JPH07156001A - Knot machining cutting tool - Google Patents

Abstract

PURPOSE:To prevent diffusion of a binder component contained in a sintered body and components contained in a material to be cut and suppress deposit of chips due to this diffusion so as to prevent any deterioration in machined surface precision by forming a coating consisting of TiN on the surface of a cutting edge tip. CONSTITUTION:Diamond powder and Co powder serving as a binder are uniformly mixed so that a binder content is approximately 5-20% by weight, and this mixture is filled in a container so as to be sintered by an ultra-high pressure high-temperature generating device, so that a cutting edge tip, which consists of a diamond sintered body and has the same shape and the same dimension as those of the cutting edge tip 3 of a machining cutting tool 1. Subsequently, on the surface of the diamond sintered body formed in this way, TiN is deposited by a PVD method based on ion plating, and various kinds of TiN coating whose thickness is 1-10mum are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knotting tool for forming knots in a groove formed in a circumferential direction on a roll made of cemented carbide along the axial direction of the roll.

[0002]

2. Description of the Related Art FIGS. 1 to 3 show an example of such a knot cutting tool.
Is composed of a shank 2 made of cemented carbide and a cutting edge tip 3 attached to the tip of the shank 2. The shank 2 is formed into a substantially square columnar shape, and its tip is cut in half along the central axis O of the shank 2 to attach the cutting blade tip 3 to the mounting seat 4
It is said that.

On the other hand, the cutting edge tip 3 attached to the attachment seat 4 contains diamond as a main component,
As shown in FIG. 1, the upper surface 5 serving as a rake surface is formed of a diamond sintered body sintered through a binder such as Ni, and the central portion of one long side in a plan view protrudes in a mountain shape. It has a rectangular flat plate shape. The cutting edge tip 3 has a lower surface 6 which is a seating surface opposite to the upper surface 5 facing the mounting seat 4 side, the one long side facing the tip end side in the axis O direction, and both side portions thereof. The shank 2 is integrated with the shank 2 by being joined to the mounting seat 4 by brazing in a state of protruding from the side part of the shank 2.

The central portion of the one long side of the cutting blade tip 3 projecting in the chevron shape is formed in a straight line extending in a direction perpendicular to the axis O. Further, in the one long side, the portions from the central portion to both side portions are respectively connected to the central portion and are concavely curved inwardly of the cutting blade tip 3 in plan view and smoothly connected to the concave curved portion. And a straight portion that reaches the short side of the rectangle, and is formed so as to gradually move toward the base end side in the direction of the axis O from the central portion side toward both side portions. A cutting edge 7 is formed over the entire length of the one long side of the cutting edge tip 3 protruding in the mountain shape.

The knotting tool 1 having such a structure is attached to a rotary shaft 11 on the machine tool side as shown in FIG. That is, the roll 1 which is the work material
2 is sequentially rotated around its axis X to be positioned, and the joint processing tool 1 is rotated together with the rotary shaft 11 to form a groove 13 formed in the drum 12 along the circumferential direction. , The node 1 extending in the X-axis direction of the roll 12
A plurality of 4 are formed along the circumferential direction. According to the knot cutting tool 1 having the above structure, however, since the cutting edge 7 involved in cutting the work material is formed on the cutting edge tip 3 containing diamond as a main component, the roll 12 is made of cemented carbide. Even when it is made of a hard material such as an alloy, it is possible to apply the above-mentioned knot processing to it.

[0006]

However, even the knotting tool 1 having such a diamond sintered body as the cutting edge tip 3 is used for processing a work material made of a cemented carbide as described above. In such a case, it is unavoidable that chips generated during cutting will be welded to the cutting edge of the cutting edge tip 3 during repeated processing. When such welding of chips occurs, not only the finished surface roughness is significantly deteriorated, but also the chipping of the cutting edge is caused by the deposited material, which shortens the tool life accidentally. This may result in a loss of tool life or a variation in tool life.

[0007]

Here, the inventors of the present invention have conducted various studies to solve the above-mentioned problems, and as a result, the work material contains Co as a binder as in the above-mentioned cemented carbide. In the case where it is contained in the composition, the components such as Co and Ni contained as a binder in the diamond sintered body used as the cutting edge tip and the Co component contained in the work material are used for the progress of cutting. Accompanying this, we have come to the knowledge that diffusion occurs between them, which facilitates welding.

The present invention has been made on the basis of such knowledge to solve the above-mentioned problems. The cutting edge tip made of a diamond sintered body is joined to the tip of the shank, and the cutting edge tip is formed. In a knotting tool having a cutting edge protruding in a mountain shape at its tip, a coating made of TiN is formed on the surface of the cutting edge tip.

[0009]

In such a knot cutting tool, the TiN coating film formed on the surface of the diamond sintered body acts as a barrier, whereby the components such as Co and Ni contained in the sintered body as a binder and It is possible to suppress and prevent the diffusion of the Co component contained in the cemented carbide as the cutting material. Therefore, according to the knotting tool having the above structure, it is possible to prevent the occurrence of welding due to such diffusion, prevent the deterioration of the finished surface roughness and the occurrence of chipping defects, and perform stable processing. Is possible.

By the way, in the diamond sintered body obtained by sintering the diamond particles together with the binder as described above, the diamond particles are in a textured state in which they are bonded through the phase of the binder. The existence of grain boundaries is inevitable. When chipping occurs in the cutting edge tip, a crack is generated starting from such a grain boundary, and by extension of this, the chipping of the cutting edge tip is caused. In particular,
In a portion where such a grain boundary is exposed on the surface of the sintered body, this grain boundary acts as a notch and promotes the generation of cracks, which is one of the factors that hinder the prevention of the above chipping defect. turn into.

Here, the inventors of the present invention have tried various film forming methods for forming the TiN film on the diamond sintered body as described above, and found that PVD (physical) represented by ion plating and sputtering. Evaporation)
By forming the TiN film by the method, a kind of compressive stress-like bonding force is given between the diamond particles located in the vicinity of the surface of the sintered body, and the chipping is achieved by the synergistic effect of the TiN film and the diffusion suppressing effect. It was possible to obtain a second finding that the occurrence of defects is more effectively prevented. From the viewpoint of effectively preventing chipping loss of the cutting edge based on such knowledge, it is desirable to perform the TiN coating on the surface of the diamond sintered body by the PVD method.

[0012]

EXAMPLES Examples of the present invention will be described below. In this embodiment, diamond powder and Co as a binder are used.
The powder and the binder are uniformly mixed so that the content of the binder is 5 to 20 wt%, and the mixture is filled in a container and sintered by an ultrahigh pressure and high temperature generator, and knot processing shown in FIGS. 1 to 3 is performed. A cutting edge tip made of a diamond sintered body having the same shape and size as the cutting edge tip 3 of the cutting tool 1 was formed. However, the sintering conditions at this time were as follows. Sintering temperature: 1300 ° C. Pressure: 6.0 GPa Sintering time: 30 minutes

Then, TiN was vapor-deposited on the surface of the thus-formed diamond sintered body by a PVD method by ion plating to form various TiN coating films having a thickness of 1 to 10 μm. Here, the vapor deposition conditions of the film by the PVD method were as follows.

Further, the cutting edge tip thus formed with the coating made of TiN of various thicknesses is mounted on the mounting seat of the shank of the same shape and size as the shank 2 of the knotting tool 1 shown in FIGS. This example 1 is joined by brazing.
~ 4 knotting tools were constructed. Then, using these knotting tools, a knotting test is performed on the roll 12 made of cemented carbide in the same manner as shown in FIG. 4, and the presence or absence of chipping defect of the cutting edge tip after the cutting is checked. It was The results are also shown in Table 1. However, in this processing test, knot processing of 100 knots was performed on the cemented carbide roll 12 in each of Examples 1 to 4, and the result was examined. Further, as a comparative example to the above-mentioned example,
A similar processing test was conducted by using a conventional knot cutting tool that does not form a TiN film, and the results were examined. This is also shown in Table 1. The cutting conditions in this processing test were as follows. Work Material: Cemented Carbide Cutting Speed: 220 rev / min Feed Rate: 0.013 mm / rev

[0015]

[Table 1]

As shown in Table 1, in the conventional knot cutting tool, immediately after the start of cutting, chips are deposited on the cutting blade tip, especially on the rake face thereof, and the surface roughness of the finished surface begins to deteriorate. Continuing, when 20 to 30 sections were processed, chipping defects occurred in the cutting edge, and the test had to be stopped. In particular, this chipping defect was remarkable on the rake face of the cutting edge tip where welding was likely to occur. On the other hand, in each of the above-mentioned Examples 1 to 4, the occurrence of welding is significantly suppressed as compared with the conventional knot cutting tool,
Even after the predetermined number of knots were processed, chipping defects and the like due to this welding were not recognized at all, including the rake face of the cutting edge tip where welding was likely to occur. Further, when the finished surface roughness was measured at the beginning and the end of processing, no extreme deterioration was observed.

As described above, according to the knotting tool of the present embodiment, the components such as Co and Ni contained in the diamond sintered body as the cutting edge tip as the binder and the Co component contained in the work material. And Ti are prevented by the barrier effect of the TiN coating film formed on the surface of the sintered body, which makes it possible to prevent and prevent the welding of chips due to such diffusion. And this
As shown in the above processing test results, it is possible to maintain the accuracy of the finished surface, prevent the occurrence of chipping defects of the cutting edge, and enable stable cutting, while extending the tool life. It is possible to prevent variations in the tool life.

Further, in the knotting tool of this embodiment, the TiN coating is formed by the PVD method, and therefore, based on the above-mentioned second finding, the diamond particles in the vicinity of the surface of the sintered body have compressive stress. A strong bonding force can be exerted, which can increase the bonding force between the diamond particles. Therefore, according to the present embodiment, this and the above-mentioned barrier effect of the TiN coating are synergized, whereby it becomes possible to more effectively prevent chipping defects of the cutting edge tip.

In this embodiment, as described above, the TiN coating film was formed on the surface of the diamond sintered body so as to have a thickness of 1 to 10 μm. However, if the thickness of the TiN coating film is set to be extremely thin, There is a possibility that the barrier effect described above may not be sufficiently achieved. On the contrary, even if the thickness of the TiN coating is gradually increased, if the thickness exceeds a certain value, the barrier effect is improved enough to correspond to the increase in the thickness of the TiN coating. Not only will it disappear, but it will also have the adverse effect of requiring much time, labor, and cost to form the coating. Therefore, the thickness of the TiN coating depends on the cutting conditions etc.
It is desirable to set in the range of 10 μm.

[0020]

As described above, according to the present invention, T
By using a diamond sintered body on the surface of which a film made of iN is formed as a cutting edge tip, the barrier effect of this TiN film prevents diffusion of the binder component contained in the sintered body and the component contained in the work material. Since it is blocked, it becomes possible to suppress the welding of chips due to this diffusion. Then, due to such welding, the finish surface accuracy may be deteriorated, or chipping may occur in the cutting edge due to this welding, and the tool life may be shortened accidentally or the tool life may vary. It is possible to prevent such a situation.

[Brief description of drawings]

FIG. 1 is a plan view of a conventional knot cutting tool (which has the same external shape as the embodiment of the present invention).

2 is a side view of the barb cutting tool 1 of FIG. 1. FIG.

3 is a front view of the barb cutting tool 1 of FIG. 1 viewed from the front end side in the direction of the axis O. FIG.

FIG. 4 is a view showing a case where the knotting is performed by the knotting tool 1 of FIG. 1 or the embodiment of the present invention.

[Explanation of symbols]

 1 Barb processing tool 2 Shank 3 Cutting edge tip 7 Cutting edge 12 Roll 13 Groove 14 Section

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // C23C 16/34

Claims (2)

[Claims] 1. A knot cutting tool comprising a cutting edge tip made of a diamond sintered body joined to the tip of a shank, and a mountain-shaped protruding cutting edge formed at the tip of the cutting edge tip. A cutting tool for bite processing, wherein a film made of TiN is formed on the surface of the cutting edge tip. 2. The barb cutting tool according to claim 1, wherein the coating film made of TiN is formed by a PVD method.