JPH0641720A - Blade for cutting timber - Google Patents

Abstract

PURPOSE:To provide the blade for cutting timber which is more improved in cutting quality and life than a blade provided with a chromium nitride coating layer. CONSTITUTION:Tool steels, such as high-speed tool steel and high-chromium tool steel, or cemented carbide is used as the base material for the blade and one or both of its relief surface or rake surface are provided with intermediate layers consisting of CrN, Cr2N or a mixture composed of the CrN and Cr2N. The intermediate layers are further provided with outside layers consisting of Cr thereon. As a result, the retreat quantity of a blade tip decreases to 1/2 to 1/3 at the same thickness of the coating layers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wood cutting tools such as rotary cutting tools and planing tools used for wood cutting.

[0002]

2. Description of the Related Art Cutting blades for wood cutting have been coated with various materials for the purpose of improving sharpness and extending cutting life, and many proposals have been made so far. Can be seen.

For example, Japanese Patent Application No. 1-75889 (Japanese Patent Application Laid-open No. 2-75889)
252501), Japanese Patent Application No. 2-257864 (JP-A-4-257864)
135107), the tool base material is any one of tool steel such as high speed tool steel and high chromium alloy tool steel and cemented carbide, and one of the flanks or the scooping surface is CrN.
, Cr ₂ N or chromium nitride consisting of a mixture of CrN and Cr ₂ N (hereinafter simply referred to as “chromium nitride”)
0.5 to 6.0 μm (Japanese Patent Application No. 1-75889) or 0.2 to 6.0
A blade for cutting wood with only μm (Japanese Patent Application No. 2-257864)
(Cutting tool for rotary cutting or cutting tool for planing) is disclosed, the cutting tool for wood cutting provided with such a coating layer, wear of the cutting edge of the coating layer is suppressed, compared to the conventional one without a coating layer. It is known that excellent effects on sharpness and life are exhibited.

[0004]

SUMMARY OF THE INVENTION A general object of the present invention is to provide a wood cutting blade capable of exerting excellent effects which have not been seen in the past in terms of sharpness and life.

A more specific object of the present invention is to provide a blade for cutting wood, which has further improved sharpness and life than the blade provided with the above-mentioned chromium nitride coating layer.

[0006]

By the way, the sharpness and life of a cutting tool for wood cutting are generally judged by the occurrence of defects (misalignment, fluffing, reverse blurring) of the cut surface of wood. On the other hand, this can be evaluated by the wear of the cutting edge when viewed from the side of the cutting tool.

With respect to this point, in the above-mentioned conventional technique, a corresponding effect can be obtained by coating with chromium nitride, but in the present invention, various cutting tests are repeated in order to develop a more excellent wood cutting blade, and the cutting edge wear state Was examined while observing in detail with an electron microscope, etc.,
The present invention has been completed, knowing that the progress of wear of the chromium nitride layer can be suppressed more effectively by providing the outer layer made of Cr.

[0008] The present invention is a cutting tool for wood cutting, which uses any of tool steel such as high speed tool steel and high chromium alloy tool steel and cemented carbide as a tool base material, and has flanks and scooping surfaces. On one or both sides of CrN, Cr ₂ N, or
A wood cutting blade characterized in that an intermediate layer made of a mixture of CrN and Cr ₂ N is provided, and a composite coating layer having an outer layer made of Cr further provided on the intermediate layer is used as a basic coating layer.

According to a preferred embodiment of the present invention, the thickness of the chromium nitride coating layer on the flank surface and / or the scooping surface is 0.3 to.
By setting the thickness of the outer layer of the Cr layer to 6.0 μm to 0.3 to 1.5 μm, the wear of the coating layer at the cutting edge is reduced even during long-term cutting, and sharpness and life are remarkably improved.

Thus, according to the present invention, by providing the composite coating layer on the flank surface and / or the scooping surface, abrasion of the composite coating layer is effectively suppressed, mass productivity is high, cost is not increased, and the blade by polishing is provided. It is possible to obtain a long-life wood cutting blade which has good attachability and can obtain a good cutting surface.

[0011]

Next, the reason why the structure of the present invention is limited as described above will be explained in relation to the operation of the present invention.

First, the tool steel such as high speed tool steel and high chromium alloy tool steel or cemented carbide used as the tool base material in the present invention are all well known as the tool base material. Also, since the blade itself manufactured from it is already well known, further description will be omitted.

According to the present invention, an intermediate layer made of chrome nitride is provided on one or both of the flank and the scooping surface of the wood cutting blade made of the base material of the cutting blade, and then further on it. An outer layer made of Cr is provided on the to form a composite coating layer. By providing this outer layer, the progress of wear of the coating layer near the cutting edge can be effectively suppressed, and the sharpness and the life can be improved over a long period of time.

That is, Cr is coated as an outer layer on the intermediate layer consisting of the chromium nitride coating layer. By providing this Cr outer layer, corrosion and oxidation of the chromium nitride intermediate layer by the acid contained in the wood during cutting are provided. Not only has the precise mechanism been suppressed, but the synergistic effect with the chromium nitride intermediate layer has significantly reduced the amount of wear receding at the cutting edge, thereby reducing the wear. It is possible to delay the occurrence of fluffing and reverse eyebrow, which are cutting defects, and improve the sharpness, that is, the life.

Here, considering the case where a Cr coating layer is provided as an intermediate layer and a chromium nitride coating layer is provided as an outer layer, not only can the chemical corrosion as described above not be sufficiently endured, but the wear retreat amount of the cutting edge is also considered. However, the desired effect of the present invention cannot be achieved.

According to the present invention, as an underlayer of the chromium nitride intermediate layer, the adhesion between the intermediate layer and the blade base material is further improved, and the cutting performance is not adversely affected.
A layer having an intermediate coefficient of thermal expansion between the blade base material such as TiN and chromium nitride may be provided, and this point is not particularly limited.

The means for providing the intermediate layer made of the chromium nitride coating layer and the outer layer made of Cr of the present invention is not particularly limited.

Usually, in order to provide these coating layers, various coating methods such as chemical vapor deposition method (CVD method) and physical vapor deposition method (PVD method) can be used. Considering the decrease in the hardness of the blade base metal and the problem of adhesion due to the temperature of the coating process on the tool steel such as chromium alloy tool steel,
The ion plating method, which is a type of PVD method, is preferable.

The outer layer made of Cr may be formed continuously after forming the intermediate layer made of chromium nitride by using the same device and means.

At this time, for example, in the case of the PVD method, a so-called gradient composition layer can be obtained by gradually reducing the N ₂ partial pressure and gradually increasing the Ar partial pressure. That is, since high stress concentration at the bonded interface between the intermediate layer and the outer layer causes delamination, the graded composition of this bonded interface eliminates the interface where the physical properties suddenly change. Therefore, the stress singularity disappears,
Due to the stress relaxation, the outer layer does not turn over during cutting or cutting by polishing or honing, and the progress of wear of the intermediate layer can be effectively suppressed.

As the intermediate layer, CrN, Cr ₂ N, or CrN
A mixture of Cr ₂ N is coated, and in that case, PVD treatment may be performed with a Cr target, for example, in a nitrogen atmosphere, and at that time, the morphology of CrN to Cr ₂ N is changed by adjusting the pressure of N _2. Can be changed. At intermediate pressures a mixture of both forms.

The thickness of this chromium nitride intermediate layer is
0.3 to 6.0 μm is preferable, and if it is too thin, the wear resistance is not sufficiently improved, and if it is too thick, it becomes brittle and causes chipping of the blade.

The thickness of the outer layer made of Cr is 0.3 to 1.5 μm.
If it is too thin, it is not possible to suppress wear due to chemical reactions such as corrosion and oxidation due to the acid contained in wood,
The progress of wear of the intermediate layer cannot be effectively suppressed,
On the other hand, if the thickness is too large, the Cr layer may be chipped during the blade attachment due to polishing, honing, etc., which deteriorates the sharpness of the initial wood cutting.

As described above, if necessary, the interface of the laminated body between the intermediate layer and the outer layer is made to have a gradient composition layer, so that the outer layer can be prevented from being turned over and its effect can be maximized.

The present invention can be widely applied not only to throwaway type plane blades, but also to blades for cutting wood such as plane blades which are molded or re-polished from either the flank or the scooping surface.

Next, the present invention will be described more specifically by way of examples.

[0027]

[Embodiment 1] In this embodiment, as shown in FIG. 1, a work material is provided under a blade 12 attached to a rotary plane (not shown).
It was carried out by a test machine in which 14 fixed tables 16 were cut by moving.

The test blade was manufactured by forming it to a predetermined size, providing the composite coating layer according to the present invention, and further polishing with a blade so that the blade angle was 42 degrees from the flank side.

Therefore, the coating layer is only the scooping surface.
Cutting test conditions are feeding speed of 8 m / min, rotation speed of 6000 rpm, cutting depth of 0.8 mm, cutting method up-cut, number of simultaneous mounting blades 1
The blade had a cutting diameter of 122 mm (φ) and a rake angle of 20 degrees.

Cutting edge honing was performed on some of the test blades before cutting, and the land width (width of the arc surface formed on the blade edge by honing) was set to be about 0.5 mm for all the test blades. At this time, the blade angle of the blade tip is inevitably 70 degrees.

By the way, in the rotary cutting of wood, a plurality of blades of two or more are generally mounted on the axis of rotation and used. However, since the height of each blade, that is, the cutting radius is slightly different, this blade height is As a method of aligning, a lap grindstone is lightly applied to the cutting edge while rotating the rotary plane with the blade attached. This method of aligning the cutting edges is called honing.

As the work material, spruce (air-dry material) was used, and the evaluation was made with the final cutting material length of 1000 m. In addition, the blade base material that forms the coating layer is the same type of high-speed tool steel (SKH-51)
The coating layer was formed by an arc discharge type ion plating device.

The constitution and results of the coating layer of this example are summarized in Table 1.

First, in comparison with the blade of Sample No. 0 which was not subjected to any coating treatment as a comparative example, the amount of retreat of the blade edge after cutting 1000 m was 11.5 μm (FIG. 2 (a)). The blade of the sample No. 1, which is a comparative example in which the scooping surface side of the base material was coated with CrN 2.5 μm, was 4.5 μm (FIG. 2 (b)). This sample No. 1 corresponds to the blade disclosed in the above-mentioned Japanese Patent Application No. 1-75889.

Next, in Sample No. 3 which is an example of the present invention,
On the side of the scooping surface, 2.0 μm of CrN is used as an intermediate layer and 0.5 μm of Cr is used as an outer layer, that is, a composite coating layer consisting of two layers with a total film thickness of 2.5 μm, which is the same as sample No. 1, The amount of retreat of the cutting edge after the cutting test of the blade of sample No. 3 is 2.
It was 5 μm (FIG. 2 (c)).

In the sample No. 2 which is a comparative example, only 2.5 μm of Cr is coated on the scooping surface side, but since the amount of retreat of the cutting edge after cutting of the blade of this sample No. 2 is 8.5 μm, It can be seen that, by itself, is inferior in wear resistance to CrN.
Comparing No.1 and Sample No.3, even if the total film thickness is the same, in Sample No.3, even though the film thickness of CrN, which is effective for wear resistance, is small From the small number, it can be seen that by providing the Cr layer as the outer layer, the wear resistance is synergistically improved as compared with the case where only the CrN layer is coated.

As a result of investigating the cross section of the cutting edge at this time with an electron microscope, as shown in FIG. 2 (d), as shown in FIG. 2 (d), the outer surface of the CrN layer near the cutting edge covered by the scooping surface was rubbed by abrasion. It is shown in Fig. 2 (e) that Sample No.
It was confirmed that such wear was obviously suppressed by the Cr layer provided as the outer layer as shown in FIG.
That is, it was confirmed that by coating Cr as the outer layer of the chromium nitride coating layer coated on the scooping surface side of the blade base material, a remarkable effect on the blade life could be obtained.

As a method for treating the coating layer in the present invention, for example, PVD treatment is carried out with a Cr target. When CrN is coated, N ₂ gas is used as an active gas, and when Cr is coated, Can be generated over time using the same device by using Ar gas as the inert gas.

At this time, by gradually changing the partial pressures of the N ₂ gas and the Ar gas while keeping the gas pressure constant, Cr
The N 2 layer and the Cr layer are generated as layers having a graded composition. Sample No. 4 in which the CrN layer of the intermediate layer and the Cr layer of the outer layer were coated via the gradient composition layer thus provided
The blade retreat amount after cutting was 2.0 μm, which is superior to the blade of Sample No. 3 in which the intermediate CrN layer and the outer Cr layer do not have a graded composition layer It turns out that it is more effective.

As a result of investigating the state of the cutting edge on the scooping surface side after cutting or after cutting the sample No. 3 and No. 4 blades, as shown in FIG. 3 (a) of sample No. 3 The fine swelling of the layer was drastically reduced in Sample No. 4 having a graded composition (Fig. 3 (b)), and it was confirmed that the effect of Cr coated as the outer layer was further exerted. Especially when performing honing, since a grindstone that is coarser than a general whetstone for grinding with a blade is used, it is easy for the Cr layer to turn over, but using a graded composition layer is effective in preventing such turning over. is there.

A similar cutting test (however, the honing was not performed and the blade edge angle of the blade was 42 degrees) was performed, and the composite coating layer according to the present invention was provided only on the flank and on both the scooping surface and the flank. It was carried out with a rotary cutting blade not provided, but in the case of the present invention, better results were obtained in durability than the coating with chromium nitride alone. (Sample No.5 to No.8)

[0042]

[Embodiment 2] This embodiment shows an example of a planing process using a super-finishing plane, a disc plane, a hand plane, etc. among wood cutting blades, and particularly when performing unidirectional feed (cut feed). In the reverse feed (counter feed), it is carried out by a so-called auto-return type super finishing plane which is conveyed while rubbing the cutting edge from the flank side.

FIGS. 4 (a) and 4 (b) show the test procedure at this time. The work material supported by the material feeding belt 30 and reciprocated.
32 is pressed against the finishing plane blade 34 to perform cutting. FIG. 4B is a partial plan view.

In this example, the test blade was manufactured by forming it to a predetermined size, grinding it with a blade angle from the flank side to 32 degrees, and then providing the composite coating layer according to the present invention.

The cutting conditions are a skew angle of 25 degrees and a feeding speed of 65 m /
Min, cutting depth was 0.06 mm, and scooping angle was 35 degrees. As the work material, spruce (air-dry material) was used, and evaluation was performed at a final cutting length of 1000 m. Further, the blade base material on which the coating layer was formed was the same high-speed tool steel (SKH-51), and the coating layer was formed by an arc discharge type ion plating device. The constitution of the coating layer and the test results are summarized in Table 2. The results are similar to those of Example 1, and the sample No. 11 of the comparative example (Japanese Patent Application No. 2-25
(Equivalent to the blade disclosed in No. 7864), the total thickness of the coating layer is the same, but the amount of retreat of the cutting edge after cutting is small even though the thickness of the CrN layer, which has an effect on wear resistance, is smaller than that of the Cr layer. Therefore, it was found that even in planing and cutting, providing Cr as the outer layer is more effective in wear resistance than the coating layer having only the CrN layer.

[0046]

[Table 1]

[0047]

[Table 2]

In this way, as described in Example 1, Cr was coated as the outer layer and, if necessary, the laminated body joint interface was formed into a gradient composition layer.
As shown in 2 and 2, the blade cutting property and the wear resistance are effective regardless of whether the cutting tool is a rotary cutting tool or a planing cutting tool, and at least one surface is irrespective of whether the scooping surface or the flank surface is covered. It can be seen that the effect is exhibited by the coating treatment.

In addition, in Examples 1 and 2, an additional confirmation test was conducted on samples in which Cr ₂ N or a mixed layer of CrN and Cr ₂ N was used as the intermediate layer instead of the CrN intermediate layer. The result was almost the same as the sample.

[0050]

As described above, according to the present invention, a chromium nitride coating layer is provided as an intermediate layer on one or both sides of a flank and a scooping surface, and a Cr layer is provided as an outer layer on the outside thereof, and if necessary, an intermediate layer is provided. By using a composition in which the laminated body bonding interface between the outer layer and the outer layer is changed in an inclined manner, defects of the cut surface can be effectively prevented, and the life can be further extended. It is particularly remarkable from a practical point of view.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a procedure of a cutting test according to an example of the present invention.

FIG. 2 (a) to FIG. 2 (e) are explanatory views of the retreat amount of the cutting blade according to the embodiment of the present invention.

3 (a) and 3 (b) are schematic explanatory views showing a comparison of the state of turning over of the Cr outer layer.

4 (a) and 4 (b) are explanatory views of the procedure of a cutting test of another embodiment of the present invention.

[Explanation of symbols]

 12: Blade 14: Work material 16: Table

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] July 27, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

[0046]

[Table 1]

Claims (1)

[Claims] 1. A wood cutting blade comprising a tool base material of any one of a tool steel such as a high speed tool steel and a high chromium alloy tool steel and a cemented carbide, which is one of a flank and a scooping surface, or Wood characterized by using a composite coating layer having a CrN, Cr ₂ N, or a mixture of CrN and Cr ₂ N mixture on both sides, and an outer layer of Cr on the intermediate layer as a basic coating layer. Cutting blade.