JPH0871807A - Cutting insert - Google Patents

Abstract

PURPOSE: To allow chips to be discharged unforcibly in spiral spring shape by forming large protrusions on the rear side of front protrusions, and positioning the axis of each rear protrusion further from a side part cutting edge than the center axis of each front protrusion. CONSTITUTION: A chip cut by a front end cutting edge 3 first comes in contact with first protrusions 6, 6 of semi-spherical shape and then face inward to the front in the position directly behind the first protrusions 6 in second protrusions 7 and also comes in contact with a pair of inward curved faces 8, 8 faced more inside than the first protrusions 6. The chip is thereby discharged unforcibly in spiral spring shape, and the diameter of the formed spiral spring does not become too small so as to prevent a groove from being plugged with the chip during grooving work. Also, since the chip comes in contact with the protruding curved faces (the first protrusions 6 and the inward curved faces 8 and outward curved faces 9 of the second protrusions 7), the contact area is extremely small, and cutting resistance is small so as to prevent the occurrence of deflection on the processed face.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a cutting insert made of wear resistant material such as cemented carbide and cermet and used for various kinds of cutting such as grooving, cutting, inner diameter processing, outer shape processing 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 a breaker shape of a cutting insert in order to improve chip discharge performance.

Among such cutting inserts, the cutting insert 2 described in Japanese Patent Application Laid-Open No. 1-115503.
0 is the front tip deflector surface 23 and the side cutting edge 24 which are scooped up in a concave shape on the insert top surface 21 at a distance from the front end cutting edge 22 as shown in FIG.
It was provided with longitudinally projecting tip forming means 26 comprising side tip deflector surfaces 25 oriented along.

This cutting insert 20 has a front edge 2
The chips cut by 2 are bent and discharged in a spiral shape along the front tip deflector surface 23, while the chips cut by the side cutting edge 24 are smaller by the side tip deflector surface 25. Since the insert 20 was curved in a spiral shape with a radius of curvature and discharged, the insert 20 was multifunctional and improved in chip discharge.

[0005]

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

That is, the conventional cutting insert 20 described above.
Then, after the chips cut by the front edge cutting edge 22 sink into the recess 27 that is continuous from the front edge cutting edge 22, they are forcibly scooped up by the concave front tip deflector surface 23 and curved in a spiral shape. However, since the spring of the formed chips is dense, that is, the diameter is small, for example, the chip is caught in the groove during the grooving process and the insert 20 is damaged, or the front chip deflector surface 23 is concave. Since it is formed, the contact area between the chips and the front tip deflector surface 23 is large, and the stress that the insert 20 receives from the chips becomes excessive.

Further, the chips cut by the side cutting edge 24 are spirally curved and discharged by the side tip deflector surface 25, and the side tip deflector surface 25 is the long side of the insert 20. Since it is formed like a wall along the direction, the chip deflection angle y
However, there is a problem in that there is a risk of discharge to the worker in a spiral shape having a relatively large pitch although the diameter is large.

[0008]

In order to solve the above problems, in the insert of the present invention, a pair of substantially hemispherical first projections near the front cutting edge of the upper surface and the first projections on the rear side of the first projections. 1
Forming a pair of second protrusions that are larger than the protrusions, and
The central axis of the protrusion is located farther from the side cutting edge than the central axis of the first protrusion.

[0009]

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, and a front end cutting blade is provided on three peripheral edges of one end of an insert upper surface 2. The edge 3 and the side cutting edge 4 are formed, and a V-shaped groove 5 for attaching a holder is formed in the central portion.

On the one end side of the insert upper surface 2, two smaller first projections 6, 6 are formed at intervals immediately after the front end cutting edge 3, and further each first projection 6 is formed. A second protrusion 7 that is larger than the first protrusion 6 is formed immediately after.

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. Eccentric elliptical shape, that is, an eccentric substantially semi-elliptical spherical shape.

Of these, the second protrusions 7, 7 are the first protrusions 6,
6 is located farther from the side cutting edge 4 than the central axis of 6, and the long axis direction of the ellipse is open to the front and outer direction with the crossing angle α ° with respect to the longitudinal direction of the insert 1. Immediately after the first projections 6, 6, a pair of inwardly curved surfaces 8 directed inward and narrowed inward from the first projections 6, 6.
8 and a pair of outward curved surfaces 9 located outside the inward curved surfaces 8 and facing the front and the outside.

FIG. 3 is a partial plan view showing another aspect of the second projection 7. Here, a pair of left and right symmetrically independent second projections 7, 7 are formed in FIG. The rear portion of the second protrusion 7, 7 is continuous.

The insert 1 thus constructed has the following actions. That is, the chips cut by the front edge cutting edge 3 first come into contact with the substantially hemispherical first projections 6, 6 and then face forward inward at the position immediately after the first projection 6 in the second projection 7 and Since it is configured to hit a pair of inward curved surfaces 8 and 8 that are narrower inward than the first protrusion 6, chips are reasonably discharged in a spiral shape and the diameter of the formed spring is not too small. Sometimes the chips do not get caught in the groove, and the chips contact the convex curved surfaces (the inward curved surface 8 and the outward curved surface 9 of the first protrusion 6 and the second protrusion 7), so the contact area is very small. Since the cutting resistance is small, there is no blurring on the processed surface. Furthermore, since the cross section of the chips has a curved shape in which the inside is squeezed, it does not get entangled with the holder.

When the cutting amount is small, the chips at the time of lateral running hit the spherical surface on the front outer side of the first protrusion 6, and when the cutting amount is small, the chips are immediately after the first protrusion 6 in the second protrusion 7. The deflection angles x ₁ and x ₂ are small because they are configured to hit a pair of outward curved surfaces 9 and 9 which are located outside of the inward curved surfaces 8 and face forward and outward, so that the chips are easily cut and are temporarily spiraled. Even if the chips are discharged, chips having a small spiral pitch are discharged, so that the chips do not fly to the worker and 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 disposal ability is excellent, and if it is within that range, it is 0. 6 ~
More preferably, it is 1.0 mm. On the contrary,
When the distance t is less than 0.5 mm, the first projection 6 is too close to the side cutting edge 4 in the lateral running, so that the chips ride on the first projection 6 and grow without curling,
On the other hand, when it is larger than 1.2 mm, the first projection 6 is too far from the side cutting edge 4 in lateral running with a small feed amount, so that chips are generated on the first projection 6 and the outward curved surface 9 of the second projection 7.
There is a risk that it will not hit and will curl inward and extend backward.

If the distance E from the front edge 3 of the cutting edge to the center of the first projection 6 is in the range of 0.5 to 1.5 mm, the chip disposal capability is excellent and the distance E is within the range of 0. 6 ~
More preferably, it is 1.2 mm. On the contrary,
When the distance E is less than 0.5 mm, the chips cut by the front edge 3 are curved in a spiral shape.
The spring of the formed chips becomes overdense (small diameter), resulting in excessive cutting resistance, and the chip is caught in the groove during grooving, causing damage to the insert 1.
On the other hand, when it is larger than 1.2 mm, the chips are the first projections 6
There is a risk that you may get on and grow without curling.

The crossing angle α ° between the major axis direction of the ellipse of the second projection 7 and the longitudinal direction of the insert 1 is 5 ° to 20 °.
Within the range, the chip disposal ability is excellent, and within the range, it is more preferable that the angle is 7 to 15 °. On the other hand, when the crossing angle α ° is less than 5 °, the deflection angle x ₂ becomes large in the lateral running process with a large cutting depth, and therefore the spiral chips with a small diameter but a relatively large pitch are cut by the operator. Is discharged toward the other side, while the crossing angle α is
When ° is larger than 20 °, the deflection angle x ₂ becomes very small in the lateral running with a large depth of cut, the cutting resistance applied to the insert 1 may become excessive, and the second protrusion 7 may be damaged. There is.

Further, the height of the first protrusion 6 and the second protrusion 7 is preferably in the range of 0.02 mm to 0.3 mm. If this height is less than 0.02 mm, the chips do not curl. On the other hand, if the length is larger than 0.3 mm, the curved mainspring becomes too dense and the cutting resistance becomes excessive, and the chip may be caught in the groove during the grooving process and the insert 1 may be damaged.

Example 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 t = 0.6 mm, and the front projection 3 is the first projection. Distance to the center of 6 E = 0.6
mm, the intersection angle α = 10 °, and the height of the first protrusion 6 and the second protrusion 7 is 0.25 mm.
Grooving was performed under the following conditions by changing the feed amount as described in.

[0021]

[Table 1]

Work Material: φ54 mm SCM435 V = 150 m / min. Wet In addition, as a comparative example, a front tip scooped up in a concave shape at a distance from the front end cutting edge 22 as shown in FIG.
The same process is performed using the insert 20 formed with the vertically projecting tip forming means 26 including the deflector surface 23 and the side tip deflector surface 25 oriented along the side cutting edge 24, The state of chips and the state 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, chips are cut and discharged in a spiral shape even if the feed amount is large or small, whereas in the insert 20 of the comparative example, the chips are cut. Although the mainspring is cut and discharged in a spiral shape, the spiral spring formed may be jammed in the groove due to overcrowding. At a smaller feed amount, the spiral shape is discharged instead of the spiral shape. Further, in the insert 1 of the present example, no blur was generated on the machined surface, while 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 described in Table 2, lateral running was performed under the following conditions, and the state of chips was observed.

[0025]

[Table 2]

Work Material: φ54 mm SCM435 V = 150 m / min. f = 0.20 mm / rev. Wet results are shown in Table 2. As is clear from Table 2, according to the insert 1 of the present embodiment, regardless of whether the feed amount is large or small, the chips are spiral-shaped and have a small pitch and diameter, and are shortly cut and discharged, or In the insert 20 of the comparative example, chips were formed in a spiral shape having a large pitch when the feed amount was small, while the chips were finely cut and discharged.

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

[0028]

[Table 3]

The results are shown in Table 3. As shown in Table 3, 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 disposal capability is excellent, and if it is in that range, it is 0. More preferably, the distance t is 0.5.
If it is smaller than mm, the chips will run on the first protrusion 6 and grow without curling in the lateral running with a small feed amount. On the other hand, if it is larger than 1.2 mm, the chips will be scraped in the lateral running with a small feed amount. The second also on the first protrusion 6
It was found that there is a possibility that the protrusion 7 may not hit the outward curved surface 9 and may curl inward without curling.

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

[0031]

[Table 4]

Work Material: φ54 mm SCM435 V = 150 m / min. r = 1.5 mm Wet results are shown in Table 4. As shown in Table 4, the distance E from the front edge 3 to the center of the first protrusion 6 is 0.5 to
Within the range of 1.5 mm, the chip disposal ability is excellent, and within that range, it is more preferable that it is 0.6 to 1.2 mm. On the other hand, when the distance E is less than 0.5 mm , The spring of the formed chips becomes too dense and the cutting resistance becomes excessive, and at the time of grooving, the chip is caught in the groove and the insert 1 is damaged.
It has been found that when the size is larger than 2 mm, the chips may run on the first protrusions 6 and may be curled without being curled.

Example 5 In the insert 1 of Example 1, the crossing angle α ° between the long axis direction of the ellipse of the second projection 7 and the longitudinal direction of the insert 1 was changed as shown in Table 5, and the conditions of Example 2 were changed. Lateral machining was performed and the state of chips and the state of the machined surface were observed.

[0034]

[Table 5]

The results are shown in Table 5. As shown in Table 5, when the crossing angle α ° is in the range of 5 ° to 20 °, the chip disposal ability is excellent and within the range of 7 to 15
More preferably, On the other hand, when the crossing angle α ° is smaller than 5 °, the deflection angle x ₂ becomes large in the lateral running with a large depth of cut, so that spiral chips with a small diameter but a relatively large pitch are discharged. On the other hand, when the crossing angle α ° is larger than 20 °, the deflecting angle x ₂ becomes very small, the cutting resistance applied to the insert 1 may become excessive, and the second protrusion 7 may be damaged. I knew it was.

Example 6 In the insert 1 of Example 1, the heights of the first protrusion 6 and the second protrusion 7 were changed as shown in Table 6, and the lateral running was performed under the conditions of Example 4, and the state of chips and The situation such as the processed surface was observed.

[0037]

[Table 6]

The results are shown in Table 6. As shown in Table 6, the height of the first protrusion 6 and the second protrusion 7 is 0.02 mm.
It is preferable to be in the range of 0.3 mm. If this height is smaller than 0.02 mm, the chips will grow without curling, while if it is larger than 0.3 mm, the curved spring will become overcrowded and cut. With excessive resistance,
Insert 1 when the chip is caught in the groove during grooving
It was found that there is a risk of damaging the.

[0039]

As described above, according to the present invention, the chips cut by the front edge of the cutting edge first come into contact with the substantially hemispherical first protrusion, and then immediately after the first protrusion in the second protrusion. Since it is configured to hit a pair of inward curved surfaces that face inward toward the front and squeeze inward from the first protrusion, chips are reasonably discharged in a spiral shape and the diameter of the formed spring is not too small. Therefore, the chips do not get caught in the grooves during the grooving process, and since the chips contact the convex curved surface, the contact area is very small and the cutting resistance is small, so that the machining surface is not shaken. Furthermore, since the cross section of the chips is curved with the inside narrowed, it does not get entangled with the holder.

Further, when the horizontal cutting is performed, the chips hit the spherical surface on the front outer side of the first projection when the cutting amount is small,
On the other hand, when the depth of cut is small, the second projection is located immediately after the first projection and is located outside the inward curved surface and hits a pair of outward curved surfaces facing forward and outward, so that the deflection angle is small and chips are cut. Even if the chips are spirally discharged, chips having a small spiral pitch are discharged, so that the chips do not fly to the worker and hurt the worker.

[Brief description of 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 portion of the insert shown in FIG.

FIG. 3 is a top view showing one end portion of a cutting insert having a second protrusion of another aspect.

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

[Explanation of symbols]

1 (Cutting) Insert 2 Upper Surface 3 Front End Cutting Edge 4 Side Cutting Edge 5 V-shaped Groove 6 First Protrusion 7 Second Protrusion 8 Inward Curved Surface 9 Outward Curved Surface x ₁ x ₂ Deflector Angle y Deflector Angle t Distance E Distance

Claims (1)

[Claims] 1. A cutting insert in which cutting edges are formed at three peripheral edges of an upper surface end portion, and a pair of first protrusions each having a substantially hemispherical shape and said first protrusion are formed on the upper surface of said insert in the vicinity of a front cutting edge.
A pair of second projections larger than the first projection is formed on the rear side of the projection, and a central axis of the second projection is located farther than a central cutting edge of the first projection than a side cutting edge. And a cutting insert.