JPH0790468B2 - Cutter for cutting castings - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutter for cutting castings, and more particularly to a cutter for cutting castings suitable for foil or band saw for finishing pig iron castings or cutting cast iron pipes.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, a cutter of this type has a base 10 on which metal powder and diamond or a cube are formed.
There are a segment type 12 in which a chip 11 obtained by mixing and sintering abrasive grains of crystalline boron nitride (CBN) is brazed or laser-welded, and a Kimberley type 13 in which abrasive grains are simultaneously and integrally sintered with a base. (See JP-A-64-2871) In addition, as shown in FIG.
Abrasive grains 1 of diamond or cubic boron nitride on the substrate 14
It was manufactured by fixing No. 5 to the fixing layer 16 in the first step and continuously plating the plating layer 17 in the second step. (See JP-A-59-161267)

[0003]

However, in the above conventional technique, metal fatigue occurs in the base due to the heat generated by the friction between the base and the casting (work), so that diamond, CBN , Although hard particles such as alumina and zirconia are embedded, there is a lack of consideration for further improving safety against heat generated by friction between the hard particles and the work. Further, in the case where hard particles are embedded in a part of the side surface of the base, theoretically the base and the work do not come into direct contact with each other because there are hard particles, but as shown in FIGS. Due to the irregular cutting motion such as the inclination of the work or the base in the inside, or the twisting of the base, the base and the work actually contact and generate frictional heat, and due to the thermal expansion of the base due to the heat generation. Not only high cutting efficiency cannot be obtained due to twisting, but also a problem occurs in cutting work. Therefore, heat generation is reduced by mixing highly abrasive particles into the hard abrasive grains to further increase the lubricity with the object to be cut.

In addition, since the difference in height occurs due to a large difference in particle size in the case of hard particle size in practical mesh units, the number of effective cutting edges at the time of cutting becomes small, and the initial machinability is good, but the sharpness of the hard particles increases with wear. Was poor and there was a problem with durability.

An object of the present invention is to solve the above problems, and it is an object of the present invention to provide a cutter having high cutting efficiency and durability, which prevents frictional heat generation for cutting a casting.

[0006]

In order to solve the above-mentioned problems, a casting cutting cutter according to the present invention has a step on both side surfaces.
Rotating wheel cup for pig iron castings formed on parallel planes
A terpolymer, the peripheral edge surface to form a cutting edge portion of the metal base, nickel abrasive grains diamond or nickel alloy鍍
Secured by a metal, said cutting edge portion and the base center of the metal base
Over almost the entire exposed side surface between the fastening part of the
Multiple areas of hard abrasive grains consisting of a single layer
Dispersed disposed in, as the hard abrasive grains, diamond <br/> de, abrasive grains Alumina or zirconia, in foundry cutting cutter comprising fixed by nickel or nickel alloy plated, the metal base Hard distributed on the exposed side of
A solid lubricant is added to the abrasive grains fixed to the abrasive grain region .

Further, a powder of hexagonal boron nitride or molybdenum disulfide is used as the solid lubricant. Further, the abrasive grains adhered to the peripheral edge surface of the metal base have a grain size range of 10 to 30 microns. The metal substrate is made of a Ni-Fe alloy or a Fe-Ni-Co alloy.

[0008]

[Operation] According to the above configuration, the exposed side surface of the metal substrate is appropriately
Solid lubricant is added to hard abrasive grains and adheres to scattered areas
By doing so, the pig iron cast that is the object to be cut at the time of cutting rotation
The exposed side of the board is prevented from directly contacting the object,
Frictional heat generated by contact with iron at high speed
Not only is vibration suppressed, but the lubrication of the side surface of the metal substrate further prevents the generation of frictional heat.
Generates less heat, prevents problems such as cutting work,
Cutting efficiency is improved. Further, since the coefficient of friction during casting material contact decreases, also improved hard abrasive grains of cutting performance that is fixed to the peripheral edge surface (tip) of the metal base. In addition, the abrasive quality abrasive
By setting the grain size range of the grain to 10 to 30 μ, the effective working grain of the cutter is improved, and the initial machinability is about 20.
%, But the work per abrasive grain is small, so the edge of the abrasive grain can be held for a long time, and as a result, the durability is greatly improved. Furthermore, Ni-Fe alloy or Fe-Ni-C
Alloy o is a material with a low coefficient of thermal expansion, and has a very small coefficient of thermal expansion compared to high strength materials such as tool steel and alloy steel that are commonly used in general diamond cutters, and there is no base deformation, so thrust is sufficient. Can be transmitted to the tip ,
Cutting efficiency is also improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. FIG. 1 is a side view of a Kimberley wheel cutter showing an embodiment of the present invention. Abrasive grains 2 of diamond or CBN are fixed to the peripheral edge surface of the metal substrate 1 by nickel or nickel alloy plating.
Hard abrasive grains 3 are formed on a part of the side surface of the metal base 1,
As shown in FIG. 2, the hard abrasive grain portion 3 is formed on a hard abrasive grain 4 of diamond, CBN , alumina or zirconia.
A solid powder lubricant 5 of boron nitride or molybdenum disulfide is added and fixedly formed by nickel or nickel alloy plating.

[0010] The abrasive grains secured to the peripheral edge surface of the metal base 1, as shown in FIG. 4, is classified to a particle size range of 10 to 30 microns, such as that shown in FIG. 3, the abrasive grains of the conventional example Adjust the height difference. Further, the metal substrate 1 is, as shown in Table 1, a Ni-36% Fe alloy or Fe-31% Ni.
-5% Co alloy is used.

Next, an embodiment according to claim 2 will be described together with an experimental example. In the first place, hard abrasive grains are fixed to both sides or part of the metal base because part of the casting comes into contact with the side of the cutter base during cutting due to irregular cutting motion such as inclined cutting in casting cutting work and mechanical cutting. However, frictional heat is generated to prevent metal fatigue of the substrate.
The so-called lubrication effect cannot be brought out simply by fixing the hard abrasive grains. In this example, 10 to 30% (volume ratio) of hexagonal boron nitride and molybdenum disulfide were added to a part of the hard abrasive grains. The added hexagonal boron nitride and molybdenum disulfide reduce the friction coefficient at the time of contact with the casting, thereby promoting the machinability of the abrasive grains fixed to the peripheral edge surface of the metal substrate.

An experimental example of this embodiment will be shown below. Sample a Conventional hard abrasive grain 100% Sample b Hard abrasive grain + Boron nitride (20% volume ratio added) Work with FCD-40 (40 x 40 mm) under conditions where the cutter is rotated and the substrate is slightly bent. The change in the current resistance value of the samples a and B having different specifications was measured only on the side surface of the cutter by automatic feed cutting. Sample a 18.5 to 19.0 amps Sample b 17.0 to 17.5 amps Incidentally, it is 13 amps in the unloaded state. As a result, Sample b shows a current decrease of about 1.5 amperes, which indicates that the addition of boron nitride decreases the frictional resistance. This is a result of effectively increasing the solid lubrication effect, and in actual work, increases the cutting resistance to the abrasive grains at the base end (surrounding edge surface),
With the same thrust, it became possible to obviously increase the cutting speed. If only boron nitride is simply used, the strength of the material will immediately collapse, and it will not be possible to work effectively for a long period of time. Therefore, it will work effectively when added to hard abrasive grains.

Next, an embodiment according to claim 3 will be described together with an experimental example. As the hard abrasive grains 4 adhered to the side surface, those having a particle size of 30 to 50% smaller than the abrasive grains 2 adhered to the peripheral edge surface of the metal base 1 are used. Therefore, even if a fixed cutter is attached and the feed speed is made extremely small and straight cutting is performed, there is a tendency for the casting to come into contact with the side surface of the base due to the irregular cutting motion as described above when actually cutting the casting. . According to this embodiment, the deformation and thermal fatigue of the metal base due to the frictional heat when cutting the casting are prevented, and the cutting efficiency is improved.

Next, an experimental example of this embodiment will be shown. For example, when a hard abrasive grain is fixed by using 40/45 # which is a mesh unit, the grain size has a range of 350 to 420μ, and therefore the grain height difference has a grain size range of 70μ. Will result. This is the A type, and the one of this embodiment is B
Assuming that the type is a type, when the casting (FCD-400) 30Φ is completely cut by an electric grinder, (A type) Work load of all cutting: (30 ² × π / 4) × 2.8 = 1978 (mm) ³ Rotation speed of electric grinder: Approx. 5000 rpm Time required for total cutting: 14 seconds Therefore, work per cutter rotation: 1978 / (5000/60) × 14≈1.696 (mm) ³ Average contact surface of casting work: 26 .6 × 2.8 ≒ 74.4 (mm) 2 Accordingly, one rotation per depth of cut: a 1.696 / 74.4 ≒ 22μ. In addition, this numerical value is a numerical value given to the initial work.

(B type) A type, mesh (40 /
45) The cutting time by the particle size classified into 10 to 30 microns with respect to the particle size is 17 seconds, and the initial cutting time is reduced. Similar to the A type, the cutting depth per rotation is 18 microns. As a result, A type 40
The effective working grain of the cutter to which the hard abrasive grain of / 45 mesh is fixed is only 22/70 × 100 (%) ≅31%. Therefore, the A type may be used in actual work up to the state where the hard abrasive grains have been considerably worn, but since the work amount per grain increases, the edges of the hard abrasive grains exhibit flat wear, The frictional heat during rotation increases, the abrasive grains are rapidly damaged, and the life is reached.

On the other hand, about 50 to 100% of hard abrasive grains act as effective working grains of a cutter having a B type grain size range of 10 to 30 microns and a grain size (for example, 390 to 420 microns). . In actual work, the initial machinability is reduced by about 20%, but since the work per abrasive grain is small, the edge of the abrasive grain can be maintained for a long period of time, resulting in a drastic improvement in durability. It was

Further, in the actual work, it has become possible to select a particle size that arbitrarily matches the conditions of the machine used, such as an engine cutter and a machine-mounted cutter, in addition to the electric grinder. For example, as the machinability of the B type decreases, as shown in FIGS. 5 and 6, the plating layer 6 on the peripheral circular surface of the metal base 1 is provided with the abrasive grains 2 in any geometrical arrangement as needed. It is also possible to improve the machinability by setting a constant interval, and in order to maintain an effective working grain size, the initial machinability is the same as that of the conventional A type (100% diamond embedding rate, full surface electrodeposition). Even in such a case, the durability is improved by about 20%. In the type A cutter having this geometrical arrangement, the diamond embedding rate was reduced, and the life was only reduced at the same rate as the reduced rate. This means that, in the present embodiment, since expensive hard abrasive grains can be effectively used, an inexpensive casting cutter can be provided.

FIG. 7 shows a cutting speed when the ductile cast iron pipe is cut with an engine cutter by using the type A shown in FIG. 3 and the type B shown in FIG. 4 (particle size range 10 to 30 μ). It is the result of testing the relationship between the cutting length and the total cutting length. The initial speed of the A type is better than that of the B type, but the A type has a lower speed at any time and becomes less sharp than the resinoid grindstone (fine cutter). Is also inferior. Although the B type has a lower initial speed, it tends to be cut while maintaining a certain speed, and has a longer life than the A type. For both A and B types,
It has a cutting speed faster than the initial speed of a conventional resinoid grindstone (fine cutter). As shown in the data of FIG. 7, it became possible to greatly improve the life of the cutter with the particle size in the range of 10 to 30 microns.

Next, an embodiment of claim 4 will be described using a table. In this embodiment, as the base material, a Ni-Fe alloy,
Alternatively, although it is composed of a Fe-Ni-Co alloy,
Table 1 shows the experimental results of automatic feed cutting by a lathe of a cutter in which only the base material is separately used.

[0020]

[Table 1]

The fact that the cutting load is reduced is a result of the fact that thrust is more likely to be applied to the tip and the bending resistance of the side surface is reduced due to the improvement of the base strength. Generally used segment type diamond cutters (for cutting roads and stones) are made of high strength materials such as tool steel and alloy steel, and are set so that thrust can be quickly transmitted to the tip. Even if is used for a cutter for cutting castings (Kinvale foil), since the coefficient of thermal expansion is high, heat generation causes substrate runout, which causes a very dangerous state in work. This example solves these problems, but Fe-Ni-C
With the o alloy, the thermal expansion coefficient and the strength are improved as compared with the conventional Fe-Ni alloy, and the thrust can be further transmitted to the tip. In addition, since it is practically impossible to increase the thickness of the mounting machine and the thickness of the substrate, the strength is one-dimensionally improved. Regarding the strength of the low thermal expansion material, we use rolled steel sheets, and if we use a material with a high rolling ratio, we can further increase the strength, but the heat generated in actual work is not constant, and the residual heat generated by cold rolling remains. Since stress strain may act irregularly due to cutting heat and cause substrate runout, it is unavoidable to perform a complete stress relief treatment.

Examples of application of the present embodiment include ordinary pig iron castings for machine structures, cast iron castings such as ductile pig iron castings, finish of cutting and removal of risers, gates, weirs, etc., or cast iron for piping such as water and sewerage. It is suitable for dry-use Kimberley-type foils or band saws used for cutting pipes. Conventionally, in the cutting work using a fine wheel (resinoid grindstone), wear (reduction in diameter) often necessitates a tool change, and the scattering of the grindstone adversely affects the working environment and adversely affects the human body. Also, long-term cutting with an engine cutter or the like was likely to cause white wax disease due to slight vibration. According to the present embodiment, as described above, the cutting efficiency is improved and the base is not shaken, so that a tool with higher safety can be obtained.

[0023]

As described above, according to the present invention, it is possible to provide a cutter having high cutting efficiency and durability, which prevents generation of frictional heat for cutting a casting.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a detailed sectional view of the present embodiment.

FIG. 3 is a view showing a conventional abrasive grain.

FIG. 4 is a diagram showing abrasive grains of this example .

FIG. 5 is a side view showing another embodiment of the present invention.

FIG. 6 is a detailed cross-sectional view of that of FIG.

FIG. 7 is a graph showing the relationship between the cutting speed and the life of a ductile cast iron pipe.

FIG. 8 is a side view showing a conventional type.

FIG. 9 is a detailed cross-sectional view showing another conventional example.

FIG. 10 is an explanatory view showing a slant cutting of a work and a cutter.

FIG. 11 is an explanatory diagram showing twisting of the cutter.

[Explanation of symbols]

 1 Metal Substrate 2 Abrasive Grains 3 Hard Abrasive Grains 4 Hard Abrasive Grains 5 Solid Powder Lubricant 6 Plating Layer 10 Substrate 11 Chip 12 Segment Type 13 Kimberley Type 14 Substrate 15 Abrasive Grains 16 Fixing Layer 17 Plating Layer

Claims (4)

[Claims] 1. Both side surfaces are formed into parallel flat surfaces without steps.
A rotary wheel cutter for pig iron castings, the peripheral edge surface to form a cutting edge portion of the metal base, the abrasive grains of diamond and fixed by nickel or nickel alloy plating, the gold <br/> genus foundation Exposed side between the cutting edge part and the tightening part in the center of the board
From almost one layer, covering almost the entire surface
The hard abrasive grain area is formed in a plurality of locations dispersedly,
As hard abrasive grains, diamond, abrasive grains Alumina or zirconia, in foundry cutting cutter comprising fixed by nickel or nickel alloy plating, the metal base
A cutter for cutting a casting, wherein a solid lubricant is added to the abrasive grains fixed to the hard abrasive grain regions dispersedly arranged on the exposed side surface . 2. The cutter for cutting a casting according to claim 1, wherein the solid lubricant is powder of hexagonal boron nitride or molybdenum disulfide. 3. The cutter for cutting a casting according to claim 1, wherein the abrasive grains fixed to the peripheral edge surface of the metal substrate have a particle size range of 10 to 30 μm. 4. The Ni-Fe alloy or F is used as the metal substrate.
The casting cutting cutter according to claim 1, which is made of an e-Ni-Co alloy.