KR20080094751A - Cutting inserts with corner projections - Google Patents

Abstract

The present invention discloses a cutting insert for a cutting tool having a structure capable of effectively controlling the chips generated in the workpiece. The cutting insert according to the invention has an upper surface, a lower surface and a central hole formed in a plurality of side and center portions connecting them. In addition, a flat seating surface is formed at the highest height of the upper surface, a plurality of side cutting edges are formed at the boundary between the top surface and the plurality of side surfaces, and a corner having a cutting edge is formed at the boundary between two adjacent side cutting edges. A cutting edge portion is formed, and the corner cutting edge portion is formed with a land portion, a descending slope, a corner bottom surface, a first protrusion, an inclined slope surface and a seating surface in order along a diagonal line from the cutting edge toward the center hole. A pair of second projections are formed symmetrically on both sides, and are disposed to surround the corner bottom surface with the descending slope and the first projection, and the height of the corner bottom surface is the lowest along the diagonal, and the seating surface. It is characterized in that the height of the highest.

Description

Cutting insert with protrusions formed at corner area

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting insert, and more particularly to a cutting insert having a structure capable of easily controlling a chip generated in a workpiece during cutting.

In general, cutting tools are used in the field of cutting operations such as drilling, milling and turning. In the field of drilling and milling, tools have the property of rotating and are useful for the machining of fixed and movable work-pieces.

On the other hand, the tool used for turning is used for the purpose of processing the workpiece to be rotated in a fixed state. In general, the machining tool comprises a cutting insert which is fixed to the mounting surface of the holder via the holder and the clamping means and in contact with the workpiece.

In turning with a machining tool, chips produced in the workpiece by the cutting insert should be naturally separated and removed from the workpiece. If a chip is present between the cutting insert and the workpiece, the surface of the rotating workpiece is affected by the chip. This will be described in more detail as follows.

Effective removal of chips generated in the workpiece depends largely on the design of the cutting insert for efficient chip control. It is desirable to deform the chips generated with minimal energy consumption and effective heat dissipation to break away from the cutting area or to break or cut into relatively small chips.

For this purpose cutting inserts with properly formed depressions or grooves or cutting inserts with protrusions adjacent the cutting edges designed to deform, crack or cut chips with minimal energy consumption and effective heat dissipation Is provided.

However, the effective control of the chip direction by smooth movement between the particular shape of the chip forming groove and the other parts of the chip groove depends on the position of the cutting insert on the tool.

Thus, the chip formed by the cutting edge with the negative rake angle and located in the cutting tool is bent in the direction toward the workpiece without being spaced apart from the workpiece. As a result, damage to the workpiece and the processing tool may occur.

In particular, curved cutting inserts are required to process mild steel that produces chips that are difficult to control, i.e., are not well bent. In addition, there is a need for a cutting insert that can easily remove chips and minimize cutting forces even under low feed rates and deep cutting depths.

The present invention is to solve the above-described problems caused by the structure of the cutting insert during the cutting process, to provide a cutting insert for a cutting tool having a structure that can effectively control the chips generated in the workpiece. The purpose is.

According to the present invention, a cutting insert of a polygon having an upper surface, a lower surface and a plurality of side surfaces and a central hole formed in a central portion thereof, a flat seating surface is formed at the highest height of the upper surface, and the upper surface and the A plurality of side cutting edge portions are formed at the boundary of the plurality of side surfaces, and corner cutting edge portions having a cutting edge are formed at the boundary portions of two adjacent side cutting edge portions, and the corner cutting edge portions are directed from the cutting edge toward the center hole. The land portion, the descending slope, the corner bottom surface, the first projection, the inclined slope and the seating surface are sequentially formed along a diagonal line, and a pair of second protrusions are formed symmetrically on both sides of the diagonal line, and the falling slope and the first slope face are formed symmetrically. It is arranged to surround the corner bottom surface with a projection, the height of the corner bottom surface along the diagonal is the lowest, It characterized in that the height of the highest chakmyeon.

In the cutting insert according to the present invention, the first protrusion and the second protrusion have a hemispherical shape, and the height of the first protrusion is higher than the height of the second protrusion. The height of the first protrusion is higher than the height of the corner cutting edge, and the height of the second protrusion is higher than the height of the corner cutting edge.

On the other hand, the land portion, the descending groove surface, the side bottom surface and the rising groove surface are formed in turn from the side cutting edge toward the inside, the height of the side bottom surface is lower than the height of the corner bottom surface.

In addition, in the cutting insert according to the present invention, the side bottom surface is formed with a ridge extending from the raised groove face toward the side cutting edge.

1 and 2 are a perspective view and a plan view of a cutting insert according to the invention.

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

4 is a cross-sectional view taken along the line BB ′ of FIG. 2.

Hereinafter, with reference to the accompanying drawings of the present invention will be described in detail.

1 and 2 are a perspective view and a plan view of a cutting insert according to the present invention, showing a cutting insert having a structure capable of effective chip control.

The cutting insert 100 has an upper surface 10, a lower surface 20 and a side surface 30, and two side edges adjacent to four corner cutting edge portions 110, 120, 130 and 140. Formed at the intersections of the cutting edges (eg, 31 and 32), respectively.

As one example, the cutting insert 100 is an equilateral parallelogram member having a diamond shape at a predetermined angle. That is, as shown in FIG. 2, one side 30 of the cutting insert 100 has a predetermined acute angle with another adjacent side.

The upper surface 10 and the lower surface of the cutting insert 100 have a substantially flat seating surface 11, which seating surface 11 preferably has corner cutting edges 110, 120, 130 and 140. It protrudes above a certain height. This seating surface 11 functions as an insert support surface when the cutting insert 100 is mounted to the cutting tool.

Detailed configurations of the corner cutting edge portions 110, 120, 130, and 140 of the cutting insert 100 configured as described above will be described in detail. The structure of all the corner cutting edge parts 110, 120, 130 and 140 of the cutting insert 100 according to the present invention is the same, so, for convenience, one of the corner cutting edge parts 110 will be described below. .

3 is a cross-sectional view taken along the line A-A 'of FIG. 2, and FIG. 4 is a cross-sectional view taken along the line B-B' of FIG. 2, and a cross section of one corner cutting edge portion 110. The structure and some configurations of the side cutting edge 32 adjacent thereto are shown.

The corner cutting edge part 111 formed in the intersection part of two adjacent side cutting edge parts 31 and 32 is formed with the corner cutting edge 111 in the front-end | tip. A land portion 112 of a predetermined width is formed on the adjacent upper surface of the corner cutting edge 111.

A first inclined surface 113 having a predetermined width and an inclination angle is formed inside the land part 112, and a corner bottom surface 114 having a predetermined width is formed inside the first inclined surface 113. The first inclined surface 113 is inclined downward inward with respect to the land portion 112, so that the height of the corner bottom surface 114 is lower than the height of the corner cutting edge 111.

Inside the corner bottom 114, a first protrusion 115 of a predetermined area is formed. The first protrusion 115 has a height higher than that of the corner cutting edge 111 and has a hemispherical shape.

The seating surface 11 of the first protrusion 115 and the upper surface 10 is connected via a second inclined surface 116. The second inclined surface 116 is inclined upwardly toward the seating surface 11 with respect to the first protrusion 115.

Here, the land portion 112, the first inclined surface 113, the corner bottom surface 114, the first protrusion 115 and the second inclined surface 116 described above may have the cutting insert 100 at the corner cutting edge 111. Are arranged in order on the diagonal connecting the center of the.

On the other hand, the second projections 170 are formed on both sides of the boundary of the corner bottom surface 114, respectively. The second protrusion 170 has a smaller size (height and diameter) than the first protrusion 115 and is symmetrically disposed about the diagonal of the cutting insert 100.

By such a structure, the corner bottom surface 114 of the corner cutting edge portion 110 is surrounded by the first protrusion 115, two second protrusions 170, and the first inclined surface 113.

Along with this, a downward groove surface 151, a side surface is provided in a predetermined area of each side cutting edge 31, 32, 33, and 34, that is, an area between two adjacent corner cutting edges (eg, 120 and 130). The groove 150 is formed of the bottom surface 152 and the upward groove surface 153.

Referring to the specific function of each component constituting the cutting insert 100 according to the present invention as follows.

A predetermined volume is formed by the first protrusion 115, the second protrusion 170 adjacent to the first protrusion 115, the first inclined surface 113, and the corner bottom surface 114 as described above. This recess enables smooth chip control under a variety of cutting conditions, and can reduce the cutting resistance and extend the life of the cutting insert.

The first protrusion 115 and the second protrusion 170 have a hemispherical shape, the first protrusion 115 is on a diagonal, and the second protrusion 170 is symmetrical on both sides of the first protrusion 115. Are placed in a state. The first and second protrusions 115 and 170 having a hemispherical shape may minimize frictional force with the chip, and may prevent the chip from being fused to the surface. In addition, the surface area is maximized according to the hemispherical shape to maximize heat transfer to the chip, thereby minimizing heat transfer to the cutting insert. In addition, even if the chip is guided in any direction due to the hemispherical shape, the first and second protrusions 115 and 170 may perform their intended functions.

On the other hand, when the cutting depth is smaller than the allowable depth of the second protrusion, the chip generated by the corner cutting edge 111 collides with the corner bottom surface 114, and then collides with the first protrusion 115 to form the non-cut edge Is controlled in the direction of. Thereafter, the chip collides with the second protrusion 170 on the non-cut edge side and is cut to an appropriate length. As such, the second protrusion 170 prevents the chip from directly colliding with the non-cut edge 111 to increase the life of the cutting insert.

On the contrary, when the workpiece is cut under the condition that the cutting depth is greater than the allowable depth of the second protrusion 170, the chips generated by the corner cutting edge 111 and the side edges are formed at the corner bottom surface ( It is primarily controlled by the 114 and the second protrusion 170, and finally controlled by the first protrusion 115 and the second inclined surface (116).

At this time, on the corner bottom surface 114 and the second protrusion 170, the chip is bent rapidly by the shear stress difference in the longitudinal direction, and then the chip is in contact with the first protrusion 115. Here, a minimum resistance is generated between the chip and the first protrusion 115 by the sphere shape of the first protrusion 115, so that the chip can be smoothly controlled.

The center of the second protrusion 170 is spaced apart from a predetermined distance, preferably 0.2 mm or more, most preferably 0.4 to 1.2 mm at the end of the corner cutting edge 111 in the lateral length direction. If the second protrusion 170 is too close to the corner cutting edge 111, there is not enough space for the chip to be formed, and thus the chip cannot be controlled smoothly.

The center of the first protrusion 115 and the center of the second protrusion 170 and 1.5mm or less, preferably 0.7mm or less with respect to the lateral longitudinal direction. This spacing is determined according to the size of the corner cutting edge portion 110 and the angle formed by the side surface 30 of the cutting insert 100. If the distance between the first protrusion 115 and the second protrusion 170 is too large, the chip is in excessive contact with any one of the protrusions, and the chip is not properly controlled in this state.

On the other hand, as described above, the height of the second protrusion 170 is preferably higher than the height of the corner cutting edge 111. When the height of the second protrusion 170 is lower than the height of the corner cutting edge 111, the resistance between the chip and the second protrusion 170 may be reduced to some extent, but proper chip control at a small cutting depth is difficult.

In particular, since the chip separated from the workpiece has already absorbed the cutting resistance to some extent by receiving the pressure necessary for controlling the chip at the corner bottom surface 114, more reliable chip control function is required than the reduction of the cutting resistance. Therefore, it is preferable that the height of the second protrusion 170 is higher than the height of the corner cutting edge 111.

In addition, when the height of the second protrusion 170 is lower than the height of the corner cutting edge 111, the induced chip may collide with the sub-cutting edge portion on the side surface 30 to shorten the life of the cutting insert.

The first protrusion 115 has a height greater than the height of the corner cutting edge 111, and preferably has a height of 0.03 to 0.2 mm greater than the corner cutting edge 111. The first protrusion 115 having such a condition guides the chip controlled by the second protrusion 170 toward the corner portion where chip control is easier, and also facilitates chip control by generating more stress on the chip.

Meanwhile, the first protrusion 115 has a height greater than that of the second protrusion 170. If the height of the second protrusion 170 is greater than the height of the first protrusion 115, effective chip control is difficult to expect.

The vertical distance (depth) from the corner cutting edge 111 to the corner bottom surface 114 is smaller than the depth of the groove 150 formed in each side cutting edge portion 31, 32, 33 and 34. In this structure, the shear stress is rapidly generated on the chips generated under the conditions of small cutting depth, so that the chip control at the corner cutting edge portions 110, 120, 130, and 140 is more smoothly, and under the conditions of large cutting depth. The chip is distributed in different shear stresses over its entire length so that the chip can be smoothly twisted.

On the other hand, a ridge 152-1 having a predetermined height is formed on the side bottom surface 152 of the groove 150 formed on each side cutting edge portion 31, 32, 33, and 34. This ridge 152-1 extends from the raised groove face 153 toward the side cutting edge. This ridge 152-1 generates a large amount of twist of the chip generated under conditions of large cutting depth, thereby making it easier to control the chip.

 Preferred embodiments of the present invention described above are disclosed for purposes of illustration, and those skilled in the art having various ordinary knowledge of the present invention may make various modifications, changes, and additions within the spirit and scope of the present invention. And additions should be considered to be within the scope of the following claims.

The cutting insert according to the present invention having the structure and function as described above can control the chip even under the conditions of shallow cutting depth and deep cutting depth, and can process the workpiece with small cutting force.

Claims (7)

In a polygonal cutting insert having an upper surface, a lower surface and a plurality of side surfaces connecting them, and having a central hole in the center thereof, A flat seating surface is formed at the highest height of the upper surface, A plurality of side cutting edge portions are formed at the boundary between the upper surface and the plurality of side surfaces, At the boundary of two adjacent side cutting edges, corner cutting edges with cutting edges are formed, The corner cutting edge portion is formed along the diagonal line from the cutting edge toward the center hole, the land portion, the falling slope, the corner bottom surface, the first projection, the rising slope surface and the seating surface in turn, A pair of second projections are formed symmetrically on both sides of the diagonal, and is arranged to surround the corner bottom surface with the descending slope and the first projection, The cutting insert according to claim 1, wherein the height of the corner bottom surface is the lowest, and the height of the seating surface is the highest. The cutting insert according to claim 1, wherein the first protrusion and the second protrusion have a hemispherical shape, and the height of the first protrusion is higher than the height of the second protrusion. The cutting insert according to claim 2, wherein the height of the first protrusion is higher than the height of the corner cutting edge. The cutting insert according to claim 2, wherein the height of the second protrusion is higher than the height of the corner cutting edge. The cutting insert according to any one of claims 1 to 4, wherein the land portion, the lower groove surface, the side bottom surface, and the raised groove surface are sequentially formed from the side cutting edge toward the inside. 6. The cutting insert according to claim 5, wherein the side bottom surface is lower than the height of the corner bottom surface. 6. The cutting insert according to claim 5, wherein the side bottom surface has a ridge extending from the raised groove surface toward the side cutting edge.

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