.   6. The throw-away tip according to claim 1, wherein a narrow portion is formed by narrowing a land width of the nose portion.   7. The throw-away tip according to claim 1, wherein the width of the land portion is increased toward the center portion of the cutting edge.

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