JP2002103107A - Throwaway tip for precision working - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a throwaway tip capable of heightening sharpness and chip treatment in precision working, in particular, super-precision working of a hard-to-cut material, and realizing consistent and excellent working. SOLUTION: A breaker groove 6 has rake angles α1 and α2 in the direction of bisector of a nose round part 5 in plane view and in the direction orthogonal to the direction of the bisector, respectively, the rake angles α1 and α2 are in a range of 8 to 30 deg., and the distance d from a tip of the nose round part 5 to a riser to a breaker projection 7 is within a range of 0.1 to 0.4 mm in the direction of the bisector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indexable insert for precision machining having a breaker groove for chip processing and a breaker projection on a rake face, and particularly to ultra-precision machining such as HDD (hard disk drive) part machining. A technology effective for improving the chip disposal performance.

[0002]

2. Description of the Related Art A nose radius portion used for ultra-precision machining such as outer diameter machining of an HDD rotating shaft has a size of 0.4 mm or less (a radius of curvature of the nose radius). 7 to 10). This tip 20 has a cutting edge 21
A breaker groove 22 is formed along the entire circumference along the axis, and has a rake angle of 5 ° or less in a bisector direction of the nose R portion 23 and a direction orthogonal thereto, and a nose R portion in the breaker groove 22. A breaker projection 24 which rises from a position about 0.6 mm apart from the tip of the tip 23 in the bisector direction.
It was equipped with.

As another conventional chip, there has been one shown in FIGS. This chip 30
Has a large rake angle in the bisector direction of the nose R portion 31, while a rake angle in a direction perpendicular to the bisector direction is formed along the cutting edge 32 excluding the nose R portion 31. ,
The central portion is a flat surface 33.

[0004]

With the dramatic improvement in the performance of personal computers in recent years, the requirements for processing accuracy of components such as HDD rotating shafts have become strict. For example, the outer diameter of the HDD rotating shaft has a very strict requirement for processing accuracy. However, in order to improve the durability of the members for the HDD rotating shaft, stainless steel, which is a difficult-to-cut material, has come to be used instead of the conventional aluminum material.

[0005] That is, in the conventional insert shown in FIGS. 7 to 10, if an attempt is made to finish with a very small notch of 0.1 mm or less, the cutting edge of the insert does not bite into the work material.
As a result, the work surface may be roughened, or the chip discharge direction may not be stable, and the chips may be entangled and discharged, and may enter the work material and roughen the work surface. there were. The reason why the cutting edge of the tip does not bite into the work material is that the rake angle of the nose portion is small. Further, it is considered that the reason why the chip discharge direction is unstable is that the position of the breaker projection is too far from the tip of the nose.

In addition, the conventional chips shown in FIGS. 11 to 14 have no breaker projections, so that chips tend to extend for a long time, and there is a risk of problems such as being entangled with a work material.

[0007]

In order to solve the problems of the prior art, a chip according to the present invention is a polygon having a plane as a rake face, a bottom face and a side face as a flank face. A cutting edge is formed at an intersection ridge portion between the rake face and the flank face of the plate-like body, and a nose R portion of 0.4 mm or less formed at the intersection of two adjacent cutting edges is provided. A precision machining indexable insert having a breaker projection protruding toward the nose R portion in a breaker groove formed in the rake face inside the nose R portion, wherein the breaker groove is formed in a plan view. The nose R portion has a bisector direction and a rake angle α1, α2 in a direction perpendicular to the bisector direction, and the rake angles α1, α2 are in the range of 8 ° to 30 °. Nose R in bisector direction Distance d from the tip to the rising of the breaker projection is characterized in that in the range of 0.1 to 0.4 mm.

According to this configuration, the biting of the cutting blade into the work material is ensured, and the chip is hardly extended, so that the chip processing can be stabilized.

The chip according to claim 2 is characterized in that the tip of the breaker projection has a flat surface.

[0010] With this configuration, even if the entering direction of the chips is slightly changed, the chip discharging direction is not largely changed, so that the chip processing can be extremely stabilized.

The chip according to a fifth aspect of the present invention is further characterized in that the breaker surface further includes a raised portion which is lower than the breaker projection and is continuous with the breaker projection in the bisector direction. .

According to this configuration, chips that are going to extend in the direction crossing the front of the breaker projection from the direction greatly inclined with respect to the bisector of the nose R portion are guided by the protrusion to the breaker projection, and thus are surely. Can be curled.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a chip according to the present invention will be described below with reference to FIGS.

In these figures, reference numeral 2 is a rake face, 3 is a flank, 4 is a cutting edge, 5 is a nose R portion, 6 is a breaker groove, 7
Indicates a breaker projection.

The chip 1 of the present embodiment has a substantially rhombic plate shape in plan view, and has a plane defined as a rake face 2 and side faces and a bottom defined as a flank 3, and the rake face 2 and the flank 3 are provided. The cutting edge 4 is formed at the intersection ridge line portion. In addition, two adjacent
A nose R portion 5 formed at the intersection of the two cutting edges 4 and having a nose radius of curvature of 0.4 mm or less (nose radius of curvature) is provided, and a breaker groove 6 is formed in the rake face 2 inside the nose R portion 5. Is provided. Further, a breaker projection 7 is formed in the breaker groove 6. The inside of the breaker projection 7 is a land portion 8, and a mounting hole 10 is provided in the center of the land portion 8 for inserting a fixing bolt that passes from the rake face 2 to a bottom surface that is a seating surface 9. .

As shown in FIGS. 3 to 6, the breaker groove 6 has a rake angle α in a bisecting direction of the nose R portion 5 in a plan view and in a direction orthogonal to the bisecting direction.
1, α2, and α1, α2 are in the range of 8 ° to 30 °.

If the rake angles α1 and α2 are less than 8 °, the finished surface tends to have a large roughness, while
When the angle exceeds °, the edge strength tends to decrease and the edge chipping tends to occur. Note that the rake angles α1, α2
Both need to be within the above range, even in ultra-precision machining, because the direction of chip entry changes during machining,
This is in order to sufficiently cope with this change. For this purpose, along the cutting edge 4, in the direction perpendicular to the cutting edge 4, 8 ° to 3 °
Preferably, a rake angle of 0 ° is formed.

As shown in FIG. 5, the breaker groove 6 has a distance d from the tip of the nose R portion 5 to the rising of the breaker projection 7 in the bisector direction of 0.1 to 0.1 mm.
It is in the range of 4 mm.

Although it is very difficult in manufacturing to make the distance d up to the rise of the breaker projection 7 less than 0.1 mm, even if it is made in this way, the function of the breaker groove 6 cannot be exerted. It is considered that the chip processing becomes unstable due to the entanglement of the chips. On the other hand, if the distance d is 0.
If it exceeds 4 mm, the chips may be entangled with each other and the chip processing may become unstable.

The breaker projection 7 preferably has a flat surface at the tip. Thereby, even if the entering direction of the chips is slightly changed, the chip discharging direction is not greatly changed, so that the chip processing can be extremely stabilized.

In this embodiment, as shown in FIG. 3, the breaker projection 7 has two flat surfaces 71, 71 arranged in parallel at the tip or a single flat surface formed at the tip of the breaker projection 7. It is. When the two planes 71 and 71 are arranged in parallel, it is preferable that the angle formed by the two planes in a plan view is in a range of 90 ° or more and less than 180 °.

If this angle is less than 90 ° or 180
When the temperature exceeds °, the swarf may be entangled due to insufficient chip treatment.

The flat surfaces 71, 71 may be provided at any height at which chips mainly collide. In this embodiment,
Flat surfaces 71, 7 are provided at substantially intermediate portions in the height direction of the breaker projections 7.
1 are formed.

The inclination angles of the side portions 72, 72 adjacent to the tip of the breaker projection 7 are steeper below the upper end. This is effective to prevent the skirt of the side portion 72 from opening and approaching the cutting edge 4, and to prevent chips from extending without colliding with the breaker projection 7 due to bouncing at a position close to the cutting edge 4. It is.

The breaker groove 6 is provided with a raised portion 73 which is lower than the breaker protrusion 7 and is continuous with the breaker protrusion 7 in a bisector direction of the nose R portion 5. Chips that are going to extend in a direction crossing in front of the breaker projection 7 from a direction greatly inclined with respect to the bisector by the protrusion 73 are guided by the breaker projection 7 by the protrusion 73 and are surely curled. .

This raised portion 73 is preferably lower than the cutting edge 4. This is because if the raised portion 73 is higher than the cutting edge 4, the chips strongly hit the raised portion 73 and are discharged without hitting the breaker projections 7, so that the chip processing may become unstable. Further, it is preferable that the raised portion 73 has a shape in which the ridge line smoothly continues in a direction orthogonal to the bisector direction of the nose R portion 5.

Further, the raised portion 73 has a nose R portion 5.
Should not be too close to the tip of the If it is too close, the function of the breaker groove 6 becomes insufficient, and there is a possibility that the chip processing becomes unstable.

[0028]

[Experimental Example] (Experimental Example 1) An experimental example of the present invention will be described below.

In the chip 1 shown in FIGS. 1 to 6, the distance d from the tip of the nose R portion 5 to the rise of the breaker projection 7 is fixed to 0.2 mm, and the rake angles α1 and α2 of the breaker groove 6 are set. A plurality of different samples were prepared, and these were used for processing under the following cutting conditions. Chip shape: DCGT070202 type Work material: HDD rotating shaft (outer diameter finishing) SUS43
0F Number of revolutions: 4000 rpm Feed: 0.04 mm / rev Depth of cut: 0.1 mm Wet type Maximum number of machining of one sample: 500 The finished surface roughness Ry of the work material after machining is measured, and is 3.2 μm or less. The number in the range was counted. Table 1 shows the results.

[0030]

[Table 1]

As is clear from Table 1, the rake angle α1,
The finished surface roughness exceeded the reference value at the stage of processing 200 samples 1 having α2 of less than 8 °. On the other hand, in Sample 5 having a rake angle α2 of more than 30 °, the finished surface roughness was within the standard at the stage of processing up to 300 pieces, but the cutting edge was chipped at the stage of 300 pieces.

On the other hand, Samples 2 to 4 which were the products of the examples of the present invention had no cutting edge defects even after processing 500 pieces, and the finished surface roughness was within the reference value.

(Experimental Example 2) Chip 1 shown in FIGS. 1 to 6
The rake angle α1 of the breaker groove 6 = 17 °, α2
= 18 ° and a plurality of samples having different distances d from the tip of the nose R portion 5 to the rise of the breaker projections 7 were prepared, and using these, processing was performed under the following cutting conditions. Chip shape: DCGT070202 type Work material: HDD rotating shaft (outer diameter finishing) SUS43
0F Number of revolutions: 4000 rpm Feed: 0.02 to 0.05 mm / rev Depth of cut: 0.1 mm Wet processing In this processing, whether the curl shape of the chips is stable and good chip processing is performed, or whether there is a problem that chips are entangled It was visually confirmed whether or not. Table 2 shows the results.

[0034]

[Table 2]

As is apparent from Table 2, the distance d to the rising of the breaker projection was larger than 0.4 mm.
In the case of No. 0, the chip treatment was insufficient and the entanglement of the chips occurred. On the other hand, in the samples 6 to 9 of the products of the present invention, the curl shape of the chips was stable and the chip processing was good.

(Experimental Example 3) Chip 1 shown in FIGS. 1 to 6
The rake angle α1 of the breaker groove 6 = 17 °, α2
= 18 °, the distance d from the tip of the nose R portion 5 to the rise of the breaker projection 7 is fixed to 0.2 mm, and the flat face 71 provided at the tip of the breaker projection 7 is two flat faces. Different angles and one plane 7
A sample (sample 15) provided with No. 1 was prepared, and using these, processing was performed under the cutting conditions of Experimental Example 2 above, and the curl shape of the chip was stable and the chip processing was good, or the chips were entangled. It was visually confirmed whether there was any defect. Table 3
Shows the results.

The chip 1 of the sample 16 has two flat surfaces at the tip end of the breaker projection 7 in a plan view with a concave shape with respect to the nose R portion 5.

[0038]

[Table 3]

As is clear from Table 3, in Sample 11 in which the angle between the planes is smaller than 90 ° and in Sample 16 in which the angle is larger than 180 °, the chip treatment is insufficient and chip entangling occurs. I have. On the contrary,
Samples 12 to 15 of the examples of the present invention had a stable chip curl shape and were excellent in chip processing.

As described above, the embodiments of the present invention have been exemplified. However, the present invention is not limited to the above-described embodiments, and may be in any form without departing from the essence of the invention.

[0041]

As described above, in the chip of the present invention, in the chip of the present invention, the breaker groove has a rake angle α1 in a bisector direction of the nose R portion and a direction orthogonal to the bisector direction in a plan view. , Α2, where α1, α2 are 8 ° to 30 °
And the distance d from the tip of the nose R portion to the rise of the breaker projection in the bisector direction is within the range of 0.1 to 0.4 mm. Biting into the work material is assured, and the chips are hardly elongated, so that the chip processing can be stabilized.

When the chip of the present invention has a configuration in which the tip of the breaker projection has a flat surface, the chip discharge direction does not change significantly even if the chip entry direction changes slightly. The chip disposal can be very stable.

Further, the chip of the present invention further comprises a raised portion which is lower than the breaker protrusion and is continuous with the breaker protrusion in the bisector direction in the breaker groove. The chips which extend from the direction greatly inclined with respect to the bisector in the direction crossing the front of the breaker projection can be reliably curled by being guided by the breaker projection by the raised portion.

[Brief description of the drawings]

FIG. 1 is a perspective view of a throw-away tip according to the present invention.

FIG. 2 is a plan view of the throw-away tip shown in FIG.

FIG. 3 is an enlarged perspective view of a region X shown in FIG.

4 is an enlarged plan view of a region X shown in FIG.

FIG. 5 is a longitudinal sectional view showing a section taken along line AA of FIG. 2;

FIG. 6 is a longitudinal sectional view showing a section taken along line BB of FIG. 2;

FIG. 7 is a plan view of a conventional throw-away tip.

8 is an enlarged plan view of a region Y shown in FIG.

FIG. 9 is a longitudinal sectional view showing a section taken along line CC of FIG. 7;

FIG. 10 is a longitudinal sectional view showing a section taken along line DD of FIG. 7;

FIG. 11 is a plan view of another conventional indexable insert.

FIG. 12 is an enlarged plan view of a region Z shown in FIG.

FIG. 13 is a longitudinal sectional view showing a section taken along line EE of FIG. 11;

FIG. 14 is a longitudinal sectional view showing a section taken along line FF of FIG. 11;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 throw-away tip 2 rake face 3 flank face 4 cutting edge 5 nose R portion 6 breaker groove 7 breaker projection 71 flat surface 72 side portion 73 raised portion 8 land portion 9 seating surface 10 mounting hole

Claims (5)

[Claims] A cutting edge is formed at a crossing ridge portion of the rake face and the flank of a polygonal plate-like body having a plane as a rake face, a bottom face, and a side face as a flank; 0.4mm formed at the intersection of two adjacent cutting edges
A precision away throw insert having the following nose R portion and having a breaker projection protruding toward the nose R portion in a breaker groove formed in the rake face inside the nose R portion. The breaker groove has rake angles α1 and α2 in a bisecting direction of the nose R portion and a direction orthogonal to the bisecting direction of the nose R portion in a plan view, and those α1 and α2 are 8 ° to 8 °. 30 °, and the distance d from the tip of the nose R portion to the rise of the breaker projection in the bisector direction is 0.
A throw-away insert for precision machining, which is within a range of 1 to 0.4 mm. 2. The indexable insert for precision machining according to claim 1, wherein a flat surface is provided at the tip of said breaker projection. 3. The breaker projection has two planes arranged in parallel at the tip end thereof, and an angle formed by the two planes is 90 in plan view.
The indexable insert for precision machining according to claim 2, wherein the angle is in the range of not less than 180 ° and less than 180 °. 4. The indexable insert for precision machining according to claim 2, wherein one end of said breaker projection has one flat surface. 5. The precision machining device according to claim 1, wherein a protrusion that is lower than the breaker projection and is continuous with the breaker projection is provided in the breaker groove in the bisector direction. Indexable tip.