CN110798971A

CN110798971A - Low-cost tin-connection-preventing PCB

Info

Publication number: CN110798971A
Application number: CN201911224844.3A
Authority: CN
Inventors: 满文斌; 杨量
Original assignee: Shenzhen Niuwei Communication Technology Co Ltd
Current assignee: SHENZHEN YOUHUA TECHNOLOGY Co.,Ltd.
Priority date: 2019-12-04
Filing date: 2019-12-04
Publication date: 2020-02-14

Abstract

The invention relates to a low-cost tin-connection-preventing PCB, wherein at least one row or at least one column of welding holes for inserting PIN PINs of components and bonding pads arranged around the welding holes are arranged on the PCB, the bonding pads are of special-shaped structures, and the directions of two adjacent bonding pads are different. The invention avoids the phenomenon of tin connection caused by the close proximity of the adjacent bonding pads when passing through the wave soldering furnace, and the probability of tin connection between PIN PINs of the component can be greatly reduced no matter which direction the component passes through the furnace.

Description

Low-cost tin-connection-preventing PCB

Technical Field

The invention relates to the technical field of USB material packaging, in particular to a low-cost tin connection prevention PCB based on a simple packaging process.

Background

Factors influencing the tin soldering in wave soldering are as follows: flux flow/specific gravity/rosin content also has its activity and temperature resistance, preheating temperature, over-conveying speed, guide rail angle, soldering time, temperature difference between two waves, distance between two waves, waveform, wave crest flow rate, height of two waves, wave crest unevenness, furnace passing direction, too large a pad design, too close a pad design, no tin supporting point, copper content of tin, PCB quality, PCB moisture, environmental factors, tin furnace temperature and the like.

The USB material of simple and easy packaging technology in the market at present, the material design of simple and easy encapsulation is succinct and save the PCB space, but the ubiquitous condition of continuous tin between the PIN foot, when having a plurality of USB on same PCB not on same straight line, only one orientation continuous tin probability is low, other orientation general tin.

Disclosure of Invention

Therefore, it is necessary to provide a low-cost anti-wicking PCB to solve the above-mentioned wicking problem in the prior art.

In order to achieve the above purpose, the invention adopts the following technical scheme.

The invention provides a low-cost tin-connection-preventing PCB, wherein at least one row or at least one column of welding holes for inserting PIN PINs of components and bonding pads arranged around the welding holes are arranged on the PCB, the bonding pads are of special-shaped structures, and the directions of two adjacent bonding pads are different.

Preferably, the pad is oval, and one end of the pad in the length direction is close to the welding hole, and the other end of the pad is far away from the welding hole.

Preferably, in the pads in the same row or column, except for the first and last pads, every two adjacent pads in the rest of pads are parallel to each other and opposite in direction.

Preferably, the first pad extends in a direction away from the second pad; the last pad extends away from the penultimate pad.

Preferably, every two adjacent bonding pads in the rest of bonding pads except the first and the last bonding pads are parallel to each other and are perpendicular to a straight line where the bonding holes in the same row or the same column are located.

Preferably, the first and the last bonding pads are all parallel to the straight line of the bonding holes in the same row or the same column, and the directions are opposite.

Preferably, the blank area between the pads on the PCB is coated with a white oil layer for supporting tin.

Preferably, the component is a USB interface.

Preferably, the PINs of the component PIN are sequentially arranged according to the sequence of VCC, GND, DP and DM.

The invention makes the bonding pads into the special-shaped structure, and makes the directions of the two adjacent bonding pads different, thereby avoiding the phenomenon of tin connection caused by the close proximity of the adjacent bonding pads when passing through a wave soldering furnace, and greatly reducing the probability of tin connection between PIN PINs of the component no matter which direction the bonding pads pass through the furnace. The scheme adopted by the invention does not increase the content of the soldering flux or increase the furnace temperature, so that the soldering flux has the advantages of low cost, high reliability, easiness in implementation and the like.

Drawings

Fig. 1 is a schematic structural view of a PCB board used in a conventional simple packaging process;

fig. 2 is a schematic structural diagram of the low-cost anti-wicking PCB in this embodiment.

The implementation of the objects of the present invention and their functions and principles will be further explained in the detailed description with reference to the attached drawings.

Detailed Description

The following further description is made with reference to the drawings and specific embodiments.

The structure of a PCB board adopted in a currently common simple packaging process is shown in fig. 1, where at least one row or at least one column of solder holes 1 for inserting PIN PINs of a component and a pad 2 disposed around the solder hole 1 are disposed on the PCB board 100, and the pad 2 is substantially in a circular ring shape concentric with the solder hole 1.

When adopting the wave-soldering stove to weld, if cross the stove according to direction one, the probability of continuous tin between the PIN foot is lower, can cross the stove according to direction two, then probably the probability produces continuous tin phenomenon, and this is the common phenomenon in the simple and easy packaging technology, and main influence factor includes: flux flow/specific gravity/rosin content also has its activity and temperature resistance, preheating temperature, over-conveying speed, guide rail angle, soldering time, temperature difference between two waves, distance between two waves, waveform, wave crest flow rate, height of two waves, wave crest unevenness, furnace passing direction, too large a pad design, too close a pad design, no tin supporting point, copper content of tin, PCB quality, PCB moisture, environmental factors, tin furnace temperature and the like.

The invention mainly aims at the current common simple packaging technology to improve the adopted PCB, and the specific scheme is as follows: the bonding pads are made into special-shaped structures, and the directions of two adjacent bonding pads are different.

As shown in fig. 2, the pad 2 'in the present embodiment is designed in an oblong shape, and one end of the pad 2' in the length direction is close to the solder hole 1 ', and the other end is far from the solder hole 1'. Meanwhile, in the pads 2 'in the same row or the same column, except for the first and the last pads 2', every two adjacent pads 2 'in the remaining pads 2' are parallel to each other and opposite in direction.

Thus, when the PCB100 'of the present embodiment is used to replace the PCB of fig. 1, the distance between the pads 2' is indirectly increased, so that no continuous tin phenomenon occurs no matter the PCB passes through the furnace in the first direction or the second direction.

In addition, the arrangement direction of the bonding pads 2 ' is optimized in this embodiment, for example, except for the first and the last bonding pads 2 ', every two adjacent bonding pads 2 ' in the remaining bonding pads 2 ' are parallel to each other and are perpendicular to the straight line where the bonding holes 1 ' in the same row or the same column are located. And the first and the last bonding pads 2 'are all parallel to the straight line of the bonding holes 1' in the same row or column, and the directions are opposite.

Taking fig. 2 as an example to explain as follows, the component of the present embodiment is USB, and has four PIN PINs VCC, GND, DP and DM from left to right, and corresponds to four solder holes 1 'on the PCB 100', and the connection line of each solder hole 1 'is a horizontal line, and is correspondingly provided with 4 pads 2', wherein the length direction of the first pad (corresponding to VCC)2 'is also horizontal, but extends toward the direction away from the second pad 2' (corresponding to GND). The last pad 2 '(corresponding to DM) is also horizontal in length but extends away from the third pad 2' (corresponding to DP). And the second pad 2 'and the third pad 2' have other pads 2 'on both left and right sides thereof, and in order to maximally increase the distance therebetween, the present embodiment sets the extending directions of the second pad 2' and the third pad 2 'to a vertical direction, i.e., a direction perpendicular to the line connecting the solder holes 1', and the extending directions of the second pad 2 'and the third pad 2' are opposite. With the structure design, no matter the PCB100 'is passed through the furnace from the first direction, the second direction or any other direction, the tin connection phenomenon can not be generated, thereby improving the wave soldering yield of the PCB 100'.

It is understood that in other embodiments, the pads 2 'may be designed to have other special-shaped structures, such as an oval shape, a kidney-shaped hole shape, etc., and similar technical effects can be achieved as long as the directions of two adjacent pads 2' are different.

In addition, the blank area between the bonding pads on the PCB is coated with a white oil layer 3' for supporting tin. Therefore, the soldering tin dropped on the white oil layer can not be scattered and adhered, the possibility of tin connection can be further reduced, and the wave-soldering yield is improved.

In conclusion, the bonding pads are made into the special-shaped structures, and the directions of the two adjacent bonding pads are different, so that the phenomenon that tin is connected due to the fact that the adjacent bonding pads are too close to each other when the bonding pads pass through a wave soldering furnace is avoided, and the probability of tin connection between PIN PINs of the component can be greatly reduced no matter which direction the bonding pads pass through the furnace. The scheme adopted by the invention does not increase the content of the soldering flux or increase the furnace temperature, so that the soldering flux has the advantages of low cost, high reliability, easiness in implementation and the like.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Claims

1. The utility model provides a low-cost continuous tin PCB board of preventing, be provided with at least one row or at least one row on the PCB board and be used for pegging graft the solder hole of components and parts PIN foot and set up the pad around the solder hole, its characterized in that: the bonding pads are of special-shaped structures, and the directions of the two adjacent bonding pads are different.

2. The low-cost anti-wicking PCB of claim 1, wherein: the welding pad is oblong, one end of the welding pad in the length direction is close to the welding hole, and the other end of the welding pad is far away from the welding hole.

3. The low-cost anti-wicking PCB of claim 2, wherein: in the pads in the same row or column, except the first and the last pads, every two adjacent pads in the rest pads are parallel to each other and opposite in direction.

4. The low-cost anti-wicking PCB of claim 3, wherein: the first bonding pad extends to a direction far away from the second bonding pad; the last pad extends away from the penultimate pad.

5. The low-cost anti-wicking PCB of claim 3, wherein: except the first bonding pad and the last bonding pad, every two adjacent bonding pads in the other bonding pads are parallel to each other and are perpendicular to a straight line where the welding holes in the same row or the same column are located.

6. The low-cost anti-wicking PCB of claim 4, wherein: the first bonding pad and the last bonding pad are parallel to the straight line where the welding holes in the same row or the same column are located, and the directions are opposite.

7. The low-cost anti-wicking PCB of claim 1, wherein: and white oil layers for supporting tin are coated on blank areas among the bonding pads on the PCB.

8. The low-cost anti-wicking PCB as recited in any of claims 1-7, wherein: the component is a USB interface.

9. The low-cost anti-wicking PCB of claim 8, wherein: and the PIN PINs of the components are sequentially arranged according to the sequence of VCC, GND, DP and DM.