JP5110849B2 - Cutting insert - Google Patents

Description

  The present invention relates to a cutting insert used for cutting metal or the like.

  2. Description of the Related Art Conventionally, as a cutting insert that is detachably attached to a holder, a technique of forming a groove, a protrusion, a step, an inclined surface, or the like on a rake face and acting as a breaker has been used. Thereby, it becomes possible to adjust suitably the magnitude | size, discharge | emission direction, etc. of the chip | tip cut with the cutting blade of the cutting insert.

As the shape of the protrusion formed on the rake face, for example, a shape formed in a truncated cone shape is known, and in particular, a plurality of protrusions are formed around the vicinity of the cutting edge. As a document disclosing such a technique, for example, Patent Document 1 is cited.
JP-A-10-118807

The cutting insert as described above is made of, for example, a hard material such as ceramic, cermet or cemented carbide, and these materials are blended with a desired composition of several kinds of known raw material powders, pulverized, mixed, and raw material process, raw material The raw material powder obtained in the process is manufactured through a molding process for embossing and compressing the raw material powder into a predetermined shape, and a firing process for heating and sintering the molded body obtained in the molding process.

  In this case, in a narrow region where the protrusions are adjacent to each other in the molding process, a difference in height is generated between the protrusion and the rake face. The density of the obtained molded body varies greatly between the protrusions and the rake face between the protrusions. And, when such a molded body is fired, the shrinkage during sintering becomes non-uniform, so that the shape of the protrusion is irregularly deformed and a desired breaker function cannot be obtained. there were.

  In addition, in order to use both the upper and lower surfaces of the cutting insert as a rake face, a structure is known in which a cutting edge is formed at each of the flank on the side surface of the cutting insert and the intersecting ridge of the upper and lower surfaces Yes. Thereby, the upper and lower sides of one cutting insert can be exchanged and attached to the holder, and cutting can be performed with both the cutting blade on the upper surface side and the cutting blade on the lower surface side, so that an economical cutting insert can be obtained. In such a double-sided cutting insert, both the upper surface and the lower surface need to have a function of a rake surface and a function as a seating surface for attachment to a holder.

  Therefore, in addition to the protrusions that perform the function of the breaker as described above, it is necessary to provide protrusions for contacting the seating surface on the upper surface and the lower surface, respectively. Specifically, a plurality of protrusions formed higher than the cutting edge in the vertical direction are formed, and the upper surfaces of the plurality of protrusions are formed at the same height on the same virtual plane. Thereby, a sufficient contact area with the seating surface of the holder can be ensured, and the cutting process can be stabilized. Further, since the upper surfaces of the plurality of protrusions are positioned higher than the cutting edge, there is no problem that the cutting edge located on the lower surface side is lost in the cutting process.

  However, as described above, the shape of the protrusion at the time of the molding process is changed by the firing process, so that the upper surface of the protrusion serving as a constraining surface to the holder of the cutting insert is not flat. There was a problem that the restraint of the was unstable.

  In view of the above problems, the present invention provides a cutting insert that can prevent a shape of a region where a protrusion is formed from being changed by a firing process in a cutting insert that forms a plurality of protrusions on a rake face. For the purpose.

The cutting insert in one aspect of the present invention is a cutting insert having a rake face on the upper surface, a seating surface on the lower surface, and a flank surface on the side surface, and having a cutting edge at least at the intersection ridge between the upper surface and the side surface. , Having a recessed area lower than the cutting edge in the thickness direction, and a plurality of protrusions are formed on the recessed area, and all of the plurality of protrusions are on the rake face. And are connected to each other by an intermediate wall that is lower in the thickness direction than the protrusion, and the recessed area is a first region surrounded by the protrusion and the intermediate wall on the rake face. And a second region located outside the first region and having a height different from that of the first region .

  According to the cutting insert of the present invention, since the plurality of protrusions are all connected by the intermediate wall, the difference in forming density between the protrusions or the recessed area between the protrusions is sufficient when the cutting insert is formed. Can be made smaller. Moreover, since the intermediate wall is formed along the cutting edge, the influence on the shape of the cutting edge during molding can be suppressed.

  By these actions, a cutting insert capable of a stable cutting process can be provided.

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

  1 to 3 show an embodiment of the present invention. FIG. 1 is a top view of a cutting insert according to an embodiment of the present invention, FIG. 2 is a side view, and FIG. Sectional drawing, (b) BB sectional drawing, (c) is CC sectional drawing.

  In FIG. 1, the cutting insert 1 according to the present embodiment has a substantially polygonal plate shape, and specifically has a rhombus shape when viewed from above. The cutting insert 1 includes a rake face 2 on the upper surface, a relief surface 3 on the side surface, and a seating surface 4 attached to a holder such as a rolling tool on the lower surface. A cutting edge 5 is formed at the intersecting ridge line portion between the rake face 2 and the flank face 3. The rake face 2 has a recessed area 2 a that is lower than the cutting edge height in the thickness direction of the cutting insert 1.

  The cutting insert 1 has the same shape on the upper surface and the lower surface, and a rake surface and a plurality of protrusions 10 are also formed on the lower surface side. Therefore, the plurality of protrusions formed on the lower surface side become the seating surface 4 restrained by the holder (not shown).

  On the rake face 2, each of the four corners is formed with a corner-side protrusion 10 a that is a triangular frustum on an approximately isosceles triangle in a top view. Of the corner portions, the two corner-side protrusions 10a located on the acute angle side act as breakers for processing chips during cutting.

  On the rake face, a plurality of truncated cone protrusions 10b having a circular top view are formed along the cutting edge 5 between the corner-side protrusions 10a. In addition, the height position of the upper surface of the corner side protrusion 10a and the height position of the upper surface of the truncated cone protrusion are substantially the same, and are formed in substantially the same plane.

  Furthermore, between the corner | angular side protrusion 10a and the truncated cone protrusion 10b, and between the two truncated cone protrusions 10b, it is higher than the dent area | region 2a of the rake face 2, and lower than the height of each protrusion 10. A wall 15 is formed, and each protrusion 10 and the intermediate wall 15 are all connected. The recessed area 2a on the rake face 2 has different heights in the area surrounded by the protrusions 10 and the intermediate wall 15 and outside the area, and the height surrounded by the protrusions 10 and the intermediate wall 15 is different. The recessed area 20b is formed higher than the low recessed area 20a located outside the area. That is, the height in the thickness direction of the cutting insert 1 is in the order of each protrusion 10> the cutting edge 5> the intermediate wall 15> the high recess area 20a> the low recess area 20b. In the present invention, there is no particular problem even if the height relationship between the cutting edge 5 and the intermediate wall 15 is reversed.

  The present invention improves the strength of the corner-side protrusion 10a acting as a breaker by providing a configuration in which the protrusions 10 on the rake face 2 are connected by an intermediate wall 15 formed on the rake face. be able to.

  The plurality of protrusions 10 and the recessed area 2a of the rake face 2 have a large difference in height, and the density of the formed body in the protrusion 10 and the density of the formed body in the vicinity of the recessed area 2a of the rake face 2 are greatly different. . However, the intermediate wall 15 suppresses the difference in shrinkage between the protrusion 10 and the dent area 2a of the rake face 2 in the firing process, and thus the protrusion 10 on the rake face 2 is made larger than the shape formed by the molding process. It is possible to prevent the change.

  Moreover, the intermediate wall 15 which connects between the corner-side protrusion 10a and the truncated cone protrusion 10b and between the two truncated cone protrusions 10b is formed along the cutting edge of the cutting insert. Thereby, it can prevent that the shape of the cutting blade 5 changes with the shrinkage | contraction at the time of a baking process. Further, the intermediate wall 15 formed along each cutting edge 5 is not formed in a straight line, but is shifted to the left and right with an imaginary line L passing through the center of the circumscribed line of two adjacent protrusions as an axis. Has been. Thereby, in addition to the direction along the cutting edge 5, the shrinkage | contraction of the direction orthogonal to the cutting edge 5 can fully be relieve | moderated. Further, the intermediate wall 15 is alternately formed along the cutting edge with those that curve inward and those that curve outward. Thereby, the effect which relieves the shrinkage | contraction of the direction orthogonal to the above-mentioned cutting blade 5 becomes still larger.

  Further, in the cutting insert of the present invention, the recessed area 2a on the rake face 2 has different heights in the area surrounded by the protrusions 10 and the intermediate wall 15 and the outside of the area. The high depression area 20b surrounded by the part 10 and the intermediate wall 15 is formed at a position higher than the low depression area 20a located outside the area. With this configuration, the difference between the low recess area 20a and the high recess area 20b can be reduced compared to the height of the intermediate wall 15 formed subsequently to the inside of the cutting insert. The shrinkage | contraction in a baking process by the difference in the molding density of the direction orthogonal to 5 can be prevented. This effect synergizes with the effect in the direction along the cutting edge described above, and the effect of preventing the shape of the rake face from changing from that at the time of molding is further enhanced.

  In the above embodiment, the cutting insert has a rhombus shape as viewed from above, but other shapes such as a square, a rectangle, a parallelogram, a circle, an ellipse, and a triangle are used as the shape of the cutting insert. Is possible.

[Production method]
The cutting insert of the present invention is produced by the following method.

  First, 87 wt% of tungsten carbide (WC) powder, 8 wt% of metallic cobalt (Co) powder, 2 wt% of titanium carbide (TiC) powder, 1 wt% of niobium carbide (NbC) powder, 2 wt% of zirconia carbide (ZrC) powder % Were mixed and formed into a predetermined shape including a protrusion on the rake face by press molding.

  Next, a firing process was performed in which the temperature was raised from 500 ° C. to 1500 ° C. and held for 1 hour to prepare a base material made of cemented carbide. The firing step shrunk from the shape at the time of molding to about 80% in volume ratio, but the shape of the protrusion on the rake face and the shape of the cutting edge hardly changed.

Thereafter, a coating layer made of titanium carbide (TiC), titanium nitride (TiN), and aluminum oxide (Al ₂ O ₃ ) is formed on the entire surface of the base material using CVD (Chemical Vapor Deposition). The cutting insert in this invention was produced by these.

  In the above embodiment, the cutting insert using tungsten carbide as a main component and a cemented carbide containing metallic cobalt as a base material is exemplified, but the present invention is not limited to this, and for example, a cycle including at least tungsten carbide. It is possible to use a cemented carbide containing at least one selected from carbides, nitrides, and carbonitrides of Group 4, 5, and 6 metals in the table and one or more types of iron group metal metals. In addition to cemented carbide, any cutting insert made of ceramic, cermet, etc. by forming and firing a powder by a molding process can be used in the present invention.

  Moreover, in the said one Embodiment, although what provided the same rake face and several protrusion on an upper surface and a lower surface was illustrated, even if there is a protrusion only on an upper surface, the protrusion of a protrusion on a rake surface is shown. It is possible to obtain an effect that the shape can be prevented from changing greatly even after the firing step.

  In the present invention, the shape of the protrusion is not particularly limited, and can be used in various shapes such as a polygon, a circle, and an ellipse when viewed from above.

  As mentioned above, although embodiment of this invention was illustrated, this invention is not limited to the said embodiment, It cannot be overemphasized that it can be made arbitrary, unless it deviates from the objective of invention.

It is a top view of the cutting insert by one Embodiment of this invention. It is a side view of the cutting insert by one Embodiment of this invention. It is AA sectional drawing (a), BB sectional drawing (b), and CC sectional drawing (c) of the cutting insert of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cutting insert 2 Rake face 2a Indentation area 20a Low indentation area 20b High indentation area 3 Relief surface 4 Seating surface 5 Cutting edge 10 Protrusion 10a Corner side protrusion 10b Frustum protrusion 15 Intermediate wall

Claims (7)

In a cutting insert having a rake face on the upper surface, a seating surface on the lower surface, a flank surface on the side surface, and a cutting edge at least at the intersection ridge of the upper surface and the side surface,
The rake face has a recessed area lower than the cutting edge in the thickness direction,
A plurality of protrusions are formed on the recessed area,
All of the plurality of protrusions are formed on the rake face and are connected to each other by an intermediate wall lower in the thickness direction than the protrusions,
The recessed area has a first area surrounded by the protrusion and the intermediate wall on the rake face, and is located outside the first area and has a height different from that of the first area. A cutting insert comprising: a second region.   2. The recessed area according to claim 1, wherein the second area is a low recessed area, and the first area is a high recessed area higher in the thickness direction than the second area. Cutting insert as described. The cutting insert according to claim 1 , wherein the protrusion is positioned higher than the cutting edge in the thickness direction. In a cutting insert having a rake face on the upper surface, a seating surface on the lower surface, a flank surface on the side surface, and a cutting edge at least at the intersection ridge of the upper surface and the side surface,
The rake face has a recessed area lower than the cutting edge in the thickness direction,
A plurality of protrusions are formed on the recessed area,
All of the plurality of protrusions are formed on the rake face and are connected to each other by an intermediate wall lower in the thickness direction than the protrusions,
The intermediate wall is formed to extend along the cutting edge;
The plurality of protrusions include a plurality of triangular pyramid-shaped protrusions formed at corners of the rake face, and a truncated cone-shaped protrusion formed between the plurality of corner-side protrusions. And comprising
Said intermediate wall, said switching cutting insert you characterized in that it is formed so as to extend along the edge which connects the said angle side projection truncated cone projection. In a cutting insert having a rake face on the upper surface, a seating surface on the lower surface, a flank surface on the side surface, and a cutting edge at least at the intersection ridge of the upper surface and the side surface,
The rake face has a recessed area lower than the cutting edge in the thickness direction,
A plurality of protrusions are formed on the recessed area,
All of the plurality of protrusions are formed on the rake face and are connected to each other by an intermediate wall lower in the thickness direction than the protrusions,
The intermediate wall is formed to extend along the cutting edge;
Intermediate wall formed along each cutting edge comprises two projections switching milling insert you characterized in that it is formed shifted to an imaginary line on the left and right as the axis passing through the center of the circumscribed line of adjacent. In a cutting insert having a rake face on the upper surface, a seating surface on the lower surface, a flank surface on the side surface, and a cutting edge at least at the intersection ridge of the upper surface and the side surface,
The rake face has a recessed area lower than the cutting edge in the thickness direction,
A plurality of protrusions are formed on the recessed area,
All of the plurality of protrusions are formed on the rake face and are connected to each other by an intermediate wall lower in the thickness direction than the protrusions,
The intermediate wall extends along the cutting edge, and is curved between each protrusion.
Each cutting edge intermediate wall formed along, the switching milling insert you characterized in that those outwardly curved and those curved inward are formed alternately. The cutting insert includes at least one selected from carbides, nitrides, and carbonitrides of Group 4, 5, and 6 metals of the periodic table including at least tungsten carbide, and a mother including one or more types of iron group metal metals. With materials,
The cutting insert according to any one of claims 1 to 6 , wherein a coating layer having a hardness higher than that of the base material is formed on at least the cutting edge portion of the surface of the base material.

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