JPS63318288A - Cutting tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a cutting tool, and more specifically, a slitter for electrostatic plotters, a paper pattern cutting blade, a lead wire cutter, a slitter for films such as polyester, and a magnetic tape slitter. , relates to a cutting tool made of ceramics, such as a metal foil slitter, which has particularly excellent toughness and improved wear resistance.

(Prior art and problems) Conventionally, cutting tools such as slitters for electrostatic plotters, pattern cutting blades, lead wire cutters, slitters for films such as polyester, magnetic tape slitters, and metal foil slitters have been made using carbon tool steel or high-speed cutting tools. It is generally made of steel or even cemented carbide.

However, the object to be cut as described above has a hard phase (for example, clay material for paper, ferrite particles for magnetic tape).
or because they are highly ductile metals (lead wires and metal foils), tool steels have the problem of insufficient wear resistance and sharpness in a short period of time, resulting in extremely short service life. . Cemented carbide has good wear resistance, that is, long life, but since it is made of rare metals such as WC and Go, it is expensive and has a specific gravity of approximately 13 g 70 m
” and the weight of the blade is heavy, so improving productivity by increasing the diameter or the number of blades of round-blade tools being considered for magnetic tape slitter and metal foil slitter is due to the rigidity of the shaft. There are problems such as difficulty in maintaining dimensional accuracy due to the shortage.

From the above point of view, various studies have been conducted on ceramic cutting tools that are lightweight and have excellent wear resistance comparable to cemented carbide, but due to their low toughness and lack of mechanical strength, Chipping occurs, resulting in a decrease in sharpness and cutting accuracy, so it has not been put into practical use.

(Means for Solving the Problems) The present invention has been made in view of the problems of the conventional cutting tools described above, and is suitable as a ceramic cutting tool having excellent toughness and improved wear resistance. As a result of intensive research to develop a material, we found that a zirconia-based composite sintered body with high toughness, high strength, and high hardness, which is a combination of alumina or titanium carbide hard layer with zirconia, is suitable for this purpose.

The cutting tool of the present invention, which is made of a zirconia-based composite sintered body with high toughness, high strength, and high hardness, in which a hard layer of alumina or titanium carbide is combined with zirconia, has a hard layer of alumina or titanium carbide with an average particle size of 10 μm or less. It is characterized by consisting of partially stabilized zirconia containing ~5 mol%.

Next, the reason for limiting the range of components of a zirconia-based composite sintered body having high toughness, high strength, and high hardness in which a hard layer of alumina or titanium carbide is combined with zirconia will be described.

The hard layer of alumina or titanium carbide has an average particle size of 10
If the thickness exceeds μ, the hard layer itself acts as a defect and reduces the strength, so the thickness was set to 10 μm or less.

The amount should be set at 5 to 40% without reducing toughness and strength, and in order to play the role of a hard layer. range.

Partially stabilized zirconia is made by adding a small amount of ittria as a stabilizer, leaving a tetragonal structure even at room temperature, and exhibiting high toughness and strength through stress-induced transformation, but the amount of ittria is less than 1 mol%. If it is more than 5%, the tetragonal crystals will decrease and the cubic crystals will become the main crystal, so high toughness and high strength cannot be obtained due to transformation, which is unsuitable. The range was set at 5 mol%.

The product of the present invention is a slitter for an electrostatic plotter, a paper pattern cutting blade, and a ceramic slitter for an electrostatic plotter, which has excellent wear resistance and can be used for a long time without chipping at the cutting edge due to the characteristics of high toughness, high strength, and high hardness ceramic. It can be widely applied as a cutting tool such as a lead wire cutter, a slitter for films such as polyester, a magnetic tape slitter, and a metal foil slitter. Furthermore, it is possible to fully respond to improvements in productivity due to an increase in the number of teeth, which has been a problem with cemented carbide.

(Example) The present invention will be explained in detail below using examples.

1st Example Volume ratio: 80% partially stabilized zirconia, 20% alumina
was blended.

The zirconia powder is partially stabilized zirconia with an average particle size of 0.2 μι, stabilized with 2 mol % (3.5 wt %) ittria. The alumina powder has a purity of 99% or more, an average particle size of 0.7 μm, and an α-type crystal form.

This raw material was mixed with ethyl alcohol in a ball mill using an alumina container and an alumina ball.
After 4 hours of mixing, these mixed powders were dried. This mixed powder was molded using a mold press, and sintered in the atmosphere at normal pressure at a sintering temperature of 1,500°C for a sintering time of 2 hours.
A sintered body of 011 m x 50 mm x 2.5 nv+ was obtained.

Second example Volume ratio: 70% partially stabilized zirconia, 30% titanium carbide
% was added.

As in the first example, the zirconia powder was 2 mol% (3,5
(% by weight) Partially stabilized zirconia stabilized with ittria and having an average particle size of 0.2 μm. Titanium carbide has a purity of 95%
The above particles have an average particle size of 1.5 μI.

This raw material was mixed with ethyl alcohol in a ball mill using an alumina container and an alumina ball.
The powder mixture was mixed for 4 hours and then dried. This mixed powder was molded using a hot press method in an argon gas atmosphere at a pressure of 300 kg/cm" and a temperature of 1600°C.
Sintering was performed for 0 minutes to obtain a sintered body with a diameter of 50 mm and a thickness of 2 mm.

From the sintered bodies obtained in the first and second examples, bending test pieces with a thickness of 1.5 mm x width of 2.5 mm x length of 25 mm, hardness measurement test pieces of 1.5 mm x 10 m + m x 10 mm, and fracture toughness A test piece was taken, the surface was polished to a mirror finish, and the following tests were conducted: (1) Bending test (2) Hardness test (3) Fracture toughness test As a comparison, alumina ceramics and zirconia ceramics were used to perform the same tests. The test was conducted under the following conditions.

The test results are shown in Table 1.

The test method is as follows.

(1) Bending test A three-point bending test method based on JIS R1601 (bending strength test method for fine ceramics) was used. A load was applied at a crosshead speed of 0.5 mm/win to one point between two test pieces placed at a distance of 20 mm, and the maximum load until the test piece broke was measured.

(2) Hardness test Hardness measurement was performed using a Vickers hardness meter.

(3) Fracture toughness test In this test, toughness was evaluated by the indentation method using a Vickers hardness meter. The toughness was evaluated by determining the fracture toughness Kc. Fracture toughness Kc was calculated by Shinryo's formula.

Table 1 Inventive product ■: Zirconia 20% by volume Alumina ■: Zirconia - 30% by volume Titanium carbide Comparative product ■: Alumina ■: Zirconia As is clear from Table 1, the bending strength and fracture toughness of the invented products are The compound ■ is 92 kg/mm
", 7, 8 M Pav'm, titanium carbide composite ■ is 85, 4 kg/am", 7, 2 M P
Zirconia with excellent strength and toughness compared to AV'M ■
On the other hand, it shows performance equivalent to that of Alumina ■, which is a comparative product, and more than double the performance.

In addition, the hardness of the alumina composite product of the present invention and the titanium carbide composite product (■) are close to that of alumina (■), which has comparatively excellent wear resistance, and the wear resistance is significantly improved. It is recognized that

From the above results, it has approximately twice the strength and fracture toughness of alumina, which is a conventional ceramic with excellent wear resistance, and its hardness is close to that of alumina, and has excellent wear resistance.

It is also confirmed that it has almost the same performance as zirconia, which has excellent toughness and strength.

Below, various cutting tools were created and cutting tests were conducted.

Third Example A 32φ x 4.5φ x 2mm sintered body obtained under the same conditions with the same composition as the first and second examples was polished with a diamond grindstone to 28φ x 5φ x 0.3 rr.
When a slitter for an electrostatic plotter was ground and tested for cutting processed paper for an electrostatic plotter, it showed good cutting performance without fuzzing, and had a lifespan more than twice that of cemented carbide.

Fourth Example A sintered body of a disk of 50φ×3+m which was obtained under the same conditions with the same compounding composition as in the first and second examples was ground to 2φ×23mm by using a diamond grindstone.
■A pattern cutting blade with an ugly cutting edge at a 30 degree angle was obtained.

Fifth Example A sintered body obtained from the same composition and under the same conditions as the first and second examples was ground to a diameter of 100φ×66φ×0.6m using a diamond grindstone.
A slitter for polyester tape and magnetic tape was obtained which had a combination of an upper blade of m and a lower blade of 80φ x 60φ x 811III.

Sixth Example A sintered body obtained from the same compounding composition and under the same conditions as the first and second examples.

40φ×25 by grinding with a diamond whetstone
A metal foil slitter with a diameter of φX2+++m was obtained.

Using the paper patterns, polyester tape and magnetic tape slitter, and metal foil slitter obtained in Examples 4, 5, and 6, cutting tests were conducted on paper patterns, polyester tape, magnetic tape, and metal foil, and all results were good. It showed superior cutting performance and had a lifespan more than twice that of cemented carbide.

This is because the cemented carbide has excellent wear resistance because it contains hard alumina or titanium carbide instead of the soft metal bonding layer. Furthermore, as shown in Table 1, it has significantly superior toughness compared to conventional alumina ceramics, so it does not cause chipping at the cutting edge.
It is understood that it is an extremely excellent tool for various cutting tools.

In addition, in magnetic tape slitter, the composite ceramic of the present invention has a specific gravity of approximately 5.6 to 5.7 g/Cm, which is lighter than cemented carbide, which is sufficient to improve productivity by increasing the number of blades. It became possible to respond.

(Effects) The cutting tool of the present invention has excellent toughness and improved wear resistance due to the excellent characteristics of high toughness, high strength, and high hardness of zirconia-based composite ceramics that are composited with a hard layer of alumina or titanium carbide. The effect of having good cutting performance over a long period of time is remarkable.

Claims (1)

[Claims] 5 alumina or titanium carbide with an average particle size of 10 μm or less
~40% by volume; remainder substantially 1-5 mol% yttria
A cutting tool comprising a zirconia-based composite sintered body containing partially stabilized zirconia.