JPH04283009A - Throw-away tip - Google Patents

Abstract

PURPOSE:To improve the sharpness of a tool at the time of cutting and to increase the strength of a tool edge against shock caused by chips by forming the tool edge part on the side of a tip body so that a clearance angle may continuously change from a nose radius part toward the center of a cutting edge part. CONSTITUTION:The clearance angle on a clearance face formed on the side of a tip body near a nose radius part 7 is increased to the maximum to make a tool edge sharp. The clearance angle is moreover continuously decreased in the direction withdrawing from the nose radius part 7 along the tool edge part to turn into zero near the center of the tool edge part.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tip shape capable of improving the tip strength and workability of indexable inserts used for cutting.

0002

2. Description of the Related Art A throw-away tip is a tool tip that is attached to a holder and used for cutting metal materials. An example of a conventional indexable tip is shown in FIG. Figure 6 shows the special public service issued in 1977-253.
22 is a plan view of the throw-away tip disclosed in Publication No. 22. FIG. Referring to FIG. 6, the indexable tip 1 has a triangular flat plate shape, and cutting edges 10 are formed at positions corresponding to each side of the triangle. The portion corresponding to the apex of the triangle constitutes the nose radius portion 7, and the cutting edges 10, 10 adjacent to each other are provided so as to be continuous. A chip breaker groove 3 is formed in the inner portion of the indexable insert 1 along the cutting edge 10 for breaking chips of a workpiece. Also, throw away tip 1
This indexable tip 1 is placed in the tip holder in the center of the
A mounting hole 8 for mounting is formed.

[0003] In general, indexable tips used for cutting are required to have the following characteristics due to the structure of the tip. The first is to reduce cutting resistance and improve cutting quality. For this purpose, it is effective to reduce the wedge angle of the nose radius of the indexable tip. Also,
The second purpose is to prevent chipping at the boundary due to uneven thickness on the surface of the workpiece and chipping due to chips hitting the cutting edge. For this purpose, it is effective to increase the wedge angle at the center of the cutting edge of the indexable insert.

In order to satisfy these two requirements, the following structure has been proposed for the conventional throw-away chip shown in FIG.

FIG. 7 is a cross-sectional structural diagram taken along the cutting line A-A in FIG. 6, and FIG.
FIG. 3 is a cross-sectional structural diagram taken along the direction -B. Referring to both figures, this indexable insert 1 has a small wedge angle formed between the cutting edge land 4 and the side surface 5 in the vicinity of the nose radius section 7 which has a major effect on cutting, and also has a small wedge angle between the cutting edge land 4 and the side surface 5. In the central portion, a reinforcing surface 9 is formed in contact with the cutting edge land 4, thereby forming a large wedge angle of the cutting edge portion 10. This structure improves the cutting quality near the nose radius and increases the strength of the cutting edge near the center of the cutting edge. Note that a similar structure was published in JP-A-62
-173104 publication is also disclosed.

However, in the above structure, the cutting edge land 4 and the chip breaker groove 3 are continuously formed on the same plane. Therefore, if the wedge angle of the cutting edge portion 10 is to be formed at an acute angle, the chip breaker groove must be formed deeply. However, the depth of the concave portion of the chip breaker groove 3 is determined based on the requirements for the chip disposal characteristics of the work material. Therefore, it is not preferable in terms of chip disposal characteristics that the shape of the chip breaker groove 3 is limited by the conditions for forming the wedge angle of the cutting edge.

[0007] Furthermore, as another method that satisfies the above two conditions required for the throw-away tip, a structure as shown in FIG. 9 has been proposed. Figure 9 shows the special public service issued in 1111, 1973.
FIG. 2 is a perspective view of the throw-away tip shown in Publication No. 06. Referring to FIG. 9, this indexable insert has a recess 13 in the vicinity of the nose radius section 7 sandwiched between the flank surfaces 12 of the tool, and a wedge of the cutting edge 10 composed of the rake surface 11 and flank surface 12 of the tool. The corners are formed to be acute, especially near the nose radius portion 7. Further, in the main portion of the cutting edge portion 10, the wedge angle of the cutting edge portion constituted by the rake face 11 and the flank face 12 is formed to be an obtuse angle compared to the vicinity of the nose radius portion 7. This improves the cutting quality of the tool near the nose radius section 7 and increases the strength of the cutting edge section at the center of the cutting edge section 10.

However, such a structure has a limitation in that it can only be processed by polishing with a normal grindstone, and therefore, the recess 13 is limited to a location in the vicinity of the nose radius portion 7. Therefore, there is a problem in that the portion that contributes to improving the sharpness of the cutting edge portion is limited to a narrow area.

[0009] Therefore, the present invention has been made to solve the above-mentioned problems, and is to provide a throw-away system that can improve cutting quality without impairing chip disposal characteristics and increase the strength of the cutting edge of the chip. The purpose is to provide tips.

0010

[Means for Solving the Problems] The indexable tip according to the present invention is a flat plate having a polygonal shape and consisting of a pair of upper and lower main surfaces parallel to each other and a side surface connecting the upper and lower main surfaces. It has a shaped main body, a cutting edge formed along the intersection line of the upper and lower main surfaces of the main body and the side surface, a rake surface formed on the upper and lower main surfaces, and a flank surface formed on the side surface. . The clearance angle formed by the side surface and a plane passing through the cutting edge and perpendicular to the upper and lower main surfaces is maximum near the end of the cutting edge formed along one side of the upper and lower main surfaces. , is characterized in that it is formed so as to gradually change to 0 at the center.

Furthermore, in the indexable tip according to another invention, chip breaker grooves are formed on the upper and lower main surfaces of the tip body along the cutting edge.

0012

[Operation] The indexable insert according to the present invention improves the cutting quality by forming the cutting edge at an acute angle by forming a large relief angle near the nose radius section which performs the main cutting function. In addition, in the area where chipping caused by chips hitting the chip surface is a problem, that is, near the center of the cutting edge, the clearance angle is set to 0 and the wedge angle of the cutting edge, which is composed of the rake face and the flank face, is increased. This prevents chipping caused by the impact of chips.

[0013]

[Embodiments] Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

FIG. 1 is a plan view of an indexable tip according to an embodiment of the present invention, and FIG. 2 is a side view thereof. Referring to both figures, the indexable tip 1 has a substantially triangular plate shape composed of upper and lower main surfaces 2, 2 and a side surface 5. As shown in FIG. A nose radius portion 7 is provided at each apex portion of the triangular shape.
is configured. A cutting edge portion 10 is formed along the intersection line between the upper and lower main surfaces 2, 2 and the side surface 5. A cutting edge land 4 is continuously formed inside the cutting edge portion 10 within the plane of the upper and lower main surfaces. Furthermore, a chip breaker groove 3 is formed along the inside of this cutting edge land 4. Furthermore, a mounting hole 8 is formed in the center of the indexable tip 1 for attachment to a tip holder.

Note that this indexable tip 1 is formed by injection molding. Therefore, an injection molded gate 6 is formed on the side surface of the indexable tip 1.

Next, the shape of the cutting edge portion of the indexable tip 1 according to this embodiment will be explained. Figure 3 is Figure 1
FIG. 4 and FIG. 5 are cross-sectional views taken along section line III-III in FIG.
FIG. 4 is a cross-sectional structural view taken from a direction along V and a cutting line V-V. The cut shows the shape of the cutting edge near the nose radius 7, and shows the state where the clearance angle θ1 of the clearance surface 12 formed on the side surface 5 of the chip is at its maximum. Moreover, FIG. 4 shows the cross-sectional shape of the cutting edge at a position L/2 with respect to the distance L from the nose radius portion 7 to the position where the clearance angle is 0. Furthermore, FIG. 5 shows the position of the distance L, that is, the clearance angle θ3
shows the cross-sectional structure of the cutting edge at the position where is 0.

With respect to the shape of the cutting edge shown in FIGS. 3 to 5,
In the case of indexable inserts for general-purpose cutting of stainless steel materials, the depth of cut is mainly 1 to 5 mm, and the distance L = 4.0 to 5 mm.
5.0mm, relief angle θ1 = 7° ~ 15°, θ2 = 5
It is desirable to set θ3 to 10° and θ3 = 0°.

In addition, in the case of an indexable insert for finish cutting of mild steel, distance L = 2.0 to 4.0 mm, clearance angle θ1 = 10° to 20°, θ2 = 5° to 10°, θ
3 = 0° is preferred.

Furthermore, in indexable inserts for rough cutting of general steel, distance L = 3.0 to 7.0 mm, relief angle θ1 = 5° to 10°, θ2 = 2° to 5°, θ3
=0° is preferred.

Further, chip breaker grooves 3 are formed on the upper and lower main surfaces 2 of the indexable chip 1. Therefore, the shape of the concave portion of the chip breaker groove 3 can be set to an optimal shape depending on the characteristics of chip disposal. This is because the shape of the cutting edge in terms of cutting quality or strength of the cutting edge is determined by the value of the clearance angle θ1 to θ3 of the flank 12 formed on the side surface 5 of the chip, and has no effect on the shape of the chip breaker 3. This is because it does not give

[0021] In the above embodiment, a triangular plate-shaped indexable tip has been described, but the tip shape is not limited to this, and other polygonal-shaped indexable tips such as a rectangular plate shape can be used. It goes without saying that the present invention can also be applied to.

[0022]

[Effects of the Invention] As described above, the indexable insert according to the present invention has a cutting edge section on the side surface of the insert body so that the relief angle changes continuously from the nose radius toward the center of the cutting edge. , it is possible to realize an indexable insert that has improved cutting quality during cutting and has increased strength of the cutting edge against impact from chips.

In addition, by forming the chip breaker groove on the upper and lower main surfaces, which are different from the flank surface, an indexable insert is realized that improves the sharpness and strength of the cutting edge and independently maintains the optimum chip disposal characteristics. can do.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an indexable tip according to an embodiment of the invention.

FIG. 2 is a side view of the indexable tip shown in FIG. 1.

FIG. 3 is a cross-sectional structural diagram taken along the cutting line III-III shown in FIG. 1;

4 is a cross-sectional structural diagram taken along cutting line IV-IV in FIG. 1. FIG.

5 is a cross-sectional structural diagram taken along the cutting line V-V in FIG. 1. FIG.

FIG. 6 is a plan view of a conventional indexable tip.

7 is a cross-sectional structural diagram taken along the cutting line AA in FIG. 6. FIG.

8 is a cross-sectional structural diagram taken along the cutting line BB in FIG. 6. FIG.

FIG. 9 is a perspective view of another conventional indexable tip.

[Explanation of symbols]

1 Throwaway tip 2 Upper and lower main surfaces 3 Chip breaker groove 4 Cutting blade land 5 Side 7 Nose radius part 10 Cutting blade part 12 Relief surface

Claims (2)

[Claims] 1. A flat main body having a polygonal shape and consisting of a pair of upper and lower main surfaces parallel to each other and a side surface connecting the upper and lower main surfaces, the upper and lower main surfaces of the main body In the indexable insert, the insert includes a cutting edge formed along a line of intersection with a side surface, a rake face formed on the upper and lower main surfaces, and a flank surface formed on the side surface, the side surface being The clearance angle formed by the side surface and the plane passing through the cutting edge and perpendicular to the upper and lower main surfaces is maximum near the end of the cutting edge formed along one side of the upper and lower main surfaces, and the clearance angle is at the center. 1. A throw-away tip, characterized in that the tip is formed so as to gradually change to 0 at a certain point. 2. The indexable insert according to claim 1, wherein a chip breaker groove is formed in the upper and lower main surfaces along the cutting edge portion.