JP3297544B2 - Cutting insert - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting insert composed of wear-resistant materials such as cemented carbides and cermets, and used for various kinds of cutting such as grooving, cutting, inner diameter machining, and outer machining of metal materials. It is about.

[0002]

2. Description of the Related Art Conventionally, in the field of metal cutting, various improvements have been made to the shape of a breaker of a cutting insert in order to improve chip dischargeability.

[0003] Among such cutting inserts, cutting insert 2 described in Japanese Patent Application Laid-Open No. 1-115503 is disclosed.
Reference numeral 0 denotes a front chip deflector surface 23 and a side cutting edge 24 which have been scooped in a concave shape on the insert top surface 21 at a distance from the front cutting edge 22 as shown in FIG.
Along with a side tip deflector surface 25 oriented along the top surface.

[0004] The cutting insert 20 has a front edge 2.
The chips cut by the cutting edge 2 are discharged in a curved manner along the front chip deflector surface 23, while the chips cut by the side cutting edge 24 are reduced by the side chip deflector surface 25. Since the insert 20 is ejected in a spiral shape with a radius of curvature, the insert 20 is multifunctional and has improved chip ejection properties.

[0005]

However, the above-mentioned conventional cutting insert cannot avoid the following problems.

That is, the above-mentioned conventional cutting insert 20
In this case, the chips cut by the front edge 22 sink into the concave portion 27 that is continuous from the front edge 22, and are then forcibly picked up by the concave front tip / deflector surface 23 and curved in a spring-like manner. However, since the formed spring is dense, that is, the diameter becomes small, for example, when the grooving process is performed, the insert is damaged due to the chip becoming clogged in the groove, or the front tip deflector surface 23 becomes concave. As a result, the contact area between the chip and the front chip deflector surface 23 is large, and the stress applied to the insert 20 from the chip becomes excessive.

[0007] Chips cut by the side cutting edge 24 are helically curved and discharged by the side chip deflector surface 25, and the side chip deflector surface 25 is elongated by the length of the insert 20. Since it is formed like a wall along the direction, the deflection angle y of the chip
However, there is a problem that there is a risk that the spiral is discharged toward the operator in a spiral shape having a relatively large pitch although the diameter is small.

[0008]

In order to solve the above problems, a cutting insert according to the present invention is provided with three cutting edges at the top end.
In a cutting insert having two front cutting edges and two side cutting edges, a pair of substantially hemispherical protrusions near the front cutting edge are provided on the upper surface of the insert, and a rear side of the first protrusion. , A pair of second protrusions that are larger than the first protrusions and whose mutual distance is smaller than the distance between the first protrusions are formed, and an inward curved surface is formed at a position of the second protrusions immediately after the first protrusions. It is characterized by the following.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a cutting insert (hereinafter, abbreviated as “insert”) 1 of the present embodiment. The insert 1 has a substantially quadrangular prism shape. An edge 3 and a side cutting edge 4 are formed, and a V-shaped groove 5 for mounting a holder is formed in a central portion.

On one end of the upper surface 2 of the insert, two smaller first projections 6, 6 are formed at a position immediately behind the front edge 3 at intervals. A second protrusion 7 larger than the first protrusion 6 is formed at a position immediately after the second protrusion.

FIG. 2 is a plan view of one end of the insert 1. As shown in FIG. 2, the first protrusion 6 has a circular shape in plan view, that is, a substantially hemispherical shape, and the second protrusion 7 has a plan view. To form an eccentric elliptical shape, that is, an eccentric substantially semi-elliptical spherical shape.

The second protrusions 7, 7 are the first protrusions 6,
6 is located farther than the side cutting edge 4 than the central axis, and the major axis direction of the ellipse is open to the front-outer direction with the intersection angle α ° with respect to the longitudinal direction of the insert 1. Immediately after the first protrusions 6, 6, a pair of inwardly curved surfaces 8, which face inward in front and are squeezed inward from the first protrusions 6, 6,
8 and a pair of outwardly curved surfaces 9, 9 which are located outside the inwardly curved surfaces 8, 8 and are directed outward and forward.

FIG. 3 is a partial plan view showing another embodiment of the second protrusion 7, in which a pair of symmetrical independent second protrusions 7, 7 in FIG. 2 are formed. The rear portions of the second projections 7, 7 are continuous.

The insert 1 thus configured has the following functions. That is, the chips cut by the front end cutting edge 3 first contact the substantially hemispherical first projections 6, 6, and then face forward inward at a position immediately after the first projections 6 in the second projections 7. Since it is configured to hit the pair of inwardly curved surfaces 8, 8 squeezed inward from the first projections 6, chips are easily discharged in a spring-like manner, and the diameter of the formed spring is not too small, so that grooving is performed. Sometimes the chips do not get caught in the grooves, and the chips come into contact with the convex curved surfaces (the inwardly curved surfaces 8 and the outwardly curved surfaces 9 of the first projections 6 and the second projections 7), so that the contact area is very small. Since the cutting force is small, no blurring occurs on the machined surface. Further, the chip has a curved cross section with the inside narrowed, so that the chip does not become entangled with the holder.

When the cutting amount is small, the chips on the front and outer sides of the first projection 6 are in contact with the swarf at the time of the transverse running processing. Since it is constituted so that it may be located outside the inwardly curved surfaces 8 and 8 and hit a pair of outwardly curved surfaces 9 and 9 facing forward and outward, the deflection angles x ₁ and x ₂ are small, so that chips are easily cut off, and are temporarily spiral. Even if the chips are discharged, chips with a small helical pitch are discharged, so that the chips do not fly to the worker and do not hurt the worker.

If the distance t from the side cutting edge 4 to the center of the first projection 6 is in the range of 0.5 to 1.2 mm, the chip processing ability is excellent. 6 ~
More preferably, it is 1.0 mm. On the contrary,
When the distance t is smaller than 0.5 mm, in the horizontal running, the first protrusion 6 is too close to the side cutting edge 4, so that the chip runs on the first protrusion 6 and extends without curling.
On the other hand, when it is larger than 1.2 mm, in the transverse running with a small feeding amount, the first projection 6 is too far from the side cutting edge 4, so that chips are also present on the first projection 6 on the outward curved surface 9 of the second projection 7.
There is a danger that it will extend inward and backward without curling.

If the distance E from the front cutting edge 3 to the center of the first projection 6 is in the range of 0.5 to 1.5 mm, the chip processing ability is excellent. 6 ~
More preferably, it is 1.2 mm. On the contrary,
When the distance E is smaller than 0.5 mm, the chips cut by the front edge 3 are curved like a spring.
The formed springs become overly dense (small diameter) and the cutting resistance becomes excessive, and at the time of grooving, the inserts become jammed in the grooves and damage the insert 1,
On the other hand, when the diameter is larger than 1.2 mm,
There is a risk that it will grow without curling.

The intersection angle α ° between the major axis direction of the ellipse of the second protrusion 7 and the longitudinal direction of the insert 1 is 5 ° to 20 °.
Is within the range, the chip processing ability is excellent, and within the range, it is more preferably 7 to 15 °. On the other hand, if the crossing angle α ° is smaller than 5 °, the deflecting angle x ₂ becomes large in the transverse machining with a large cutting depth. , While the intersection angle α
If ° is greater than 20 °, Defurekuto angle x ₂ in greater Yokohashiri machining depth of cut is extremely small, or become cutting force applied to the insert 1 is excessive, a possibility that the second projection 7 or accidentally damaged There is.

Further, the height of the first projections 6 and the second projections 7 is preferably in the range of 0.02 mm to 0.3 mm. If the height is smaller than 0.02 mm, the chips will not curl. If it is elongated and on the other hand is larger than 0.3 mm, the curved spring will be overcrowded and the cutting resistance will be excessive, and at the time of grooving, the insert may be clogged in the groove and damage the insert 1.

Embodiment 1 The insert 1 shown in FIGS. 1 and 2, wherein the distance t from the side cutting edge 4 to the center of the first projection 6 is 0.6 mm, the first projection from the front cutting edge 3. Distance to center of 6 E = 0.6
mm, the cross angle α = 10 °, the height of the first protrusion 6 and the second protrusion 7 was 0.25 mm, and Table 1 was used.
And the grooving was performed under the following conditions while changing the feed amount.

[0021]

[Table 1]

Work material: φ54 mm SCM435 V = 150 m / min. Wet type In addition, as a comparative example, as shown in FIG.
A similar process is performed using an insert 20 formed with a vertically protruding chip forming means 26 having a side tip deflector surface 25 oriented along a deflector surface 23 and a side cutting edge 24, The condition of the chips and the condition of the machined surface were observed.

Table 1 shows the results. As shown in Table 1, according to the insert 1 of the present embodiment, the chips are cut and discharged in a spring-like manner even if the feed amount is large or small. Although the mainspring is cut and discharged in the form of a spring, the formed mainspring may be overcrowded and jammed in the groove. At a smaller feed rate, the mainspring is discharged in a spiral shape having a large diameter instead of a mainspring. In addition, in the insert 1 of the present example, no blurring occurred on the machined surface, whereas in the insert 20 of the comparative example, slight blurring was confirmed.

Example 2 Insert 1 of Example 1 and insert 20 of the comparative example
Was used, the feed amount was changed as shown in Table 2, and the side running process was performed under the following conditions, and the state of the chips was observed.

[0025]

[Table 2]

Work material: φ54 mm SCM435 V = 150 m / min. f = 0.20 mm / rev. Table 2 shows the results. As is clear from Table 2, according to the insert 1 of the present embodiment, even if the feed amount is large or small, the chips are spirally formed with a small pitch and a small diameter and are cut short and discharged, or In contrast, the insert 20 of the comparative example formed a helical chip having a large pitch when the feed amount was small, while the chip 20 was finely cut and discharged.

Embodiment 3 In the insert 1 of the embodiment 1, the first from the side cutting edge 4
The same processing was performed under the conditions of Example 2 while changing the distance t to the center of the protrusion 6 as shown in Table 3, and the state of the chips, the state of the processed surface, and the like were observed.

[0028]

[Table 3]

The results are shown in Table 3. As shown in Table 3, when the distance t from the side cutting edge 4 to the center of the first projection 6 is in the range of 0.5 to 1.2 mm, the chip processing ability is excellent, and within this range, 0 0.6 to 1.0 mm, and the distance t is 0.5
If the diameter is smaller than 1 mm, the chip runs on the first protrusion 6 and expands without curling in the laterally traversing processing with a small feed amount. The first protrusion 6 also has the second
It has been found that the projections 7 may extend inward and rearward without curling because they do not hit the outward curved surface 9 of the projection 7.

Example 4 In the insert 1 of Example 1, the distance E from the front edge 3 to the center of the first projection 6 was changed as shown in Table 3.
Grooving was performed under the following conditions, and the state of the chips, the state of the processed surface, and the like were observed.

[0031]

[Table 4]

Work material: φ54 mm SCM435 V = 150 m / min. r = 1.5 mm wet type The result is shown in Table 4. As shown in Table 4, the distance E from the front edge 3 to the center of the first projection 6 is 0.5 to 0.5.
When the distance E is in the range of 1.5 mm, the chip processing ability is excellent, and it is more preferable that the chip processing ability is in the range of 0.6 to 1.2 mm. However, the formed spring becomes too dense and the cutting resistance becomes excessive, and at the time of grooving, the insert becomes damaged due to the chip getting stuck in the groove.
When it is larger than 2 mm, it has been found that chips may run on the first protrusions 6 and extend without curling.

Fifth Embodiment In the insert 1 of the first embodiment, the intersection angle α ° between the major axis direction of the ellipse of the second projection 7 and the longitudinal direction of the insert 1 is changed as shown in Table 5, and the condition of the second embodiment is changed. Lateral running was performed, and the conditions of the chips and the processing surface were observed.

[0034]

[Table 5]

Table 5 shows the results. As shown in Table 5, if the crossing angle α ° is in the range of 5 ° to 20 °, the chip processing ability is excellent, and within the range, 7 to 15
° is more preferable. On the other hand, if the crossing angle α ° is smaller than 5 °, the deflecting angle x ₂ becomes large in the transverse machining with a large cutting depth, so that spiral chips having a small diameter but a relatively large pitch are discharged. , on the other hand, the case crossing angle alpha ° is greater than 20 °, Defurekuto angle x ₂ becomes very small, or become cutting force applied to the insert 1 is excessive, possibly second protrusions 7 or accidentally damaged I found it to be.

Example 6 In the insert 1 of Example 1, the heights of the first projections 6 and the second projections 7 were changed as shown in Table 6, and the horizontal running was carried out under the conditions of Example 4 to obtain the chip condition and The condition of the machined surface was observed.

[0037]

[Table 6]

Table 6 shows the results. As shown in Table 6, the height of the first protrusion 6 and the second protrusion 7 was 0.02 mm.
When the height is smaller than 0.02 mm, the chips are extended without curling, and when the height is larger than 0.3 mm, the curved spring becomes too dense and the cutting is performed. As the resistance becomes excessive,
Insert 1 when insert is clogged in groove during grooving
Has been found to cause damage.

[0039]

As described above, the cutting insert according to the present invention is a cutting insert in which one front edge and two side edges are formed on the three peripheral edges of the upper surface end portion. A pair of substantially hemispherical protrusions near the front edge of the cutting edge, and a pair of second protrusions on the rear side of the first protrusions, the second protrusions being larger than the first protrusions and less than the distance between the first protrusions. Is formed, and an inwardly curved surface is formed at a position immediately after the first projection in the second projection, so that chips are easily discharged in a spring-like manner and the diameter of the formed mainspring does not become too small. Chips do not become jammed in the groove during the insertion process. In addition, since the contact area between the chip and the projection is very small and the cutting resistance is high,
There is no blurring on the machined surface. Furthermore, since the cross section of the chip has a curved shape narrowed inward, the chip does not become entangled with the holder.

When the cutting amount is small, the chips at the time of the flattening process hit the front outer spherical surface of the first projection.
On the other hand, when the cut amount is small, the second protrusion is located outside the inward curved surface immediately after the first protrusion and hits a pair of outward curved surfaces facing forward and outward, so that the deflection angle is small, so that chips are cut. Even if the chips are spirally discharged, chips with a small spiral pitch are discharged, so that the chips do not fly to the worker and do not hurt the worker.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cutting insert according to an embodiment of the present invention.

FIG. 2 is a top view showing one end of the insert of FIG. 1;

FIG. 3 is a top view showing one side end of a cutting insert having another embodiment of a second projection.

FIG. 4 is a perspective view of a conventional insert.

[Explanation of symbols]

Reference Signs List 1 (cutting) insert 2 Top surface 3 Front cutting edge 4 Side cutting edge 5 V-shaped groove 6 First projection 7 Second projection 8 Inwardly curved surface 9 Outwardly curved surface x ₁ x ₂ Deflector angle y Deflector angle t Distance E Distance

Claims (1)

(57) [Claims] 1. A cutting insert in which one front edge and two side edges are formed at three peripheral edges of an upper end portion.
On the upper surface of the insert, a pair of substantially hemispherical projections near the front edge of the cutting edge, and behind the first projection, the distance between the first projection and the first projection is smaller than the distance between the first projections. A cutting insert, wherein a pair of second protrusions is formed, and an inward curved surface is formed at a position of the second protrusion immediately after the first protrusion.