CN108115854B - Resin diamond wire and preparation method thereof - Google Patents

Abstract

The invention provides a resin diamond wire and a preparation method thereof. The resin diamond wire provided by the invention comprises a bus and a resin coating coated on the surface of the bus; the raw materials for forming the resin coating comprise resin, modified diamond abrasive and filler; the modified diamond grinding material is diamond micro powder processed by plasma. The resin diamond wire provided by the invention greatly improves the bonding force between the resin and the diamond, the resin holds the diamond more firmly, the diamond is not easy to fall off, the number of the diamonds which effectively participate in cutting is more, the diamond loss is lower, and thus the cutting force of the resin diamond wire is improved. In addition, the resin diamond wire provided by the invention does not generate low-molecular volatile matters in the processing process, and is very environment-friendly.

Description

Resin diamond wire and preparation method thereof

Technical Field

The invention relates to the technical field of diamond wire cutting, in particular to a resin diamond wire and a preparation method thereof.

Background

In the early days, in order to solve the processing problem of large-sized silicon wafers, people generally used wire saw processing technology to cut silicon rods into slices. Early wire saw processing techniques employed bare wire and free abrasive, which was added as a third to the gap between the wire and the workpiece during the process to produce the cutting action. This technique has been successfully used for the processing of silicon and silicon carbide. To further shorten the machining time, as well as to machine other hard and difficult to machine ceramics, diamond abrasives have been fixed to metal wires in a manner that results in a fixed diamond wire saw.

The diamond wire is also called as a diamond wire, and refers to a method of fixing a diamond abrasive on a metal wire (i.e., a bus) by using an electroplating process or a resin bonding method. The electroplating type diamond wire is a linear superhard material tool made by depositing a layer of metal (generally nickel and nickel-cobalt alloy) on a bus bar by an electroplating method and solidifying diamond abrasive in the metal. The resin type diamond wire uses resin as a bonding agent to fix the diamond abrasive on the bus. The electroplating process of the electroplating diamond wire needs to involve a large amount of heavy metal ions, the environmental protection pressure is high, the resin diamond wire has the advantages of simple manufacturing process, low production cost, high production efficiency, good surface quality of a silicon wafer and the like, the resin diamond wire gradually becomes a main mode of cutting and processing the crystal silicon wafer, and the diamond wire cutting technology is paid more and more attention in the photovoltaic field.

At present, the resin diamond wire is mainly obtained by solidifying phenolic resin and diamond abrasive to a bus bar, and the following problems are generally existed: the bonding force between the resin and the diamond is poor, the holding force of the resin on the diamond is further reduced due to heating in the grinding process, the improvement of the performance of the resin diamond is restricted, and researches show that in the cutting process, about 70% of the diamonds directly fall off without effectively participating in cutting, and the effective cutting performance is poor.

Disclosure of Invention

In view of this, the present invention provides a resin diamond wire and a method for manufacturing the same, which greatly improves the bonding force between resin and diamond, thereby improving the cutting force of the resin diamond wire.

The invention provides a resin diamond wire, which comprises a bus and a resin coating coated on the surface of the bus;

the raw materials for forming the resin coating comprise resin, modified diamond abrasive and filler;

the modified diamond grinding material is diamond micro powder processed by plasma.

The resin diamond wire provided by the invention greatly improves the bonding force between the resin and the diamond, the resin holds the diamond more firmly, the diamond is not easy to fall off, the number of the diamonds which effectively participate in cutting is more, the diamond loss is lower, and thus the cutting force of the resin diamond wire is improved.

In the present invention, the type of the bus is not particularly limited, and the bus may be a bus known to those skilled in the art; in one embodiment, the bus bar is a high carbon steel wire.

In the present invention, the diameter of the bus bar is preferably 50 to 70 μm.

In the invention, the raw material for forming the resin coating adopts the modified diamond abrasive; the modified diamond grinding material is diamond micro powder processed by plasma.

In the invention, the diamond micro powder is modified by plasma treatment, so that the surface characteristics of the diamond micro powder are changed, the wettability and holding force of resin are obviously improved, and the cutting efficiency is improved; moreover, the plasma treatment process is environment-friendly and has no waste liquid and waste gas emission.

The plasma is different from solid, liquid and gas three-state substances, belongs to the fourth state of the substances, and is a non-condensation system generated by electrically separating gas (steam) parts under specific conditions; it is composed of electrons in high-speed motion state, neutral atoms, molecules, radicals (free radicals) in activated state, ionized atoms and molecules, ultraviolet ray generated in the process of molecule dissociation reaction, unreacted molecules and atoms, etc. plasma acts on the surface of material to recombine the chemical bonds of surface molecules and introduce new radicals to form new surface characteristics. The plasma or plasma treatment can be obtained in a variety of ways, including thermal ionization, shock wave, photoionization, radiation exposure, and direct current, low frequency, radio frequency, microwave gas discharge, among others. However, the mechanism of action between the plasma and the surface of the material to be treated is very complicated, and it has not been reported so far to clearly describe what kind of chemical reaction between the active species in the plasma and the surface of the material to be treated occurs. The applicant researches and discovers that the bonding property between the resin and the diamond can be remarkably improved by treating the diamond micro powder by the following plasma treatment technology.

In the invention, the plasma treatment is low-temperature plasma quasi-glow discharge plasma treatment; the method has no special limitation on the temperature, does not need additional temperature rise and can be carried out at normal temperature.

In the present invention, the atmosphere for the plasma treatment preferably includes one or more of air, oxygen, nitrogen and argon. Under the atmosphere, the diamond can obtain beneficial polar groups, so that the diamond micro powder forms new excellent surface characteristics, and the bonding property between the diamond micro powder and resin is further improved.

In the invention, the gas flow rate of the atmosphere is preferably 3-300L/h.

In the present invention, the voltage of the plasma treatment is preferably 10 to 50 KV.

In the plasma treatment, the single treatment capacity of the diamond micro powder is preferably 2000-10000 ct.

In the invention, the time of the plasma treatment is preferably 15-30 min.

In the invention, the particle size of the diamond micro powder to be treated is preferably 4-25 μm.

The experimental result shows that compared with the common unmodified diamond abrasive, when the resin diamond wire of the modified diamond abrasive is used for cutting, the diamond falling rate is reduced by at least half, and the diamond wear rate is reduced by about 55%, which shows that the modified diamond abrasive has stronger bonding force with resin and firmer holding.

In the invention, the raw material for forming the resin coating also comprises resin; the resin is preferably a polyimide resin. The polyimide main chain contains a polyimide ring (-CO-NH-CO-), no low-molecular volatile matters are generated during curing, and the polyimide resin has good compatibility with other components and high bonding strength. The research of the applicant finds that compared with other resins and the conventional phenolic resin, the polyimide resin and the modified diamond abrasive material are combined, so that the polyimide resin and the modified diamond abrasive material have excellent mechanical strength and heat resistance in the cutting process, the cutting force of the resin diamond wire can be improved in a multiplied mode, the use cost of a slicing client is greatly reduced, and the market competitiveness of the resin diamond wire is further improved.

In the invention, the raw material for forming the resin coating also comprises a filler; the filler preferably comprises one or more of copper powder, zinc oxide, silicon carbide and alumina.

In the invention, the mass ratio of the resin, the modified diamond abrasive and the filler is preferably (15-45) to (20-40) to (5-25).

In the invention, the thickness of the resin coating is 3-8 μm.

In the invention, the diameter of the resin diamond wire is 62-86 μm.

The resin diamond wire provided by the invention greatly improves the bonding force between the resin and the diamond, the resin holds the diamond more firmly, the diamond is not easy to fall off, the number of the diamonds which effectively participate in cutting is more, the diamond loss is lower, and thus the cutting force of the resin diamond wire is improved. In addition, the resin diamond wire provided by the invention does not generate low-molecular volatile matters in the processing process, and is very environment-friendly.

The invention also provides a preparation method of the resin diamond wire in the technical scheme, which comprises the following steps:

a) carrying out plasma treatment on the diamond micro powder to obtain a modified diamond grinding material;

b) mixing resin, a modified diamond abrasive, a filler and a solvent to obtain slurry;

c) and coating the slurry on the bus, drying and curing to obtain the resin diamond wire.

In the step a), the granularity of the diamond micro powder and the plasma treatment conditions are consistent with those in the technical scheme, and are not repeated here.

In the step b), the types, the use amounts and the like of the resin, the modified diamond abrasive and the filler are consistent with those in the technical scheme, and are not repeated.

In the present invention, the solvent preferably includes one or more of dimethylformamide (i.e., DMF), cresol, tetrahydrofuran (i.e., THF), and toluene.

In the present invention, the mass fraction of the solvent in the slurry is preferably 20% to 40%.

In the step c), the coating mode is not particularly limited, and is a means for coating the bus bar, which is conventional in the art, such as coating the bus bar by passing the bus bar through a coating die.

In the present invention, the dry curing preferably includes: precuring at 200-400 ℃; curing at 160-230 ℃ for 3-16 h.

The precuring time is short, the precuring of the bus is completed at 200-400 ℃ preferably at a wiring speed of 30-150 m/min, and the resin slurry coated on the bus generates certain strength through precuring; after the pre-curing, the resin is further crosslinked to 100% by a long-time curing treatment, thereby obtaining a resin diamond wire.

The preparation method provided by the invention is simple and feasible, low-molecular volatile matters are not generated in the preparation process, the preparation method is very environment-friendly, the obtained resin diamond wire has excellent holding force, diamond is not easy to fall off in the cutting process, the number of diamonds effectively participating in cutting is more, the diamond loss is lower, and the cutting force of the resin diamond wire is improved.

Experimental results show that when the resin diamond wire is used for cutting, the diamond falling rate is lower than 25%, and the diamond wear rate is lower than 26%.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic view of a resin diamond wire S-1 obtained in example 1 of the present invention.

Detailed Description

For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.

Example 1

Carrying out plasma treatment on diamond micro powder with D50 of 9.1 mu m in an oxygen atmosphere, wherein the gas flow is 150L/h, the voltage is 30KV, the single treatment capacity of the diamond micro powder is 5000ct, and the treatment time is 30min, so as to obtain the modified diamond abrasive. A slurry was obtained by mixing 36% of polyimide resin, 25% of modified diamond abrasive, 15% of alumina, and 24% of DMF. Coating slurry on a high-carbon steel wire bus through a die, drying and rolling the high-carbon steel wire bus in a 300 ℃ oven at a wiring speed of 90m/min, and performing aftertreatment at 220 ℃ for 5 hours to obtain a resin diamond wire (marked as S-1). The morphology structure of the obtained resin diamond wire is shown in FIG. 1, and FIG. 1 is a morphology diagram of the resin diamond wire S-1 obtained in the embodiment.

Setting a comparison sample: the preparation is carried out according to the preparation process, except that the diamond micro powder is not subjected to plasma treatment; the resin diamond wire obtained was designated as D-1.

The resin diamond wires S-1 and D-1 were used as cutting lines, respectively, and 8-inch single crystal silicon rods were used as cutting objects to perform cutting tests, and the falling rate of the resin diamond wires after cutting was measured, and the test results are shown in table 1:

TABLE 1 cutting data for resin diamond wires S-1 and D-1 in inventive example 1

Item	D-1	S-1
			Diamond micropowder granularity D50	9.1μm	9.1μm
Diameter of bus	70μm	70μm
			Diameter of resin diamond wire	84.1μm	84.1μm
400 times of microscope diamond number	91	92
			Thickness of resin coating	7.05μm	7.05μm
Silicon rod specification	600mm8 inch single crystal	600mm8 inch single crystal
			Cutting machine table	PV500HD	PV500HD
Cutting time	2.5h	2.5h
			Single-chip consumption line	2.5m/pcs	2.5m/pcs
Diamond falling rate	40％	13％
			Wear rate of diamond	45％	18％

In table 1, the diamond peeling rate is (number of original diamonds before cutting-number of remaining diamonds after cutting)/number of original diamonds before cutting; the diamond wear rate is (original diamond exposure height before cutting-remaining diamond exposure height after cutting)/original diamond exposure height before cutting.

The test results in table 1 show that, compared with the common diamond abrasive material which is not subjected to modification treatment, when the resin diamond wire of the modified diamond abrasive material is used for cutting, the diamond falling rate is reduced by at least more than half, and the diamond wear rate is reduced by 55%, which indicates that the bonding force between the modified diamond abrasive material and resin is stronger, the holding is firmer, diamond is not easy to fall off in the cutting process, the number of diamonds which effectively participate in cutting is more, the diamond loss is lower, and therefore the cutting force of the resin diamond wire is improved.

Example 2

Carrying out plasma treatment on diamond micro powder with D50 of 9.1 mu m in an oxygen atmosphere, wherein the gas flow is 150L/h, the voltage is 20KV, the single treatment capacity of the diamond micro powder is 5000ct, and the treatment time is 30min, so as to obtain the modified diamond abrasive. 25% of polyimide resin, 30% of modified diamond abrasive, 20% of copper powder and 25% of DMF were mixed to obtain a slurry. Coating slurry on a high-carbon steel wire bus through a die, drying and rolling the high-carbon steel wire bus in a 300 ℃ oven at a wiring speed of 90m/min, and performing aftertreatment at 220 ℃ for 5 hours to obtain a resin diamond wire (marked as S-2).

The resin diamond wire S-2 obtained was subjected to a cutting test according to the cutting test method of example 1, and the test results showed that: the diamond falling rate is 19 percent, and the diamond wear rate is 22 percent. The modified diamond abrasive has strong binding force with resin, is firmly held, is not easy to fall off in the cutting process, has a large number of diamonds effectively participating in cutting, and has low diamond loss.

Example 3

Carrying out plasma treatment on diamond micro powder with D50 of 9.1 mu m in an oxygen atmosphere, wherein the gas flow is 50L/h, the voltage is 30KV, the single treatment capacity of the diamond micro powder is 5000ct, and the treatment time is 30min, so as to obtain the modified diamond abrasive. 25% of polyimide resin, 30% of modified diamond abrasive, 20% of silicon carbide and 25% of DMF were mixed to obtain slurry. Coating slurry on a high-carbon steel wire bus through a die, drying and rolling the high-carbon steel wire bus in a 250 ℃ oven at a wiring speed of 90m/min, and performing aftertreatment at 200 ℃ for 6 hours to obtain a resin diamond wire (marked as S-3).

The resin diamond wire S-3 obtained was subjected to a cutting test according to the cutting test method of example 1, and the test results showed that: the diamond falling rate is 18 percent, and the diamond wear rate is 22 percent. The modified diamond abrasive has strong binding force with resin, is firmly held, is not easy to fall off in the cutting process, has a large number of diamonds effectively participating in cutting, and has low diamond loss.

Example 4

And (2) carrying out plasma treatment on the diamond micro powder with the D50 of 9.1 mu m in an oxygen atmosphere, wherein the gas flow is 300L/h, the voltage is 50KV, the single treatment capacity of the diamond micro powder is 8000ct, and the treatment time is 30min, so as to obtain the modified diamond abrasive. 25% of polyimide resin, 30% of modified diamond abrasive, 20% of silicon carbide and 25% of DMF were mixed to obtain slurry. Coating slurry on a high-carbon steel wire bus through a die, drying and rolling the high-carbon steel wire bus in a 250 ℃ oven at a wiring speed of 90m/min, and performing aftertreatment at 200 ℃ for 6h to obtain a resin diamond wire (marked as S-4).

The resin diamond wire S-4 obtained was subjected to a cutting test according to the cutting test method of example 1, and the test results showed that: the diamond falling rate is 23 percent, and the diamond wear rate is 25 percent. The modified diamond abrasive has strong binding force with resin, is firmly held, is not easy to fall off in the cutting process, has a large number of diamonds effectively participating in cutting, and has low diamond loss.

Example 5

The resin diamond wire S-4 was prepared according to the procedure for the preparation of the resin diamond wire S-4, except that the polyimide resin was replaced with a phenol resin, and the resulting resin diamond wire was designated as S-5.

The cutting test was performed according to the cutting test method of example 1, and the test results are shown in table 2:

TABLE 2 cutting data of resin diamond wires S-4 and S-5 in inventive examples 4 and 5

Item	S-4	S-5
			Diamond micropowder granularity D50	9.1μm	9.1μm
Diameter of bus	70μm	70μm
			Diameter of resin diamond wire	84.1μm	84.1μm
400 times of microscope diamond number	92	92
			Thickness of resin coating	7.05μm	7.05μm
Silicon rod specification	600mm8 inch single crystal	600mm8 inch single crystal
			Cutting machine table	PV500HD	PV500HD
Cutting time	2.5h	2.5h
			Single-chip consumption line	2.5m/pcs	2.5m/pcs
Diamond falling rate	23％	32％
			Wear rate of diamond	25％	30％

The test results in table 2 show that compared with other resins, the polyimide resin can further improve the bonding force between the resin and the diamond and reduce the falling rate of the diamond; thereby improving the cutting force of the resin diamond wire.

The foregoing examples are provided to facilitate an understanding of the principles of the invention and their core concepts, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that approximate the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims (7)

1. The resin diamond wire is characterized by comprising a bus and a resin coating coated on the surface of the bus;

the raw materials for forming the resin coating comprise resin, modified diamond abrasive and filler;

the modified diamond grinding material is diamond micro powder subjected to plasma treatment;

the plasma treatment is low-temperature plasma quasi-glow discharge plasma treatment;

the atmosphere of the plasma treatment comprises one or more of air, oxygen, nitrogen and argon;

the voltage of the plasma treatment is 10-50 KV;

the gas flow of the atmosphere is 3-300L/h.

2. The resin diamond wire according to claim 1, wherein the resin is a polyimide resin.

3. The resin diamond wire according to claim 1, wherein in the plasma treatment, the single treatment capacity of the diamond micro powder is 2000-10000 ct;

the plasma treatment time is 15-30 min.

4. The resin diamond wire according to claim 1 or 2, wherein the mass ratio of the resin, the modified diamond abrasive and the filler is (15-45) to (20-40) to (5-25).

5. The resin diamond wire according to claim 1, wherein the filler comprises one or more of copper powder, zinc oxide, silicon carbide, and aluminum oxide.

6. A method for manufacturing a resin diamond wire according to any one of claims 1 to 5, comprising the steps of:

a) carrying out plasma treatment on the diamond micro powder to obtain a modified diamond grinding material;

b) mixing resin, a modified diamond abrasive, a filler and a solvent to obtain slurry;

c) and coating the slurry on the bus, drying and curing to obtain the resin diamond wire.

7. The method according to claim 6, wherein the drying and curing in step c) comprises: precuring at 200-400 ℃; curing at 160-230 ℃ for 3-16 h.

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