Tinning device and tinning method for circular welding strip

Abstract

The present invention provides a tinning device for circular solder strips, comprising a mold support fixing plate and a sizing mold; a tin liquid pool is provided below the mold support fixing plate, a mold support and a lower pressing wheel are provided on the mold support fixing plate in order from top to bottom, the mold support includes a horizontal baffle, a first through hole is provided in the middle of the horizontal baffle; a vertical tangent of the lower pressing wheel on the side close to the mold support passes through the first through hole; the diameter of the sizing mold is larger than the diameter of the first through hole, a second axial through hole is provided in the center of the sizing mold, the inner wall of the second through hole is uniformly provided with a plurality of axial ribs, and the diameter of the circle formed by the tops of the plurality of ribs is larger than the diameter of the solder strip; the average density of the sizing mold is less than the density of the liquid tin; the present invention also provides a tinning method. The tinning device for circular solder strips of the present invention has a simple structure, requires little human intervention, and has a low error rate. The solder strips produced by the tinning method of the present invention have a uniform coating thickness and high product quality.

Description

Technical Field

[0001] The present invention relates to the field of welding strip manufacturing, and in particular to a tinning device and a tinning method for a circular welding strip. Background Art

[0002] In the photovoltaic industry, there are two primary methods for producing photovoltaic ribbons: electroplating and hot-dip plating. Electroplating is relatively expensive and holds a relatively small market share in the industry, while hot-dip plating, the mainstream method, is lower cost and holds a significant advantage. Tinning is a key process in the hot-dip production process. This tinning process impacts important characteristics of the photovoltaic ribbon, such as coating thickness, finished product dimensions, and surface quality. Currently, the primary tinning method used in hot-dip photovoltaic ribbon production is the air knife method, also known as air wiping. The coating thickness and surface quality of the photovoltaic ribbon surface are primarily determined by the air knife's installation position, dimensions, angle, and compressed air pressure and flow rate. Different production speeds require different adjustments to the position of the air knife to ensure consistent product quality. The air knife method requires high technical skills from production staff, and the product's surface quality is inconsistent, leading to a high scrap rate. Summary of the Invention

[0003] In order to solve the above technical problems, the main purpose of the present invention is to provide a tinning device and a tinning method for a circular solder strip, which can accurately control the thickness of the coating and make the coating thickness uniform.

[0004] In order to achieve the above purpose, the present invention adopts the following technical solutions to solve it.

[0005] In the first aspect, a tin-plating device for a circular welding strip comprises a mold support fixing plate and a sizing mold; a tin liquid pool is provided below the mold support fixing plate, and a mold support and a lower pressing wheel are sequentially provided on the mold support fixing plate from top to bottom, and the mold support comprises a horizontal baffle, and a first through hole is provided in the middle of the horizontal baffle; an annular groove concentric with the lower pressing wheel is provided on the outer peripheral surface of the lower pressing wheel; a vertical tangent of the lower pressing wheel close to the mold support side passes through the first through hole; the sizing mold is cylindrical, and the diameter of the sizing mold is larger than the diameter of the first through hole, and an axial second through hole is provided in the center of the sizing mold, and a plurality of axial convex ribs are evenly distributed on the inner wall of the second through hole, and the diameter of the circle formed by the tops of the plurality of convex ribs is larger than the diameter of the welding strip; the average density of the sizing mold is less than the density of the liquid tin.

[0006] Furthermore, the sizing mold includes a circular mold core fixing plate, a third through hole is provided in the middle of the mold core fixing plate, a sizing mold core is provided in the third through hole, the second through hole is located on the sizing mold core, and the convex rib is located on the inner wall of the second through hole.

[0007] Furthermore, the material of the mold core fixing plate is titanium alloy, and the material of the sizing mold core is polycrystalline diamond.

[0008] Furthermore, the height of the sizing mold core is smaller than the height of the mold core fixing plate, the sizing mold core is centrally arranged in the middle of the mold core fixing plate, the upper end of the third through hole is in the shape of a trumpet with an upper opening, and the lower end of the third through hole is in the shape of a trumpet with a lower opening.

[0009] Furthermore, the number of the horizontal baffles is three, the number of the sizing dies is three, and the spacing between the horizontal baffles is greater than the height of the sizing dies.

[0010] Furthermore, it also includes a fixing seat, on which a three-axis linear displacement platform is provided, and the mold bracket fixing plate is fixedly connected to the three-axis linear displacement platform.

[0011] Furthermore, the number of the convex ribs is three, four, five or six.

[0012] Furthermore, an upper pressing wheel is provided above the mold support fixing plate, and the vertical tangent of the upper pressing wheel close to the mold support is collinear with the vertical tangent of the lower pressing wheel close to the mold support.

[0013] In a second aspect, a tinning method for a circular solder strip is provided. Based on the tinning device for the circular solder strip, the tinning method comprises the following steps:

[0014] Step 1: Place tin-lead alloy in a tin liquid pool and heat it to 200°C to 235°C to prepare tin liquid;

[0015] Step 2: Pass the copper wire around the lower pressing wheel, through the second through hole of the sizing die, and vertically upward through the first through hole of the horizontal baffle;

[0016] Step 3: Start the winding mechanism to wind the wire, move the mold bracket fixing plate into the tin liquid pool, and make the sizing mold partly submerged under the liquid surface of the tin liquid.

[0017] The tinning device for the circular welding strip of the technical solution of the present invention has a simple structure, less human involvement, and a small error rate. The welding strip produced by the tinning method has a uniform coating thickness and high finished product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 Schematic diagram of the tinning process of the tinning device for the circular solder strip of the present invention;

[0020] Figure 2 It is a three-dimensional schematic diagram of the tinning device of the circular solder strip of the present invention;

[0021] Figure 3 A cross-sectional view of an embodiment of a sizing die;

[0022] Figure 4 A top view of a first embodiment of a sizing die;

[0023] Figure 5 A top view of a second embodiment of a sizing die;

[0024] Figure 6 It is a top view of the third embodiment of the sizing die.

[0025] In the above diagram:

[0026] 1. Mold support fixing plate; 2. Sizing mold; 201. Raised rib; 202. Mold core fixing plate; 203. Sizing mold core; 204. Second through hole; 3. Tin liquid pool; 4. Mold support; 401. Horizontal baffle; 5. Lower press wheel; 6. Three-axis linear displacement stage; 7. Upper press wheel; 8. Copper wire; 9. Fixed seat. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] The following description sets forth specific details to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art will be able to make similar generalizations without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] (1) Reference Figure 1 、 Figure 2 and Figure 3, a tinning device for a circular welding strip, comprising a mold support fixing plate 1 and a sizing mold 2; a tin liquid pool 3 is provided below the mold support fixing plate 1, and a mold support 4 and a lower pressing wheel 5 are provided on the mold support fixing plate 1 from top to bottom, the mold support 4 comprises a horizontal baffle 401, and a first through hole 402 is provided in the middle of the horizontal baffle 401; an annular groove concentric with the lower pressing wheel 5 is provided on the outer circumference of the lower pressing wheel 5; the vertical tangent of the lower pressing wheel 5 close to the mold support 4 passes through the first through hole 402; the sizing mold 2 is cylindrical, the diameter of the sizing mold 2 is larger than the diameter of the first through hole 402, and an axial second through hole 204 is provided in the center of the sizing mold 2, and the inner wall of the second through hole 204 is evenly distributed with a plurality of axial convex ribs 201, and the diameter of the circle formed by the tops of the plurality of convex ribs 201 is larger than the diameter of the welding strip; the average density of the sizing mold 2 is less than the density of the liquid tin.

[0030] In the production of soldering ribbon, the raw material is copper wire 8, and a tin layer needs to be evenly plated on the surface of the copper wire 8. During production, the copper wire 8 first passes around the lower pressing wheel 5, then passes through the second through hole 204 of the sizing die 2, and then passes through the first through hole 402 of the die holder 4 and is pulled vertically upward, so that the sizing die 2 is below the horizontal baffle 401. After the tin liquid is heated to a preset temperature, the die holder 4 plate is moved as a whole into the tin liquid pool 3. Since the average density of the sizing die 2 is less than the density of the tin liquid, the sizing die 2 is under the action of buoyancy, and the upper surface of the sizing die 2 is close to the lower surface of the horizontal baffle 401, and the sizing die 2 can move freely back and forth. After passing through the tin liquid, the copper wire 8 is pulled vertically upward, and the thickness of the tin liquid adhered to the copper wire 8 is greater than the required coating thickness. The diameter of the second through hole 204 of the sizing die 2 is the set soldering ribbon diameter. Because the inner wall of second through-hole 204 is uniformly provided with multiple ribs 201, the copper wire 8 is constrained to pass through the center of second through-hole 204 during its passage, ensuring that the molten tin on the surface of the copper wire 8 is evenly scraped off. The presence of ribs 201 creates grooves on the surface of the copper wire 8 where they are blocked. Under the surface tension of the liquid, the molten tin on both sides fills the grooves, resulting in a uniform coating thickness on the solder strip.

[0031] For further reference, Figure 2 The sizing die 2 includes a circular mold core fixing plate 202. A third through-hole is provided in the middle of the mold core fixing plate 202. A sizing die core 203 is provided in the third through-hole. The second through-hole 204 is located on the sizing die core 203. The rib 201 is located on the inner wall of the second through-hole 204. The mold core fixing plate 202 is made of titanium alloy, and the sizing die core 203 is made of polycrystalline diamond.

[0032] During production, in order to ensure that the welding strip is subjected to uniform force during the coating forming process, the copper wire 8 needs to be pulled vertically upward after passing through the lower winding wheel. Since errors are inevitable in the manufacture of the equipment, if the sizing die 2 is fixed, it will inevitably lead to uneven force. Therefore, the sizing die 2 does not need to be limited in the horizontal direction. In this embodiment, since the tin liquid is a tin-lead alloy, a titanium alloy with a density less than that of the tin-lead alloy is preferably used as the material for the sizing die 2. Furthermore, since the production is in a high-temperature environment, the copper wire 8 has friction at the second through hole 204 passing through the sizing die 2. In order to extend the service life of the sizing die 2, the sizing die 2 is divided into a mold core fixing plate 202 and a sizing die core 203. The sizing die core 203 is embedded in the center of the mold core fixing plate 202, and the second through hole 204 is set on the sizing die core 203. The mold core fixing plate 202 is made of titanium alloy, and the sizing die core 203 is made of polycrystalline diamond. By ensuring that the average density of the mold core fixing plate 202 and the sizing mold core 203 is less than the density of the tin-lead alloy, the sizing mold 2 can be attached to the lower surface of the horizontal baffle 401 under buoyancy.

[0033] For further reference, Figure 3 The height of the sizing mold core 203 is smaller than the height of the mold core fixing plate 202. The sizing mold core 203 is centrally arranged in the middle of the mold core fixing plate 202. The upper end of the third through hole is in the shape of a trumpet with an upper opening, and the lower end of the third through hole is in the shape of a trumpet with a lower opening.

[0034] In the above embodiment, when the copper wire 8 with tin liquid passes through the second through hole 204, a trumpet-shaped bottom opening is provided at the lower end of the third through hole, so that excess tin liquid can be scraped off more smoothly, thereby improving the quality of the plating layer.

[0035] Furthermore, the number of the horizontal baffles 401 is three, the number of the sizing dies 2 is three, and the spacing between the horizontal baffles 401 is greater than the height of the sizing dies 2 .

[0036] In the above embodiment, preferably, the number of the horizontal baffles 401 is three, and correspondingly, the number of the sizing dies 2 is three. By providing a plurality of sizing dies 2, the tin liquid on the copper wire 8 can be repaired to ensure that no plating is missed.

[0037] Furthermore, it also includes a fixing seat 9 , on which a three-axis linear displacement platform 6 is provided, and the mold support fixing plate 1 is fixedly connected to the three-axis linear displacement platform 6 .

[0038] In the above embodiment, since the production of the soldering strip is a high-precision production, the adjustment of the position of the mold bracket 4 immersed in the tin liquid pool 3 is very fine, so the mold bracket fixing plate 1 is connected to the three-axis linear translation table 6, and then the three-axis linear translation table 6 is fixed on the fixed seat 9. The three-axis linear translation table 6 can accurately realize precise adjustment in the X, Y, and Z directions. Therefore, the position of the mold bracket 4 in the tin liquid pool 3 can be accurately adjusted through the three-axis linear translation table 6.

[0039] For further reference, Figure 3 、 Figure 4 、 Figure 5 and Figure 6 The number of the ribs 201 is three, four, five or six. Regardless of the number of ribs 201, they need to be evenly distributed on the inner surface of the second through hole 204 to ensure that the copper wire passes through the center of the second through hole 204 of the sizing die.

[0040] Furthermore, an upper pressing wheel 7 is provided above the mold support fixing plate 1 , and the vertical tangent of the upper pressing wheel 7 close to the mold support 4 is collinear with the vertical tangent of the lower pressing wheel 5 close to the mold support 4 .

[0041] In the above embodiments, in order to ensure that the copper wire 8 passing through the lower winding wheel can be pulled vertically upward, an upper pressing wheel 7 is usually provided above the lower pressing wheel 5, so that the vertical tangent of the upper pressing wheel 7 close to the mold support 4 is collinear with the vertical tangent of the lower pressing wheel 5 close to the mold support 4, thereby ensuring that the copper wire 8 can be pulled vertically upward.

[0042] (2) A tinning method for a circular solder strip, based on the above tinning device for a circular solder strip, the tinning method comprises the following steps:

[0043] Step 1: Place tin-lead alloy in the tin liquid pool 3 and heat it to 200°C to 235°C to prepare tin liquid;

[0044] Step 2: Pass the copper wire 8 around the lower pressing wheel 5, through the second through hole 204 of the sizing die 203, and vertically upward through the first through hole 402 of the horizontal baffle 401;

[0045] Step 3: Start the winding mechanism to wind the wire, adjust the three-axis linear displacement stage 6, and move the mold support fixing plate 1 into the tin liquid pool 3 so that half of the uppermost sizing mold core 203 is below the liquid level of the tin liquid.

[0046] Since the average density of the mold core fixing plate 202 and the sizing mold core 203 is less than the density of the tin liquid, the sizing mold 2 will float on the tin liquid. Due to the obstruction of the horizontal baffle 401, the sizing mold 2 is constrained below the horizontal baffle 401. Since the sizing mold 2 is not constrained, the sizing mold 2 can automatically adapt to allow the copper wire 8 to pass through the center of the second through hole 204.

[0047] Although the present invention has been described in detail in this specification using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the present invention, are intended to fall within the scope of protection claimed herein.

Claims

1. A tinning device for a circular solder strip, characterized in that: The invention comprises a mold support fixing plate (1) and a sizing mold (2); a tin liquid pool (3) is provided below the mold support fixing plate (1); a mold support (4) and a lower pressing wheel (5) are provided on the mold support fixing plate (1) from top to bottom; the mold support (4) comprises a horizontal baffle (401); a first through hole (402) is provided in the middle of the horizontal baffle (401); an annular groove coaxial with the lower pressing wheel (5) is provided on the outer peripheral surface of the lower pressing wheel (5); the lower pressing wheel (5) is close to the mold support (4) A vertical tangent on one side passes through the first through hole (402); the sizing die (2) is cylindrical, the diameter of the sizing die (2) is larger than the diameter of the first through hole (402), an axial second through hole (204) is provided at the center of the sizing die (2), the inner wall of the second through hole (204) is uniformly distributed with a plurality of axial convex ribs (201), and the diameter of the circle formed by the tops of the plurality of convex ribs (201) is larger than the diameter of the solder strip; the average density of the sizing die (2) is smaller than the density of the liquid tin; The sizing die (2) comprises a circular die core fixing plate (202), a third through hole is provided in the middle of the die core fixing plate (202), a sizing die core (203) is provided in the third through hole, the second through hole (204) is located on the sizing die core (203), and the convex rib (201) is located on the inner wall of the second through hole (204); The material of the mold core fixing plate (202) is titanium alloy, and the material of the sizing mold core (203) is polycrystalline diamond; The height of the sizing die core (203) is smaller than the height of the die core fixing plate (202), the sizing die core (203) is centrally arranged in the middle of the die core fixing plate (202), the upper end of the third through hole is in the shape of a trumpet with an upper opening, and the lower end of the third through hole is in the shape of a trumpet with a lower opening; The number of the horizontal baffles (401) is three, the number of the sizing dies (2) is three, and the spacing between the horizontal baffles (401) is greater than the height of the sizing dies (2).

2. The tinning device for a circular solder strip according to claim 1, characterized in that: It also includes a fixed seat (9), a three-axis linear displacement platform (6) is provided on the fixed seat (9), and the mold support fixing plate (1) is fixedly connected to the three-axis linear displacement platform (6).

3. The tinning device for a circular solder strip according to claim 1, characterized in that: The number of the convex ribs (201) is three, four, five or six.

4. The tinning device for a circular solder strip according to claim 1, characterized in that: An upper pressing wheel (7) is provided above the mold support fixing plate (1), and a vertical tangent of the upper pressing wheel (7) close to the mold support (4) is collinear with a vertical tangent of the lower pressing wheel (5) close to the mold support (4).

5. A method for tinning a circular solder strip, characterized in that: Based on the tinning device for the circular solder strip according to claim 1, the tinning method comprises the following steps: Step 1: placing a tin-lead alloy in a tin liquid pool (3) and heating it to 200° C. to 235° C. to prepare tin liquid; Step 2: Pass the copper wire (8) around the lower pressing wheel (5) through the second through hole (204) of the sizing die (203) and vertically upward out of the first through hole (402) of the horizontal baffle (401); Step 3: Start the winding mechanism to wind the wire, move the mold support fixing plate (1) into the tin liquid pool (3), and make the sizing mold (2) partially immersed under the liquid surface of the tin liquid.

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