KR100448465B1 - Fabrication of diamond wheel for precision cutting using bronze powder-base metal bonder - Google Patents

Abstract

Disclosed is a bronze with 3 to 15% (Volume%) of diamond added to a bronze with nickel (Ni), cobalt (Co) and chromium (Cr) added up to 10% (mass%), respectively. Diamond powder (powder) is characterized in that formed by sintering (sintering).

In addition, in the present invention, the particles of the diamond powder is used 5-40㎛, nickel, cobalt, chromium powder particles 5-10㎛ added to maximize the filling rate of the powder particles, vacuum, hydrogen or inert gas atmosphere (Ar, N2, etc.) characterized in that the sintering while pressing at a pressure of 10-40MPa at 700-900 ℃ temperature.

According to the present invention having the above-described configuration, the diamond wheels using the bronze alloy-based powder binder material is excellent in characteristics, there is an advantage that can be produced in a simple process and low cost.

Description

Fabrication method of diamond wheel for cutting using bronze alloy powder binder {Fabrication of diamond wheel for precision cutting using bronze powder-base metal bonder}

The present invention relates to a method for manufacturing a diamond wheel for cutting using a bronze alloy powder binder having excellent cutting power by simultaneously adding nickel, cobalt, chromium and diamond to a bronze powder to which tin (Sn) is added 10%. .

Conventionally, cemented carbide, coated cemented carbide, TIC, and TIN cermet are used as materials processing tools, but the cutting surface (m / min) to feed rate (mm / rev) is low, so the surface of the workpiece has a high roughness and high precision. Has the disadvantage of not suitable for processing. Therefore, the development of a diamond wheel using diamond has been required.

Since the diamond tool is excellent in durability and the replacement cycle can be increased, it can also contribute to productivity. Therefore, it can also be used in high-speed cutting processing of cast iron parts such as cylinder blocks of automobiles, thereby improving productivity.

Diamond wheels for cutting consist of diamond powder and binders that support it. Binders that support diamond powder include metal bonds mainly composed of metals, resin bonds mainly composed of synthetic resins, and vitrified bonds mainly composed of oxide-based inorganic materials. In the case of metal bonds based on bronze alloys, binders can hold diamonds more firmly than resin bonds, which are commonly used, and have a long service life because they can withstand high temperatures without deterioration even after excessive grinding.

Wafer saws used in silicon wafer processing are tools that require cutting performance and precision after cutting, which contributes greatly to the electronics industry.

Dicing Saw is a diamond tool used in wafer processing, and is most widely used for cutting silicon wafers, and is generally manufactured by electrodeposition.

However, in the case of electrodeposition type, the thickness of the wheel is very thin, so the cutting performance is excellent. However, if the processing is performed for a long time, the wear of the tool is severe and the life is very short.

In general, in order to obtain a diamond wheel with excellent grinding ability, the binder should be appropriately worn, firmly caught diamond particles, lubricated, not fused, and contain a malleable component. .

Therefore, to find a binder to satisfy the above function is a technical problem to achieve the present invention, for this purpose it is preferable to adjust the strength of the binder by adjusting the binding component around a strong metal bond.

The copper alloy used in the present invention has excellent conductivity of heat generated during grinding and cutting, and the addition of tin (Sn) to copper (Cu) improves strength and hardness, so that the copper-tin alloy is a base alloy of the diamond wheel. Can act as a bond. At the same time, copper-tin-based alloys have attracted attention as future metal bond materials, and are less reactive with carbon than cobalt, nickel, and iron, but have excellent wettability for bonding powders in the sintering process.

Therefore, in the present invention, the most widely applied metal bonds are excellent diamond wheels by grasping the mechanical properties according to the manufacturing process of diamond wheels using copper-tin alloys and sintering operation conditions, optimum alloy powder composition, and the effects of additive elements. To provide.

An object of the present invention is to solve the problems of the above-mentioned binders and to produce an excellent diamond wheel using a relatively inexpensive binder.

1 is a graph showing a change in the relative density of the sintered body using the bronze alloy powder binder according to the present invention according to the addition amount of nickel, cobalt and chromium.

Figure 2 is a graph showing the change in hardness value of the sintered body using the bronze alloy powder binder according to the present invention according to the addition amount of nickel, cobalt, chromium.

Figure 3 is a graph showing a change in the wear value of the sintered body using the bronze alloy powder binder according to the present invention according to the addition amount of nickel, cobalt, chromium.

Figure 4 is a graph showing the change in shear strength value of the sintered body using the bronze alloy powder binder according to the present invention according to the addition amount of nickel, cobalt, chromium.

In order to achieve the above object, the bronze powder used in the present invention uses Cu-10wt% Sn, which is the maximum employment composition of tin in copper having excellent hardness and strength, and has a chemical affinity with carbon to improve mechanical properties and wettability. This excellent nickel, chromium, cobalt was added.

In the present invention, since copper and tin do not locally exhibit segregation and extreme characteristics in the specimen during powder mixing or hot pressing, bronze and bronze are not used. Sintering was carried out using an alloy powder.

Therefore, the present invention is a bronze in which 3 to 15% (Volume%) of diamond is added to a bronze to which nickel (Ni), cobalt (Co) and chromium (Cr) are added to 10% or less, respectively. Diamond powder (powder) is characterized in that formed by sintering (sintering).

The properties of the diamond sintered wheel sintered body are influenced by the size (μm) of the particles of the diamond and the size (μm) of the binder and the components.

Therefore, in the present invention, sintered with the diamond particles by hot pressing in the powder composition of Cu-Sn, rather than the conventional powder composition as diamond and the matrix binder.

The reason why the casting method is not used in the production process is that the super abrasive is suspended or segregated to the edge.

Therefore, in the present invention, the particles of the diamond powder is used 5-40㎛, nickel, cobalt, chromium powder particles 5-10㎛ added to maximize the filling rate of the powder particles, vacuum, hydrogen or inert gas atmosphere (Ar, N2 Sintering under pressure at 700-900 ° C at a pressure of 10-40 MPa.

Contact surface between cutting tool and work piece during cutting operation Due to the high cutting temperature generated at the contact surface between cutting tool and work piece during cutting operation, the function of the general tool may be weakened, but in case of diamond, It has a high thermal conductivity of about 6 times higher than that of (Cu), so it can be quickly transferred to the grinding wheel or tool through the superabrasive material, reducing the thermal damage to the workpiece and reducing the compressive residual stress on the surface of the workpiece. Corrosion resistance can be improved.

Powder metallurgy processes include the preparation of metals and diamond powders, cold compression, and sintering of diamonds and metal forming bodies, and are very important for the manufacture of diamond wheels using metal as a binder.

Therefore, in the present invention, the diamond and the metal powder are stirred for at least 1 hour using a mixer to uniformly disperse the metal powder, and when the powder is cold pressed, the flowability and compressibility of the powder can be improved.

After the mixing is completed, the size and shape of the wheel to be finally manufactured is charged into a sinter mold and cold-extruded, and the diamond wheel is finished by pressing under high temperature in a vacuum, reducing component or inert gas atmosphere. The characteristics are determined by the sintering temperature and time. In this case, resistance heating or induction heating may be used, and any of stainless steel, cast steel, and graphite may be used as the molding mold.

In the present invention, a bronze alloy powder of Cu-10% Sn composition is used. Cobalt, nickel, and chromium were added to improve the interfacial bonding properties of the metal matrix and the diamond particles of the bronze powder, thereby improving mechanical retention and chemical bonding. In this case, the mechanical holding force means that the diamond is separated from the bronze powder during wear and is improved by tensile stress. In addition, the chemical bonding force means that the metal base component is chemically bonded to the diamond particles, it is advantageous in the case of a metal (carbide forming element) having a strong bonding force with carbon or a metal that is easy to employ carbon.

When cobalt and nickel are added to bronze alloy powder, tensile strength is improved, and chrome is easy to form chromium carbide due to its affinity with carbon, so that impact resistance and stable compound are formed. Has an excellent impact on the maintenance of its life.

In the present invention, the present invention was carried out using the composition of the following ten specimens through the previous preliminary experiment. Nickel, chromium, and cobalt were added as 3, 5, and 10 wt%, respectively, as biadditives to the specimen in which 10 vol% of diamond was added to the bronze alloy.

NO. Bronze (wt%) Ni (wt%) Cr (wt%) Co (wt%) diamond (vol%) One 100 - 10 2 97 3 3 95 5 4 90 10 5 97 3 6 95 5 7 90 10 8 97 3 9 95 5 10 90 10

Powder nickel, chromium, and cobalt used as bi-additives increased the density by reducing the amount of pores in the sintered body during the sintering process using a powder of more than 99% purity and less than 5㎛.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a graph showing a change in the ratio of the relative density to the theoretical density according to the addition of diamond, nickel, chromium, cobalt in the bronze base according to the present invention. In general, the theoretical density of the bronze-alloy system with diamonds decreased by about 10% compared to the case without adding diamonds, and the chromium-added bronzes were the largest, and cobalt and nickel were almost similar.

Figure 2 is a graph showing the effect of nickel, chromium, cobalt on the hardness value of the bronze alloy added diamond powder according to the present invention.

As can be seen in FIG. 2, in the case of the bronze alloy system containing diamond, the hardness value of all the composition alloys increased by more than 150% overall compared to before adding diamond.

As the amount of each added element in the sintered bronze alloy system containing nickel, chromium and cobalt increases, the hardness value increases. Nickel and cobalt have a certain degree of solid solubility with copper in the bronze alloy system. Therefore, the addition of these elements acts as a solid solution strengthening mechanism for the bronze alloy.

However, chromium added in the present invention is hardly dissolved in bronze and chromium was observed as a precipitated phase in the sintered bronze alloy system, as can be seen from the previous literature. As the amount of chromium added to the bronze alloy increases, the hardness increases rapidly. It can be seen that the precipitation hardening effect by chromium and copper having a very low solubility is much larger than the solid solution strengthening effect by nickel or cobalt.

The reason why the hardness value is higher when cobalt is added than when nickel is added is that cobalt reacts with copper to produce a minute amount of precipitate.

In the accompanying drawings, FIG. 3 is a graph showing the non-wear amount by using an Amsler abrasion tester for the effects of nickel, chromium, and cobalt on the wear characteristics of the bronze alloy system sintered by diamond according to the present invention.

Nickel, chromium, and cobalt content in the bronze alloy is excellent in wear resistance up to 5%, but wear resistance is reduced when more than 5% is added.

Therefore, it can be seen that the bronze alloy system added with diamond shows the best wear resistance when the content of nickel, chromium and cobalt is 5%.

In the accompanying drawings, Figure 4 shows a graph of the bending test results of the wheel sintered material added with diamond, nickel, chromium, cobalt according to the present invention. Diamond wheels require mechanical properties in order to withstand loads and continuous shocks from pressing above when rubbing against the workpiece during grinding.

When nickel and cobalt were added, the values were around 400 MPa. However, when 3% of chromium is added, the strength value rapidly increases to 600 MPa, but when added, the strength value decreases to 500 MPa. That is, when chromium is added to the sintered bronze alloy-based diamond wheel, chromium is precipitated due to low solid solubility with copper, thereby playing a role of reinforcing phase.

As described above, the present invention adds nickel, chromium, and cobalt to the bronze alloy system to which diamond is added, thereby producing a diamond wheel for precision cutting. Therefore, when chromium is added, the hardness value and the bending strength value are improved in the bronze alloy system, and the relative density value with respect to the theoretical density is also improved.

In addition, in the case of cobalt and chromium, the mechanical properties and the ductility of the bronze alloy are improved, thereby providing excellent wear characteristics.

According to the present invention, it is possible to improve the characteristics of the material processing tool using the conventional cemented carbide, and to improve the life of the existing resin bond and electrodeposited silicon wiper cutting material, reduce the material cost and simplify the process.

Claims (7)

In the method of manufacturing a diamond wheel for cutting using a bronze alloy powder binder, Bronze alloy powder containing 3-15 Vol% diamond is sintered in a vacuum atmosphere within 60 minutes while being sintered at 700-900 ° C and pressurized at 10-40 MPa pressure. Method of manufacturing a diamond wheel for processing. The method of claim 1, The bronze powder of the bronze alloy is a method of manufacturing a diamond wheel for cutting using a bronze alloy powder binder, characterized in that the tin is the maximum solid composition of Cu-10wt% Sn. delete The method of claim 1, The bronze alloy is a method for producing a diamond wheel for cutting using a bronze alloy powder binder, characterized in that the addition amount of nickel, chromium, cobalt is less than 10mass%. The cutting method according to any one of claims 1 to 4, wherein the diamond particles have a size of 5-40 μm, and the particles of nickel, chromium and cobalt have a size of 5-10 μm. Method of manufacturing a diamond wheel. The method of claim 1, A method of manufacturing a diamond wheel for cutting using a bronze alloy powder binder, wherein the sintering atmosphere is a hydrogen atmosphere. The method of manufacturing a diamond wheel for cutting using a bronze alloy powder binder according to claim 1, wherein the sintering atmosphere is an inert gas atmosphere (Ar, N2, etc.).