CN109158718B - Preparation method of electrode tip, tool electrode and preparation method of tool electrode - Google Patents

Abstract

The invention relates to the technical field of electrical discharge machining, in particular to a preparation method of an electrode tip, a tool electrode and a preparation method of the tool electrode. The preparation method includes the following steps: mixing graphene, tungsten carbide, cobalt and anhydrous ethanol, and grinding to obtain a mixed grind; drying the mixed grind to obtain a dried grind; The dried ground object is obtained to obtain a shaped green body; the green body is sintered to form the electrode tip. The preparation method and the preparation process of the electrode tip provided by the present invention are simple and fast, and do not need to use complicated equipment, which can greatly reduce the manufacturing cost of the electrode tip. The obtained electrode tip can also retain the characteristics of the prepared material to the greatest extent.

Description

Preparation method of electrode tip, tool electrode and preparation method of tool electrode

technical field

The invention relates to the technical field of electrical discharge machining, in particular to a preparation method of an electrode tip, a tool electrode and a preparation method of the tool electrode.

Background technique

Tungsten carbide material has the characteristics of high wear resistance, high hardness, high melting point and corrosion resistance, and is often used for surface strengthening of workpieces. Cobalt is often used as a binder in cemented carbide, which ensures the toughness of cemented carbide to a certain extent. Tungsten carbide-cobalt cemented carbide is composed of tungsten carbide and metal cobalt, and it is also one of the common cemented carbides. It is also a commonly used tool motor material in the field of EDM surface strengthening.

As a new type of carbonaceous material, graphene has the characteristics of high electrical conductivity, high thermal conductivity, high specific surface area, and increased strength in the case of dealloying and metal compounding. It is precisely because of these properties of graphene that graphene can be added to traditional tool electrodes to change the strength of the tool electrodes. The graphene composite tool electrode can increase the thermal conductivity, electrical conductivity and strength of the electrode to a certain extent; it can also reduce the consumption of the electrode, improve the work efficiency, and reduce the processing cost.

At this stage, the use of tungsten carbide, cobalt and graphene to make tool electrodes has been more and more widely used. However, the existing methods for preparing such tool electrodes are cumbersome, and the electrodes finally obtained have poor overall performance and low yield.

In addition, most of the existing tool electrodes are integrated. The integrated tool electrode is usually directly processed from a whole material. Because of its simple structure, the production efficiency is high and the quality can be better guaranteed. However, due to the large consumption of the tool electrode, once a part of the tool electrode is damaged, the entire tool electrode must be scrapped, thus resulting in a higher use cost of the tool electrode.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of an electrode tip, a tool electrode and a preparation method of a tool electrode, so as to solve the technical problems of poor performance and high yield of the existing tool electrode.

At the same time, the present invention can also solve the problem of high use cost of the existing tool electrodes.

In order to solve the above technical problems, the present invention provides a preparation method of an electrode tip, comprising the following steps:

Mixing graphene, tungsten carbide, cobalt and anhydrous ethanol, and grinding to obtain a mixed grinding material;

drying the mixed grinding material to obtain the drying grinding material;

Pressing the dried ground product to obtain a shaped green body;

The green body is sintered to form the electrode tip.

Further, the mass ratio of the tungsten carbide to the cobalt is 4 to 9, the mass ratio of the graphene to the tungsten carbide and the cobalt is 0.00001 to 0.02, the absolute ethanol to the graphene, The mass ratio of the tungsten carbide to the cobalt is 0.4-0.6.

Further, using a ball mill to grind the graphene, the tungsten carbide, the cobalt and the absolute ethanol, the grinding speed is 130-160 revolutions per minute, and the grinding time is 8-24 hours.

Further, after drying the mixed ground product, sieving is performed to obtain the dried ground product.

Further, drying treatment is performed on the mixed ground product at a temperature of 50-80° C. using a drying oven.

Further, drying the mixed ground product in a drying oven for 6-12 hours.

Further, the sieving treatment is carried out using a screen mesh of at least 325 meshes.

Further, using a pressing die to press the dried ground object, and pressing under a pressure of 150MPa-350MPa, to obtain the shaped green body;

Wherein, the pressing time lasts 2 to 5 minutes, and the pressing speed is 2 to 5 mm per minute.

Further, placing the green body in a tube furnace and sintering at a temperature of 1050-1150° C. to obtain the electrode tip;

Wherein, high-purity nitrogen is introduced into the tube furnace to discharge air, and the flow rate of the high-purity nitrogen is 3-8 ml per minute, and the duration is 13-17 minutes.

In order to solve the above problems, the present invention also provides a tool electrode, the tool electrode includes a conductor, on which the electrode tip as described above is fixed, and between the conductor and the electrode tip able to power on.

In addition, the present invention also provides a method for preparing the above-mentioned tool. The method uses conductive silver glue to adhere the electrode tip as claimed in claim 10 on the conductor, and uses an oven at 50-80 Under the condition of ℃, the temperature is maintained for 6 to 12 hours to form the tool electrode.

The preparation method of the electrode tip provided by the present invention, the preparation process thereof is simple and fast, and no complicated equipment is required, and the fabrication cost of the electrode tip can be greatly reduced. The obtained electrode tip can also retain the characteristics of the prepared material to the greatest extent. In addition, the combined tool electrode provided by the present invention can replace the electrode tip multiple times, thereby greatly reducing the use cost of the tool electrode and improving the utilization rate of resources.

Description of drawings

1 is a flowchart of a method for preparing an electrode tip provided by an embodiment of the present invention;

2 is a schematic structural diagram of a combined tool electrode provided by an embodiment of the present invention;

FIG. 3 is a schematic diagram of a pie-shaped electrode tip provided by an embodiment of the present invention.

Detailed ways

According to the foregoing, among the tool electrodes used for EDM at this stage, some tool electrodes can improve the machining performance of tool electrodes by using tungsten carbide and cobalt materials; some tool electrodes can further improve the performance of tool electrodes by adding graphene materials. Thermal conductivity, electrical conductivity, and its own strength. However, the existing methods for preparing such tool electrodes are cumbersome, and the electrodes finally obtained have poor overall performance and low yield. To this end, the present invention provides a method for preparing a tool electrode for electrical discharge machining.

In addition, due to the high use cost of the existing one-piece tool electrodes, especially the one-piece tool electrodes made of some relatively expensive materials (eg, tungsten carbide, copper-tungsten alloy, etc.). To this end, the present invention proposes a combined tool electrode, which is formed by combining two conductors with the same or different properties to form a tool electrode, and one of the conductors is used as an electrode tip (for discharging the workpiece, which can be The material is more expensive and the material with better performance is used in EDM to reduce the cost of tool electrodes. Since the preparation method in the above content can be used to prepare a tool electrode for electric discharge machining, it can also be used to prepare the electrode tip in the combined tool electrode provided by the present invention.

Furthermore, the present invention also provides a method for preparing the tool electrode, so as to realize the fixing of the electrode tip and the conductor to form a completed tool electrode.

The preparation method of the electrode tip, the tool electrode and the preparation method of the tool electrode proposed by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become apparent from the following description and claims. It should be noted that, the accompanying drawings are all in a very simplified form and in inaccurate scales, and are only used to facilitate and clearly assist the purpose of explaining the embodiments of the present invention.

Example 1

This embodiment provides a method for preparing an electrode tip, as shown in FIG. 1 , which is a flowchart of the method for preparing an electrode tip provided in this embodiment.

The preparation method of an electrode tip provided in this embodiment includes the following steps:

S1: mixing graphene, tungsten carbide, cobalt and absolute ethanol, and grinding to obtain a mixed grinding product;

S2: drying the mixed grinding material to obtain the drying grinding material;

S3: pressing the ground object after the drying to obtain a shaped green body;

S4: Sintering the green body to form the electrode tip.

Specifically, in S1, the mass ratio of the tungsten carbide to the cobalt is 4 to 9, the mass ratio of the graphene to the tungsten carbide and the cobalt is 0.00001 to 0.02, and the anhydrous ethanol to the cobalt is 0.00001 to 0.02. The mass ratio of the graphene, the tungsten carbide and the cobalt is 0.4-0.6. For example: measure 9g of tungsten carbide powder (tungsten carbide powder with a particle size of 1 micron can be selected), 1g of cobalt powder (cobalt powder with a particle size of 1-2 microns can be selected), and 0.101g of graphene material through a balance And measure 5g of absolute ethanol. When grinding, in order to improve the grinding efficiency, the above materials can be put into a ball mill for grinding.

Further, when using a ball mill to grind the mixture of tungsten carbide, cobalt, graphene and absolute ethanol, the grinding speed of the ball mill can be set to 130-160 revolutions per minute, and the grinding is continued for 8-24 hours, such as maintaining The rotation speed of the ball mill was 150 revolutions per minute, and the grinding was continued for 24 hours, so that the above-mentioned materials could be ground sufficiently to form the mixed grinding product.

Specifically, in S2, after drying the mixed ground product, sieving is performed to obtain the dried ground product. When sieving, at least 325 mesh screen can be used for sieving treatment. For example, a 400-mesh screen can be selected for sieving according to actual needs, so as to screen out the larger particles in the mixed grind, and obtain the dried grind.

Also, before the sieving treatment, the mixed ground material needs to be dried to prevent the ground mixture from sticking and forming agglomerates. During the drying process, a drying box can be used as a drying device, and the temperature of the drying box is set at a temperature of 50 to 80° C. to perform drying treatment on the mixed ground product. Of course, in order to more thoroughly dry the ground object, the drying time can also be set to 6-12 hours. For example, the temperature is set to 80°C and the drying time is set to 12 hours to ensure that the ground mixture is dried more thoroughly.

Specifically, in S3, a pressing die can be used to press the dried ground material, and in order to make the pressed green body more dense, the dried ground material can be pressed under a pressure of 150MPa-350MPa. , to obtain the shaped green body; and the pressing time lasts 2-5 minutes, and the pressing speed is 2-5 mm per minute. When pressing the electrode tip, the electrode tip can be made into a smaller volume to save raw materials and costs. For example, 3g of the dried ground material can be taken and put into a set or specified pressing The pressed mold is put into a 100KN press and pressed for 5 minutes at a pressure of 250 MPa, and then the pressed green body is taken out from the pressed mold.

The green body is placed in a tube furnace and sintered at a temperature of 1050-1150° C. to obtain the electrode tip; in addition, in order to avoid oxidation of the green body, before sintering, High-purity nitrogen is introduced into the tube furnace to evacuate the air inside, and the flow rate of the high-purity nitrogen is 3-8 ml per minute, and the time for introducing the high-purity nitrogen can be controlled within 13-17 minutes. For example, according to the above-mentioned green body obtained by taking 3g of the dried ground material for pressing, the temperature can be set to 1100 ° C, and the heating time can be set to 10 hours, the holding time can be set to 1 hour, and the feeding The high-purity nitrogen can be set at a flow rate of 3 ml per minute, and the duration of feeding the high-purity nitrogen is 15 minutes. Finally, the required electrode tip is obtained.

To sum up, the preparation method of the electrode tip provided in this embodiment has a simple and fast preparation process, and does not need to use complicated equipment, which can greatly reduce the manufacturing cost of the electrode tip. The obtained electrode tip can also retain the characteristics of the prepared material to the greatest extent.

Example 2

This embodiment provides a tool electrode, as shown in FIGS. 2 and 3 . FIG. 2 is a schematic structural diagram of the tool electrode provided in this embodiment; and FIG. 3 is a schematic diagram of an electrode tip provided in this embodiment. The tool electrode includes a conductor 1 , and in general, the tool electrode is made of copper and has a cylindrical shape, so this embodiment is exemplified by a copper cylindrical conductor 1 . The electrode tip 2 obtained by the preparation method in Example 1 is fixed on the conductor 1 , and electricity can be energized between the conductor 1 and the electrode tip 2 .

Since the main purpose of the tool electrode provided in this embodiment is to reduce the use cost of the tool electrode, the volume of the electrode head 2 can be made small enough, and the conductor 1 can also be made into a cylindrical shape in order to fit, and then the The cylindrical electrode tip 2 is fixed on one end of the conductor 1 to obtain a combined tool electrode. If the electrode head 2 is damaged during use, it is also possible to replace the electrode head 2 to avoid scrapping the entire tool electrode.

Of course, when the electrode tip 2 is fixed on the conductor 1, the electrode tip 2 can be adhered to the conductor 1 by using conductive silver glue, and an oven can be used at a temperature of 50-80°C. Hold for 6-12 hours to form the tool electrode. For example, the electrode tip 2 and the conductor 1 that are glued together by conductive silver are placed in an oven at 80° C. for 12 hours and taken out.

Based on the above content, the combined tool electrode provided in this embodiment can replace the electrode tip 2 multiple times, thereby greatly reducing the use cost of the tool electrode and improving the utilization rate of resources.

Claims (11)

1. A method for producing an electrode head, characterized in that it comprises the following steps:

mixing graphene, tungsten carbide, cobalt and absolute ethyl alcohol, and grinding to obtain a mixed ground substance;

drying the mixed ground material to obtain a dried ground material;

pressing the dried ground material to obtain a molded green body;

sintering the green compact to form the electrode tip;

the tungsten carbide and the cobalt form a first group of substances, and the mass ratio of the graphene to the first group of substances is 0.00001-0.02.

2. The method according to claim 1, wherein the mass ratio of the tungsten carbide to the cobalt is 4 to 9, the graphene, the tungsten carbide and the cobalt constitute a second group of substances, and the mass ratio of the absolute ethyl alcohol to the second group of substances is 0.4 to 0.6.

3. The method according to claim 1, wherein the graphene, the tungsten carbide, the cobalt and the absolute ethyl alcohol are milled by a ball mill at a milling speed of 130 to 160 revolutions per minute for 8 to 24 hours.

4. The method of claim 1, wherein the mixed grind is dried and then screened to obtain a dried grind.

5. The method according to claim 4, wherein the mixed ground product is dried in a drying oven at a temperature of 50 to 80 ℃.

6. The method of claim 5, wherein the mixed grind is dried in a drying oven for 6 to 12 hours.

7. A method as claimed in claim 4, wherein the screening treatment is carried out using a screen of at least 325 mesh.

8. The method of claim 1, wherein the dried abrasive article is pressed using a pressing die and pressed at a pressure of 150MPa to 350MPa to obtain the shaped green body;

wherein the pressing time lasts for 2-5 minutes, and the pressing speed is 2-5 mm per minute.

9. The method of claim 1, wherein the green body is placed in a tube furnace and sintered at a temperature of 1050 to 1150 ℃ to obtain the electrode head;

and introducing high-purity nitrogen into the tubular furnace to exhaust air, wherein the flow rate of the high-purity nitrogen is 3-8 ml per minute, and the duration time is 13-17 minutes.

10. A tool electrode for electric discharge machining, comprising an electric conductor to which an electrode tip according to any one of claims 1 to 9 is fixed, the electric conductor being capable of conducting electricity with the electrode tip.

11. A method for preparing a tool electrode, characterized in that the electrode tip as claimed in claim 10 is bonded to the conductor by means of a conductive silver paste, and is kept warm for 6 to 12 hours at 50 to 80 ℃ by means of an oven to form the tool electrode.

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