阅读说明：本技术 一种减少接地焊盘焊接空洞的方法 (Method for reducing welding holes of grounding welding pad ) 是由 王军 何育林 齐照山 林东峰 鲍明明 盛壮 于 2020-06-24 设计创作，主要内容包括：本发明提供了一种减少接地焊盘焊接空洞的方法,包括步骤：对待焊接区域按照第一预设比例进行第一次印刷锡膏,并空载进行第一次回流焊接；对待焊接区域按照第二预设比例进行第二次印刷锡膏,并贴装零件进行第二次回流焊接；其中,所述第二预设比例大于所述第一预设比例,且所述第二次印刷锡膏覆盖所述第一次印刷锡膏。该方法能够更高效的排出锡膏内的气体,降低焊接部分的空洞率,有利于保证焊接的品质。(The invention provides a method for reducing welding holes of a grounding welding pad, which comprises the following steps: printing solder paste for the first time on the area to be welded according to a first preset proportion, and performing first reflow soldering in no-load mode; printing solder paste for the second time on the area to be welded according to a second preset proportion, and carrying out reflow soldering for the second time on the surface-mounted part; and the second preset proportion is larger than the first preset proportion, and the second time of printing solder paste covers the first time of printing solder paste. The method can discharge the gas in the solder paste more efficiently, reduce the void ratio of the welding part and be beneficial to ensuring the welding quality.)

1. A method for reducing ground pad solder voids, comprising the steps of:

printing solder paste for the first time on the area to be welded according to a first preset proportion, and performing first reflow soldering in no-load mode;

printing solder paste for the second time on the area to be welded according to a second preset proportion, and carrying out reflow soldering for the second time on the surface-mounted part;

and the second preset proportion is larger than the first preset proportion, and the second time of printing solder paste covers the first time of printing solder paste.

2. A method of reducing ground pad solder voids according to claim 1, wherein: comprises a first steel mesh and a second steel mesh,

the first steel mesh is provided with a plurality of first openings respectively corresponding to the areas to be welded, and the ratio of the area of each first opening to the area of the corresponding area to be welded is the first preset proportion;

the second steel mesh is provided with a plurality of second openings respectively corresponding to the areas to be welded, and the ratio of the area of each second opening to the area of the corresponding area to be welded is the second preset proportion.

3. The method for reducing the solder voids in the ground pad as recited in claim 2, wherein the first printing of solder paste on the area to be soldered according to the first predetermined ratio specifically comprises:

covering the first steel mesh on a grounding pad, so that the first openings of the first steel mesh correspond to the corresponding areas to be welded respectively;

and carrying out the first solder paste printing on the area to be welded through the first opening.

4. A method for reducing ground pad solder voids as recited in claim 2, wherein said no-load further comprises, after said first reflow soldering:

and removing the first steel net.

5. The method for reducing the solder voids in the ground pad as recited in claim 2, wherein the second printing of solder paste on the area to be soldered according to the second predetermined ratio specifically comprises:

covering the second steel mesh on a grounding pad, so that the second openings of the second steel mesh correspond to the corresponding areas to be welded respectively;

and carrying out the second solder paste printing on the area to be welded through the second opening.

6. A method of reducing ground pad solder voids according to claim 2, wherein: the thickness of the second steel mesh is greater than the thickness of the first steel mesh.

7. A method for reducing ground pad solder voids according to any one of claims 1-6, wherein: the first preset proportion is 25% -35%.

8. A method for reducing ground pad solder voids according to any one of claims 1-6, wherein: the first predetermined proportion is 28%.

9. A method for reducing ground pad solder voids according to any one of claims 1-6, wherein: the second preset proportion is between 60% and 75%.

10. A method for reducing ground pad solder voids according to any one of claims 1-6, wherein: the second predetermined proportion is 65%.

Technical Field

The invention relates to the technical field of welding, in particular to a method for reducing welding holes of a grounding welding pad.

Background

At present, most electrical products use printed circuit boards, and when the electrical products are used, grounding holes are generally arranged on the printed circuit boards to protect grounding for the safety of human bodies and the electrical products, and grounding pads are arranged on the peripheries of the grounding holes.

During welding, in order to ensure the welding quality, gas in the solder paste needs to be exhausted, and during part welding, due to blockage of parts, the solder paste only has exhaust passages in the X direction and the Y direction, and does not have the exhaust passages in the Z direction, so that the exhaust rate is reduced. In addition, because the PCB grounding pad is provided with blind holes (non-through holes), solder paste can flow into the blind holes when dissolved in a liquid state, and soldering flux, an activating agent, a reducing agent and the like in the solder paste can generate gas, so that the gas in the solder paste is more difficult to discharge when the PCB grounding pad is welded, and the welding void ratio is high. Therefore, there is a need for a method for more efficiently exhausting the gas in the solder paste and reducing the void ratio

Disclosure of Invention

The invention aims to provide a method for reducing welding holes of a grounding welding pad, which can discharge gas in solder paste more efficiently, reduce the hole rate of a welding part and is beneficial to ensuring the welding quality.

The technical scheme provided by the invention is as follows:

the invention provides a method for reducing welding holes of a grounding welding pad, which comprises the following steps:

printing solder paste for the first time on the area to be welded according to a first preset proportion, and performing first reflow soldering in no-load mode;

printing solder paste for the second time on the area to be welded according to a second preset proportion, and carrying out reflow soldering for the second time on the surface-mounted part;

and the second preset proportion is larger than the first preset proportion, and the second time of printing solder paste covers the first time of printing solder paste.

Preferably, the center of the solder paste printed for the second time and the center of the solder paste printed for the first time are located at the same position, so that the solder paste printed for the second time is perfectly covered on the solder paste printed for the first time, and the exhaust effect of the solder paste is favorably improved.

The solder paste is printed for the first time on the area to be welded according to the first preset proportion, and the first reflow soldering is carried out in a no-load mode, so that after the first reflow soldering, the solder paste on the grounding pad is in a no-load state, the air can be exhausted from X, Y, Z directions simultaneously, the air exhaust is smoother, and the residual gas in the solder paste can be reduced; and then, printing solder paste for the second time on the area to be welded according to a second preset proportion, mounting the part for the second reflow soldering, wherein the second preset proportion is larger than the first preset proportion, and the second solder paste is printed on the first solder paste in a covering manner, so that the secondary welding exhaust pressure is greatly reduced, gas in the solder paste can be discharged more efficiently, the voidage of a welding part is reduced, and the welding quality is favorably ensured.

Further, the first steel net and the second steel net are included,

the first steel mesh is provided with a plurality of first openings respectively corresponding to the areas to be welded, and the ratio of the area of each first opening to the area of the corresponding area to be welded is the first preset proportion;

the second steel mesh is provided with a plurality of second openings respectively corresponding to the areas to be welded, and the ratio of the area of each second opening to the area of the corresponding area to be welded is the second preset proportion.

Through setting up first steel mesh and second steel mesh, be provided with respectively on first steel mesh and the second steel mesh and treat welding area's first opening and second opening that corresponds for when carrying out first printing tin cream and second time printing tin cream, the homoenergetic carries out a plurality ofly simultaneously and treats welding area's printing tin cream, is favorable to improving printing efficiency, and can guarantee that first printing tin cream and second time printing tin cream go on according to first predetermined proportion and second predetermined proportion respectively.

Further, the first solder paste printing on the region to be soldered according to a first preset proportion specifically includes:

covering the first steel mesh on a grounding pad, so that the first openings of the first steel mesh correspond to the corresponding areas to be welded respectively;

and carrying out the first solder paste printing on the area to be welded through the first opening.

Further, after the first reflow soldering is performed without load, the method further comprises the following steps:

and removing the first steel net.

Further, the second solder paste printing on the region to be soldered according to a second preset proportion specifically includes:

covering the second steel mesh on a grounding pad, so that the second openings of the second steel mesh correspond to the corresponding areas to be welded respectively;

and carrying out the second solder paste printing on the area to be welded through the second opening.

Further, the thickness of the second steel mesh is greater than the thickness of the first steel mesh.

Because carry out printing tin cream the first time through first steel mesh after, the tin cream dissolves the solidification and can form a convex surface, for avoiding influencing the effect of printing tin cream the second time, so need the thickness of second steel mesh to be greater than the thickness of first steel mesh. In this embodiment, the thickness of the first steel mesh is 0.08 mm, and the thickness of the second steel mesh is 0.12 mm.

Further, the first preset proportion is between 25% and 35%.

Further, the first preset proportion is 28%.

In this embodiment, the first opening area of the first steel mesh is 0.75 × 9 — 5.0625mm²The area of the grounding pad is 4.3 x 4.3 ═ 18.49mm²The first predetermined ratio is 5.0625/18.49-27.37%.

Further, the second preset proportion is between 60% and 75%.

Further, the second preset proportion is 65%.

In this embodiment, the second opening area of the second steel mesh is 1.15 × 9 ═ 11.9025mm²The area of the grounding pad is 4.3 x 4.3 ═ 18.49mm²The second predetermined ratio is 11.9025/18.49-64.37%.

According to the method for reducing the welding holes of the grounding pad, provided by the invention, the solder paste is printed for the first time in the area to be welded according to the first preset proportion, and the first reflow welding is carried out in no-load mode, so that after the first reflow welding is carried out, the solder paste on the grounding pad is in the no-load state, the air can be exhausted from X, Y, Z directions simultaneously, the air exhaust is smoother, and the reduction of residual gas in the solder paste is facilitated; and then, printing solder paste for the second time on the area to be welded according to a second preset proportion, mounting the part for the second reflow soldering, wherein the second preset proportion is larger than the first preset proportion, and the second solder paste is printed on the first solder paste in a covering manner, so that the secondary welding exhaust pressure is greatly reduced, gas in the solder paste can be discharged more efficiently, the voidage of a welding part is reduced, and the welding quality is favorably ensured.

Drawings

The foregoing features, technical features, advantages and embodiments of the present invention will be further explained in the following detailed description of the preferred embodiments, which is to be read in connection with the accompanying drawings.

FIG. 1 is a schematic overall flow diagram of an embodiment of the present invention;

FIG. 2 is a schematic view of a first steel mesh structure according to an embodiment of the present invention;

fig. 3 is a schematic view of a second steel mesh structure according to an embodiment of the present invention.

Reference numbers in the figures: 10-a first steel mesh; 11-a first opening; 20-a second steel mesh; 21-second opening.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will be made with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.

For the sake of simplicity, the drawings only schematically show the parts relevant to the present invention, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "one" means not only "only one" but also a case of "more than one".

Example 1

In one embodiment of the present invention, as shown in fig. 1, the present invention provides a method for reducing solder voids in a ground pad, comprising the steps of:

and step S1, printing solder paste for the first time on the area to be welded according to a first preset proportion, and carrying out reflow soldering for the first time in an idle load manner.

Step S2, printing solder paste for the second time on the area to be welded according to a second preset proportion, and carrying out reflow soldering on the mounted part for the second time; and the second preset proportion is larger than the first preset proportion, and the second time of printing the solder paste covers the first time of printing the solder paste.

Specifically, in the PCB grounding bonding pad, a plurality of parts needing to be welded exist, so that the first solder paste printing and the second solder paste printing can be used for simultaneously printing a plurality of areas to be welded.

Preferably, the center of the solder paste printed for the second time and the center of the solder paste printed for the first time are located at the same position, so that the solder paste printed for the second time is perfectly covered on the solder paste printed for the first time, and the exhaust effect of the solder paste is favorably improved.

The solder paste is printed for the first time on the area to be welded according to the first preset proportion, and the first reflow soldering is carried out in a no-load mode, so that after the first reflow soldering, the solder paste on the grounding pad is in a no-load state, the air can be exhausted from X, Y, Z directions simultaneously, the air exhaust is smoother, and the residual gas in the solder paste can be reduced; and then, printing solder paste for the second time on the area to be welded according to a second preset proportion, mounting the part for the second reflow soldering, wherein the second preset proportion is larger than the first preset proportion, and the second solder paste is printed on the first solder paste in a covering manner, so that the secondary welding exhaust pressure is greatly reduced, gas in the solder paste can be discharged more efficiently, the voidage of a welding part is reduced, and the welding quality is favorably ensured. Through the two times of welding, the voidage of the PCB grounding welding pad can be reduced to be less than 20%, so that the welding quality is improved.

Example 2

As shown in fig. 2 and 3, an embodiment of the present invention further includes a first steel mesh 10 and a second steel mesh 20 on the basis of embodiment 1, the first steel mesh 10 is provided with a plurality of first openings 11 respectively corresponding to regions to be welded, and a ratio of an area of each first opening 11 to an area of the corresponding region to be welded is a first preset ratio; the second steel net 20 is provided with a plurality of second openings 21 respectively corresponding to the areas to be welded, and the ratio of the area of the second openings 21 to the area of the corresponding areas to be welded is a second preset proportion.

Through setting up first steel mesh 10 and second steel mesh 20, be provided with respectively on first steel mesh 10 and the second steel mesh 20 and treat the first opening 11 and the second opening 21 that the welding area corresponds for when carrying out first printing tin cream and second time printing tin cream, the homoenergetic carries out a plurality of printing tin creams of treating the welding area simultaneously, is favorable to improving printing efficiency, and can guarantee that first time printing tin cream and second time printing tin cream carry out according to first predetermined proportion and second predetermined proportion respectively.

Preferably, the first printing of the solder paste on the region to be soldered according to a first preset proportion specifically comprises:

covering the first steel net 10 on the ground pad so that the first openings 11 of the first steel net 10 correspond to the corresponding areas to be welded, respectively; the solder paste is printed for the first time on the area to be soldered through the first opening 11, so that the solder paste can be printed for the first time on the area to be soldered according to a first preset proportion.

Further preferably, after the first reflow soldering is performed without load, the method further comprises the following steps: the first steel net 10 is removed to facilitate a second subsequent printing of solder paste.

Further, the second printing of solder paste on the region to be soldered according to a second preset proportion includes: covering the second steel net 20 on the ground pad so that the second openings 21 of the second steel net 20 correspond to the corresponding regions to be welded, respectively; and performing second solder paste printing on the area to be soldered through the second opening 21, so that the area to be soldered can be subjected to second solder paste printing according to a second preset proportion.

Example 3

In an embodiment of the present invention, based on embodiment 2, the thickness of the second steel net 20 is greater than that of the first steel net 10.

Since the solder paste is dissolved and cured to form a convex surface after the first solder paste printing is performed on the first steel mesh 10, the thickness of the second steel mesh 20 is required to be greater than that of the first steel mesh 10 in order to avoid affecting the effect of the second solder paste printing.

In this embodiment, the thickness of the first steel net 10 is 0.08 mm, and the thickness of the second steel net 20 is 0.12 mm.

Preferably, the first predetermined proportion is between 25% and 35%, within which range the degassing of the first printing solder paste is facilitated.

Further preferably, the first predetermined proportion is 28%, at which the first printing solder paste has an optimum degassing effect.

In this embodiment, the first opening area of the first steel mesh is 0.75 × 9 — 5.0625mm²The area of the grounding pad is 4.3 x 4.3 ═ 18.49mm²The first predetermined ratio is 5.0625/18.49-27.37%.

Preferably, the second predetermined proportion is between 60% and 75%, within which range the degassing of the second printing solder paste is facilitated.

Further preferably, the second predetermined proportion is 65%, at which the second printing solder paste has an optimum degassing effect.

In this embodiment, the second opening area of the second steel mesh is 1.15 × 9 ═ 11.9025mm²The area of the grounding pad is 4.3 x 4.3 ═ 18.49mm²The second predetermined ratio is 11.9025/18.49-64.37%.

In other embodiments, the size and thickness of the first and second steel nets 10 and 20, and the size distribution of the first and second openings 11 and 21 may be adjusted according to the actual size of the PCB ground pad and the tape bonding area.

It should be noted that the above embodiments can be freely combined as necessary. The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.