A connection method for improving the pull-out force of welding between FPC wire and copper sheet

Abstract

The invention belongs to the technical field of FPC wire welding, and specifically relates to a connection method for improving the welding pull-out force of an FPC wire and a copper sheet, comprising the following steps: S1, machining a groove on a copper sheet; S2, machining a pattern on the groove bottom of the groove; S3, machining a pull-out hole in the center of the groove bottom of the groove; S4, tinning one side of the copper sheet provided with the groove and the hole wall of the pull-out hole; S5, tinning the soldering pad of the FPC wire; S6, pressing the soldering pad into the groove, heating the side of the copper sheet away from the groove and then cooling it, so that the tin layer of the soldering pad and the tin layer of the copper sheet are melted and then cooled and solidified.

Description

Technical Field

[0001] The invention belongs to the technical field of FPC wire welding, and in particular relates to a connection method for improving the welding pulling force of an FPC wire and a copper sheet. Background Art

[0002] When connecting the FPC wire connection to the copper sheet body, if the laser welding process is used, the production cost and equipment investment will be high, and waste gas (smoke) is easily generated during the laser welding process. If the ordinary manual soldering process is used, the pull-out force between the FPC wire connection and the copper sheet body is small, it is easy to peel off and is not durable, and it is not easy for automotive products to pass vibration tests. Summary of the invention

[0003] In view of the above-mentioned shortcomings, an object of the present invention is to provide a connection method for improving the welding pull-out force between FPC wire and copper sheet.

[0004] The present invention provides the following technical solutions:

[0005] A method for improving the pull-out force of welding between an FPC line and a copper sheet, comprising the following steps:

[0006] S1, processing a groove on the copper sheet;

[0007] S2, processing the groove bottom to form a pattern;

[0008] S3, a pull hole is machined in the center of the groove bottom;

[0009] S4, tinning the grooved side of the copper sheet and the hole wall of the pull hole;

[0010] S5, tin the pads of the FPC line;

[0011] S6. Press the soldering pad into the groove, heat the side of the copper sheet facing away from the groove and then cool it, so that the tin layer of the soldering pad and the tin layer of the copper sheet melt and then cool and solidify.

[0012] In S1, the groove is in the shape of a truncated cone.

[0013] In S2, the texture is in the shape of “#”.

[0014] The groove depth of the texture is 0.5-0.7mm.

[0015] The cross-sectional area of ​​the pull hole accounts for 8-10% of the bottom area of ​​the groove.

[0016] The cross-sectional area of ​​the lines accounts for 0.3-1.0% of the bottom area of ​​the groove.

[0017] In S6, the pads of the FPC line are welded to the copper sheet by the Hotbar welding process.

[0018] In S4, the thickness of the tin-plated layer of the copper sheet 101 is 2-10 microns; in S5, the thickness of the tin-plated layer of the pad is greater than 15 microns.

[0019] The beneficial effects of the present invention are as follows: the present invention increases the amount of tin adhesion at the welding position of the copper sheet by adding a coarse-grained well-shaped texture effect, and at the same time opens a hole at the welding position of the copper sheet to make the reserved tin amount at the welding position more sufficient, thereby increasing the welding area of ​​the pads of the copper sheet and the FPC line, and the copper sheet can be fully connected to the pad of the FPC line after welding, thereby increasing the adhesion between the solder layers and improving the pull-out force at the connection between the FPC line and the copper sheet plane. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of the present invention;

[0021] Figure 2 It is a schematic diagram of the copper sheet structure of the present invention.

[0022] The markings in the figure are: copper sheet 101, groove 102, texture 103, and pull hole 104. DETAILED DESCRIPTION

[0023] As shown in the figure, a connection method for improving the pull-out force of welding between FPC wire and copper sheet includes the following steps:

[0024] S1. Processing a groove 102 on the copper sheet 101. The groove 102 can be processed by a stamping process, and the shape of the groove 102 after processing can be a truncated cone or a cylindrical shape.

[0025] S2. Processing a pattern 103 at the bottom of the groove 102. The pattern 103 can be made by stamping. The pattern 103 is in a "#" shape. The "#"-shaped pattern 103 is evenly distributed at the bottom of the groove 102. The groove depth of the pattern 103 is 0.5-0.7mm, and the groove width of the pattern 103 is 0.1-0.3mm, so that a tin layer can be left on the groove wall of the pattern 103 during tin plating.

[0026] S3. A pull hole 104 is machined in the center of the bottom of the groove 102. The cross-sectional area of ​​the pull hole 104 accounts for 8-10% of the bottom area of ​​the groove 102. The cross-sectional area of ​​the pattern 103 accounts for 0.3-1.0% of the bottom area of ​​the groove 102.

[0027] S4. Tinning is performed on one side of the copper sheet 101 provided with the groove 102 and the hole wall of the pull hole 104. The thickness of the tinning layer is 2-10 microns.

[0028] S5. Tin the pads of the FPC line, and the thickness of the tin plating layer is greater than 15 microns.

[0029] S6. Press the pad into the groove, heat the side of the copper sheet away from the groove and then cool it, so that the tin layer of the pad and the tin layer of the copper sheet melt and then cool and solidify. Specifically, the pad of the FPC line can be welded to the copper sheet by the Hotbar welding process. By quickly heating and cooling the back of the copper sheet, the reserved tin layer of the pad of the FPC line and the tin-plated layer on the copper sheet are quickly melted and cooled and solidified, and finally the FPC line is connected to the copper sheet.

[0030] In a high temperature environment of 120℃, the pull-out force of the weld was tested, and the results are as follows:

[0031]

[0032]

[0033] In the prior art, the pull-out force between the copper sheet and the FPC line that are directly welded is less than 5N in a high temperature environment of 120°C.

[0034] As can be seen from the above, under a high temperature environment of 120°C, the pull-out force at the welding point between the copper sheet and the FPC wire of the present invention is increased to greater than 15N, which can meet the application of higher application scenarios. At the same time, it effectively reduces gas pollution and diffusion in the construction environment, has low investment cost, is easy to realize automated production, and has high production efficiency; the pull-out force at the connection can be improved so that it can pass the pull-out test and vibration test, making it more durable and vibration-resistant in high temperature application scenarios of 120°C.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A connection method for improving the pull-out force of welding between FPC wire and copper sheet, characterized in that: The following steps are involved: S1. Processing a groove (102) on a copper sheet (101); the groove (102) is in a truncated cone shape; S2, processing a groove (103) at the bottom of the groove (102); S3, machining a pull hole (104) in the center of the bottom of the groove (102); S4, tinning the copper sheet (101) provided with one side of the groove (102) and the hole wall of the pull hole (104); S5, tin the pads of the FPC line; S6. Press the soldering pad into the groove, heat the side of the copper sheet facing away from the groove and then cool it, so that the tin layer of the soldering pad and the tin layer of the copper sheet melt and then cool and solidify.

2. The method for improving the pull-out force of welding between FPC wire and copper sheet according to claim 1, characterized in that: In S2, the pattern (103) is in the shape of "#".

3. The method for improving the pull-out force of welding between FPC wire and copper sheet according to claim 2, characterized in that: The groove depth of the pattern (103) is 0.5-0.7 mm.

4. The method for improving the pull-out force of welding between FPC wire and copper sheet according to claim 1, characterized in that: The cross-sectional area of ​​the pull hole (104) accounts for 8-10% of the bottom area of ​​the groove (102).

5. The method for improving the pull-out force of welding between FPC wire and copper sheet according to claim 4, characterized in that: The cross-sectional area of ​​the lines (103) accounts for 0.3-1.0% of the bottom area of ​​the groove (102).

6. The method for improving the pull-out force of welding between FPC wire and copper sheet according to claim 1, characterized in that: In S6, the pads of the FPC line are welded to the copper sheet by the Hotbar welding process.

7. The method for improving the pull-out force of welding between FPC wire and copper sheet according to any one of claims 1 to 6, characterized in that: In S4, the thickness of the tin-plated layer of the copper sheet (101) is 2-10 micrometers; in S5, the thickness of the tin-plated layer of the pad is greater than 15 micrometers.

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