JP2003191110A - Throwaway tip for face milling cutter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throwaway tip having a breaker groove particularly suitable for milling stainless steel. <P>SOLUTION: The breaker groove 6 hugging a whole circumference with a cutting edge in another side of a narrow land 7 is provided on a top face of a tip body 1 which is a positive tip. The breaker groove 6 has inclined faces 8 and 9 where a rake angle θ2 in a frontal cutting edge 4 is 10-20° and a rake angle θ1 in an outer circumferential cutting edge 3 is 15-25°. Recessed grooves 10 are added to the inclined faces 8 and 9 throughout whole circumferences. Protrusions 12 are formed to hug the outer circumferential cutting edge 3 on a wall surface 11 rising from a groove bottom to the top face. <P>COPYRIGHT: (C)2003,JPO

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 for face milling, and more particularly to a breaker groove suitable for cutting stainless steel.

[0002]

2. Description of the Related Art Since milling is basically an interrupted cutting, breaker grooves for cutting chips have long been unnecessary. However, even for positive-type cutting edge chips, it has been rapidly put into practical use after it has been found that the performance such as cutting resistance and chip discharge can be further improved by providing the breaker groove. Recently, due to improvements in powder molding technology, manufacturers have provided indexable inserts having breaker grooves with complicated shapes.
For example, JP-A-6-179111 and JP-A-8-
Examples include those disclosed in Japanese Patent No. 57709, Japanese Patent Laid-Open No. 8-174327, and the like.

[0003]

The conventional indexable inserts as exemplified above are suitable for milling general steel materials. Therefore, while arranging the breaker groove on the outer peripheral cutting edge part, the front cutting edge part has a rake angle of 0 ° or comparison to prevent cutting edge damage such as chipping due to impact when biting on the work material. The rake angle is set to a weak angle. The introduction of such throw-away inserts has greatly improved cutting performance, but its high ductility and work hardening tend to occur, so it is not sufficient for cutting stainless steel, which is one of the difficult-to-cut materials. , Especially the chips and fine chips deposited on the front cutting edge part roughen the processed surface.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and is a positive chip in which a side face of a polygonal flat plate-shaped chip body is provided with a clearance angle, and an upper surface thereof is provided. Is a throw-away tip for face milling in which breaker grooves are provided along the entire circumference of the cutting edge, the breaker groove is formed by sandwiching a narrow land between the cutting edge and the front cutting edge. Rake angle at 10 to 20 °, rake angle at the outer peripheral cutting edge is 15 to 25
There are slanted surfaces that are at an angle of 0 °, concave grooves are provided all around the slanted surfaces, and protrusions are formed along the outer peripheral cutting edge in the wall surface that rises from the groove bottom to the upper surface. Characterize. Further, the front cutting edge is mounted on the front milling cutter with a dish angle of 5 to 30 '.

The rake angle of the outer peripheral cutting edge is set to 15 to 25 °, which is suitable for cutting stainless steel. This is because if the angle is less than 15 °, the rake effect is not sufficiently observed, and if the angle exceeds 25 °, the cutting edge strength decreases. For the front cutting edge,
It was confirmed that the rake angle should be offset from the outer peripheral cutting edge by 5 ° to the negative side because there is an impact when biting into the work material. In order to prevent the cutting edge strength from being lowered due to such a large rake angle, a narrow land is used. Specifically, the land width is 0.1
0.3 mm is preferable, and the edge strength can be further improved by adding chamfered honing with a width of about 1/2 thereof.

Further, in this breaker groove, a concave groove is provided on the inclined surface forming the rake angle so that the chips flowing out do not come into strong contact with the wall surface of the groove to cause an increase in cutting resistance or chip welding. A protrusion is provided in the middle of the wall surface that rises from the bottom to the upper surface to form a non-contact portion between the chip back surface and the breaker groove surface. In addition, providing an extremely small dish angle of 5 to 30 'prevents the front cutting edge and the processing surface from hitting the entire surface and fine chips are pressed against the processing surface. It is designed to obtain a flat machined surface with a small dish angle.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. The throw-away tip shown in FIGS. 1 and 2 is a positive tip in which four corners of a rectangular flat plate-shaped tip body 1 are chamfered and a side surface 2 including a chamfered portion is provided with clearance angles all around. A cutting edge is formed on a ridge line intersecting the upper surface of the chip body 1 and the side surface 2, and a main ridge line portion of the cutting edge is the outer peripheral cutting edge 3. The chamfered portion is the front cutting edge 4 arranged on the front side of the milling cutter when the throw-away tip is mounted. More specifically, a smaller chamfering blade 5 is attached to the corner where the outer peripheral cutting edge 3 and the front cutting edge 4 intersect to improve the fracture resistance of the corner.

A breaker groove 6 is provided on the upper surface of the chip body 1.
However, it is provided on the entire circumference with a narrow land 7 interposed between the cutting edge and the cutting edge. As shown in FIG. 3, the breaker groove 6 has an inclined surface 8 at which the rake angle θ1 at the outer peripheral cutting edge 3 is 15 to 25 °, and as shown in FIG. 4, the rake angle θ2 at the front cutting edge 4 is shown. Is formed having an inclined surface 9 having an angle of 10 to 20 °. A concave groove 10 is attached to the inclined surfaces 8 and 9 over the entire circumference. In this embodiment, the arcuate groove 10 is used. Further, a protrusion 12 is arranged along the outer peripheral cutting edge 3 in the wall surface 11 rising from the groove bottom of the breaker groove 6 to the upper surface. In this embodiment, the mountain-shaped projections 12 are arranged side by side, but they may be arranged in a bank shape.

The rake angle θ1 of the outer peripheral cutting edge 3 is selected to be the optimum angle for cutting stainless steel. If the rake angle θ1 is too large, the fracture resistance is deteriorated, but due to the combination with the reinforcing effect of the land 7, θ1 =
It realizes a large rake angle of 25 °. The rake angle θ1 of 15 ° is the lower limit for preventing chip welding during cutting of stainless steel. The rake angle θ2 of the front cutting edge 4 is in the range of a small rake angle minus 5 ° from θ1 in order to withstand the impact when biting on the work material.

The chips generated by the cutting blade flow out by rubbing the inclined surfaces 8 and 9, but do not rub in the concave groove portion 10, so that the entire rubbing area can be kept small.
In addition, the wall surface 1 that originally exerts a forced deformation action on the chips
Providing the protrusions 12 on the 1 also has the effect of preventing the pressure contact and the increase in cutting resistance caused by strong rubbing by reducing the chip contact area.

When the throw-away tip of the present invention is mounted on a face mill, as shown in FIG. 5, the face cutting edge 4 has a dish angle β of 5 to 30 'with the work material 13. To be installed. In the case of milling of stainless steel, the cause of roughening the machined surface is not only the welding but also the fact that fine chips generated by the front cutting edge 4 are pressed against the machined surface. Welding angle is rake
It is suppressed by the effect of 2, and the pressure bonding of the chips is prevented by the dish angle β. However, if the dish angle β is too large, the theoretical surface roughness becomes large, so this is not recommended.

FIG. 6 shows the results of tests carried out by changing the combination of the rake angle θ2 and the dish angle β of the front cutting edge 4 in the milling of stainless steel, and the state of the machined surface is judged by the amount of the pressure-bonded object. It was done. From this, the effects of the rake angle θ2 and the dish angle β can be confirmed.

[0013]

EFFECTS OF THE INVENTION The throw-away insert for face milling according to the present invention has ductility such as stainless steel due to the unique breaker groove provided on the upper surface of the positive insert and the dish angle formed when the face milling is installed. For highly difficult-to-cut materials, the cutting resistance of the cutting edge is not impaired, welding is less likely to occur, and cutting with reduced cutting resistance becomes possible. Further, the machined surface becomes good, but particularly fine chips are not pressed to roughen the machined surface.

[Brief description of drawings]

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

FIG. 2 is a side view of FIG.

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

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

FIG. 5 is an explanatory diagram of a cutting state showing a relationship between a front cutting edge and a work material.

FIG. 6 is a result of a cutting test in which the state of a pressure-bonded object is examined.

[Explanation of symbols]

3 outer cutting edge 4 front cutting edge 6 breaker grooves 7 land 10 groove 12 protrusions θ1, θ2 rake angle β dish angle

Claims (2)

[Claims] 1. A throw for a face milling machine, which is a positive chip having a polygonal flat plate-shaped chip body with a clearance angle provided on a side surface thereof, and whose upper surface is provided with a breaker groove along the entire circumference of a cutting edge. In the away tip, the breaker groove is formed by sandwiching a narrow land between the cutting edge, and the rake angle of the front cutting edge is 10 to 20 ° and the rake angle of the outer peripheral cutting edge is 15 to 25 °. Has inclined surfaces, and concave grooves are attached to these inclined surfaces over the entire circumference,
A throw-away tip for face milling, characterized in that a projection along the outer peripheral cutting edge is formed in the wall surface rising from the groove bottom to the upper surface. 2. The throw-away tip for a front milling cutter according to claim 1, wherein the front cutting edge forms a dish angle of 5 to 30 ′ and is mounted on the front milling cutter.