JPH08174327A - Throwaway tip for face milling cutter - Google Patents

Abstract

PURPOSE: To reduce the cutting resistance of a throwaway tip fitted to a face milling cutter for right-angle shoulder cutting. CONSTITUTION: In a square positive type throwaway tip, a cutting edge section is placed lower than a boss surface 4. A sub cutting edge 7 having a middle projecting circular arc form is provided between a main cutting edge 5 and a corner edge 6 with its angle δ with the main cutting edge 5 set in the range of 0.5 deg. to 2 deg.. As it moves away from the corner edge 6, the main cutting edge 5 is gradually lowered within a fixed range. The cross-sectional shape of a breaker groove 8 is formed of an inclined surface 9 inclined so as to be gradually placed lower than the main cutting edge 5 toward the center and an inclined surface risen toward the boss surface 4 and nearly circular recesses 11 are provided in parallel to each other on these inclined surfaces. These may be formed into stepped inclined surfaces.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away tip mounted on a face mill for right angle shoulder milling.

[0002]

2. Description of the Related Art In a face milling machine for a right-angled shoulder with a corner angle of 0 °, the main cutting edge is perpendicular to the milling face and the second auxiliary cutting edge forms a clearance with respect to the milling face. It is necessary to have Therefore,
A very common shape of a conventional throw-away tip that realizes such a face mill is a triangle or a parallelogram. However, in the case of a positive throwaway tip with a clearance provided on the outer circumference, the triangular or parallelogram throwaway tip has three or two main cutting edges, which is less than four square main cutting edges. Further, the former shape is more disadvantageous in fracture resistance than a square having an apex angle of 90 ° because the apex angle in plan view is an acute angle.

Therefore, recently, a face milling machine for square shoulder milling has been realized using a square throw-away tip.

There are two main methods for realizing a face milling machine for square shoulder milling using a square throw-away tip.
One way, one is to make the throw-away tip a very complicated special shape, and many inventions and inventions have been made. Another method is to secure a clearance on the front side of the milling cutter by making the corner angle slightly larger than 0 ° in the machining in which the squareness is not important. In this case, it can be realized by a relatively simple square throw-away chip.

[0005]

The present invention is based on the latter method described above. However, in such a face mill, if the rake angle in the axial direction is positive, the rake angle in the center direction is inevitably compared. You cannot secure a sufficient escape on the front side unless you make a big negative. This causes an increase in cutting resistance. The present invention aims to reduce the increasing cutting resistance and also improve the chip discharge property.
At the same time, we are working to improve the roughness of the machined surface.

[0006]

According to the present invention, the corner angle is set to 0.
It relates to a face milling cutter that is slightly larger than ゜ to enable approximate right angle shoulder milling, and this face milling cutter is equipped with a square and positive type throw-away tip. On the upper surface of the throw-away tip, a boss surface, which is a main plane, is arranged in the central portion, and a cutting edge portion slightly lower than the boss surface is arranged on the outer side thereof.

The cutting edge portion is mounted on the front milling cutter between the main cutting edge composed of four main edges of the outer edge, the arcuate corner edge formed in the corner, and the main cutting edge and the corner edge. Sometimes the angle δ with the main cutting edge on the side that becomes the front cutting edge
Is formed by a sub-cutting edge formed of a medium-convex arc formed so as to be 0.5 ° to 2 °, and a breaker groove along each cutting edge.

The breaker groove is composed of at least an inclined surface inclined so as to be gradually lowered toward the central portion from the main cutting edge and an inclined surface rising toward the boss surface, and the main cutting edge is As the distance from the corner blade increases, it is formed so as to be gradually lower in a certain range.

Furthermore, substantially circular recesses may be arranged on the inclined surface rising toward the boss surface so as to be scattered in parallel with the main cutting edge. Alternatively, the inclined surface that rises toward the boss surface may be configured by two first and second inclined surfaces so that the second inclined surface is lower than the extension plane of the first inclined surface.

[0010]

The clamping structure of the face milling cutter using the wedge parts is widely and generally used. In this clamp structure, the boss surface of the throw-away tip is a flat surface that receives the pressing force of the wedge component. In the present invention, the cutting edge portion is located lower than the boss surface so that the cutting edge portion does not directly receive this strong pressing force and thus no chipping or chipping occurs.

The sub cutting edge provided between the main cutting edge and the corner edge is such that the sub cutting edge becomes the front cutting edge when the throw-away tip is mounted on the front milling cutter. Then, when the cutting is performed, the middle convex arc shape is directly transferred to the processing surface.

In the case of a straight front cutting edge, a perfectly flat machined surface can be obtained if the straight blade and the front can be exactly aligned, but it is practical in a complicated cutting phenomenon. It is impossible to do so, and when actually observing the machined surface cut by such a cutting edge in an enlarged manner, it becomes a sawtooth-shaped machined surface. However, if it is a medium convex arc cutting edge, even if the front cutting edge is attached slightly inclined to the front, the front side always appears as an arc blade, so it was created by a continuous arc after cutting. It remains as a wavy transfer surface. Then, if the radius of the arc is large, it becomes possible to obtain good processed surface roughness.

The breaker groove provided along the main cutting edge has the effect of reducing the rake angle toward the center of the face milling cutter for right-angled shoulders, which is set as a relatively large negative angle. The purpose is to improve sharpness and suppress vibration. On the other hand, although the axial rake angle is normally set to a regular angle, in order to more clearly have the same effect as described above, in the present invention, not only the milling body but also the throwaway tip has a larger positive angle. The rake angle is set to the axial direction. In addition, we have devised an inclined surface of the breaker groove that rises on the boss surface to further reduce cutting resistance. That is,
The inclined surface is a place where the chips discharged by cutting come into contact with each other with a strong force to be deformed, but the contact area is reduced to reduce scratch resistance.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings.

1 to 3, the throw-away tip 1 has a square shape in a plan view, and its outer periphery has an upper surface 2
It is a positive throw-away tip in which relief is provided toward the lower surface 3. The upper surface 2 is formed by a boss surface 4 which is a flat surface located in the central portion and a cutting edge portion arranged around the boss surface 4.

The cutting edge portion includes a main cutting edge 5 having four outer edges, an arcuate corner edge 6 formed at a corner, and a sub cutting edge formed between the main cutting edge 5 and the corner edge 6. The cutting edge 7 and the breaker groove 8 along each cutting edge. The cutting edge portion is formed so as to be slightly lower than the boss surface 4 as a whole. More specifically, the main cutting edge 5 is
According to the distance from the corner blade 6 in the length direction,
It is formed so as to gradually lower in a certain range. Where it exceeds a certain range, it may be parallel to the lower surface 3 as in the present embodiment, or may move to a lower position. Then, the main cutting edge 5 rises at the rear end of the breaker groove 8.

FIG. 4 is an enlarged view for explaining the details of the corner portion. A sub-cutting edge 7 having a convex arc shape with a radius R is provided so as to be smoothly connected to an arc having a corner radius r of the corner blade 6. The auxiliary cutting edge 7 is provided on the side that becomes the front side when the throw-away tip 1 is mounted on the front milling cutter. The angle δ formed by the sub cutting edge 7 and the main cutting edge 5 is 0.5 ° to 2 °.

FIG. 5 shows a cross-sectional shape of the breaker groove 8 taken along the line AA in FIG. 2. At least, the inclined surface 9 is inclined so as to be gradually lowered toward the central portion from the main cutting edge 5. , And an inclined surface 10 that rises toward the boss surface 4. Further, the present embodiment is an embodiment including the invention described in claim 2, in which substantially circular concave portions 11 are arranged on the inclined surface 10 in parallel with the main cutting edge 5. Has been done. Therefore, the cross-sectional shape along the line BB in FIG. 2 becomes the shape shown in FIG.

7 to 9 show another embodiment including the invention described in claim 3, and the same portions are denoted by the same reference numerals. This throw-away tip 1
The cross-sectional shape of the breaker groove 8 is different from that described above. That is, the cross-sectional shape along the line CC of FIG.
As shown in FIG. 10, at least an inclined surface 9 that inclines so as to gradually lower from the main cutting edge 5 toward the central portion,
It is formed by a first inclined surface 12 that rises toward the boss surface 4 and a second inclined surface 13 that has a step from the middle and is positioned lower than the extension plane of the inclined surface 12.

Next, an embodiment of a right-faced shoulder milling mill 14 for mounting the throw-away tip 1 as described above is shown in FIGS. 11 and 12. A notch is provided on the outer periphery of the tool body 15, and a locator 16 tightened and fixed by a bolt and a wedge component 1 that can be floated and lowered by a screw 17.
And 8 are incorporated in the notch. The throw-away tip 1 is placed on the tip seat provided in the locator 16 and is pressed and fixed to the wall surface of the cutout portion by the wedge component 15 being depressed by the tightening operation of the screw 17. At this time, the cutting edge portion of the throw-away tip 1 is arranged lower than the boss surface 4 because the contact surface of the wedge component 18 abuts only on the boss surface 4, so that the cutting edge is chipped or chipped. This is to prevent it.

The front milling cutter 14 is for square shoulder milling, but has a square throw-away tip 1.
The corner angle γ is slightly larger than 0 ° to secure the front clearance. If the rake angle α in the axial direction is a positive angle in order to exert the features of the positive type, the rake angle β in the central direction is a negative angle. This is because as the rake angle β in the central direction becomes larger, the corner angle γ cannot be held smaller in the three-dimensional combination of the three angles α, β and γ. The breaker groove 8 provided in the throw-away tip 1 improves the cutting resistance due to the negative rake angle β in the central direction by the rake effect of the inclined surface 9 of the breaker groove 8.

The chips discharged by cutting come into contact with an inclined surface rising to the boss surface 4 of the breaker groove 8 to curl due to the force of forcibly bending and deformed into a shape that is easily discharged. However, on the one hand, this causes an increase in cutting resistance. In the present invention, the substantially circular recesses 11 arranged in parallel on the inclined surface 10 of the breaker groove 8 and the inclined surface 13 lower than the inclined surface 12 aim to reduce the area of scraping between the chips and the inclined surface. Therefore, the cutting resistance is further reduced.

As mentioned above, the axial rake angle α is attached to the front milling cutter 14 so as to be a regular angle when the positive type throw-away tip is used. In the present invention, the main cutting edge 5 in the vicinity of the corner blade 6 is gradually lowered so that the axial rake angle α becomes a larger positive angle to reduce cutting resistance and at the same time This is for making the scrap into a coiled chip shape that is easy to process when it receives a force that extends in the axial direction.

The auxiliary cutting edge 7 of the throw-away tip 1 is
Since it is attached to the front milling cutter 14 to form a front cutting edge, the angle δ formed with the main cutting edge 5 is 0.5 ° so that the auxiliary cutting edge 7 faces the front side corresponding to the corner angle γ. It is set to be in the range of 2 °. Then, if the radius R of the arcuate sub-cutting edge 7 is increased, some angular assembly error of the throw-away tip 1 is absorbed, and a wavy transfer surface is formed by a continuous constant arc. To be done. As a result, good processed surface roughness can be obtained.

[0025]

As described above, according to the present invention, the cutting resistance is reduced by the action of the breaker groove and the main cutting edge in the right-angled shoulder milling face milling cutter to which the square type positive throw-away tip is mounted. It is possible to realize a face milling machine that excels in chip discharge while having good sharpness. Further, due to the action of the arcuate auxiliary cutting edge, it becomes possible to obtain a machined surface having a good machined surface roughness.

Since it is a square throw-away tip, it has a large number of main cutting edges that can be used out and has a high fracture resistance due to the effect of the 90 ° vertical angle.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a front view of FIG. 2;

FIG. 4 is an enlarged view of a corner portion of FIG.

5 is a cross-sectional view taken along the line AA of FIG.

6 is a cross-sectional view taken along the line BB of FIG.

FIG. 7 is a perspective view showing another embodiment of the present invention.

FIG. 8 is a plan view of FIG.

9 is a front view of FIG. 8. FIG.

10 is a cross-sectional view taken along the line CC of FIG.

FIG. 11 is a plan view showing an embodiment of a front milling cutter for right-angled shoulders to which the throw-away tip of the present invention is attached.

12 is a partial front view of FIG.

[Explanation of symbols]

 1 Throw-away tip 4 Boss surface 5 Main cutting edge 6 Corner cutting edge 7 Secondary cutting edge 8 Breaker groove 9, 10, 12, 13 Sloping surface 11 Recess 14 Front milling cutter α Axial rake angle β Center rake angle γ Corner angle δ Main Angle with cutting edge

Claims (3)

[Claims] 1. A throw-away tip to be mounted on a face milling cutter 14 for right-angle shoulder milling, which is formed so that a corner angle γ is approximately 0 °, and has a square flat plate shape, and an outer periphery thereof. In a positive throw-away tip provided with relief, the upper surface 2 of the throw-away tip 1 has a boss surface 4 arranged at the center and a slightly lower position than the boss surface 4 on the outer side thereof. The cutting edge portion is provided, and the cutting edge portion includes a main cutting edge 5 having four outer edges, an arcuate corner edge 6 formed at a corner, and the main cutting edge 5
And the corner blade 6 and the front cutting edge when mounted on the front milling cutter 14 is formed so that the angle δ with the main cutting edge 5 is 0.5 ° to 2 °. It consists of a sub cutting edge 7 consisting of a circular arc and a breaker groove 8 along each cutting edge, and the breaker groove 8 is an inclined surface that is inclined at least gradually toward the central portion from the main cutting edge 5. 9
And a sloped surface that rises toward the boss surface 4, and the main cutting edge 5 is formed so as to be gradually lower within a certain range as the main cutting edge 5 is separated from the corner edge 6. A throwaway tip for face milling. 2. An inclined surface 1 rising toward a boss surface 4.
2. The throw-away tip for face milling according to claim 1, wherein substantially circular recesses 11 are arranged on 0 in parallel with the main cutting edge 5. 3. The sloped surface rising toward the boss surface 4 is composed of a first sloped surface 12 and a second sloped surface 13, and the second sloped surface 13 is a first sloped surface 12.
The throw-away tip for face milling according to claim 1, which is formed so as to be lower than the extension plane of the.