Preparation method of preformed solder with soldering flux

Abstract

The invention relates to a preparation method of a preformed solder with a soldering flux, which comprises the following steps: S1, preparation of the soldering flux: grinding the required soldering flux until the particle size of the powder is 25-150 microns; s2, preparing a solder main body, wherein the solder main body is made of tin-based alloy; s3, the tin-based alloy is ground into two or three kinds of particle sizes, when the two kinds of particle sizes are adopted, the particle size of coarse powder ranges from 100 micrometers to 160 micrometers, and the particle size of fine powder ranges from 20 micrometers to 45 micrometers; in the three particle sizes, the particle size of the coarse powder is 100-160 microns, and the particle size of the medium powder is 45-75 microns; the particle size of the fine powder is 15-38 microns; s4, the tin-based alloy powder with different particle sizes is proportionally mixed; s5, the scaling powder and the solder main body powder are fully mixed, wherein the scaling powder accounts for 0.3%-5% of the total mass of the solder; and S6, carrying out extrusion molding on the mixed powder. The method is simple, convenient, low in cost and uniform and accurate in scaling powder proportion.

Description

Technical Field

[0001] The present application relates to a method for preparing a preformed solder with its own flux, which is mainly suitable for the preparation of metal material welding materials. Background Art

[0002] Existing methods for making preformed solder sheets generally fall into the following two approaches: Option 1: First, the alloy is prepared by mixing and smelting the ingredients; then, the preformed solder sheet is obtained by casting an ingot, extruding a strip, and then rolling and punching it. The surface of the strip is then coated with flux by methods such as dip coating, thermal spraying, electrostatic spraying, and electrostatic vibration. The surface flux is then cured by methods such as resistance, infrared heating, and ultraviolet radiation. After cooling, the preformed solder sheet is pressed and punched to obtain the desired shape. Option 2: Using the above methods, the main body of the solder sheet is produced by mixing, smelting, casting, extruding, rolling, and punching. The flux is then applied to the sheet by processes such as dip coating and spraying. The surface of the flux-coated sheet is then dried to obtain the desired preformed solder sheet.

[0003] Since the preformed solder sheets in these two processes are in sheet form and stacked and packaged, the flux must be prevented from sticking to each other before and after surface curing or drying. Also, since most preformed solder sheets are small, spraying flux on the smaller punched solder sheets requires the use of special tooling equipment to arrange and separate the semi-finished solder sheets. The overall coating process is relatively complex and costly, and the content and uniformity of the flux coating cannot be precisely controlled. The overall efficiency is low, making it only suitable for the production of larger preformed solder sheets. Summary of the Invention

[0004] The technical problem solved by the present application is to overcome the above-mentioned deficiencies in the prior art and to provide a simple, convenient, low-cost solder preparation method with uniform and accurate flux ratio.

[0005] The technical solution adopted by the present application to solve the above technical problems is: a method for preparing a preformed solder with its own flux, which is characterized by comprising the following steps: S1 flux preparation: grind the required flux to a powder particle size between 25μm and 150μm; S2. Preparation of solder body, wherein the solder body is made of tin-based alloy, which is composed of tin and at least one of copper, lead, bismuth, antimony, silver, and nickel; S3 grinds the tin-based alloy into two or three particle sizes. When the particle size is two, the particle size of the coarse powder is between 100-160 μm, and the particle size of the fine powder is between 20-45 μm; when the particle size is three, the particle size of the coarse powder is between 100-160 μm, the particle size of the medium powder is between 45-75 μm; and the particle size of the fine powder is between 15-38 μm. S4 Tin-based alloy powders of different particle sizes are mixed in proportion: when there are two particle sizes, the proportion is that the coarse powder accounts for 65%-85% of the total mass of the Tin-based alloy, and the fine powder accounts for 15%-35% of the total mass of the Tin-based alloy; when there are three particle sizes, the proportion is that the coarse powder accounts for 55%-65% of the total mass of the Tin-based alloy, the medium powder accounts for 10%-20% of the total mass of the Tin-based alloy, and the fine powder accounts for 20%-30% of the total mass of the Tin-based alloy powder; S5: Thoroughly mix the flux powder and the solder main body (tin-based alloy) powder, where the flux accounts for 0.3%-5% of the total mass of the solder; The mixed powder is extruded into a mold by an extruder.

[0006] The S6 step includes: The mixed powder of S61 is extruded through an extruder, and the height-to-diameter ratio is controlled between 0.4 and 1.0 during extrusion to produce solder blanks; S62 makes solder strips through an extruder.

[0007] The raw materials used in this application are powdered materials. Therefore, before being extruded into strips, the powdered materials need to be initially pressurized into large solid blocks (billets) and then extruded into strips. In addition, the powdered materials undergo two high-pressure processes to better ensure the density of the strips.

[0008] This application can also set S7 step, S7 rolls the solder strip into a desired thickness.

[0009] This application can also set S8 step, S8 punches or laser cuts the solder strip material in S7 into a desired shape.

[0010] The solder body described in this application is SAC0307 or SAC305, and the solder body accounts for 98%-99% of the total mass of the solder.

[0011] The soldering flux described in the present application is composed of hydrogenated rosin, adipic acid and benzotriazole.

[0012] The soldering flux described in the present application is composed of one, two or three of hydrogenated rosin, adipic acid, benzotriazole, chlorobridgeic acid, diethylimidazole and succinic acid.

[0013] Compared with the prior art, the present invention has the following advantages and effects: simplicity, convenience, low cost, and uniform and accurate flux ratio. DETAILED DESCRIPTION

[0014] The present application will be further described in detail below through specific implementation methods. The following examples are intended to explain the present application but the present application is not limited to the following examples.

[0015] S1 flux preparation, the required flux is ground to a powder particle size of 25-150 μm; S2 solder body preparation, the solder body is a tin-based alloy, the main element of which is tin, and the remaining elements are at least one of copper, lead, bismuth, antimony, silver and nickel; S3 grinding the above-mentioned tin-based alloy into two or three particle sizes, when two particle sizes, the coarse powder particle size is between 100-160 μm, and the fine powder particle size is between 20-45 μm; when three particle sizes, the coarse powder particle size is between 100-160 μm, the medium powder particle size is between 45-75 μm, and the fine powder particle size is between 15-38 μm; S4 mixing the tin-based alloy powders of different particle sizes: when two particle sizes, the mixing scheme is that the coarse powder accounts for 65%-85% of the total mass of the tin-based alloy, and the fine powder accounts for 15%-35% of the total mass of the tin-based alloy; when three particle sizes, the mixing scheme is that the coarse powder accounts for 55%-65% of the total mass of the tin-based alloy, the medium powder accounts for 10%-20% of the total mass of the tin-based alloy, and the fine powder accounts for 20%-30% of the total mass of the tin-based alloy; S5 mixing the flux powder and the solder body powder thoroughly, wherein the flux accounts for 0.3%-5% of the total mass of the solder; S6 extruding the mixed powder into a shape by an extruder.

[0016] The S6 step comprises: S61 extruding the mixed powder by an extruder, and the height-diameter ratio is controlled to be between 0.4-1.0 to produce a solder blank; S62 producing a solder strip by the extruder.

[0017] The application can further comprise an S7 step, S7 rolling the solder strip into a desired thickness.

[0018] The application can further comprise an S8 step, S8 punching or laser cutting the solder strip of S7 into a desired shape.

[0019] Table 1 Flux formula Table 2 Tin-based alloy powder particle size ratio Table 3 Specific example Note: The specific components of SAC0307 and SAC305 refer to the standard J-STD-006. The particle size refers to the diameter of the tin-based alloy powder.

[0020] The application has the following characteristics: 1. There are no special requirements for the shaping of the flux in solid state, which makes it easier to make and less likely to stick; 2. The flux content can be precisely controlled as required; 3. The flux is distributed very evenly, avoiding the risk of uneven flux coating thickness in existing technologies; 4. Surface dimensions are more accurate; 5. No need to design special tooling and molds, high efficiency; 6. The flux is evenly distributed inside the main material and will not be damaged during transportation and use.

Claims

1. A method for preparing a preformed solder with its own flux, characterized in that The following steps are involved: S1 flux preparation: grind the required flux to a powder particle size between 25μm and 150μm; S2. Preparation of solder body, wherein the solder body is made of tin-based alloy, which is composed of tin and at least one of copper, lead, bismuth, antimony, silver, and nickel; S3 grinds the tin-based alloy into two or three particle sizes. When the particle size is two, the particle size of the coarse powder is between 100-160 μm, and the particle size of the fine powder is between 20-45 μm; when the particle size is three, the particle size of the coarse powder is between 100-160 μm, the particle size of the medium powder is between 45-75 μm; and the particle size of the fine powder is between 15-38 μm. S4 Tin-based alloy powders of different particle sizes are mixed in proportion: when there are two particle sizes, the proportion is that the coarse powder accounts for 65%-85% of the total mass of the Tin-based alloy, and the fine powder accounts for 15%-35% of the total mass of the Tin-based alloy; when there are three particle sizes, the proportion is that the coarse powder accounts for 55%-65% of the total mass of the Tin-based alloy, the medium powder accounts for 10%-20% of the total mass of the Tin-based alloy, and the fine powder accounts for 20%-30% of the total mass of the Tin-based alloy powder; S5: Thoroughly mix the flux powder and the main solder powder, wherein the flux accounts for 0.3%-5% of the total mass of the solder; The mixed powder is extruded into a mold by an extruder.

2. The method for preparing the preformed solder with self-contained flux according to claim 1, characterized in that: The S6 step includes: The mixed powder of S61 is extruded through an extruder, and the height-to-diameter ratio is controlled between 0.4 and 1.0 during extrusion to produce solder blanks; S62 makes solder strips through an extruder.

3. The method for preparing the preformed solder with self-contained flux according to claim 1, characterized in that: There is also an S7 step, S7 rolls the solder strip into a desired thickness.

4. The method for preparing the preformed solder with self-contained flux according to claim 3, characterized in that: Also set S8 step, S8 punches or laser cuts the solder strip material in S7 into a desired shape.

5. The method for preparing the preformed solder with self-contained flux according to claim 1, characterized in that: The solder body is made of SAC0307 or SAC305, and the solder body accounts for 98%-99% of the total mass of the solder.

6. The method for preparing the preformed solder with self-contained flux according to claim 1, characterized in that: The soldering flux consists of hydrogenated rosin, adipic acid and benzotriazole.

7. The method for preparing a preformed solder with self-contained flux according to claim 1, characterized in that: The soldering flux consists of one, two or three of hydrogenated rosin, adipic acid, benzotriazole, chlorobridgeic acid, diethylimidazole and succinic acid.

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