CN209806191U

CN209806191U - Improved SMT steel mesh opening structure

Info

Publication number: CN209806191U
Application number: CN201822081661.8U
Authority: CN
Inventors: 张龙; 田友良
Original assignee: Dbg Holdings Ltd
Current assignee: Dbg Holdings Ltd
Priority date: 2018-12-12
Filing date: 2018-12-12
Publication date: 2019-12-17
Anticipated expiration: 2028-12-12

Abstract

The utility model relates to a modified SMT steel mesh open structure, including the steel mesh body, the steel mesh body includes a plurality of BGA openings, a plurality of BGA openings correspond to a plurality of BGA pads on the PCB, the BGA opening is the rhombus, BGA open-ended center with the center coincidence of BGA pad. The beneficial effects of the utility model reside in that: by arranging the rhombic BGA openings and rounding the BGA openings, on one hand, the area of the openings is unchanged, and the transfer rate of solder paste is ensured; on the other hand, two adjacent BGA openings are formed to be opposite in corner, so that a sufficient distance is ensured, a region which is likely to generate continuous tin is reduced, the generation of poor continuous tin is effectively avoided, and the production quality is improved.

Description

Improved SMT steel mesh opening structure

Technical Field

The utility model relates to a SMT template technical field particularly, relates to a modified SMT steel mesh open structure.

Background

With the rapid development of the electronic information product manufacturing industry in China, the Surface Mount Technology (SMT) in China is also rapidly developed. Surface mount technology is a modern circuit board assembly technology, and the process flow mainly comprises: solder paste is coated on one surface to be welded of a Printed Circuit Board (PCB), then the components to be welded are mounted on the corresponding positions of the PCB, reflow soldering is carried out after the mounting of the components is completed, the mounting of the components on one surface of the PCB is completed, and surface mounting can be completed after the inspection is qualified.

In the process of coating the solder paste on the PCB substrate, the amount of the coated solder is a key factor influencing the welding quality, and the amount of the solder is determined by the shape and the size of the opening design of the steel mesh. The excellent steel mesh opening design can ensure good demoulding effect, can not cause welding short circuit, open circuit or produce tin balls, and ensures good hardware connection and welding reliability.

BGA, known as Ball Grid Array (BGA), is formed by making an Array of solder balls on the bottom of a package substrate to interconnect I/O terminals of a circuit to a Printed Circuit Board (PCB). The opening that current steel mesh corresponds BGA is square usually, and when BGA's interval was less, two adjacent open-ended intervals need corresponding dwindling, and square design leads to the interval not enough easily to produce and link the tin bad, influence the PCB quality, lead to PCB to scrap even.

Disclosure of Invention

An object of the utility model is to provide a modified SMT steel mesh open structure can improve the not enough problem of BGA opening interval, improves the production quality.

The utility model provides a modified SMT steel mesh open structure, includes the steel mesh body, the steel mesh body includes a plurality of BGA openings, a plurality of BGA openings correspond to a plurality of BGA pads on the PCB, the BGA opening is the rhombus, BGA open-ended center with the center coincidence of BGA pad.

Preferably, four sides of the BGA opening are tangent to the perimeter of the BGA pad.

Preferably, four corners of the BGA opening are rounded.

Preferably, the radius of the round angle is 0.03mm-0.05 mm.

Preferably, the steel mesh body is a PRO steel mesh.

The beneficial effects of the utility model reside in that: by arranging the rhombic BGA openings and rounding the BGA openings, on one hand, the area of the openings is unchanged, and the transfer rate of solder paste is ensured; on the other hand, two adjacent BGA openings are formed to be opposite in corner, so that a sufficient distance is ensured, a region which is likely to generate continuous tin is reduced, the generation of poor continuous tin is effectively avoided, and the production quality is improved.

Drawings

Fig. 1 is a schematic structural view of the improved SMT steel mesh opening structure of the present invention.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. The preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

As shown in fig. 1, in a preferred embodiment, the improved SMT steel mesh opening structure of the present invention mainly includes a steel mesh body 1, a plurality of BGA openings 2 are arranged on the steel mesh body 1, and the BGA openings 2 correspond to BGA pads of a PCB one-to-one. The BGA opening 2 is diamond shaped with its center coinciding with the center of the BGA pad. Four sides of BGA opening 2 are tangent with the periphery of BGA pad, and four bights of BGA opening 2 all have a fillet, and the radius of fillet is 0.03mm-0.05 mm.

The utility model discloses a set up the BGA opening into the rhombus, it is adjacent to become two angles adjacent with current square open-ended both sides to become the point by the line with the region that probably takes place to link tin, reduced the possibility of linking tin. Four bights of rhombus BGA open-ended are all the radius angles, have increased the distance between the BGA open-ended, further avoid taking place continuous tin.

In this embodiment, the steel mesh body 1 preferably uses a PRO steel mesh, which is a steel mesh coated on the inner wall and bottom (the surface contacting with the PCB) of the steel mesh, i.e. a resin coating is formed on the non-printing surface and the side wall of the steel mesh by means of coating infiltration after the laser template is completed, the film has a repellent effect on organic solvents such as water, soldering flux, etc., and the solder paste particles and the soldering components are not easily adhered to the surface and the bottom of the steel sheet, thereby reducing the frequency of wiping the steel mesh, improving the transfer rate and providing the printing quality.

While the invention has been described in conjunction with the specific embodiments set forth above, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. The utility model provides a modified SMT steel mesh open structure, includes the steel mesh body, the steel mesh body includes a plurality of BGA openings, a plurality of BGA openings correspond to a plurality of BGA pads on the PCB, its characterized in that, the BGA opening is the rhombus, BGA open-ended center with the center coincidence of BGA pad, two adjacent BGA openings form to the bight relative.

2. An improved SMT steel mesh opening structure according to claim 1, wherein four sides of the BGA opening are tangential to a perimeter of the BGA pad.

3. An improved SMT steel mesh opening structure according to claim 1, wherein four corners of the BGA opening are rounded.

4. An improved SMT steel mesh opening structure according to claim 3, wherein the radius of the rounded corners is 0.03mm to 0.05 mm.

5. An improved SMT steel mesh opening structure as defined in claim 1, wherein said steel mesh body is a PRO steel mesh.