JP4784378B2 - Super high pressure sintered body cutting tool - Google Patents

Description

  The present invention relates to an ultra-high pressure sintered body cutting tool in which at least a cutting edge portion and a chip breaker projection are made of an ultra-high pressure sintered body containing cubic boron nitride.

  This type of cutting tool is used for cutting high-hardness materials such as carburized hardened steel and induction hardened steel having a hardness of about 40 to 60 HRC, for example. As shown in FIGS. 6 and 7, a cutting tool employing an ultra-high hardness sintered body mainly composed of cubic boron nitride or the like is used for the cutting edge. The cutting tool shown in FIG. 6 is obtained by providing a seat groove 2 at a tip corner portion of a base metal of a throw-away tip serving as a tool body 1 and joining an ultra-high hardness sintered body 3 thereto. The ultra-high hardness sintered body 3 is tilted in the direction in which the rear part falls, and a breaker wall is formed by a part of the surface of the seat groove 2. The cutting tool shown in FIG. 7 is a chamfered portion having a height H at the intersection between the upper surface and the side surface of the ultra-high hardness sintered body 3 mainly composed of cubic boron nitride and the tool body 1 to which the cutting tool is bonded. 8 and a chip breaker 5 that lowers the cutting edge by h in the ultra-high hardness sintered body 3, and the relationship between H and h is H> h, and the cutting edge portion is constituted by a part of the surface of the chamfered portion 8. The chamfered portion 6 for strengthening treatment is generated (for example, see Patent Document 1).

JP-A-8-155702

  In the cutting tool shown in FIG. 6, since the distance from the intersection of the corner and the bisector of the corner to the rising position of the breaker wall is large, the setting range of the cutting condition is narrow, and the chip is effective in finishing cutting. I couldn't expect it. Alternatively, since the breaker wall formed by a part of the face of the seat groove is easily worn by the collision of chips, there is a problem that it is difficult to maintain a good chip treatment.

  In the cutting tool shown in FIG. 7, the chip breaker 5 needs to be formed in a range corresponding to the cutting depth, and at a cutting depth smaller than the cutting depth, chips do not contact the rising wall surface of the chip breaker 5. Effective chip disposal could not be expected.

  In the cutting tool shown in FIGS. 6 and 7, when cutting a hard material such as carburized hardened steel or induction hardened steel, chipping or chipping occurs at the incision boundary portion where the vicinity of the surface having high hardness is cut. Since it is easy, the tool life may be shortened.

  The present invention has been made to solve the above-described problems, and is an ultra-high pressure sintered cutting tool that is excellent in chip disposal in a wide range of cutting conditions and further improves tool life in cutting of hard materials. The purpose is to provide.

In order to solve the above problems, the present invention employs the following means. That is, a cutting blade member (30) made of an ultra-high pressure sintered body containing cubic boron nitride is fixed to the corner portion (21) of the upper surface (20a) of the tool body (20), and at least the cutting blade member described above. An ultra-high-pressure sintered body cutting tool in which a cutting edge (33) is formed at the intersection ridge line portion between the rake face (31) formed on the upper surface of (30) and the flank face (32) formed on the peripheral surface. In
The cutting edge (33) includes a corner (33a) having a circular arc shape in plan view provided in the corner portion (21) and a pair of linear cutting edges (33b) extending from the corner (33a). The ridge portion of the cutting edge (33) is provided with a chamfered honing surface (50) along the cutting edge (33). When viewed from the side, the honing surface (50) and the flank surface ( 32) and an intersection ridge line portion are formed equally over the entire circumference of the cutting edge (33), and in the direction along the cutting edge (33), the corner (33a) and 2 of the corner (33a) An inclined rake face (31a) formed by at least one of a flat surface or a curved surface that gradually increases as the distance from the corner tip (34), which is the intersection with the equipartition line (B), is provided. Rake face (31a) Super high pressure sintering characterized in that the width of adjacent honing surfaces (50) is formed so as to gradually increase in the direction along the cutting edge (33) as it is separated from the corner tip (34). It is a body cutting tool.

According to the ultra-high pressure sintered body cutting tool of the present invention, when viewed in plan, the width of the honing surface (50) adjacent to the inclined rake face (31a) is in the direction along the cutting edge (33), and the corner tip ( 34) Since it is formed so as to gradually increase as it moves away from 34), the action of restraining chips by the honing surface (50) becomes stronger as the depth of cut increases, so that excellent chip disposal is obtained. It is done. Furthermore, since the strength of the cutting blade (33) is also increased, chipping and chipping of the cutting blade (33) are prevented. In particular, in cutting of hard materials such as carburized hardened steel and induction hardened steel, damage at the incision boundary is suppressed and tool life is improved.
In the vicinity of the corner tip (34), since the width of the honing surface (50) in a plan view is relatively small, an increase in cutting resistance is suppressed, chattering and heat generation are prevented, and chips adhere to the cutting edge. Is suppressed and the machined surface accuracy is improved.

  Below, one Embodiment of the ultra-high pressure sintered compact cutting tool which concerns on this invention is described with reference to drawings. FIG. 1 is a perspective view of a corner portion of the ultrahigh-pressure sintered body cutting tool according to the present embodiment. FIG. 2 is a plan view of a corner portion of the cutting tool. FIG. 3 is a side view of a corner portion of the cutting tool. 4 is an end view taken along line S1-S1 in FIG. FIG. 5 is an end view taken along line S2-S2 in FIG.

  As shown in FIG. 1, the ultra-high pressure sintered body cutting tool according to the present embodiment has a corner on the upper surface 20a of a substantially polygonal plate-shaped chip base 20 made of a hard material such as cemented carbide, cermet, or ceramics. The chip 10 is obtained by brazing and fixing a cutting blade member 30 made of an ultrahigh-pressure sintered body containing cBN to a notch 22 formed in the portion 21. The tip 10 is detachably attached to a body of a cutting tool such as a bite holder or a predetermined position of the holder by a known fixing means (not shown), and functions as a cutting blade for turning a work material. is there. Further, the ultra-high pressure sintered body cutting tool of the present invention is not limited to the chip mounted on the body or the holder, and may be an embodiment in which it is directly brazed and fixed to the body or the holder, for example.

  As illustrated in FIG. 1, in the corner portion 21, a continuous rake face 31 is formed on each of the upper surfaces 30 a and 20 a across a part of the cutting blade member 30 and the chip base 20, and A continuous flank 32 is formed on the peripheral surface. As shown in FIG. 3, a honing surface 50 formed by planar chamfering with an inclination angle α <b> 1 with respect to the upper surface 20 a of the chip base 20 is formed at the intersecting ridge line portion between the rake face 31 and the flank 32. A cutting edge 33 is formed at the intersecting ridge line portion between the honing surface 50 and the flank 32. And this chip | tip 10 is what is called a negative chip | tip with the relief angle of 0 degrees by which the flank 32 extended at right angle with respect to each said upper surface 30a, 20a.

  In the plan view shown in FIG. 2, the cutting edge 33 is composed of an arcuate corner 33a and a pair of linear cutting edges 33b extending from the corner 33a and forming a straight line. The pair of linear cutting blades 33 b are formed across the cutting blade member 30 and the chip base 20. Here, the intersection of the corner 33a and the bisector B of the corner 33a is referred to as a corner tip 34.

  As can be seen from FIG. 1, the rake face 31 is formed so as to cut out a part of the honing face 50, and is formed in a plane substantially parallel to the upper surface 20a of the chip base 20 adjacent to the entire periphery of the corner 33a. Adjacent to the pair of straight cutting edges 33b, a curved inclined rake face 31a is formed which is recessed downward and gradually becomes higher in the extending direction of the straight cutting edges 33b as the distance from the corner tip 34 increases. In the cross section cut by the plane orthogonal to the straight cutting edge 33b, the inclined rake face 31a is substantially parallel to the upper surface 20a of the chip base 20 in the same manner as the cross sectional shape in the bisector B direction of the corner 33a shown in FIG. The rake angle is 0 °. The rake face 31a is formed by any one of, for example, a grinding method using a grindstone, an electric discharge machining method, a laser machining method, or an electron beam machining method.

  When viewed in plan as shown in FIG. 2, the width A1 of the honing surface 50a adjacent to the corner 33a is constant, and the width A2 of the honing surface 50b adjacent to the inclined rake surface 31a provided on the straight cutting edge 33b is In the direction along the straight cutting edge 33b, the distance gradually increases as the distance from the corner tip 34 increases.

  A chip provided with a pair of breaker wall surfaces 41 that rise upward with respect to the rake face 31 and intersect with each other on the bisector B of the corner 33a, inward of the rake face 31. A breaker protrusion 40 is formed. In plan view, the pair of breaker wall surfaces 41 extend substantially parallel to the direction in which the straight cutting edge 33b extends, and an intersecting portion 43 that intersects with each other is formed to protrude toward the corner tip 34 side. A pair of breaker wall surfaces 41 extending upward intersect with a breaker top surface 42 constituted by the chip base 20 and the upper surfaces 20a and 30a of the cutting blade member 30. Here, the distance (breaker width at the corner tip 34) B1 from the corner tip 34 to the position at which the intersection 43 starts to rise from the rake face 31 is B1 from which the breaker wall surface 41 starts to rise from the rake face 31. The distance to the position (breaker width in the straight cutting edge 33b) is set smaller than B2.

  The corner 33a and the straight cutting edge 33b are lowered with respect to the top surface 42 of the chip breaker protrusion 40, and the amount H of the lowered core is set to 0.15 mm.

According to the tip 10 having the above configuration, the honing surface 50b provided on the straight cutting edge 33b gradually increases in width A2 as it is separated from the corner tip 34 in both directions in the direction along the straight cutting edge 33b. Since it forms so that the action which restrains the chip | tip by the honing surface 50b becomes strong as the cutting depth increases, the excellent chip disposal property is obtained. Further, since the strength of the straight cutting edge 33b is increased, the chipping and the chipping of the straight cutting edge 33b are prevented. In particular, damage to the cutting boundary caused by a hard surface portion of a high hardness material such as carburized hardened steel or induction hardened steel is suppressed, and the life of the cutting edge can be improved.
On the other hand, the honing surface 50a of the corner 33a that cuts the inside having a lower hardness than the surface of the high hardness material is formed to be narrower than the honing surface 50b of the straight cutting edge 33b, thereby suppressing an increase in cutting resistance. In addition, it prevents chattering and heat generation and suppresses the adhesion of chips to the cutting edge to improve the accuracy of the machined surface.
For the purpose of reinforcing the cutting edge and improving the surface roughness of the machined surface, an arc having a radius of curvature in the range of 0.02 mm to 0.2 mm at the intersecting ridge line portion between the honing surface 50 and the rake face 31 and / or the flank face 32. You can connect them smoothly.
Further, in finishing cutting in which the cutting is limited to the corner 33a, in consideration of suppressing damage to the cutting boundary portion generated in the corner 33a, the corner 33a is inclined so as to include the cutting boundary portion. A rake face 31a is preferably provided. It can be appropriately selected whether the inclined rake face 31a is provided in the entire corner 33a or is provided in a part of the corner 33a so as to be separated from the corner tip 34.

In the honing surface 50, the widths A <b> 1 and A <b> 2 when viewed in plan are preferably set in a range of 0.05 mm to 0.50 mm. If it is less than 0.05 mm, the cutting edge is not strong enough to prevent damage to the cutting boundary, and if it exceeds 0.50 mm, problems such as chatter, heat generation, and deterioration of the machined surface accuracy occur. It is because there is a possibility of doing.
In the honing surface 50, the inclination angles α1 and α2 with respect to the upper surface 20a of the chip base 20 are preferably set in the range of 15 ° to 60 °. This is because if it is less than 15 °, there is a possibility that the effect of restraining chips and the effect of preventing damage to the cutting boundary portion may not be obtained, and if it exceeds 60 °, the cutting resistance is increased, resulting in heat generation. This is because the machined surface accuracy is deteriorated.

  The chip breaker protrusion 40 cooperates with the honing surface 50 to reliably restrain the chip and curl or sever it, thus enabling a very effective chip treatment. By securing the chip breaker protrusion 40 to 0.05 mm or more, preferably 0.10 mm or more, the chips at the time of finish cutting, which are difficult to process with a small width and thickness, can surely collide with the breaker wall surface 41. As a result, good chip disposal is possible. In addition, the upper limit value of the core down amount H is about 1 mm at which the above effect reaches its peak.

  In the embodiment described above, when at least the breaker wall surface 41 is formed in the cutting blade member 30 made of an ultra-high pressure sintered body containing cBN, high hardness chips when cutting a high hardness material. Since sufficient wear resistance is ensured in contact with the chip, it is possible to prevent the chip disposal from deteriorating at an early stage.

The present invention is not limited to the above-described embodiment, and can be changed and added without departing from the gist of the present invention. For example, the chip can be changed to a positive chip with the clearance angle of the flank 32 being positive, and the outer shape of the chip 10 can also be applied to a substantially polygonal flat plate such as a regular triangle, square, or rhombus.
The inclined rake face 31a is not limited to a curved surface, and may be a flat surface.

It is a perspective view of the corner part of the ultra-high pressure sintered compact cutting tool concerning the embodiment of the present invention. It is a top view of the corner part of the ultra-high pressure sintered compact cutting tool. It is a side view of the corner part of the ultra-high pressure sintered compact cutting tool. FIG. 3 is an end view taken along line S1-S1 in FIG. It is the S2-S2 line end view in FIG. It is a figure explaining the conventional cutting tool, (a) is a top view, (b) is a side view. It is a figure explaining another conventional cutting tool, (a) is a top view, (b) is a side view.

Explanation of symbols

10 Cutting tool (chip)
20 Tool body (chip base)
21 Corner part 30 Cutting edge member 31 Rake face 31a Inclined rake face 32 Relief face 33 Cutting edge 33a Corner 33b Straight cutting edge 34 Corner tip 40 Tip breaker projection 41 Breaker wall surface 42 Breaker top face 43 Crossed ridges 50, 50a, 50b Honing Surface B Corner bisectors A1 and A2 Honing surface widths B1 and B2 Distances α1 and α2 from the cutting edge to the rising start position of the breaker raised surface The inclination angle of the honing surface with respect to the upper surface of the chip base (cutting tool) H Chip breaker Amount of centering of the cutting edge against the top surface of the protrusion

Claims (2)

A cutting blade member (30) made of an ultra-high pressure sintered body containing cubic boron nitride is fixed to the corner portion (21) of the upper surface (20a) of the tool body (20), and at least the cutting blade member (30 In the ultra-high pressure sintered body cutting tool in which the cutting edge (33) is formed at the intersecting ridge line portion between the rake face (31) formed on the upper surface of) and the flank face (32) formed on the peripheral surface,
The cutting edge (33) includes a corner (33a) having a circular arc shape in plan view provided in the corner portion (21) and a pair of linear cutting edges (33b) extending from the corner (33a). ,
The cutting edge (33) ridge line portion is provided with a chamfered honing surface (50) along the cutting edge (33),
When viewed from the side, the intersecting ridge line portion of the honing surface (50) and the flank surface (32) is formed equally over the entire circumference of the cutting blade (33), and
A plane that gradually increases in the direction along the cutting edge (33) as it is away from the corner tip (34) that is the intersection of the corner (33a) and the bisector (B) of the corner (33a), or An inclined rake face (31a) formed by at least one of the curved surfaces is provided;
When viewed in plan, the width of the honing surface (50) adjacent to the inclined rake surface (31a) is gradually increased in the direction along the cutting edge (33) as it is separated from the corner tip (34). An ultra-high pressure sintered compact cutting tool characterized by being formed. A chip breaker protrusion provided with a pair of breaker wall surfaces (41) that rises upward from the rake face (31) and intersects with each other on the bisector (B) at the inside of the corner (21) (40) is provided, the pair of breaker wall surfaces (41) extend in a direction substantially parallel to the direction of the pair of straight cutting edges (33b), and the intersecting portion (43) is the tip of the corner (34). 2. The ultrahigh-pressure sintered body cutting tool according to claim 1, wherein the cutting tool is formed so as to protrude to the side.

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