JP2001212788A - Cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool having high abrasion resistance in relation to a hard article to be cut and having the long life. SOLUTION: The cutting tool is formed of ultrafine particle cemented carbide in which the mean crystal particle diameter of tungsten carbide as a main component is not more than 0.5 μm and the fracture toughness is not less than 23 MNm-3/2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade used for cutting an aluminum foil used for an aluminum electrolytic capacitor or an optical fiber.

[0002]

2. Description of the Related Art For example, the surface of an aluminum foil used for an aluminum electrolytic capacitor is electrolytically treated to increase its surface area due to the characteristics of the capacitor, and the surface layer is made of alumina. Since it is difficult to cut, high-speed steel and cemented carbide have been conventionally used as a material of a cutting tool for cutting this. The aluminum foil that is the object to be cut has a width of about 500 mm and a thickness of 0.1 to 0.2 mm, and is cut in the longitudinal direction, as shown in FIGS.
This is performed so that the aluminum foil 3 is sandwiched between the slitter upper blade 1 and the slitter lower blade 2.

[0003] The slitter upper blade 1 and the slitter lower blade 2
While setting a plurality of pieces each on the same axis, and winding the cut piece of aluminum foil 3, the slitter upper blade 1,
Each axis provided with the slitter lower blade 2 is relatively rotated in the opposite direction to perform cutting. The slitter upper blade 1 and the slitter lower blade 2 are made of high-speed steel or cemented carbide.

For example, as shown in FIG. 4, a blade 4 for cutting an optical fiber 5 has a donut disk shape. FIG.
As shown in the figure, a blade edge portion 4a and a pair of inclined peripheral surfaces 4b on both sides thereof are formed on the outer peripheral portion. When cutting the optical fiber 5, the blade 4 is cut into pieces of a predetermined length by so-called broaching, in which the blade 4 is cut into the optical fiber 5 without rotating and cut by pulling or folding. For this reason, it is also known that the cutting edge 4a of the cutting tool 4 needs a small chip width b having a width of 1 to 4 μm as shown in FIG.

As for the blade 4 used in this processing step, a metal such as stainless steel or a general cemented carbide is used as in the case of the above-mentioned aluminum foil cutting blade (Japanese Patent Laid-Open No. 6-155373). Gazette).

[0006]

However, if high-speed steel or cemented carbide is used as the material of the cutting tool used for cutting the aluminum foil or optical fiber, there is a problem that the wear resistance is poor and the life is short. .

[0007] For example, when the life of the aluminum foil is expressed by the processing amount, about 4 to 6 tons for high speed steel and about 5 tons for cemented carbide.
10 tons, but 50 tons
Thus, usable materials are required. Further, the aluminum foil chips at the time of cutting have a high temperature, and there is also a problem that the aluminum chips are attached to the inside of the blade and the sharpness becomes poor.

As described above, the blade 4 for cutting an optical fiber requires a blade edge 4a having a small chip width b at the tip of the blade 4, as described above. 2000 for blade 4 made of hard alloy
If you try to grind the cutting edge 4a using the No. diamond wheel, cracks are likely to occur in that part, and the size of the chip width b will vary, so it will be further ground with a finer diamond wheel than No. 2000 Need to
There was a problem that productivity became worse.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present invention relates to a method for producing tungsten carbide having an average crystal grain size of 0.5 μm.
Or less, wherein the fracture toughness was formed cutlery in 23MNm ^-3/2 or more ultrafine cemented carbide. The surface roughness in the vicinity of the cutting edge is characterized in that the center line average roughness (Ra) is 1 μm or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below.

The blade using the ultrafine-grain cemented carbide of the present invention is used, for example, for cutting an aluminum electrolytic capacitor as follows.

As shown in FIG. 3, an aluminum foil 3 to be cut has a width of about 500 mm and a thickness of 0.1 to 0.2 mm, and is cut in a longitudinal direction. Specifically, FIG.
2, a plurality of slitter upper blades 1 and a plurality of slitter lower blades 2 are set coaxially, and as shown in FIG. A method is adopted in which the aluminum foil 3 is sandwiched in a state where the thickness is set to 3 to 0.5 mm, and the respective axes are further rotated relatively in opposite directions to cut and wind.

The aluminum foil 3 has a characteristic of a capacitor.
The surface of the blade is electrolytically treated to increase the surface area and becomes alumina, and is very hard and hard to cut. Therefore, the material of the blade must be high in hardness and excellent in wear resistance. Therefore, in the present invention, as the material of the slitter upper blade 1 and the slitter lower blade 2, the average crystal particle diameter of tungsten carbide (WC) as a main component is 0.5 μm.
m or less, the fracture toughness K _IC uses 23MNm ^-3/2 or more ultrafine cemented carbide.

[0014] Here, the reason why the fracture toughness K _IC is a 23MNm ^-3/2 or more, slitter upper blade 1 when the aluminum foil 3 cleavage
This is because a higher toughness is required because of the curvature. In order to increase the toughness of the ultrafine cemented carbide,
A method of increasing the Co content is used, which increases the transverse rupture strength but decreases the hardness.

Therefore, in the present invention, the above-mentioned fracture toughness is provided by setting the average crystal grain size of tungsten carbide as the main component to 0.5 μm or less. Also,
By using the ultra-fine-grained cemented carbide as described above, finishing can be easily performed, and the surface roughness near the cutting edge can be easily reduced to 1 μm or less in center line average roughness (Ra).

By setting the surface roughness in the vicinity of the cutting edge to 1 μm or less in terms of center line average roughness (Ra), adhesion of chips of the aluminum foil 3 which has become high temperature during cutting is reduced,
The life can be 50 ton or more in terms of the processing amount of the aluminum foil 3.

Next, another embodiment of the present invention will be described.

The blade 4 for cutting the optical fiber is
As shown in FIG. 4, it has a donut disk shape, and on the outer peripheral portion thereof, as shown in FIG. 5, a blade edge portion 4a and a pair of inclined peripheral surfaces 4b on both sides thereof are formed, and when cutting an optical fiber, An optical fiber 5 without rotating the blade 4
Cut it by pulling or breaking it. As shown in FIG. 5, the blade tip 4 a at the tip of the blade 4 has a width of 1 to 4 μm for facilitating cutting.
A small chip width b of m is provided.

Since the optical fiber is very hard, the material of the blade 4 must be high in hardness and excellent in abrasion resistance as in the case of the above-mentioned embodiment. Therefore, tungsten carbide (WC) as a main component is used. Average crystal grain size is 0.5
μm or less, the fracture toughness K _IC uses 23MNm ^-3/2 or more ultrafine cemented carbide.

[0020] Here, the reason why the fracture toughness K _IC is a 23MNm ^-3/2 or more, when an incision into the optical fiber 5, a force is applied through a hole bored in a central portion of the blade 4, and more This is because strong toughness is required. In order to increase the toughness of the ultrafine-grain cemented carbide, a method of increasing the content of Co is used, which increases the transverse rupture strength but decreases the hardness.

Therefore, in the present invention, the above-mentioned fracture toughness is provided by setting the average crystal grain size of tungsten carbide as the main component to 0.5 μm or less. Also,
By making the cemented carbide of ultrafine particles in this manner, the finishing of the inclined peripheral surface 4b is facilitated, and the surface roughness is easily reduced to 1 μm or less in center line average roughness (Ra). Therefore, even if it is ground with a coarse diamond grindstone, cracks are less likely to be formed in the cutting edge portion 4a of the cutting tool 4, thereby improving productivity.

The ultrafine-grain cemented carbide according to the present invention is made of tungsten carbide (W) having an average crystal grain size of 0.5 μm or less.
C) from 80 to 90% by weight, Co from 9 to 19% by weight,
Those containing other components such as TaC in an amount of 1 to 3% by weight are preferable. This is because the fracture toughness is improved by increasing the Co content. The concern about the decrease in hardness can be suppressed by making the particle size small.

Next, a method for manufacturing a blade using the ultrafine-grain cemented carbide of the present invention will be described below.

First, 80 to 90% by weight of WC having an average particle diameter of 0.2 to 0.5 μm, 9 to 19% by weight of Co, and 1 to 3% by weight of other components are mixed in a ball mill to form about 10 to 15%.
Mix and grind for hours. The dried material is formed into a predetermined shape by a press machine, and then the material sintered at 1350-1550 ° C is further processed at 1300-1400 ° C and 450-5
HIP treatment for 18 to 22 hours under the condition of 50 atm (Hot isostatic sintering method: Hot Isostatic Pressi)
ng) to crush the voids. Knives with ultrafine cemented carbide thus obtained has an average crystal grain size of the WC in the sintered body 0.5μm or less, the fracture toughness 23MNm ^-3/2 or more, in Hv hardness 14.5GPa more A blade having excellent wear resistance can be obtained.

The sintered body obtained in this manner is used after further finishing the vicinity of the cutting edge so as to meet the above-mentioned applications.

For example, when using an aluminum foil cutting blade, the surface roughness in the vicinity of the blade edge is determined by calculating the center line average roughness (Ra) of 1 μm.
By setting m or less, the amount of chips of the aluminum foil adhered at the time of cutting can be reduced, and the productivity is improved.

Further, in the case of the cutting edge 4 for cutting the optical fiber 5, when the inclined peripheral surface 4b is finished, the sintered body is a dense body having a WC average crystal particle diameter of 0.5 μm or less. Even if a diamond whetstone is not used, cracks are less likely to occur in that part, and the size of the cutting edge portion 4a and the chip width b can be made constant, so that the process can be shortened. .

In the above embodiment, only the blade for cutting aluminum foil and the blade for cutting optical fiber have been described.
The cutting blade of the present invention can be widely used for cutting blades for fibers such as polyester, papers for packaging and the like, and films for magnetic tapes.

[0029]

Embodiments of the present invention will be described below. (Example 1) As an example of the present invention, an average particle size of 0.2 to
83% of 0.5 μm WC, 15% of Co and about 2% of other components such as TaC are mixed and pulverized in a ball mill for about 10 hours, and the dried raw material is formed by a press machine.
The material sintered at １５1550 ° C.
HIP treatment for 20 hours at 500 ° C. and 500 atm (Hot Isostatic Pressing: Hot Isostatic Pressing)
ng) to obtain a sintered body having an average crystal grain size of 0.5 μm or less, as shown in Sample D of Table 1. The sintered body thus obtained was processed into a predetermined shape to obtain a slitter blade for an aluminum electrolytic capacitor. Further, finishing was performed to reduce the surface roughness near the cutting edge to a center line average roughness (Ra) of 1 μm or less.

As a comparative example, the average particle diameter was 0.8 μm.
m, 9.5% of WC, 9.5% of Co and about 1% of other metal components such as TaC are mixed and pulverized in a ball mill for about 10 to 15 hours, and the dried raw material is molded by a press machine, and then at 1350 to 1550 ° C. Sintered material was added to 1300-1
HIP treatment (hot isostatic sintering method: Hot Isosta) at 400 ° C. and 450 to 550 atm for 18 to 22 hours
Tic pressing) to obtain a sintered body having an average crystal grain size of about 0.8 μm (sample C in Table 1).

This was used as a slitter upper blade 1 for cutting an aluminum foil 3 for an aluminum electrolytic capacitor. In order to evaluate the difference in service life depending on the material, high-speed steel and general carbide were also carried out in the same manner. In addition, all the slitter lower blades 2 were made of general cemented carbide and evaluated.

As a result, as shown in Table 1, the slitter upper blade (sample D) of the embodiment of the present invention using ultra-fine-grained carbide was higher in wear resistance than high-speed steel and carbide of the same shape. Is high,
The adhesion of the high-temperature aluminum foil at the time of cutting was small.

[0033] The average crystal grain size as large as 0.8 [mu] m, the sample C fracture toughness is low comparative example 13MNm ^-3/2 is an unsuitable as cutlery for aluminum foil cutting low wear resistance Was.

That is, the average crystal particle diameter is set to 0.2 to 0.5.
μm, fracture toughness 23 to 26 MNm ^-3/2Of sample D
Extremely wear-resistant due to the use of ultra-fine cemented carbide
Aluminum foil, which is expensive and difficult to process
I was able to make it a thundering knife.

In the above examples, the fracture toughness was measured by the IF method (Indentation Fracture).
Method). This is calculated from the length of the crack propagated when an external force is applied to the test piece.

The average crystal particle diameter was determined by subjecting the surface of the sintered body to mirror finishing, and using a metallographic photograph or an enlarged photograph by an electron microscope according to the cutting method of JIS0501.

[0037]

[Table 1]

(Example 2) Similarly, as an example of the present invention, 83% of WC having an average particle diameter of 0.2 to 0.5 μm, C
o 15% and other ingredients about 2% in a ball mill about 1
Mixing and crushing for 0 hour, forming the dried raw material with a press machine,
Thereafter, the material sintered at 1350 to 1550 ° C.
HIP treatment under the conditions of 0 to 1400 ° C. and 500 atm (Hot isostatic sintering method: Hot Isostatic)
Pressing), the void was crushed, and processed into a predetermined shape as a cutting blade for optical fiber (sample D in Table 1). At this time, 100 V is formed on the inclined peripheral surface forming the V-shape.
Finishing processing was performed using a No. 0 diamond grindstone to make the center line average roughness (Ra) 1 μm or less.

As a comparative example, the average particle size was 0.8 μm.
m, 89.5% of WC, 9.5% of Co and about 1% of other components such as TaC are mixed and pulverized in a ball mill for about 10 to 15 hours, and the dried raw material is formed by a press machine.
The material sintered at 50 to 1550 ° C.
HI at 0 ° C. and 450-550 atm for 18-22 hours
P treatment (hot isostatic sintering method: Hot Isostati
c Pressing) to prepare an optical fiber cutting blade from the sintered body obtained (Sample C in Table 1).

In order to evaluate the difference in the life depending on the material, a high-speed steel and a general carbide were prepared and evaluated.
As shown in the figure, compared with high-speed steel and carbide of the same shape, the optical fiber cutting blade of the present invention using ultra-fine carbide particles (Sample D) had higher wear resistance.

[0041] The average crystal grain size as large as 0.8 [mu] m, fracture toughness sample C is lower comparative example 13MNm ^-3/2, abrasion resistance was unsuitable as a tool for optical fibers cut low .

That is, the average crystal particle diameter is set to 0.2 to 0.5.
μm, fracture toughness 23 to 26 MNm ^-3/2And light the material
Wear resistance due to application to fiber cutting blades
Is very high, there is no crack on the ground surface,
Very small variation in size
Was.

In the above embodiments, the fracture toughness was measured by the IF method (Indentation Fracture).
Method). This is calculated from the length of the crack propagated when an external force is applied to the test piece.

The average crystal particle diameter was determined by subjecting the surface of the above sintered body to mirror finishing, and using a metal microscope photograph or an enlarged photograph by an electron microscope according to the cutting method of JIS0501.

[0045]

As described above, according to the present invention, the average crystal grain size of the main component tungsten carbide is 0.5 μm.
Or less, by the fracture toughness was formed cutlery in 23MNm ^-3/2 or more ultra-fine particles cemented carbide, both to improve the hardness and toughness of the tool, to manufacture a tool with enhanced abrasion resistance It is now possible.

[Brief description of the drawings]

FIG. 1 is a side view showing an aluminum foil cutting blade according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a portion A in FIG.

FIG. 3 is a perspective view showing a use state of an aluminum foil cutting blade according to another embodiment of the present invention.

FIG. 4 is a perspective view showing a use state of an optical fiber cutting blade according to another embodiment of the present invention.

FIG. 5 is an enlarged sectional view of the blade shown in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Upper blade of slitter 2 Lower blade of slitter 3 Aluminum foil 4 Blade 4a Blade edge 4b Inclined peripheral surface 5 Optical fiber a Gap b Chip width

Claims (2)

[Claims] A tungsten carbide as a main component has an average crystal grain size of 0.5 μm or less and a fracture toughness of 23 MNm
A cutting tool characterized in that it is made of an ultra fine cemented carbide of ^-3/2 or more. 2. The method according to claim 1, wherein the surface roughness in the vicinity of the cutting edge is defined as a center line average roughness (R).
The cutting tool according to claim 1, wherein a) is 1 μm or less.