JP2008000837A - Throwaway tip - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throwaway tip with an excellent seating property relative to a tool body, which is capable of preventing a deterioration in cutting performance. <P>SOLUTION: The throwaway tip 1 in a substantially polygonal flat plate shape with cutting teeth formed on the ridge parts of opposed polygonal surfaces is provided with at least one boss surface 5 arranged in the central part of each polygonal surface, breaker grooves 6 arranged between the boss surface 5 and the cutting teeth, land surfaces 3a, 4a extended inwards from the cutting teeth along them. At least in one corner part of the polygonal surfaces, the width L2 of the land surface in a pair of straight cutting teeth extended respectively from the corner cutting teeth 2 is set to be larger than the width L1 of the land surface in the corner cutting teeth 2, and the distance L4 between the straight cutting teeth and the boss surface is set to be shorter than the distance L3 from the front end of the corner and the boss surface in the corner cutting teeth 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a throw-away tip used for cutting.

For example, in turning, when roughing is performed regardless of the material of the work material, as the cutting and feeding increase, a heavy load is applied to the cutting blade. As a result, cutting edge defects may occur due to vibration generated by insufficient strength or overload of the cutting edge. Therefore, when roughing is performed, it is important to improve the seating property of the throw-away tip on the tool body. As a conventional throw-away chip with improved seating performance, the following is proposed.
For example, the throw-away tip described in Patent Document 1 has a plate shape, and blade edges 2a and 2b are formed so that cutting can be performed on both sides (rake face side) in the plate thickness direction. The land portion 4 to be formed is formed in a substantially square ring shape on both rake faces in the thickness direction of the throw-away tip 1, and a chip breaker 5 as a mold breaker is formed in a substantially square ring shape around the entire periphery of the land portion 4. The seat breaker 5 is provided on the inner side of the chip breaker 5. The land portion 4 is composed of a chamfering portion 8 on the tip end side of the blade edge 2 and a straight portion 9 on the center side, and in particular, a surface in the plate thickness direction of the straight portion 9 and a surface in the plate thickness direction of the seat portion 7. Are set to be on the same plane.
For example, in the throw-away tip described in Patent Document 2, a land surface 4 is provided at the peripheral edge portion of both main surfaces, and a central surface 7 is provided on the inner side of the land surface 4 with a recess therebetween. And at least one protrusion 8 extending toward 4 is provided, and the height of the land surface is at least equal to the height of the top surface of the protrusion 8.
Japanese Patent Laid-Open No. 11-277307 (FIG. 2) JP 2004-98251 A (FIG. 1)

However, in the throw-away tip described in Patent Document 1, if the cutting edge on one side in the plate thickness direction is used, the straight part 9 is worn and cannot keep the same plane as the seating part 7. When used, a gap is generated between the holder and the straight portion 9, so that the throw-away tip is loose, and the cutting blade responsible for cutting and the cutting blade on the holder side may be damaged. Further, since the straight portion 9 is limited to a so-called negative land set so as to be flush with the seat portion 7, there is a problem that it is difficult to design the shape of the straight portion 9 in consideration of cutting performance and the like. It was.
In the throw-away tip described in Patent Document 2, the land surface 4 is limited to the negative land surface as in the above-described problem, and the protrusion 8 extends from the center surface 4 toward the land surface 4 ( Since the land and the boss surface are connected), when a straight cutting edge is used, there is a problem in that chips strongly collide with the protrusion 8 and the cutting resistance increases.

  The present invention has been made in order to solve the above-described problems. It is an object of the present invention to provide a throw-away tip that is excellent in seating property on a tool body and whose cutting performance is deteriorated.

In order to solve the above-described problem, the invention described in claim 1 is a throwaway tip having a substantially polygonal flat plate shape and having cutting edges formed on side ridges of opposing polygonal surfaces. At least one boss surface provided at the center, a breaker groove provided between the boss surface and the cutting blade, and a land surface extending inwardly from the cutting blade along the cutting blade; In at least one corner portion of the polygonal surface, the land surface width L2 of the pair of linear cutting blades respectively extending from the corner cutting blade is set larger than the land surface width L1 of the corner cutting blade. The throwaway tip is characterized in that a distance L4 between the straight cutting edge and the boss surface is set smaller than a distance L3 between the corner tip and the boss surface in the corner cutting edge.
According to the throw-away tip of the present invention, it is possible to increase the edge strength of a relatively high load straight cutting edge without impairing the sharpness of the corner cutting edge, which has a great influence on the cutting resistance and the surface roughness of the finished surface. .
With a straight cutting edge with a large land surface width, the chip thickness is larger and the curl radius is smaller than the corner cutting edge, so the boss surface is placed close to the straight cutting edge without being hit directly by the chip. It becomes possible. Therefore, when the throw-away tip is mounted on the tool main body, it is supported by the boss surface close to the straight cutting blade on the tool main body side, and thus has excellent seating properties. In particular, in rough machining in which the straight cutting edge is responsible for cutting, it is possible to prevent the straight cutting edge from being lost without rattling.
In addition, as described above, since it is difficult for the boss surface to be damaged by direct hitting of chips, after using one surface of the opposing polygonal surface, this one surface is seated on the tool body side and the other surface is In use, excellent seating properties can be maintained. Moreover, there is no adverse effect on cutting performance such as an increase in cutting resistance and a deterioration in chip disposal.
As described above, since the boss surface can be arranged at a position close to the straight cutting blade without hitting the boss surface directly, excellent seating is possible even if the cutting blade and the land surface are not flush with the boss surface. Therefore, there is no possibility that the cutting performance will be deteriorated.

The invention according to claim 2 is the invention according to claim 1, wherein a transition portion having a predetermined length in a direction along the cutting edge is formed at a boundary portion between the corner cutting edge and the linear cutting edge. The width of the land surface of the transition portion continuously changes from a width L1 at the end portion on the corner cutting edge side to a width L2 at the end portion on the straight cutting edge side.
In this way, when the transition portion having a predetermined length in the direction along the cutting edge is provided at the boundary portion between the corner cutting edge and the straight cutting edge, the change in the width of the land surface at the boundary portion becomes gentle. This prevents the cutting blade from being easily damaged.

According to the throw-away tip of the present invention, it is possible to increase the edge strength of a relatively high load straight cutting edge without impairing the sharpness of the corner cutting edge, which has a great influence on the cutting resistance and the surface roughness of the finished surface. .
With a straight cutting edge with a large land surface width, the chip thickness is larger and the curl radius is smaller than the corner cutting edge, so the boss surface is placed close to the straight cutting edge without being hit directly by the chip. It becomes possible. Therefore, when the throw-away tip is mounted on the tool main body, it is supported by the boss surface close to the straight cutting blade on the tool main body side, and thus has excellent seating properties. In particular, in rough machining in which the straight cutting edge is responsible for cutting, it is possible to prevent the straight cutting edge from being lost without rattling.
In addition, as described above, since it is difficult for the boss surface to be damaged by direct hitting of chips, after using one surface of the opposing polygonal surface, this one surface is seated on the tool body side and the other surface is In use, excellent seating properties can be maintained. Moreover, there is no adverse effect on cutting performance such as an increase in cutting resistance and a deterioration in chip disposal.
As described above, since the boss surface can be arranged at a position close to the straight cutting blade without hitting the boss surface directly, excellent seating is possible even if the cutting blade and the land surface are not flush with the boss surface. Can be realized, there are few restrictions on the shape of the land surface, and the cutting performance is not deteriorated.

Hereinafter, the throw-away tip according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is a plan view of the throw-away tip. FIG. 2 is an enlarged plan view of a main part of the throw-away tip.
As shown in FIGS. 1 and 2, the present throw-away tip 1 has a substantially rhombus plate shape, and a corner having a circular arc shape in plan view is formed at a pair of 80 ° corner portions on a diagonal line of the opposite rhombus surfaces. A cutting blade having a cutting blade 2 and a pair of linear cutting blades 3 extending from the corner cutting blade 2 is formed, and a pair of rhombus surfaces connected to the cutting blade and a circumferential surface substantially orthogonal to the rhombus surface Each has a rake face and a flank face.
A substantially flat boss surface is provided at the center of the rhombus surface, and a breaker groove 6 is provided between the boss surface 5 and the cutting edge along the entire cutting edge.
A mounting hole 10 having a substantially cylindrical shape for mounting the present throw-away tip on the tool body is formed in the center of the boss surface 5 so as to penetrate in the thickness direction.
The shape of the throw-away tip 1 is not limited to a substantially rhomboid plate shape, but may be a substantially polygonal plate shape.

As shown in FIG. 2, flat land surfaces 2 a and 3 a extending inward from the cutting blade are formed on the cutting blade. The land surfaces 2a and 3a can be appropriately selected from a positive land surface that inclines downward as it goes inward, or a negative land surface that extends parallel to the upper and lower surfaces, and in this embodiment, is a 6 ° positive land surface. Further, the land surface width L2 of the straight cutting edge is formed to be larger than the land surface width L1 of the corner cutting edge.
A transition portion 4 is provided at the boundary between the corner cutting edge 2 and the straight cutting edge 3. The land surface 4a in the transition portion is a positive land surface, similar to the land surfaces 2a and 3a in the straight cutting edge and the corner cutting edge, and the width thereof is changed from the width L1 in the corner cutting edge side end portion to the linear cutting blade side end portion. It is formed so as to have a predetermined length in the direction along the cutting edge, continuously changing to the width L2.

In plan view, the contour shape of the boss surface 5 is substantially symmetric with respect to the bisector B of the four corner portions, and the straight cutting blade 3 is substantially parallel to the straight cutting blade 3, In the region facing the transition portion 4, as it approaches the corner cutting edge 2, it is inclined so as to gradually move away from the straight cutting edge 3, and the corner cutting edge 2 is formed so as to protrude toward the corner cutting edge 2. Has been. The distance L4 between the straight cutting edge and the boss surface is smaller than the distance L3 between the corner tip C where the corner cutting edge 2 and the bisector B intersect and the boss face 5 protruding toward the corner cutting edge 2. It is set to be. The boss surface 5 is equal or higher than the highest one of all the land surfaces 2a, 3a, 4a, and when the throwaway tip 1 is mounted on a tool body (not shown), It must be a seating surface that contacts the tool body.

According to the throw-away tip 1 having the above configuration, in the corner cutting edge 2 having a large influence on the cutting resistance and the surface roughness of the finished surface, the land surface width L1 is set to be relatively small. Without damaging, since the land surface width L2 is set to be relatively large in the straight cutting blade 3 having a relatively high load, the strength of the blade edge can be increased.
On the other hand, in the straight cutting edge 3 in which the land surface width L2 is set to be relatively large, the boss face 5 is directly hit by the chip because the chip thickness is larger and the curl diameter is smaller than the corner cutting edge 2. Instead, it can be arranged at a position close to the straight cutting edge 3. Therefore, as described above, the distance L4 between the straight cutting edge and the boss surface can be set to be smaller than the distance L3 between the corner tip and the boss surface. According to such a configuration, when the throw-away tip 1 is mounted on the tool body, the throw-away tip 1 is supported by the boss surface 5 close to the straight cutting edge 3 on the tool body side, and thus has excellent seating properties. In particular, in the rough machining in which the linear cutting edge 3 is responsible for cutting, the linear cutting edge 3 is prevented from being rattled, so that the linear cutting edge 3 can be prevented from being chipped or broken. In addition, since the boss face 5 is prevented from being damaged by the direct hit of the chips, after using one rhombus surface, the one rhombus surface is seated on the tool body side and the other rhombus surface is used. In this case, excellent seating property can be maintained. Moreover, there is no adverse effect on cutting performance such as an increase in cutting resistance and a deterioration in chip disposal.

Below, the relationship between the width | variety of a land surface, chip thickness, and the curl diameter of a chip is demonstrated based on the Example shown in FIGS. FIG. 3 shows a cutting speed Vc = 250 m / min, cutting ap = 2 mm, 3 mm, feed f = 0.15 mm / rev to 0 using a throwaway tip having the same 6 ° positive land surface as the present throwaway tip. The chip shape when the outer peripheral turning of carbon steel S45C for machine structure is performed at a cutting condition of .4 mm / rev is shown. FIG. 4A shows the chip shape and the chip curl diameter under the cutting conditions of notch ap = 3 mm and feed f = 0.4 mm / rev. In addition, the numerical value described under the chip shape of FIG. 3 is a measured value of chip thickness.
As can be seen from FIG. 3, when the land surface width increases from 0.2 mm to 0.3 mm, the chip thickness increases under all cutting conditions. Further, as the width of the land surface increases, the curl diameter of the chips decreases as shown in FIG. Only some cutting conditions are shown for the change in the chip curl diameter with the change in the land surface width, but the chip curl diameter as the land surface width increases under other cutting conditions. It was confirmed that becomes smaller. Furthermore, the rate at which the curl diameter of the chips was reduced generally coincided with the reciprocal (0.2 mm / 0.3 mm) of the rate at which the land surface width was increased.

Moreover, the width of the land surface is fixed to 0.3 mm, and the result of comparing the chip thickness and the chip curl diameter between the positive land surface and the negative land surface is shown in FIGS. FIG. 5 shows a cutting speed Vc = 250 m / min, cutting ap = 2 mm, 3 mm, feed f = 0.15 mm / throw using a throwaway tip having a 6 ° positive land surface and a throwaway tip having a negative land surface. The chip shape when the outer peripheral turning of carbon steel for mechanical structure S45C under the cutting conditions of rev to 0.4 mm / rev is shown. FIG. 4B shows the chip shape and the chip curl diameter under the cutting conditions of an incision ap = 3 mm and a feed f = 0.4 mm / rev. In addition, the numerical value described under the chip shape of FIG. 5 is an actual measurement value of chip thickness.
As can be seen from FIG. 3, when the land surface changes from a positive land surface of 6 ° to a negative land surface, the chip thickness increases under all cutting conditions. Further, as the positive land surface changes to the negative land surface, the curl diameter of the chips decreases as shown in FIG. Regarding the change in the curl diameter of the chip, only a part of the cutting conditions is shown. However, in other cutting conditions, the curl diameter of the chip becomes smaller as the positive land surface changes to the negative land surface. The ratio was about 70% (range of 60% to 80%).

From the above embodiments, in the present throw-away tip 1, the ratio of the curl diameter of the chips generated from the straight cutting edge 3 to the curl diameter of the chips generated from the corner cutting edge 2 is the land in the straight cutting edge. It was found that the surface width L2 substantially coincided with the reciprocal L1 / L2 of the ratio increasing with respect to the land surface width L1 in the corner cutting edge. Therefore, if the distance L4 between the straight cutting edge and the boss surface satisfies the relationship of L3 × L1 / L2 ≦ L4 <3.0 mm (L3: distance between the corner tip and the boss surface), the corner cutting edge 2 Assuming that the distance L3 between the corner tip and the boss surface is set so that the chips generated from the boss surface facing the corner cutting blade 2 do not directly hit, the chips generated from the straight cutting blade 3 Direct hitting on the boss surface 5 facing the straight cutting edge is avoided. The distance L3 between the corner tip and the boss surface, which is the precondition, preferably satisfies the relationship of 0.5 mm ≦ L3 ≦ 3.0 mm. This is because if the distance L3 is 0.5 mm or more, the boss surface 5 facing the corner cutting edge 2 is not directly hit by the chips, so that the seating property is excellent when using the back surface, the cutting resistance is increased, and the chip disposal is improved. This is because there is no problem in cutting performance such as deterioration of the angle, and if the distance L3 is 3.0 mm or less, the seating property at the corner cutting edge 2 is prevented from being deteriorated.
The distance L4 between the straight cutting edge and the boss surface is based on the knowledge obtained from the above-described embodiment, and the ratio L3 between the corner tip and the boss surface, which is the precondition, and the ratio of increasing the width of the land surface. If it is equal to or greater than the value obtained by multiplying L1 / L2 which is the reciprocal number, it is avoided that chips generated from the straight cutting blade 3 directly hit the boss surface 5 facing the straight cutting blade. Furthermore, in order to achieve excellent seating, which is the intended purpose of the present throw-away tip 1, it is desirable that the distance L4 between the straight cutting edge and the boss surface is set to be less than 3.0 mm.

According to the above-described embodiment, when the land surface 3a of the straight cutting edge is a negative land surface, the distance L4 between the straight cutting edge and the boss surface is L3 × L1 / L2 × 0.7 ≦ L4 <3.0 mm. If the relationship of (L3: distance between the corner tip and the boss surface) is satisfied, the corner tip and the boss surface are prevented so that chips generated from the corner cutting edge 2 do not directly hit the boss surface facing the corner cutting edge 2. As a precondition that the distance L3 is set, it is avoided that chips generated from the straight cutting edge 3 directly hit the boss surface 5 facing the straight cutting edge. The distance L3 between the corner tip and the boss surface, which is the precondition, preferably satisfies the relationship of 0.5 mm ≦ L3 ≦ 3.0 mm. The reason for this is as described above.
The distance L4 between the straight cutting edge and the boss surface is based on the knowledge obtained from the above-described embodiment, and the ratio L3 between the corner tip and the boss surface, which is the precondition, and the ratio of increasing the width of the land surface. If the value is equal to or greater than the value obtained by multiplying 70% of L1 / L2, which is the reciprocal number, it is avoided that the chips generated from the straight cutting blade 3 hit the boss surface 5 facing the straight cutting blade. Furthermore, in order to achieve excellent seating, which is the intended purpose of the present throw-away tip 1, it is desirable that the distance L4 between the straight cutting edge and the boss surface is set to be less than 3.0 mm.

Thus, according to the present throw-away tip 1, in the straight cutting edge 3 in which the land surface width L2 is set to be relatively large, the chip thickness is larger than the corner cutting edge 2, and the curl diameter of the chip is reduced. Therefore, the boss surface 5 can be disposed at a position close to the straight cutting edge 3 without receiving a direct hit of chips. Therefore, the distance L4 between the straight cutting edge and the boss surface can be set to be smaller than the distance L3 between the corner tip and the boss surface. According to such a configuration, when the throw-away tip 1 is mounted on the tool body, it is supported by the boss surface 5 close to the straight cutting edge 3 on the tool body side, so that it has excellent seating properties. In particular, in the rough machining in which the linear cutting edge 3 is responsible for cutting, the linear cutting edge 3 is prevented from being rattled, so that the linear cutting edge 3 can be prevented from being chipped or chipped. In addition, since the boss surface 5 is prevented from being damaged by the direct hitting of chips, in the present throw-away tip using both of the opposing rhombus surfaces, after using one rhombus surface, this one rhombus surface Is seated on the tool body side and the other rhomboid surface is used, the excellent seating property can be maintained. Further, there is no adverse effect on the cutting performance such as an increase in cutting resistance and deterioration in chip disposal due to the direct impact of the chips. In addition, the edge strength of the linear cutting edge 3 that is higher than the corner cutting edge 2 is increased, preventing damage such as chipping and chipping and extending the cutting edge life.

Furthermore, in the present throw-away tip 1, it is preferable that the land surface width L1 of the corner cutting edge satisfies the relationship of 0.05 mm ≦ L1 ≦ 0.50 mm. This is because when the land surface width L1 of the corner cutting edge is less than 0.05 mm, chipping or chipping is likely to occur due to insufficient strength of the cutting edge, and when the width L1 exceeds 0.50 mm, the rake angle provided in the breaker groove 6 This is because the effect of reducing the cutting force is reduced and the effect of reducing the cutting resistance is reduced.

Furthermore, it is preferable that the land surface width L2 of the linear cutting edge satisfies the relationship of L1 + 0.05 mm ≦ L2 ≦ L1 + 0.30 mm. If the width L2 of the land surface in the straight cutting edge is larger than the width L1 of the land surface in the corner cutting edge plus 0.05 mm, the curl diameter of chips generated from the straight cutting edge can be reduced. The boss face 5 can be brought close to the straight cutting edge, and when the land surface width L2 of the straight cutting edge is larger than the land surface width L1 of the corner cutting edge plus 0.30 mm, the cutting resistance is increased. This is because there is a possibility that problems such as increase in size, chatter, and deterioration in processing accuracy may occur.

Further, a transition portion 4 is formed at a boundary portion between the corner cutting edge 2 and the straight cutting edge 3 over a length of 0.5 mm or more in the direction along the cutting edge, and the width of the land surface 4a of the transition portion is as follows. It is preferable that the width L1 at the corner cutting edge side end portion continuously changes from the width L2 at the straight cutting edge side end portion. This is to prevent the cutting edge from being easily damaged due to a sudden change in the width of the land surface 4a at the boundary between the corner cutting edge 2 and the straight cutting edge 3.

As described above, the present throw-away tip 1 can be disposed at a position close to the straight cutting edge 3 without directly hitting the boss surface 5, so that the cutting edge Further, since the land surfaces 2a, 3a and 4a are not made the same height as the boss surface 5 or limited to the negative land, it is possible to prevent the cutting performance from deteriorating.

In the throw-away tip according to the present invention, the shape of the boss surface in a plan view can be appropriately changed without departing from the gist of the present invention. For example, as shown in FIG. 6, a part of the contour shape of the boss surface 5 only needs to be close to the straight cutting edge 3. In this case, in consideration of the seating property, it is preferable that at least two locations of each linear cutting blade 3 are close to each other in the direction of the linear cutting blade 3. More preferably, the two locations are distributed with an interval between them on both sides of the intermediate point of the straight cutting edge 3.
Alternatively, a plurality of boss surfaces 5 may be provided separately. For example, as shown in FIG. 7, a first boss surface 5 a provided in the central portion and an island shape independently spaced from the first boss surface 5 a are formed, and the second boss surface 5 a is provided at a position close to the straight cutting edge 3. The boss surface 5b may be used. Also in this case, it is preferable that at least two second boss surfaces 5b are provided in each linear cutting blade 3 so as to be separated from each other in the direction of the linear cutting blade 3. It is further preferable that at least two second boss surfaces 5b are distributed at intervals on both sides of the intermediate point of the straight cutting edge 3.

It is a top view of the throw away tip concerning the embodiment of the present invention. It is a principal part enlarged plan view of the throw away tip. It is a figure which shows the Example of the throw away tip which concerns on embodiment of this invention. It is a figure which shows the Example of the throw away tip which concerns on embodiment of this invention. It is a figure which shows the Example of the throw away tip which concerns on embodiment of this invention. It is a top view which shows the modification of the throw away tip which concerns on embodiment of this invention. It is a top view which shows the other modification of the throw away tip which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Throw away tip 2 Corner cutting edge 2a Land surface 3 in a corner cutting edge 3 Straight cutting edge 3a Land surface 4 in a straight cutting edge 4 Transition part 4a Land surface 5 in a transition part Boss surface 6 Breaker groove B A bisector C of a corner part Corner tip L1 Land surface width L2 at the corner L2 Land surface width L3 at the straight cutting edge Distance L4 between the corner tip and the boss surface Distance between the straight cutting blade and the boss surface

Claims (2)

In a throwaway tip that has a substantially polygonal flat plate shape and has a cutting edge formed on the side ridges of the opposing polygonal surface,
At least one boss surface provided at the center of each polygonal surface;
A breaker groove provided between the boss surface and the cutting edge;
A land surface extending inwardly from the cutting edge along the cutting edge,
In at least one corner portion of the polygonal surface, the land surface width L2 of the pair of linear cutting blades extending from the corner cutting blade is set larger than the land surface width L1 of the corner cutting blade,
A throw-away tip, wherein a distance L4 between the straight cutting edge and the boss surface is set smaller than a distance L3 between the corner tip and the boss surface in the corner cutting edge. At the boundary between the corner cutting edge and the straight cutting edge, a transition portion having a predetermined length in the direction along the cutting edge is formed,
The width of the land surface of the transition portion continuously changes from a width L1 at an end portion on the corner cutting edge side to a width L2 at an end portion on the straight cutting edge side. Throwaway tip.

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