CN110677988A

CN110677988A - Prevent circuit board in pad stifled hole

Info

Publication number: CN110677988A
Application number: CN201910971760.XA
Authority: CN
Inventors: 吕昌荣; 孙明丰; 扬东建
Original assignee: Jiangsu Youwei Vision Technology Co Ltd
Current assignee: Jiangsu Youwei Vision Technology Co Ltd
Priority date: 2019-10-14
Filing date: 2019-10-14
Publication date: 2020-01-10

Abstract

The invention relates to a circuit board for preventing a bonding pad from blocking a hole, which comprises a substrate; laying a copper sheet circuit on a substrate; drilling a hole in the substrate and forming a through hole; an annular welding-assistant layer of a welding pad is arranged at the periphery of the through hole; the circle center of the welding-assistant layer of the bonding pad is superposed with the circle center of the through hole; a notch is formed in one side of the welding-assistant layer of the welding pad; the notch is communicated with the through hole; the length of the gap is 2 mm; the width of the gap is 0.1 mm-0.2 mm. The invention avoids cleaning hole soldering tin when producing welding wire harness, which affects production efficiency.

Description

Prevent circuit board in pad stifled hole

Technical Field

The invention relates to the technical field of components, in particular to a circuit board capable of preventing a bonding pad from blocking a hole.

Background

Wave soldering refers to the soldering of mechanically and electrically connecting the soldering terminal or pin of a component and the pad of a printed board by injecting nitrogen into a solder bath, wherein molten soft solder (lead-tin alloy) is sprayed into the solder wave required by design by an electric pump or an electromagnetic pump, and the solder wave is also formed by injecting nitrogen into the solder bath, so that the printed board with the component mounted in advance passes through the solder wave.

Wave soldering process: inserting the components into the corresponding component holes → pre-coating flux → preheating (temperature 90-100 ℃, length 1-1.2m) → wave soldering (220-.

Fig. 1 is a schematic diagram of a conventional circuit board. As shown in fig. 1, the conventional circuit board includes a substrate 1. A copper wiring 2 is laid on a substrate 1. A through hole 4 is drilled and formed in the substrate 1. An annular pad soldering assistant layer 3 is arranged on the periphery of the through hole 4. The circle center of the welding-assistant layer 3 of the welding pad is superposed with the circle center of the through hole 4. However, the via hole, that is, the hole on the multilayer circuit board, is used only for the purpose of electrically interconnecting layers, and when wave soldering is performed, molten tin drops due to the surface tension of the liquid, and when the solder drops cool, the molten tin turns into solder paste, so that the via hole of the bonding wire is blocked.

Disclosure of Invention

Aiming at the defects of the prior art, the invention discloses a circuit board for preventing a bonding pad from blocking a hole.

The technical scheme adopted by the invention is as follows:

a circuit board for preventing a pad from blocking a hole includes a substrate; laying a copper sheet circuit on the substrate; drilling a hole in the substrate and forming a through hole; an annular welding pad layer is arranged on the periphery of the through hole; the circle center of the welding-assistant layer of the welding pad is superposed with the circle center of the through hole; a notch is formed in one side of the welding-assistant layer of the welding pad; the notch is communicated with the through hole; the length of the notch is 2 mm; the width of the notch is 0.1 mm-0.2 mm.

The method is further characterized in that: and taking a vertical straight line passing through the circle center of the through hole as a y axis, wherein the y axis is parallel to the longitudinal symmetry axis of the substrate.

The method is further characterized in that: and the PCB lead welding input line and the PCB lead welding output line respectively penetrate through the through holes.

The invention has the following beneficial effects:

during wave soldering, in order to prevent the metal full pad from being blocked by tin liquid, the substrate adopts a C-shaped non-full-metalized via hole pad, so that the liquid surface tension of the tin liquid is damaged, and the tin liquid is not easy to form.

Because the liquid surface has tension, when crossing wave-soldering again, the tin liquid can form the bit on still pad surface, and the design of preventing stifled hole pad is just seted up the breach in one side of base plate, and the tin liquid will flow in the opposite direction of breach, prevents that the tin liquid from plugging up the through-hole because tension forms the bit on the surface of base plate.

The invention avoids cleaning hole soldering tin when producing welding wire harness, which affects production efficiency.

Drawings

Fig. 1 is a schematic diagram of a conventional circuit board.

FIG. 2 is a schematic diagram of the present invention.

In the figure: 1. a substrate; 2. a copper clad circuit; 3. a welding-assistant layer of a welding pad; 4. a through hole; 5. and (4) a notch.

Detailed Description

The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings. Directional terms as referred to in the following examples, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Therefore, the directional terminology used is for the purpose of describing, but not limiting, the invention, and moreover, like reference numerals designate like elements throughout the embodiments.

The following describes a specific embodiment of the present embodiment with reference to the drawings.

FIG. 2 is a schematic diagram of the present invention. As shown in fig. 2, a circuit board for preventing pad plugging includes a substrate 1. A copper wiring 2 is laid on a substrate 1. A through hole 4 is drilled and formed in the substrate 1. The PCB lead bonding input line and the PCB lead bonding output line pass through the through holes 4, respectively. An annular pad soldering assistant layer 3 is arranged on the periphery of the through hole 4. The vertical straight line passing through the center of the through hole 4 is taken as the y axis. The y-axis is parallel to the longitudinal symmetry axis of the substrate 1, i.e. the longitudinal symmetry axis of the substrate 1 and the y-axis do not coincide. The circle center of the welding-assistant layer 3 of the welding pad is superposed with the circle center of the through hole 4. One side of the welding-assistant layer 3 of the welding pad is provided with a gap 5. The notch 5 communicates with the through hole 4. The length of the gap 5 is 2 mm. The width of the gap 5 is 0.1 mm-0.2 mm.

During wave soldering, in order to prevent the metal full pad from being blocked by the tin liquid, the substrate 1 adopts a C-shaped non-full-metalized via pad, so that the liquid surface tension of the tin liquid is damaged, and the tin liquid is not easy to form.

Because the liquid surface has tension, when crossing wave-soldering again, the tin liquid can form the bit on still pad surface, and the design of preventing stifled hole pad is just seted up breach 5 in one side of pad layer 3, and the tin liquid will flow in the opposite direction of breach 5, prevents that the tin liquid from blocking up through-hole 4 because tension forms the bit on the surface of base plate 1.

The foregoing description is illustrative of the present invention and is not to be construed as limiting thereof, the scope of the invention being defined by the appended claims, which may be modified in any manner without departing from the basic structure thereof.

Claims

1. The utility model provides a prevent circuit board of pad stifled hole which characterized in that: comprising a substrate (1); laying a copper sheet circuit (2) on the substrate (1); drilling a hole in the substrate (1) and forming a through hole (4); an annular welding-assistant layer (3) of a welding pad is arranged on the periphery of the through hole (4); the circle center of the welding-assistant layer (3) of the welding pad is superposed with the circle center of the through hole (4); a notch (5) is formed in one side of the welding-assistant layer (3) of the bonding pad; the notch (5) is communicated with the through hole (4); the length of the gap (5) is 2 mm; the width of the notch (5) is 0.1 mm-0.2 mm.

2. The circuit board for preventing pad plugging according to claim 1, wherein: and taking a vertical straight line passing through the circle center of the through hole (4) as a y axis, wherein the y axis is parallel to the longitudinal symmetry axis of the substrate (1).

3. The circuit board for preventing pad plugging according to claim 1, wherein: the PCB lead welding input line and the PCB lead welding output line respectively penetrate through the through holes (4).