KR20090093496A - Cutting insert - Google Patents

Abstract

A cutting insert is provided to lengthen the service life of a tool by minimizing cutting load and to improve productivity by performing high feed with suppressing vibration. A cutting insert(3) of a polygonal shape comprises an upper surface(10a), a lower surface(10b), and lateral sides. A screw hole(3sh) passes through the center of the lower surface and the upper surface. The lateral sides surround the upper and lower surfaces. One among the lateral sides forms a reference surface(10c). A pair of cutting edges are formed anti-symmetrically to a cutting surface(10d) opposed to the reference surface. A pair of cutting edges have sub and main cutting edge units respectively.

Description

Cutting inserts {CUTTING INSERT}

The present invention relates to an indexable type high feed cutting insert used for heavy cutting and finishing, and more particularly, it is possible to perform smooth cutting in a high feed area while improving machining quality by reducing cutting resistance during cutting. The present invention relates to a cutting insert capable of improving the productivity of a product by optimizing a cutting edge so as to be effective.

In general, a cutting tool is mainly used for cutting ferrous, nonferrous metals, and nonmetallic materials, and is a tool that is usually mounted on a machine tool and performs cutting to process a workpiece into a desired shape. Typically, such a cutting tool consists of a cutting insert with a cutting edge and a cutter body for holding the cutting insert.

On the other hand, there are two main methods for cutting metal using a cutting tool. Firstly, turning is performed by contacting a pickled portion of a cutting tool fixed to a rotating metal workpiece. And secondly, a tool having a cutting edge, i.e., a cutting insert, is secured to a machine tool using a holder for a tool, and then under this condition, the cutting tool is rotated and contacted with a fixed workpiece before Milling is included in the shape.

In addition, the cutting tool can be divided into brazing type and indexable type according to the method of fixing the cutting insert to the cutter body. The brazing type brazes the cutting insert to a part of the cutter body. Permanently fixed, the indexable type is to mount and detach the cutting insert to the cutter body using a fixing means provided in the cutter body.

Indexable cutting tools can be easily replaced with new ones in a short period of time when the picklings reach the end of their life, thus reinforcing the problem of the brazing type cutting tool, that is, the disadvantage of having to regrind the cutting edge for a long time. As a tool, it is currently used in all parts of cutting tools.

Recently, as the market trend of cutting tools requires high productivity and high quality, various processing must be performed to improve productivity, and stable cutting performance must be achieved even at high feed and high cutting speeds for high quality and high production processing.

Particularly, in the case of a mold processed product, time productivity is very important, and for this, high feed processing may be an alternative. High feed processing means that the material removal rate (MRR) is greatly improved by reducing the production cost and production time by processing at high feed rate without increasing the cutting speed and spindle rotation compared with the conventional processing method.

Such high feed processing types typically include a method of increasing table feeds per hour by increasing the number of blades applied, and a method of increasing feeds per blade by reducing cutting loads per cut length.

First, the method of increasing the feed per hour by increasing the number of application days, the cutting insert sheet (population) and the screw seat must be manufactured in the tool body because a large number of inserts must be tightened, resulting in a larger machining diameter of the tool It becomes difficult to manufacture a small diameter product required for actual cutting. A feature of the conventional high feed tool is configured to insert a plurality of inserts having a triangular or square shape into the tool body.

However, the structure of inserting a plurality of inserts has to make the insert seat and the screw seat separately in the tool body, and the clamping structure is weak, which makes it difficult to apply to the production of high feed and hard products.

Therefore, it is urgent to develop cutting inserts that can be expected to improve economics, work quality, and productivity through high feed processing according to the cutting tool market.

The present invention was created in order to solve the problems of the prior art as described above, and an object of the present invention is to insert a high feed insert and shank of the insert type, which are mainly used for the medium cutting and finishing of the mold. The present invention provides a cutting insert capable of improving productivity by forming a special cutting edge suitable for high feed so that vibration is suppressed while cutting load is small during cutting.

Cutting insert according to an embodiment of the present invention for realizing the above object, the cutting insert of a polygonal shape consisting of the upper surface and the lower surface through which the screw hole is formed in the center and the sides surrounding the upper and lower surfaces In one aspect of the present invention, one side of the side surface is formed as a reference surface and the opposite cutting surface is characterized in that a pair of cutting edges having a subcutaneous part and a major cutting part, respectively, is anti-symmetrically formed.

As a preferable preferable feature of the present invention, the main cutout portion is formed by a combination of one or more straight lines and two or more curves.

As another preferable feature of the present invention, the major cutout portion is composed of a combination of a curve, a straight line, and a curve.

As another preferred feature of the present invention, the major cutout portion is composed of a combination of a curve, a straight line, a curve, a straight line, and a curve.

In another preferred embodiment of the present invention, a first reset groove for inducing chip discharge is formed at a boundary line of the pair of cutting edges, and a second reset groove stepped toward the reference plane is formed at a side adjacent to the reference plane. It is in becoming.

In another preferred aspect of the present invention, the side surface of which the second reset groove is formed has an inclination angle of 1 to 10 ° with respect to the surface adjacent to the reference plane at right angles.

As another preferable feature of the present invention, the cutting surface includes a subcutaneous part having an inclination of 0 to 3 ° and a main cutting part having an inclination of 0 to 15 °.

As another preferable feature of the present invention, a coolant groove is formed in the upper and lower surfaces.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in this specification and claims are not to be interpreted in a conventional and dictionary sense, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

The cutting insert according to the present invention has the advantage of being able to expect higher productivity than the conventional products because the cutting insert is not only less cutting load during cutting processing but also vibration is suppressed by forming a cutting line suitable for high feed.

In addition, it is possible to extend the life of the tool by minimizing the cutting load can reduce the interruption of work due to tool replacement and reduce the replacement cost.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the invention described in the claims. You will understand.

1 and 2 are a perspective view showing a cutting insert according to the present invention,

3 is a plan view showing the cutting insert shown in FIG.

4 is a front view showing the cutting insert shown in FIG.

5 is a side view showing the cutting insert shown in FIG.

6 is a view for explaining a chip change according to the cutting shape of the cutting insert,

7 is an enlarged view illustrating main parts for explaining a main cutting part in a cutting insert according to the present invention;

8 is a perspective view showing a coolant application structure of the cutting insert according to the present invention.

Explanation of symbols on the main parts of the drawing

1: cutting tool 3: cutting insert

5: Tool Body 5a: Seat Part

7: tightening screw 10: cutting edge

10a: upper surface 10b: lower surface

10c: reference plane 10d: cutting plane

11: temple staff 13: temple staff

The objects, features and advantages of the present invention described above will become more apparent from the following detailed description.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

First, it should be noted that like elements or parts in the drawings are denoted by the same reference numerals as much as possible. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted in order not to obscure the subject matter of the present invention.

1 and 2 are a perspective view showing a cutting insert according to the present invention, Figure 1 is a perspective view showing a cutting tool to which the cutting insert of the present invention is applied, Figure 2 is a perspective view showing a cutting insert according to the present invention.

As shown in the figure, the cutting tool 1 of the present invention is capable of multi-purpose milling such as planar machining, inclined machining, imitation processing, groove processing, etc., and the cutting insert 3, the tool body 5, and the fastening screw It consists of (7).

Here, the cutting insert (3) is mainly made of cemented carbide materials using a powder metallurgy process, that is, a process such as mold pressure, sintering, grinding, etc., and a cutting edge is used for cutting ferrous or nonferrous metals. . The cutting insert 3 has a rectangular shape having a predetermined thickness, and a screw hole 3sh penetrating through the upper surface 10a and the lower surface 10b is formed.

The tool body 5 has a seat portion 5a formed therein so that the cutting insert 3 can be inserted therein, and the seat portion 5a has a through hole into which the fastening screw 7 is inserted and seated. 5ah) is formed.

FIG. 3 is a plan view showing the cutting insert shown in FIG. 1, FIG. 4 is a front view showing the cutting insert shown in FIG. 1, and FIG. 5 is a side view showing the cutting insert shown in FIG. 1.

As shown in the drawing, the cutting insert 3 is a member having a rectangular plate shape having a predetermined thickness in which a screw hole 3sh is formed at the center thereof, and an upper surface 10a and a lower portion where the screw hole 3sh is formed. A surface 10b and sides surrounding the upper surface 10a and the lower surface 10b, one side of which one of the side surfaces is fastened to the tool body 5. And a cutting surface 10d is formed on the side opposite to the reference surface 10c.

Here, the cutting surface 10d is provided with cutting edges 10 for forming the subcutaneous portions 11 and the major cutting portions 13 on both sides with respect to the vertical line DL2, and the pair of cutting edges 10 is provided. ) Is formed to have an antisymmetrical shape about the vertical line DL2. That is, the pair of cutting edges 10 are designed to exactly match each other when rotated 180 degrees with respect to the vertical line DL2.

On the other hand, the cutting edge 10 is composed of a cutting edge portion 11 and the main cutting edge portion 13, in the present invention, the cutting edge portion 13 is minimized in consideration of the maximum cutting amount in order to enable high feed. , By combining the curve and the straight line to maximize the contact surface than the cutting edge of the straight line to disperse the cutting force according to the cutting amount and to reduce the transfer load.

That is, in the present invention, the cutting edge 10 is formed diagonally Θ about the thickness center of the cutting insert 3, that is, the horizontal line DL1, to increase rigidity.

In addition, the first reset to the boundary line of the pair of cutting edges 10, that is, the vertical line DL2, so that the cutting chips can be smoothly discharged while preventing the cutting chips from being caught on the upper, lower, and lateral sides of the cutting insert 3. A groove 15 is formed, and a stepped second reset groove 17 is formed on the side surface adjacent to the reference surface 10c to be recessed toward the reference surface 10c. The first reset groove 15 and the second reset groove 17 may be appropriately modified according to the size or shape of the cutting insert 3.

FIG. 6 is a view for explaining the chip change according to the cutting shape of the cutting insert. Referring to the chip change under the same conditions according to the cutting shape of the cutting insert 3, the chip thickness hm is a cutting edge in the milling tool. angle), the smaller the cutting edge angle at the same infeed and same feed, the thinner the cutting chip thickness and the smaller the cutting load.

On the other hand, the equation for calculating the cutting chip thickness can be calculated using hm = fz x sin (cutting edge angle), where hm is the average chip thickness, and (cutting edge angle = Cutting edge Angle) is the angle shown in FIG. . That is, as shown in (a) and (b) of FIG. 6, in the case of the corner radius type having a cutting edge angle of 90 ° and the high feed type having a small cutting edge angle (cutting angle of 20 °), the cutting edge angle is compared with the chip thickness. For corner-R type with 90 °, hm = fz, but for high feed type with 20 ° cutting edge angle, hm = 0.34 * fz. The small chip thickness means that the load is small, which means that the high feed processing is possible because the load becomes small.

In Figs. 6B and 6C, which are variations in chip thickness, in the case of (c), the chip thickness in a curved shape rather than a linear shape is shown. As shown in (c), the chip thickness can be seen that the thickness of the chip increases proportionally as the depth of cut increases. In other words, the lower the depth of cut, the smaller the cutting force. In general, the medium-finishing process of the mold is processed under a condition that the amount of cut is small, it is possible to feed higher than conventional products.

On the other hand, the cutting edge portion 13 in the cutting insert 3 is made of a combination of a curve and a straight line. That is, as described in FIG. 6, the cutting edge of the main cutting part 13 is configured by a plurality of segments (combination of a curve and a straight line) rather than a linear line to minimize the angle of the cutting edge, thereby reducing the cutting load. In addition, by forming a non-linear curved edge, the mechanical impact is reduced and the corner strength is increased. In general, the rigidity is increased when manufacturing an insert with a large R-shaped radius, but this product is difficult to produce an insert with a relatively large R-shaped because it must have a small diameter holder. Therefore, it should be composed of a combination of straight lines and curves.

In addition, the cutting edge is formed as a curved line rather than a straight line, and the section where each straight line and the curve are connected is tangentially connected. The angle from the bottom of the main cutting edge to the center point of the nose-R (not a true measurement because it is a combination of a curve and a straight line, not a straight line) is between 5˚ and 15˚, and the sub-cutting edge angle is formed between 0˚ and 3˚. have. If the sub cutting edge gets bigger, the surface roughness becomes poor, so the sub cutting edge is larger than 0 ° and it should be manufactured within 1 ° to get excellent surface finish.

Moreover, the magnitude | size of the radius R of the principal cutting part which connects the straight line of a main cutting edge angle and a straight line is R1> R2 or R1> R2> R3. The incidence angle was limited to 0˚ ~ 3˚ to secure the surface finish even in the face and ramping for medium and finishing.

Chip thickness and cutting force vary according to cutting edge angle under the same processing conditions. If the cutting edge angle is 90˚ and there is a slope, the average chip thickness will be different.

8 shows a coolant hole 5h penetrating through the tool body 5 from the end to the seat portion 5a so as to guide the coolant to the cutting portion during cutting, and the cutting insert 3 has a screw hole. A coolant groove 19 is formed around the 3sh, and is provided to enable internal oil supply during cutting.

On the other hand, the present invention is not limited to the described embodiments, it is obvious to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, such modifications or variations will have to belong to the claims of the present invention.

Claims (8)

In the cutting insert of the polygon shape consisting of the upper and lower surfaces with a screw hole through the center and the sides surrounding the upper and lower surfaces, One of the side surfaces is a cutting insert, characterized in that the opposite of the cutting surface is formed by a pair of cutting edges having a cut-out portion and a major cut-away portion oppositely formed. The cutting insert according to claim 1, wherein the major cutout shape is a combination of one or more straight lines and two or more curves. The cutting insert according to claim 1 or 2, wherein the major cutting portion is a combination of a curve, a straight line, and a curve. The cutting insert according to claim 1 or 2, wherein the major cutting portion is a combination of a curve, a straight line, a curve, a straight line, and a curve. The method of claim 1, wherein a first reset groove for inducing chip discharge is formed at a boundary line of the pair of cutting edges, and a second reset groove stepped toward the reference plane is formed at a side adjacent to the reference plane. Cutting inserts. 6. The cutting insert according to claim 5, wherein the side surface on which the second reset groove is formed has an inclination angle of 1 to 10 degrees with respect to a surface perpendicular to the reference surface. The cutting insert according to claim 5, wherein the cutting surface comprises a cutout portion having an inclination of 0 to 3 ° and a major cutout portion having an inclination of 0 to 15 °. The cutting insert according to claim 1, wherein coolant grooves are formed on upper and lower surfaces thereof.