JP3383543B2 - Cutting insert - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting insert which is detachably mounted on a tool body and used for cutting a metal material or the like. 2. Description of the Related Art Conventionally, STKM13A, SCM41
For processing of a sticky material such as 5, S15CK, SS400 or the like, which is difficult to process chips, a cutting insert having a nose portion formed with a breaker raised portion has been used. FIG. 7 shows a shape of a nose portion 21 of such a conventional cutting insert 20. As shown in FIG.
The distance A between the tip cutting edge 22 and the breaker ridge 23 is reduced, while the distance B between the breaker ridge 23 and the horizontal cutting edge 24 is gradually increased as the distance from the tip cutting edge 22 increases. there were. This cutting insert 20
Has focused on reducing the distance A between the tip cutting edge 22 and the breaker ridge 23 to deal with chip processing in a low-cut finishing area. FIG. 8 shows the shape of a nose portion 31 of another conventional cutting insert 30. As shown in FIG.
The distance A 'between the tip cutting edge 32 and the breaker ridge 33 is relatively large, while the breaker ridge 33
And the distance B 'between the cutting edge 34 and the horizontal cutting edge 34 was made smaller.
The main purpose of this cutting insert 30 is to reduce the distance B 'between the breaker ridge 33 and the horizontal cutting edge 34 to deal with chip processing in a medium-to-high feed medium and rough machining region. However, in the cutting insert 20 shown in FIG. 7, the tip cutting edge 22 and the breaker ridge 23
Chips are elongated by medium roughing, and the distance B between the breaker ridge 23 and the horizontal cutting edge 24 is equal to the tip cutting edge 22.
Although it was made to gradually increase as the distance from the center was increased, it was hard to say that the chip control in the roughing was excellent. In the cutting insert 30 shown in FIG.
Since the distance A 'between the tip cutting edge 32 and the breaker raised portion 33 is large, chips are removed by the medium roughing process.
However, the chip was curled to a small curl radius on the side wall of the breaker raised portion 33 disposed closer to the transverse cutting edge 34, so that the chip was easily broken.
In the chip processing of the finishing area, there was a problem that the curl radius of the chips was too large to be easily broken. Further, these cutting inserts 20, 30
In each case, the front ends of the breaker ridges 23 and 33 are arc-shaped when viewed from above, so that the chips are in point or line contact with the breaker ridges 23 and 33 during finishing, and the chip discharge direction is stable. In some cases, it was difficult to break. [0008] In view of the above problems of the prior art, the present invention provides:
It is an object of the present invention to provide a cutting insert having excellent chip disposal performance and long tool life not only in finishing but also in rough machining. In order to solve the above-mentioned problems, a cutting insert according to the present invention has a cutting edge formed at a ridge between a rake face and a flank, and a tip cutting edge at a tip of a nose portion. And a cutting insert having a transverse cutting edge continuous with the leading edge cutting edge, wherein the rake face has a breaker raised portion facing the leading edge cutting edge, and the nose portion tip extending from the transverse cutting edge to the inland portion has a concave shape. A two-stage breaker wall having an arc-shaped upper wall is formed, and the breaker protruding portion has a flat surface having a width of 0.02 to 0.08 mm at the front end of the breaker protruding portion, and a two-step breaker wall. Another flat surface facing the transverse cutting edge is formed in a portion adjacent to the tip end side end of the nose portion. In the insert of the present invention, even if the material is low in cutting depth, chips are formed on the front face of the tip of the breaker ridge facing the tip cutting edge having a flat surface with a width of 0.02 to 0.08 mm. The contact makes the discharge direction stable, and chips are easily broken. When the feed is small during the medium roughing, the chip hits the lower wall of the two-step breaker wall formed along the horizontal cutting edge and curls, and when the feed is large, the two-step breaker is used. The chips once decelerated on the lower wall of the breaker wall hit the upper wall and curl. According to the two-step breaker wall having a concave arc-shaped upper wall formed at the tip of the nose, the chips are also bent in the width direction, so that the chips are easily broken and the breaker protruding portion has By forming another flat surface facing the transverse cutting edge in the part adjacent to the stepped breaker wall,
Stabilizes the discharge direction during low and medium feed processing, and makes chips easy to break. [0013] Therefore, according to the insert of the present invention, finishing with a low depth of cut by one insert can be achieved.
In medium and high depth of cut machining, chips are stably processed, so that the tool life is long and cutting can be performed under a wide range of cutting conditions without replacement of inserts. An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 4 show a cutting insert 1 according to the present embodiment. The overall shape of the cutting insert 1 is such that a cutting edge 4 is formed on a ridge between a rake face 2 and a flank 3 as shown in FIG. A pair of nose portions 5 and 5 arranged in a rhombic plate shape and having an arc-shaped tip cutting edge 6 at the tip of each of the nose portions 5 and 5, and a tip cutting edge 6 on both sides of the tip cutting edge 6. A continuous horizontal cutting edge 7 is formed. As shown in a partially enlarged view of FIG. 2, the nose portion 5 is formed with a breaker ridge 10 which faces the tip cutting edge 6 and protrudes from a rake face 8 thereof. A flat surface 14 is formed at the front of the front end. In addition, the inland area 1
7, a two-step breaker wall 11 is formed. Further, the rake angle α ° of the rake face 8 of the tip cutting edge 6 shown in the vertical sectional view of FIG. 3 is as large as 15 ° to 20 °, while the horizontal cutting edge shown in the vertical sectional view of FIG. The minimum rake angle β ° of the rake face 9 is as small as 10 ° or less. The rake angle β ° of the rake face 9 of the horizontal cutting edge 7 gradually decreases as the distance from the tip cutting edge 6 increases, and the cutting edge strength of the horizontal cutting edge 7 increases. In the cutting insert 1 having the above-described configuration, the rake angle α ° of the rake face 8 of the tip cutting edge 6 is increased to 15 ° to 20 ° because the chip is cut even with a sticky material at the time of low cutting. The reason why the flat surface 14 is used for the front end of the breaker ridge 10 facing the front cutting edge 6 is that the chip is entangled by increasing the contact area with the chip and stabilizing the discharge direction. This is to prevent the swarf from breaking and make the chips easily break. Therefore, according to the cutting insert 1 described above, the chip is reliably curled even with a sticky material at the time of cutting at a low depth of cut, and further, the chip processing direction is stabilized and the chip is easily broken, so that good chip processing can be performed. If the rake angle α ° is less than 15 °, the curl radius of the chips may be large and the chips may be difficult to break. On the other hand, if the rake angle exceeds 20 °, the strength of the cutting edge may be reduced. There is. In addition, the flat surface 1
4 is preferably 0.02 to 0.08 mm. When the width w is less than 0.02 mm,
The effect of stabilizing the chip discharge direction is small.
If it exceeds 08 mm, there is a possibility that the contact area of the chips becomes larger than necessary and the cutting resistance becomes excessive. Next, the formation of the two-step breaker wall 11 along the horizontal cutting edge 7 is mainly attributable to the formation of the two-step breaker wall 11 because the chip is relatively easily curled when the feed is small due to medium roughing. The chips are curled by the short lower wall 12, thereby reducing the cutting resistance. On the other hand, when the feed is large, the chips are relatively hard to curl. Therefore, a large workable area is realized. The reason why the minimum value of the rake angle β ° of the rake face 9 of the horizontal cutting edge 7 is set to 10 ° or less is to keep the strength of the horizontal cutting edge 7 large and prevent the curl radius of the chips from becoming excessive. And the minimum value of the rake angle β ° is 10
When the angle is larger than °, the transverse cutting edge 7 may be insufficient in strength. The height h of the lower wall 12 of the lower wall 12 and the upper wall 13 of the two-step breaker wall 11 is set to 0.1.
Preferably, it is in the range of 1 to 0.5 mm. If the height h exceeds 0.5 mm, the cutting resistance may be excessively large. On the other hand, if the height h is less than 0.1 mm, the curl radius of the chips may be excessively large without the chips being caught on the lower wall 12. is there. The two-step breaker wall 11
As shown in FIG. 2, the upper wall 13 may have an arc shape with a concave center at the transverse cutting edge 7. According to such a two-stage breaker wall 11, the chip discharge direction is stabilized, and the chips are also bent in the width direction, so that the chips are easily broken. By the way, in the embodiment shown in FIG.
The breaker ridge 10 has a flat surface 1
In addition to the flat surface 15, a flat surface 15 is also formed in a portion adjacent to the two-step breaker wall 11, which has an effect of stabilizing the discharge direction at the time of low to medium feed machining and making chips easy to break. are doing. Further, the rake angle β ° of the rake face 9 of the transverse cutting edge 7 is not limited to a form in which the rake angle becomes gradually smaller as the distance from the tip cutting edge 6 increases, but about β = 10 ° from the tip cutting edge 6 to the vicinity thereof. The angle of the waveform may be increased to β = 13 ° at a position a little further away, and may gradually decrease thereafter. In addition, the chip discharge direction is stabilized, and the chip is also bent in the width direction, so that the chip is easily broken. The embodiment of the present invention has been described above.
It is needless to say that the present invention is not limited to the above-described embodiment, but can be in any form without departing from the object of the invention. Next, an experimental example using the cutting insert 1 of the present invention will be described. Experimental Example 1 A chip disposal test was performed under the following conditions using the above cutting insert 1 using a TN60 cermet material manufactured by Kyocera Corporation as a material of the insert. (Rake angle α ° = 15
°, rake angle β ° = 15 ° to 5 °, height h of lower wall 12 =
0.2 mm, width w of the flat surface 14 = 0.05 mm) Cutting conditions Work material: SCM415 (inner diameter φ30 to 50) Circumferential speed V = 200 m / min Feed f = 0.05, 0.1, 0.15 0.2mm / r
ev Depth of cut d = 0.5, 0.7, 1.0, 2.0 mm Wet holder: SCLPL2520B-09 positive byte Table 1 shows the results of this chip disposal test and its criteria. [Table 1] As is apparent from FIG. 1, the insert of the present invention exhibited very excellent chip handling performance as a whole, though there were some defects in the area of feed f = 0.05 mm. As a comparative example, a prior art insert [CPMT090304SQ (UP35) shown in FIG.
N)] and a prior art insert [CCMT09T304-UF (GC40
25)] are shown in Tables 2 and 3, respectively. [Table 2] [Table 3] When these results are compared with the results of the product of the present invention shown in Table 1 above, it is apparent that the chip processing performance of the product of the present invention is remarkably excellent. EXPERIMENTAL EXAMPLE 2 Under the cutting conditions of Experimental Example 1, the work material was SCM415.
(Inner diameter φ50 through hole), and the same test was performed. Table 4 shows the results. [Table 4] As is clear from Table 4, the insert of the present invention has a slight defect in a part of the area where the feed f is 0.15 and 0.1 mm, but has an extremely excellent chip treating ability as a whole. Indicated. As a comparative example, a conventional insert [CPMT090304SQ (UP35) shown in FIG.
N)] and the same test results are shown in Table 5. [Table 5] When this result is compared with the results of the product of the present invention shown in Table 4 above, it is apparent that the chip processing performance of the product of the present invention is remarkably excellent. Experimental Example 3 A chip disposal test was performed under the following conditions using the above-mentioned cutting insert using a TN60 cermet material manufactured by Kyocera Corporation as a material for the insert. In this test, an L-shaped rotor (SPHE material), which is difficult to process chips, was used as a work material. Cutting conditions Work material: L-shaped rotor (SPHE material) Circumferential speed V = 250 m / min Feed f = 0.1, 0.15, 0.2 mm / rev Depth of cut d = 0.5, 0.7, 1.0 mm wet holder: SCLPL2520B The results of the chip processing test are shown in Table 6, and the chip map is shown in FIG. [Table 6] As is clear from Table 6 and FIG. 5, the insert of the present invention exhibited some excellent chip handling performance as a whole, though there were some defects in the region of feed f = 0.1 mm. As a comparative example, a conventional insert [CPMT090304SQ (UP35) shown in FIG.
N)] is shown in Table 7 and a chip map is shown in FIG. [Table 7] As is clear from Table 7 and FIG. 6, the cutting insert of the prior art described above was not suitable for processing SPHE materials. In contrast, the product of the present invention has the SP
Excellent chip treatment performance was also demonstrated for the HE material. As described above, the cutting insert of the present invention has a width of 0.02
The chip is in surface contact with the front face of the tip of the breaker ridge facing the tip cutting edge having a flat face of 0.08 mm, so that the discharge direction is stable and the chip is easily broken. At the time of medium roughing, when the feed is small, the chip hits the lower wall of the two-step breaker wall formed along the horizontal cutting edge and curls.
Chips once decelerated by the lower wall of the stepped breaker wall hit the upper wall and curl. According to the two-step breaker wall having a concave arc-shaped upper wall formed at the tip of the nose, the chips are also bent in the width direction, so that the chips are easily broken, and the two-step breaker wall at the breaker ridge is provided. By forming another flat surface facing the transverse cutting edge in a portion adjacent to the end of the nose tip side, the discharge direction at the time of low-medium feed processing is stabilized, and chips are easily broken. Therefore, in both the finishing with low cutting depth and the medium and high cutting depth with one insert, the chips are stably processed, so that the tool life is long and the cutting conditions are wide without replacing the insert. Cutting below is possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a cutting insert according to the present invention. FIG. 2 is an enlarged view of a region L in FIG. FIG. 3 is a sectional view taken along line XX of FIG. 2; FIG. 4 is a sectional view taken along line YY of FIG. 2; FIG. 5 is a chip map showing the results of Experimental Example 3. FIG. 6 is a chip map showing a result of a comparative example with respect to the experimental example 3. FIG. 7 is a plan view of a cutting nose portion of a conventional cutting insert, (a) is a top view, and (b) is a side view. FIG. 8 is a plan view of a cutting nose portion of another conventional cutting insert, (a) is a top view, and (b) is a side view. [Description of Signs] 1 cutting insert 2 rake face 3 flank face 4 cutting edge 5 nose section 6 tip cutting edge 7 horizontal cutting edge 8,9 rake face α, β rake angle 10 breaker ridge 14,15 flat face 16 Blade area 17 Inland part 11 Two-step breaker wall 12 Lower wall 13 Upper wall h Height w Width

Claims (1)

(57) [Claims 1] A cutting edge is formed at a ridge between a rake face and a flank, and a tip cutting edge at a tip of a nose portion and a horizontal cutting edge continuous with the tip cutting edge. A cutting insert comprising: a two-stage breaker having a breaker ridge on the rake face facing the tip cutting edge, and an upper wall forming a concave arc at the tip of the nose from the transverse cutting edge to the inland portion. And a flat surface having a width of 0.02 to 0.08 mm at the front end of the breaker ridge and a portion adjacent to the end of the nose portion at the front end of the two-stage breaker wall. A cutting insert characterized by forming another flat surface facing the transverse cutting edge.