JPH061283Y2 - Throw-away tip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a throw-away tip that is detachably mounted on the outer periphery of the tip of various cutting tool bodies.

[Prior Art] Generally, in a turning tool in which chips are continuously discharged, in order to smoothly discharge the chips by appropriately cutting the chips extending along with the cutting on the rake face along the main cutting edge. There is a throw-away tip with a breaker groove.

FIGS. 4 to 6 show a conventional throw-away tip in which a breaker groove of this type is formed in the related art.

The throw-away tip 1 is a plate-like member having a substantially triangular outer shape, and a main cutting edge 3 is formed on a corner ridge portion of an upper surface 2 thereof. A breaker groove 4 extending along the main cutting edge 3 is formed on the upper surface 2 over the entire circumference.

As shown in FIG. 5, the breaker groove 4 has a flat land 5 extending in the same plane as the upper surface 2 in a direction orthogonal to the main cutting edge 3 and a concave shape continuous from the land 5 to the upper surface 2. Rake surface 6 and groove bottom curved surface 7 extending in a cylindrical surface shape
And the rising surface 8. Here, the width dimension B _{1 of the} breaker groove 4 is ¼ to ₁ of the diameter D ₁ of the inscribed circle 9 of the throw-away tip.
/ 8 and its depth _{H 1} is B ₁ / 10~B _1/20
Is set to.

Then, in this throw-away tip, as shown in FIG. 6, the workpiece W cut by the main cutting edge 3 is cut.
The chips W ₁ can be curled by the breaker groove 4 to be appropriately cut and smoothly discharged.

However, in the above-mentioned conventional throw-away tip, as shown in FIG. 6, although the chip W ₁ can be smoothly curled in the cutting (medium heavy cutting) having a relatively large cutting load, Small cutting (light cutting)
In the above, since the chip W ₂ extends without being curled as shown by the chain line in the figure, there is a drawback that it cannot be smoothly cut and discharged. Further, since the contact area between the breaker groove 4 and the chips W ₁ and W ₂ is large, the friction generated between the chips W ₁ and W ₂ is large, so that the cutting resistance is increased and the frictional heat is generated to cause the cutting edge. However, there is a drawback in that the tool is easily chipped and worn, and the tool life is short.

For this reason, as a solution to the above-mentioned drawbacks, the one proposed as Japanese Utility Model Publication No. 58-157504 shown in FIGS. 7 and 8 and the West German Patent No. 2241167 shown in FIGS. 9 and 10 are proposed. Things are known.

In FIG. 7 and FIG. 8, the throw-away tip 10 has a plate-like shape having a substantially triangular appearance, and its upper surface 1
1 has breaker grooves 14 ... Each having a predetermined length from the cutting edge tip 13 of each main cutting edge 12 toward the cutting edge rear end.

As shown in FIG. 8, the breaker groove 14 has a main cutting edge 1
2. A rake face 15 which is inclined from the upper face 11 toward the lower face side in a direction orthogonal to 2 and a curved face 16 which is discontinuous from the rake face 15 and suddenly drops to the lower face side at a large inclination angle.
And a groove bottom surface 17 connected to the end of the curved surface 16 and a concave columnar rising surface 18 that gently extends from the groove bottom surface 17 to the upper surface 11.

On the other hand, in FIG. 9 and FIG. 10, the throw-away tip 20 has a plate-like shape having a substantially square appearance, and the upper surface 21 thereof faces from the cutting edge 23 of each main cutting edge 22 toward the rear edge of the cutting edge. Thus, breaker grooves 24 ... Each having a predetermined length are formed.

As shown in FIG. 10, the breaker groove 24 has a rake face 25 inclined from the upper surface 21 toward the lower face side in a direction orthogonal to the main cutting edge 22, and a discontinuous and large inclination angle from the rake face 25. Curved surface 2 that suddenly drops to the bottom side
6, and a groove bottom surface 27 that is continuous with the end of the curved surface 26,
It is formed from an inclined rising surface 28 extending gently from the groove bottom surface 27 to the upper surface 21.

Here, the width dimension B _{2 of the} breaker grooves 14 and 24 of the throw-away tips 10 and 20 is 1 / the diameter D ₂ of the inscribed circle of the throw-away tips 10 and 20, respectively.
3.0 to 1 / 4.2 and the depth dimension H ₂ is B ₂ /3.0
It is set to ~ B ₁ /4.5.

In these throw-away tips 10 and 20, the rake surfaces 15 and 25 are provided with curved surfaces 16 and 26, respectively, which sharply drop toward the lower surface from the end portions thereof. Breaker groove 1
It is possible to shorten the contact length between the chips 4 and 24 and the chip W ₃ . Therefore, it is possible to improve the friction can be reduced, thus it until the indexable inserts problem shown in Figure 4-Figure 6 occurring between the chip W _3.

[Problems to be Solved by the Invention] However, the conventional throw-away tip 10,
In order to shorten the contact length between the breaker grooves 14 and 24 and the chips W ₃ , the rake faces 15 and 2 are provided.
As a result of forming the curved surfaces 16 and 26 discontinuously from No. 5 and rapidly falling to the lower surface side at a large inclination angle, there is a drawback that the cutting edge strength is naturally reduced. in addition,
Since the inclination angles of the curved surfaces 16 and 26 are large, the depths of the groove bottom surfaces 17 and 27 that are continuous with the curved surfaces 16 and 26 are considerably large. Therefore, in order to prevent clogging of chips on these groove bottom surfaces 17 and 27, it is inevitably necessary to make the width dimension B ₂ of each breaker groove 14 and 24 large. Therefore, when the breaker grooves 14 and 24 are attempted to extend to the rear end side of the cutting edges of the main cutting edges 12 and 22, the area where the rising surface indicated by L in FIG. 4 is not formed becomes large, and conversely the chip discharging performance is increased. Has a drawback that the breaker grooves 14 and 24 cannot be formed over the entire circumferences of the upper surfaces 11 and 21. Therefore, each breaker groove 14,
The shape of 24 determines the direction in which it can be used (right or left handedness), which is inconvenient to handle and uneconomical.

[Object of the Invention] The present invention has been made in view of the above circumstances, and is excellent in chip discharging performance, and can form a breaker groove over the entire circumference of the upper surface without lowering the cutting edge strength. The purpose is to provide a throw-away tip.

[Means for Solving the Problems] In the throw-away tip of the present invention, a breaker groove extending along the main cutting edge on the upper surface is provided from the main cutting edge to the lower surface side in a direction orthogonal to the main cutting edge. The inclined first rake face is drawn from the first rake face toward the lower surface side at a larger inclination angle, and the concave cylindrical surface is drawn in contact with the end of the second rake face. The groove bottom curved surface is formed of a rising surface that is in contact with the groove bottom curved surface and that reaches the upper surface.

[Embodiment] FIGS. 1 to 3 show an example of a throw-away tip of the present invention.

In FIG. 1 and FIG. 2, the throw-away tip 30 has a plate-like shape having a substantially triangular appearance, and its upper surface 3
A main cutting edge 32 is formed on each ridge line of the No. 1 and further a breaker groove 34 extending along the main cutting edge 32 is formed on the entire upper surface 31.

The breaker groove 34 has a first rake face 35 inclined at an angle θ ₁ from the main cutting edge 32 toward the lower surface side in a direction orthogonal to the main cutting edge 32, and a larger inclination from the first rake surface 35. A second rake face 36 inclined at the surface θ ₂ toward the lower surface side, a groove bottom curved face 37 that draws a concave cylindrical face in contact with the end portion of the second rake face 36, and the groove bottom curved face 3
In contact with the end portion of No. 7, the end portion is formed by a rising surface 38 reaching the upper surface 31.

The width B of the breaker groove 34 in the direction orthogonal to the main cutting edge 32 is ⅕ to ⅛ times the diameter D of the inscribed circle of the throw-away tip 30, and the groove bottom curved surface. The depth dimension H at 37 is B / 5 to B / 8, the width dimension of the first rake face 35 is B / 3 to B / 4, and the inclination angle θ ₁ of the first rake face 35 is 8 °. At ~ 20 °,
And the inclination angle θ ₂ of the second rake face 36 is the above θ ₁ + 8 °
It is set to ~ 12 °.

The reason for limiting the numerical values that define the shape of the throw-away tip as described above is as follows.

Width B If B is ⅕ or more of the diameter D of the inscribed circle of the throw-away tip, the range occupied by the breaker becomes large and the strength of the throw-away tip decreases, so that the breaker is formed over the entire circumference. I can't. Also, 1 /
When it is 8 or less, the braking action on chips becomes insufficient, and the range in which good chip discharging property can be exhibited becomes narrow.

Depth H When H is B / 5 or more, the breaker width becomes large under the condition that the rake angle is within a predetermined range, and the breaker width occupies most of the throw-away tip, resulting in a decrease in strength. The breaker cannot be formed all around the throw-away tip. Also, H is B / 8
When it is below, the braking action on the chips becomes insufficient, and the range in which good chip discharge performance can be exhibited becomes narrow.

Regarding the inclination angle θ1 of the first rake face, if θ ₁ is 8 ° or less, the sharpness becomes poor, and θ ₁
Is more than 20 °, the cutting edge strength becomes insufficient.

Regarding the point where the inclination angle θ ₂ of the second rake face is θ ₁ + 8 ° to 20 If the difference is 8 ° or less, the chips fall to the vicinity of the groove bottom curved surface 37 even in the case of heavy cutting, which may cause chip clogging. There is. Further, if a difference of 20 ° or more is provided, the chips cannot follow the angle change between the first rake face 35 and the second rake face 36, and the chips fall into the groove bottom curved surface 37 in the case of light cutting. It is difficult to curl smoothly because it is not possible.

According to the throw-away tip 30 configured as described above, the breaker groove 34 has the first and second rake faces 35,
Since 36 has been formed, as shown in FIG.
_Since the contact length with ₃ and W ₄ can be shortened, a large frictional force does not occur between the chips W ₃ and W ₄ . Therefore, it is possible to suppress the generation of cutting resistance and frictional heat, and to obtain a long tool life. Moreover, since the curved surface that sharply drops to the lower surface side of the conventional one is not formed between the first rake surface 35 and the groove bottom curved surface 37, the inclination angle θ ₁ of the first rake surface 35 is 8 °. ~ 20 °
And set the inclination angle θ ₂ of the second rake face 36 to the above θ
High cutting edge strength can be obtained by setting ₁ + 8 ° to 12 °.

Further, since the depth dimension H of the breaker groove 34 can be reduced by forming the second rake face 36, there is no possibility that chips will be clogged on the groove bottom curved surface 37, and the width dimension B of the breaker groove 34 is eventually determined. Can be made smaller. Therefore, by setting the width dimension B to 1/5 to 1/8 of the diameter D of the inscribed circle of the throw-away tip 30 and the depth dimension H to B / 5 to B / 8, respectively, The breaker groove 34 can be formed over the entire circumference of 31. For this reason, one throw-away tip 30 can be used in both left and right directions (right and left handedness), which makes handling convenient and extremely economical.

Further, the width dimension of the first rake face 35 is set to B / 3 to B /
4, the inclination angle θ ₁ is 8 ° to 20 °, and the inclination angle θ ₂ of the second rake face 36 is θ ₁ + 8 ° to 12 °.
By set, as in the case of light cutting shown by the chain line in FIG. 3, thin thickness chips W ₄ is first rake face 35
Then, it falls along the second rake surface 36 to the vicinity of the groove bottom curved surface 37 and is curled into an appropriate shape. Further, as shown by the solid line in FIG. 3 in the case of medium and heavy cutting, thick chips W ₅ thicknesses are curled into a suitable shape to collide directly rising surface 38 from the first rake face 35. Therefore, excellent chip discharging performance can be obtained in cutting under any cutting load.

Next, the throw-away tip according to the present invention, the throw-away tip described in the conventional example of FIG. 4 and FIG. 5, and the throw-away tip described in the conventional example of FIG. 7 and FIG. With respect to, the results of an experiment in which the generation state of chips is observed by changing the feed amount f and the cutting amount α will be described.

FIGS. 11 to 15 show the mode of chips generated when the feed amount f and the cutting amount α are changed. In the amount region where f is large and α is small, as shown in FIG. As extremely thin continuous chips are generated, and as f gradually decreases and α increases, as shown in FIG. 12, a spiral continuous chip with a narrow width, as shown in FIG. Thin width fragmented chips as shown, thick width fragmented chips as shown in FIG. 14,
Thick, continuous spiral chips are generated as shown in FIG. In this experiment, the case where the separated chips as shown in FIG. 13 or FIG. 14 is determined as the usable range, and the continuous chips as shown in FIG. 11, FIG. 12, or FIG. When it occurs, it is decided to be in the unusable range.

The judgment results based on the above experiment are summarized in FIG. In FIG. 16, the area indicated by the solid line is the machinable area according to the present application, the area indicated by the broken line is the machinable area by the throw-away tip of FIGS. 4 and 5, and the area indicated by the chain line is the 7th area. 8 and 9 show the machinable range by the throw-away tip.

As is clear from FIG. 16, by using the breaker having the shape of the present application, good chip discharging performance can be obtained over a wider range of feed and cutting than the conventional one, and the breaker groove that extends over the entire circumference of the throw-away tip can be obtained. Can be formed.

[Advantage of Device] As described above, the throw-away tip of the present invention is the first scoop in which the breaker groove of the throw-away tip is inclined from the main cutting edge toward the lower surface side in the direction orthogonal to the main cutting edge. A surface and a second rake surface inclined from the first rake surface toward the lower surface side with a larger inclination angle,
The breaker is formed by a groove bottom curved surface that draws a concave cylindrical surface in contact with the end of the second rake surface and a rising surface that contacts the end of the groove bottom curved surface and the end reaches the upper surface. The width dimension B of the groove in the direction orthogonal to the main cutting edge is (1/5) to (1) of the diameter of the inscribed circle of the throw-away tip.
/ 8) times and the depth dimension in the groove bottom curved surface is (B
/ 5) to (B / 8), the width dimension of the first rake surface is (B / 3) to (B / 4), and the inclination angle θ ₁ of the first rake surface is 8 ° to And the inclination angle θ ₂ of the second rake face is (θ ₁ + 8 ° to 12 °).
Is. Therefore, according to this throw-away tip,
The breaker groove can be formed over the entire circumference of the upper surface without lowering the cutting edge strength, and excellent chip discharging performance can be obtained in cutting under any cutting load.

In addition, by simply providing the breaker groove, it is possible to obtain a good chip discharging property without providing a convex portion on the nose portion even at a low cutting depth. Further, since there is no nose portion, clogging of chips does not occur even when the depth of cut is large. Furthermore, since the breaker may have a simple shape with only grooves, the die in the press molding process of the throw-away tip may have a simple shape, and the occurrence of defects such as chips in various processes such as molding and firing can be reduced. It also has the effect of being able to

[Brief description of drawings]

1 to 3 show an embodiment of a throw-away tip of the present invention. FIG. 1 is a plan view, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. Fig. 4 is a side sectional view showing a cutting state, Figs. 4 to 6 show a first example of a conventional throw-away tip, Fig. 4 is a plan view, and Fig. 5 is VV of Fig. 4. FIG. 6 is a side sectional view showing a cutting state, FIG. 7 and FIG. 8 show a second example of a conventional throw-away tip, and FIG. 7 is a plan view, FIG. Is a sectional view taken along the line VIII-VIII in FIG. 7, and FIGS. 9 and 10 show a third example of a conventional throw-away tip.
FIG. 9 is a plan view, FIG. 10 is a side sectional view showing a cutting state,
11 to 15 are perspective views showing the state of chips generated under different cutting conditions, and FIG. 16 is a table showing a comparison of the machinable ranges of the present application and the conventional example. 30 ... Throw-away tip, 31 ... Top surface, 32 ... Main cutting edge, 34 ... Breaker groove, 35 ... First rake surface, 36 ... Second rake surface, 37 ... Groove bottom curved surface, 38 ... … Rise surface, B …… breaker groove width dimension, H …… breaker groove depth dimension, D …… Inlay circle diameter of throw-away tip, θ ₁ , θ ₂ … Inclination angle.

Claims (1)

[Scope of utility model registration request] 1. A throw-away tip, which has a polygonal plate shape and has a breaker groove extending along the main cutting edge formed on an upper surface which is a rake surface with a main cutting edge formed on a ridge line portion, The breaker groove, a flat first rake surface inclined from the main cutting edge toward the lower surface side in a direction orthogonal to the main cutting edge, and to the lower surface side with a larger inclination angle from the first rake surface. A flat second rake surface that inclines toward the end, a groove bottom curved surface that draws a concave cylindrical surface smoothly at the end of this second rake surface, and a smooth continuation at the end of this groove bottom curved surface. The breaker groove has a width dimension B in the direction orthogonal to the main cutting edge of the diameter of the inscribed circle of the throw-away tip ( 1 /
5) to (1/8) times, the depth dimension in the groove bottom curved surface is (B / 5) to (B / 8), and the width dimension of the first rake face is (B / 3) to (B / 4) and
The first rake face has an inclination angle θ ₁ of 8 ° to 20 °, and the second rake face has an inclination angle θ ₂ of (θ ₁ +8).
A throw-away tip characterized in that the angle is 20 to 20 degrees.