JPH09267202A - Throw-away tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To immediately discriminate that in which corner a cutting edge exists by forming a coating layer of a titanium nitride, a titanium carbide nitride or a chrome nitride on at least a cutting face of an exposed part of a cubic system boron nitride sintered body being the cutting edge of a throw-a way tip main body. SOLUTION: In a throw-away tip 1 of an almost equilateral triangle-shaped plate-like negative type, a complex 7 composed of upper and lower two layers of a cubic system baron nitride(CBN) sintered body 5 of an almost trapezoid in a plan view and cemented carbide 6, is fixed by brazing to a recessed part 3 formed in the corner C of a cemented carbide-made throw-away tip main body 2. A coating layer of TiN is performed in a prescribed thickness (about 2 to 6μm) as a single layer on the whole (a hatching area) of a cutting face 5 of the CBN sintered body 5. When this TiN coating layer is formed, since only the CBN sintered body 5 being a cutting edge presents a clear gold color to a gray color of the main body 2, a cutting edge part can be quickly and visulally confirmed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw away cubic cubic boron nitride sintered body (hereinafter, referred to as CBN) in a throw-away tip body made of high speed steel, cemented carbide, cermet or the like.
The present invention relates to a throw-away tip (hereinafter also referred to as a throw-away tip with CBN or a CBN cutting tool) including a sintered body or simply CBN.

[0002]

2. Description of the Related Art Conventionally, as a typical example of this kind of throw-away tip, a CBN sintered body is provided in a concave portion at one or a plurality of corners of a throw-away tip body (base material) having a triangular or quadrangular shape in plan view. Two layers of cemented carbide (layer) are formed on top and bottom, and a composite (chip) formed in a plane, rectangle or isosceles triangle is fixed by brazing through the cemented carbide layer (site). Are known. FIG.
This is an example of a conventional throw-away tip 11 of this type, and the composite body 17 (C is provided at one corner C of a triangular throw-away tip body (hereinafter, also simply referred to as a body) 12.
The figure shows that the BN sintered body 15 and the cemented carbide 16) are fixed.

The CBN sintered body has excellent wear resistance and is therefore suitable for cutting a metal material having high hardness and strength such as hardened steel, but it is used as a throw-away tip because it is extremely expensive. If so, it is desirable to use as little material as possible. Therefore, normally, the CBN in the throw-away tip 11 of this type is
The sintered body 15 is provided as a minimum required size at a required position of a cutting edge (blade edge). Moreover, since it is rarely used for rough cutting and is used in a finishing cutting area with a small cut, the size of the CBN sintered body 15 is such that the cutting edge length sandwiching a corner is about 2 to 3 mm. The thickness is as small as about 1 mm at the most.

[0004]

As described above, in the throw-away tip with CBN, the CBN sintered body is minute, and the throw-away tip body 12 and the CBN sintered body 1 are provided.
CBN is gray or dark gray, which is similar to that of CBN.
The identification (discrimination) of itself, that is, the cutting edge is visually troublesome.
That is, in the conventional throw-away tip, a minute C
With a normal BN provided in one corner of a triangular throw-away tip, for example, it is difficult to tell which corner it is, before or after use, and once stored after use. However, it was not easy to visually distinguish whether or not it was used, which was also troublesome. Further, some throwaway chips of this type have CBN fixed to all the corners, but it is also troublesome to distinguish which corner has been used.

[0005] In particular, since it is easy to be contaminated by cutting oil or the like in an actual processing site, it is difficult to identify a corner where a CBN is provided and before and after use (also called a used state), and it is difficult to confirm it. In some cases, this was a factor that hindered the smooth progress of the setup work. And, such a problem has been increasing more and more recently due to the demand for cost reduction of the cutting tool, that is, the downsizing of the CBN.

By the way, it is considered that such a problem can be achieved by marking the CBN portion with paint or the like. However, in such marking, oil or the like touched in various handling processes leading to machining can be used. It is easily faded or lost, and cannot be adopted because it has no long-term reliability as a marking.

On the other hand, some CBN cutting tools have a ceramic coating of a predetermined thickness applied to the entire tool surface (the entire surface) including the CBN portion. The used state can be determined by the stains on the part and the disappearance of the coating, but before use, that is, when the product is new, the CBN also shows the same color (coating color) as the throw-away tip body.
When a CBN is provided at a corner, it is extremely troublesome to determine which corner the CBN is provided at.

The present invention has been made in view of the problems of the above-mentioned conventional throw-away tip with CBN. The purpose of the present invention is to determine the cutting edge, that is, the CBN sintered body, regardless of whether or not it is used. It is to be able to immediately determine whether it is in a corner, and at the same time, to visually and easily identify whether it has been used (whether it is usable).

[0009]

In order to solve the above problems, the present invention provides a throw away tip body made of high speed steel, cemented carbide, cermet or the like with a cubic boron nitride sintered body forming a cutting edge. In a throw-away chip provided, a coating layer of TiN, (titanium nitride), TiCN (titanium carbonitride) or CrN (chromium nitride) on at least the rake face of the exposed portion of the cubic boron nitride sintered body. Is formed.

If such a coating layer is formed on the rake face of the exposed portion of the CBN sintered body, the coating portion is provided with a throw away tip body (a dull ground color (gray or gray or cemented carbide surface) such as cemented carbide. Dark gray), T
In the case of iN, it clearly appears as a golden color, in the case of TiCN, it clearly appears as a silver color, and in the case of CrN, it clearly appears as a chrome-plated color (gloss). Therefore, according to the above means, the portion where the CBN sintered body is provided, that is, the portion of the cutting edge is obvious at a rake face. It is preferable that the coating layer be more conspicuous if it is formed on the entire rake face of the exposed portion of the CBN, but it is not necessarily formed on the entire surface in the present invention.

Therefore, when the present invention is embodied in, for example, a triangular throw-away tip provided with CBN at one corner or all corners, the surface of the throw-away tip body is ground-colored before use. As the CBN on which the coating layer is formed is extremely conspicuous, the corner with the cutting edge can be visually recognized immediately. Further, unlike the paint, this coating layer is not used and remains stable for a long period of time without deterioration such as discoloration. Further, when used, the coating is worn away or disappears, or the coating layer becomes dirty, or the dirt is conspicuous as the ground color of the coating layer, so that the usage state of the corner can be easily and quickly distinguished.

In the present invention, the ceramic coating layer is replaced by CBN instead of the rake face of CBN.
It may be formed on at least the flank of the exposed portion of, or on substantially the entire surface (the rake surface and the flank) of the exposed portion of the CBN. It is obvious that if the coating layer is formed on almost the entire exposed portion of the CBN, the cutting edge portion and its usage state can be more easily identified. On top of that, there is such a ceramic coating,
It is expected that the wear resistance of CBN will be improved. Even when the coating layer is formed on the flank, it is preferable to form it on the entire surface because it is conspicuous and preferable.

In any of the above means, T
The thickness of the coating layer of iN, TiCN or CrN is
0.5-8 μm is suitable. Each of the above-mentioned coating layers should be clear and contribute to identification,
This is because each color becomes clear when the thickness is 5 μm or more, while when it exceeds 10 μm, the surface hardness of CBN is not utilized depending on the hardness of the work material, which may rather deteriorate the cutting performance. It should be noted that each coating layer is sufficient if it is clear and contributes to identification, and a single layer is sufficient.

The coating layer is formed by the well-known CVD method.
(Chemical vapor deposition) or PVD (physical
It may be performed before or after brazing the composite with the cemented carbide forming the CBN sintered body to the main body by vapor deposition). However, when coating is performed after the brazing, the CVD method uses a temperature (1000 to 1) higher than the melting point of the brazing material (eg, about 800 ° C.) in the process.
It cannot be adopted because it is around 100 ° C). Note that P
When coated by VD, 500-600
Since the temperature does not become so high as about ℃, it can be performed after brazing, but at that time, masking is appropriately performed so that the throw away tip body is not coated.

Therefore, the coating layer is formed by C
It is desirable to perform the step before brazing the BN sintered body to the main body. However, if a coating is applied to the surface of the cemented carbide that forms the composite at that time, the throw away tip body of the cemented carbide surface should be included so that it does not hinder brazing to the body. It is necessary to remove the coating layer from the surface to be brazed to by polishing or the like. This is because brazing to the body is done through the cemented carbide of the composite. As will be described later, at the stage of the large size of the composite body forming the CBN sintered body (composite material before cutting into composite body units (one cutting edge)),
After coating the surface of the CBN sintered body,
It is recommended to cut and divide each unit. This is because the above-described polishing for brazing becomes unnecessary.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment in which a throw-away tip according to the present invention is embodied will be described in detail with reference to FIGS. In FIG. 1, reference numeral 1 denotes a negative type throw-away tip having a substantially equilateral triangular plate shape, and in this example, a concave portion formed at one corner C of a cemented carbide throw-away tip body 2 (see FIG. 3).
3 has a substantially trapezoidal shape in plan view (as viewed from the rake face 4), C
A composite body 7 composed of two upper and lower layers of a BN sintered body 5 and a cemented carbide 6 is fixed by brazing. In this example, the entire rake face 5a (hatched region in the figure) of the CBN sintered body 5 forming the composite body 7 is coated with a TiN coating layer as a single layer with a predetermined thickness (about 2 to 6 μm).

Incidentally, the concave portion 3 of the main body 2 in this example is
As shown in FIG. 3, a bottom surface 8 having a trapezoidal shape in plan view substantially parallel to the rake surface 4 and two wall surfaces 9 and 10 intersecting the bottom surface 8 at substantially right angles are formed. It is formed to have a predetermined thickness that has a trapezoidal shape in plan view that fits exactly in the recess 3 (see FIG. 4). The composite body 7 is obtained by integrally sintering and forming a pedestal of a cemented carbide (layer) 6 having a constant thickness and a CBN sintered body 5 having a predetermined thickness smaller than that. The bottom surface 8 of the recess 3 through the lower surface of the cemented carbide layer 6
Under the condition that the side surfaces are constrained by the wall surfaces 9 and 10, they are brazed and fixed to the recess 3 by silver brazing or the like. The size of the CBN in the composite 7 is such that the length of the long side sandwiching the corner C is about 3 mm, the length of the short side is about 2 mm, and the thickness is about 1 mm.

The throw-away tip 1 of the present example thus formed has the TiN coating layer formed on the exposed surface of the CBN sintered body 5, that is, the rake face 5a. Of the whole, only the CBN sintered body 5 forming the cutting edge exhibits a clear golden color with respect to the gray color of the main body 2. Thus, without such a coating layer, it is difficult to distinguish between the main body 2 and the CBN sintered body 5 at first glance, and the position of the cutting edge can be seen from the rake face 4 side before use. It is self-explanatory due to its golden color and can therefore be clamped in a holder (not shown) without hesitation.

Further, the coating layer disappears due to abrasion or the like as it is used and approaches the end of its service life. When the holder is unclamped and replaced with a new one at the end of its life, the position of the cutting edge can be simply and quickly identified by picking up the new one. Also, after replacement, the used blade can be easily recognized by checking its condition, because the cutting layer has abrasions on the coating layer and stains due to cutting oil. It is also effective. When CBNs are provided at all corners, it is obvious that all corners have cutting edges when new. Furthermore, if each of the corners is used, only the used corner makes the cutting edge C
Since abrasion of the coating layer and dirt due to cutting oil and the like remain on the BN, it is possible to easily distinguish whether it is a used corner or not by looking at the state.

In this example, the TiN coating is applied only to the rake face 5a side of the CBN sintered body 5, but the preferred method is briefly described above, but the details are as follows. That is, after sintering a large-sized composite (assembly before cutting into composite units) of a composite of CBN and cemented carbide, that is, a cemented carbide (layer) having a constant thickness and a CB having a predetermined thickness.
Of the large-sized composite body formed by integrally sintering N sintered bodies, the CBN surface serving as the rake face is coated with a predetermined ceramic by, for example, the PVD method. After that, it is cut into a plane shape of a predetermined cutting edge, and the cut surface forming the flank (side surface) of the cutting edge is polished. Thus, a composite for one cutting edge in which the coating layer is formed only on the rake face of CBN is obtained (see FIG. 4). After that, this may be brazed to the main body. That is, according to such a method, compared with the conventional manufacturing process of the throw-away tip of the same kind, only the ceramic coating process is increased in the large size of the composite, and there is almost no cost problem. It should be noted that such a coating method is the same when forming a coating layer of TiCN or a coating layer of CrN.

When the coating area of the CBN sintered body 5 is coated on the flank 5b of the exposed portion or the entire surface (the rake surface 5a and the flank 5b), the following may be done. That is, after the large size of the sintered composite body is divided and formed into each unit (one cutting edge) of the composite body, the side surface and the substantially entire surface of the CBN flank 5b of each unit may be coated. At this time, when coating only the flank surface 5b, the other portions may be appropriately masked. Further, for brazing to the main body, it is necessary to remove the coating on the cemented carbide portion of the composite body, which will be the brazing surface, by polishing or the like. Note that C
When the coating layer is formed on the entire surface of the BN, the coating is applied to the entire cutting edge, and the wear resistance is correspondingly increased.

On the other hand, when the CBN composite is brazed to the body and then the rake face or flank of CBN or the entire surface thereof is coated with PVD, the body of the throw-away tip should not be coated. Masking is appropriately performed according to the desired coating area.

In the above description, the case where the TiN coating layer is formed has been described. However, even in the case of the TiCN coating layer or the CrN coating layer, the golden color becomes silver or chrome plating color, but these are high speed steels. , Cemented carbide, because it is markedly different from the ground color of the throw-away tip body made of cermet, the CBN, that is, the cutting edge portion, can obtain the same high distinctiveness as when the TiN coating layer is formed, The usage status of the cutting blade can be easily and quickly understood.

In the present invention, the throw away tip body is not limited to the triangular shape but is embodied in the throw away tip in which the CBN is partially provided at the cutting edge portion regardless of the shape such as a rhombus, a square such as a square or a pentagon. it can. Further, it is obvious that the present invention can be embodied not only in one corner but also in a throw-away chip in which CBN is provided in a plurality of or all corners. Further, although the main body is embodied in the negative chip in the above-mentioned embodiment, it is needless to say that the main body can be embodied in the positive chip. Further, it is apparent that the planar shape of the composite containing CBN is not limited to the above-mentioned shape, and the effect can be similarly exerted even in the case of an appropriate shape such as a triangle.

[0025]

According to the present invention, the ground color (gray or dark gray) of the surface of the high-speed steel, cemented carbide, cermet or the like forming the throw-away tip body is formed on the rake face of the exposed portion of the CBN sintered body. ), A ceramic coating layer with a clear color that is completely different from
Before use (at the time of new product), even if the size of the cutting edge is very small, it can be easily used in one corner or multiple corners.
Can be seen quickly.

The ceramic coating is then
Unlike application of paints, etc., there is no deterioration such as discoloration even after unused for a long period of time, so stable identification is maintained.
Further, when used or at the end of its life, the coating is worn out or disappears, or the coating site is contaminated with cutting oil or the like, so it can be easily understood that the cutting blade is a used or used cutting edge.

Further, in the case where a coating layer of TiN, TiCN or CrN is formed on almost the entire exposed portion of the CBN sintered body, the ceramic coating layer is provided on the entire surface of the cutting edge, so that abrasion resistance is increased. There are further improvements.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment that embodies a throw-away tip with CBN according to the present invention.

FIG. 2 is an enlarged view of a main part in FIG.

FIG. 3 is an enlarged perspective view for explaining a recess in which the CBN sintered body of the throw-away tip body of FIG. 1 is provided.

FIG. 4 is an enlarged perspective view of only a composite body.

FIG. 5 is a perspective view showing a conventional throw-away tip with CBN.

[Explanation of symbols]

 1 throw-away tip 2 throw-away tip body 3 recess 4 rake face of throw-away tip body 5 CBN sintered body 5a CBN rake face 5b CBN flank face 6 cemented carbide that forms a composite with CBN 7 complex

Claims (4)

[Claims] 1. A throwaway tip comprising a throwaway tip body made of high speed steel, cemented carbide, cermet, etc., and a cubic boron nitride sintered body forming a cutting edge. A throw-away tip characterized in that a coating layer of titanium nitride, titanium carbonitride or chromium nitride is formed on at least the rake face of the exposed part of the body. 2. A throwaway chip, comprising a throwaway chip body made of high speed steel, cemented carbide, cermet, etc., and a cubic boron nitride sintered body forming a cutting edge. A throw-away tip, characterized in that a coating layer of titanium nitride, titanium carbonitride or chromium nitride is formed on at least the flank of the exposed part of the body. 3. A throwaway chip comprising a throwaway chip body made of high speed steel, cemented carbide, cermet, etc., and a cubic boron nitride sintered body forming a cutting edge. A throw-away tip characterized in that a coating layer of titanium nitride, titanium carbonitride or chromium nitride is formed on substantially the entire exposed portion of the body. 4. The throw-away tip according to claim 1, 2 or 3, wherein the coating layer of titanium nitride, titanium carbonitride or chromium nitride has a thickness of 0.5 to 8 μm.