WO2015037447A1

WO2015037447A1 - Cutting insert

Info

Publication number: WO2015037447A1
Application number: PCT/JP2014/072517
Authority: WO
Inventors: 奉章福山
Original assignee: 住友電工ハードメタル株式会社
Priority date: 2013-09-12
Filing date: 2014-08-28
Publication date: 2015-03-19
Also published as: JP2015054371A

Abstract

Provided is a cutting insert equipped with a corner cutting edge of a nose R section, straight cutting edges respectively continuous with the two ends of the corner cutting edge, a rake face provided along the cutting edges and having a positive rake angle, and a breaker projection, wherein: the rake angle at the nose R section is gradually reduced going toward a terminus of the nose R section from a bisecting position thereof; a breaker width at the nose R section is set to 0.5 to 0.6 mm; and, on a bisector of the corner angle of the nose R section, a breaker wall of the breaker projection is positioned more to the corner cutting edge side than a position at which lines orthogonal to each portion of the corner cutting edge converge.

Description

Cutting insert

This invention relates to a cutting insert that exhibits excellent chip disposal performance in finishing.

Cutting inserts used for finishing metal are required to have excellent chip disposal performance. For this purpose, a chip breaker provided with a chip breaker is used.

As the chip breaker, for example, the following Patent Document 1 is a strip-shaped climbing wall on the rake face of the nose R portion and located near both ends of the nose R portion and extending from the ridge to the boss surface (central land portion). A combination of small protrusions (ridges) is provided.

Further, in Patent Document 2 below, a breaker protrusion extending in the direction of a bisector of a corner angle and a first chip breaker groove is provided on a rake face of a nose R portion, and further, a rake angle of the first chip breaker groove is set. The rake angle of the second chip breaker groove along the straight cutting edge (side) is sequentially changed within a range smaller than the rake angle of the first chip breaker groove.

In addition to the above, as disclosed in Patent Document 3 below, a breaker wall whose height changes in two steps on the rake face of the nose R portion is also known.

Japanese Utility Model Publication No. 5-51508 Japanese Utility Model Publication 2-53304 JP 2006-110666 A

In the finishing process, chips are generated because the cutting conditions are low and the feed is low. Therefore, a technique is adopted in which chips are forcibly curled and divided by a chip breaker.

However, in the chip treatment using a general chip breaker, even if the chip contacts the breaker wall, it is difficult to be separated. This tendency is particularly increased in the processing of metals that are difficult to break, such as mild steel and general steel.

The conventional cutting inserts disclosed in the above-mentioned Patent Documents 1 to 3 etc. perform cutting of chips mainly depending on breaker protrusions (breaker walls). The nose R portion has a constant rake angle, and therefore, the rake face of the nose R portion only provides a simple curling force to the generated chips.

Chips are likely to collide with the breaker protrusion by curling, but chip breaking with a mechanism that simply curls the chip and collides with the breaker protrusion is the impact force of the chip against the breaker protrusion when the set value of the breaker width is too large. There is not enough to make chips difficult to break.

Chips discharged without being divided are difficult to control in the outflow direction and are likely to damage the work surface of the work material.

と Moreover, if the set value of the breaker width is too small, chip clogging occurs, the processing stability is impaired, and the surface properties of the processed surface of the work material deteriorate.

Therefore, an object of the present invention is to devise the shape of the chip breaker provided on the rake face so that excellent chip disposal performance can be exhibited in the finishing process.

In order to solve the above-mentioned problems, in the present invention, the corner cutting edge of the nose R portion, the straight cutting edges respectively connected to both ends of the corner cutting edge, the rake face provided along each cutting edge, and the breaker protrusion The rake angle in the nose R portion is gradually decreased from the bisected position of the nose R portion toward the end portion of the corner cutting edge, and the breaker width of the nose R portion is 0.5 mm. Set to ~ 0.6 mm, the corner cutting edge of the breaker wall of the breaker projection on the bisector of the corner angle of the nose R section is more than the position where the lines perpendicular to each part of the corner cutting edge gather in one place A cutting insert positioned on the side is provided.

Note that the bisecting position of the nose R portion means the bisecting position of the corner angle of the nose R portion. Moreover, the terminal part of a corner cutting edge means the boundary part of a corner cutting edge and a linear cutting edge.

切削 The cutting insert of the present invention configured as described above has improved chip disposal performance as compared with a cutting insert having no change in the rake angle.

It is a top view which shows an example of the cutting insert of this invention. FIG. 2 is a cross-sectional view taken along line XX of FIG. It is a perspective view of the cutting insert of FIG. It is an enlarged plan view of the nose R part of the cutting insert of FIG. It is an expansion perspective view of the nose R part of the cutting insert of FIG. FIG. 5 is a sectional view taken along line YY in FIG. 4. FIG. 5 is a cross-sectional view taken along the line ZZ in FIG. 4. It is a top view which shows the chip breaker shape of the sample V used for performance comparison. FIG. 3 is a diagram showing chips generated by samples I to V in the performance comparison test of Example 1. It is a figure which shows the chip | tip produced | generated by the cutting test of Example 2 by the samples I and V. FIG. It is a figure which shows the chip | tip produced | generated by the cutting test of Example 3 by the samples I and V. FIG. It is a figure which shows the chip | tip produced | generated by the cutting test of Example 4 by the samples I and V. FIG. It is a figure which shows the chip | tip produced | generated by the cutting test of Example 5 by the materials I and V. FIG. It is a figure which shows the measurement data of the surface roughness of the process surface in the cutting test of Example 6 by sample I- ₁ . It is a figure which shows the measurement data of the surface roughness of the processed surface in the cutting test of Example 6 by sample V- ₁ .

Hereinafter, an embodiment of a cutting insert according to the present invention will be described with reference to FIGS. 1 to 7 of the accompanying drawings. The illustrated cutting insert 1 is obtained by applying the present invention to a triangular insert.

The cutting insert 1 shown in the drawing has an upper surface 2 and a lower surface 3, a side surface 4 along each side of the upper and lower surfaces, and a cutting edge 5 formed by a ridge line at a position where the upper surface 2 and the side surface 4 intersect. Moreover, it has the attachment hole 6 penetrated in the center part of the up-and-down surface. The attachment hole 6 is not essential.

7 is a nose radius portion created at the corner between two adjacent sides. The cutting edge 5 is formed by a ridge line at a position where the upper surface 2 and the side surface 4 serving as a flank face intersect, and the corner cutting edge 5a of the nose R portion and the straight cutting that continues to both ends of the corner cutting edge, respectively. It consists of a blade 5b.

A region along the corner cutting edge 5 a and the straight cutting edge 5 b on the upper surface 2 is a rake face 8. The rake face 8 is given a positive rake angle, and the breaker groove 9 along the cutting edge is created by the positive rake angle.

Further, a breaker protrusion 10 is provided on the rake face of the nose R portion. The breaker protrusion 10 shown in FIG. 4 is a protrusion that forms a semi-ellipse when viewed from the rake face. The major axis of the ellipse is arranged so as to be on the bisector of the corner angle of the nose R portion.

The breaker projection 10 has a breaker wall 10 a rising from the bottom of the breaker groove 9. On the bisector of the corner angle of the nose R portion, the breaker wall 10a has a portion where chips flowing out from each part of the corner cutting edge concentrate (from each part of the corner cutting edge 5a) in the machining using only the corner cutting edge 5a. The discharged chips flow in a direction perpendicular to each part of the corner cutting edge 5a and are arranged closer to the corner cutting edge 5a than in FIG. 4 (concentrated at a point P where a line perpendicular to each part of the corner cutting edge 5a intersects). ing. In FIG. 6, the breaker wall 10 a is a straight portion rising from the groove bottom of the breaker groove 9.

ほか In addition to this, the amount d of centering down shown in FIG. 6 of the corner cutting edge 5a is set to 0.20 mm. By setting the center downward, the chips easily collide with the breaker protrusion 10. If the centering amount d is 0.15 mm or less, the chip breaking property of low cutting and low feeding is poor, and if it is 0.25 mm or more, chip clogging is likely to occur, so the lower limit is 0.15 mm and the upper limit is 0. .25mm is recommended.

Note that the breaker protrusion 10 shown in the drawing has a portion of the surface of the ellipsoidal sphere removed so that the top of the head is flat.

The rake angle of the rake face 8 is set such that the rake angle α1 (see FIG. 6) in the bisected section of the nose R portion 7 is 20 °, and the rake angle α2 (see FIG. 7) of the straight cutting edge 5b is 10 °. ing.

The rake angle in the heel nose R portion gradually decreases from the bisecting position of the nose R portion 7 toward the end of the nose R portion 7 (the boundary point between the corner cutting edge 5a and the straight cutting edge 5b).

言う The term “gradual decrease” as used herein includes a state in which the rake angle is changed stepwise. The nose R is usually set to about 0.2 mm to 1.2 mm. In that narrow region, the shape of the rake face whose rake angle has changed stepwise and the shape of the rake face that has changed smoothly are similar, and it is unlikely that a large difference in function will occur.

切削 For the illustrated cutting insert, the rake angle in the nose R portion 7 is 20 ° at the bisecting position of the nose R portion and 10 ° at the end position of the nose R portion.

The rake angle α1 at the bisecting position of the heel nose R portion 7 is preferably set in a range of 15 ° to 25 °, and for the illustrated tool, the rake angle α1 is 20 °. Further, the rake angle α2 of the end of the nose R portion 7 and the straight cutting edge portion 5b is preferably in the range of 5 ° to 15 °, and the rake angle α2 of the illustrated tool is 10 °.

The angle difference between the rake angles α1 and α2 is preferably 5 ° to 10 °.

It is preferable that the breaker protrusion 10 has an inclination angle β of the breaker wall 10a of about 25 ° to 50 ° because an effective braking strain is given to chips. That of the illustrated tool is set to 45 °.

Further, the illustrated tool has a breaker width W of the corner cutting edge 5a (a width to a position where a line extending the breaker wall 10a from the corner cutting edge 5a and a line extending the top surface of the breaker protrusion 10 intersect. FIG. 6). ) Is set to 0.6 mm.

Nose when considering the prevention of chip clogging and good splitting performance when used under the machining conditions of notch ap = 0.1mm to 0.8mm and feed f = 0.03mm / rev to 0.20mm / rev The breaker width W of the R part is suitably 0.5 mm to 0.6 mm.

Although this breaker width W is also set to 0.5 mm or less, the cutting speed VC = 100 m / min or more and feed f = 0.05 mm / rev to 0.20 mm / rev. Chip clogging occurs during cutting.

Therefore, it was considered to set the breaker width W to 0.5 mm to 0.6 mm. However, the breaker width was too wide in the processing under the condition of feed f = 0.10 mm / rev to 0.20 mm / rev. The function of the breaker protrusion is not fully demonstrated.

Even in that situation, the present inventors have completed the present invention by finding that chips can be treated well by increasing the dependency of breakage on the breaker groove.

In addition, the chip breaker of the illustrated cutting insert is configured by combining the breaker groove 9 and the breaker protrusion 10. The breaker protrusion 10 is formed by cutting the top of the center of the insert toward the corner of the central land portion 11 that is higher than the breaker protrusion 10, but the entire area of the top of the head is at the same height as the central land portion 11. It may be one that has been placed.

切削 In the cutting insert according to the embodiment configured as described above, by changing the rake angle in the nose R portion 7, the generated chips are curved in a concave shape in front view, and the apparent chip thickness is increased.

In addition, complex distortion is applied to the chip whose apparent chip thickness has increased due to the change in the rake angle, and the chip collides with the breaker wall, making it easier to break and improving the cutting performance. Made.

Some conventional cutting inserts have improved cutting performance by applying a complex distortion that increases the apparent thickness of the chip by colliding the chip with a breaker protrusion with a special shape. However, from the viewpoint of preventing chip clogging, it is difficult to impart complex distortion to the chips by the breaker protrusions when the breaker width is increased as described above.

切削 The cutting insert of the present invention can increase the apparent chip thickness by changing the rake angle of the corner R portion, and can give a complicated strain that makes the chip easily break.

-Example 1-
The effect of the size and angle difference between the rake angle α1 at the bisecting position of the nose R portion 7 and the rake angle α2 at the end of the nose R portion 7 on the chip disposal performance was examined. Table 1 shows the rake angle size and angle difference of the cutting inserts (both materials: cemented carbide) used in the evaluation test.

試料 Samples I-IV in Table 1 meet the requirements of this invention. Sample V is a commercially available cutting insert for finishing.

8 shows the shape of the chip breaker of Sample V.

評価 Evaluation of the chip treatment performance of these samples I to V was carried out by carrying out the inner diameter machining of the work material: S45C. The inner diameter of the machining hole is φ100 mm, and the cutting conditions are cutting speed VC = 200 m / min, feed f = 0.10 mm / rev, and cutting ap = 0.2 mm.

Fig. 9 shows the chips produced in this evaluation test together with the sample number. As can be seen from FIG. 9, all the chips generated by the processing using the samples I to IV are finely divided.

On the other hand, the chips generated by processing with the sample V are relatively long.

-Example 2-
The sample I and the sample V (both model number: TPMT110304, material: cermet T1500A) were subjected to a comparison test of chip disposal performance by changing feed and cutting.

The wrinkle test condition is an inner diameter machining of a work material: S45C, φ100 mm. The cutting speed VC was 200 m / min.

切 Chips generated in this test are shown in FIG. From FIG. 10, it can be seen that the sample I is superior to the sample V in the combination of the feed f = 0.05 mm / rev to 0.10 mm / rev and the cutting ap = 0.1 mm to 0.2 mm. Recognize.

-Example 3-
The sample I and the sample V (both model number: TPMT110308, material: cermet T1500A) were subjected to a comparative test of chip disposal performance by changing feeding and cutting.

Work material: S45C, φ30mm outer diameter machining. The cutting speed VC was 200 m / min.

切 Chips generated in this test are shown in FIG. From FIG. 11, it can be seen that Sample I is superior to Chip V in the combination of feed f = 0.08 mm / rev to 0.12 mm / rev and incision ap = 0.2 mm to 0.3 mm compared to Sample V. .

-Example 4-
The sample I and sample V (both model number: DCMT11T304, material: cermet T1500A) were subjected to a comparative test of chip disposal performance by changing feed and cutting.

切 Chips generated in this test are shown in FIG. From FIG. 12, it can be seen that Sample I is superior to Chip V in the combination of feed f = 0.08 mm / rev to 0.12 mm / rev and incision ap = 0.2 mm to 0.3 mm compared to Sample V. .

-Example 5
The sample I and the sample V (both model number: CPMT090304, material: cermet T1500A) were subjected to a comparative test of chip disposal performance by changing feeding and cutting.

-Example 6-
Using the sample I- ₁ having the same specification as the sample I and the sample V- _{1 having the} same specification as the sample V (both are model number: TPMT110304, material: cermet T1500A), cutting is performed under the following conditions, The roughness was examined.

-Cutting conditions-
Work material: Bar material with SCM415, outer diameter φ80 mm. Outside diameter machining. Cutting speed VC = 100 m / min, feed f = 0.10 mm / rev, cutting ap = 0.2 mm.

14A and 14B show measurement data of the surface roughness of the processed surface obtained in this test. As can be seen from the measurement data, the sample I- ₁ is superior in surface roughness of the processed surface compared to the sample V- ₁ .
This is because the chip is processed better than the sample V- ₁ and the processing state is stabilized.

It can be seen that Sample I- ₁ is more glossy than the processed surface of Sample V- _1, and is excellent in surface roughness of the processed surface even by visual inspection.

Of course, the application object of the present invention is not limited to a triangular cutting insert. The effects of the invention can be achieved even when applied to other shapes, particularly diamond-shaped or parallelogram-shaped cutting inserts having a nose radius portion of an acute corner.

DESCRIPTION OF SYMBOLS 1 Cutting insert 2 Upper surface 3 Lower surface 4 Side surface 5 Cutting edge 5a Corner cutting edge 5b Straight cutting edge 6 Mounting hole 7 Nose R part 8 Rake face 9 Breaker groove 10 Breaker protrusion 10a Breaker wall 11 Central land part α1 Nose R part 2 etc. Rake angle α2 in the cross section Rake angle P of the straight cutting edge portion I to V, I ₋₁ , V ₋₁ sample where chips are concentrated

Claims

A cutting insert provided with a corner cutting edge of the nose R portion, a linear cutting edge connected to each end of the corner cutting edge, a rake face having a positive rake angle provided along each cutting edge, and a breaker protrusion. Then, the rake angle in the nose R portion is gradually decreased from the bisecting position of the nose R portion toward the end of the nose R portion, and the breaker width in the nose R portion is further reduced to 0.5 mm to 0.6 mm. And the breaker wall of the breaker projection on the bisector of the corner angle of the nose R portion is positioned closer to the corner cutting edge than the position where the lines perpendicular to each part of the corner cutting edge are gathered in one place. Cutting insert.
The rake angle at the bisecting position of the nose R portion is set in the range of 15 ° to 25 °, the rake angle at the end of the corner cutting edge is set in the range of 5 ° to 15 °, and the nose R portion The cutting insert according to claim 1, wherein the angle difference between the rake angle at the bisecting position and the rake angle at the end of the corner cutting edge is set to 5 ° to 10 °.
The cutting insert according to claim 1 or 2, wherein an inclination angle of the breaker wall is set to 25 ° to 50 °.
The cutting insert according to any one of claims 1 to 3, wherein the corner cutting edge is a core-lowering cutting edge.