Circuit board tin spraying system and tin spraying method thereof

Abstract

The invention provides a circuit board tin spraying system and a tin spraying method thereof. The system includes a tin furnace, a conveying tin spraying furnace and a leveling device, wherein the conveying tin spraying furnace is disposed in a space corresponding to a tin tank of the tin furnace, the conveying tin spraying furnace has a tin spraying tank and includes a conveying module disposed in a space corresponding to the tin spraying tank, and a tin spraying module connecting the tin tank and the tin spraying tank, when the tin tank contains tin liquid, the tin spraying module can suck the tin liquid from the tin tank and spray the sucked tin liquid in the tin spraying tank, so the tin spraying tank is filled with the tin liquid to form the tin liquid environment, a substrate can beunidirectionally pulled by the conveying module to pass through the tin liquid environment to make the tin liquid infiltrate the substrate, and the leveling device is configured to spray hot liquid tothe substrate as the substrate is drawn out of the tin liquid environment to pass through the leveling device.

Description

technical field [0001] The invention relates to the field of circuit board processing and manufacturing, in particular to a circuit board tin spraying system and a tin spraying method thereof. Background technique [0002] Tin spraying on circuit boards is an important part of the circuit board process. Spraying a layer of tin on the surface of the printed circuit board (PCB) can not only prevent the oxidation of the copper surface on the surface of the printed circuit board pad, but also enhance the conductivity and solderability of the printed circuit board pad, thereby improving the solderability of the printed circuit board pad. performance of the circuit board. [0003] As a common surface coating form of circuit board surface treatment, the tin spraying process is widely used in the production of circuit boards. The flatness and uniformity of the tin spraying on the circuit board directly affect the quality and solderability of soldering during subsequent production,...

AI Technical Summary

Problems solved by technology

That is to say, the lower end of the circuit board pad first enters the hot tin pool but is finally away from the hot tin pool. Since the upper and lower ends of the circuit board pad contact the hot tin at different times, the circuit board pad The upper and lower ends of the circuit board are heated unevenly, which affects the uniformity of the tin spraying of the circuit board, such as the uniformity of the thickness of the tin layer at both ends of the circuit board pad and the uniformity of the bonding force between the tin layer and the pad, and may affect the damage to the circuit board

[0005] Furthermore, during the process that the circuit board is taken out of the hot tin pool vertically upwards, the tin on the surface of the soldering pad of the circuit board to which a layer of tin is attached is not completely cooled and unstable and has plasticity. The cooled tin liquid flows down under the action of gravity and affects the uniformity of the thickness of the tin layer at both ends of the circuit board pad. In the prior art, the tin surface that is not completely cooled is often leveled by hot air, but it is worth noting What is more important is that in order to enhance the bonding force between the tin layer and the pad and ensure the uniformity of the tin layer, the hot air should have a higher uniformly distributed pressure and a suitable temperature, so that the energy consumption of the hot air leveling process is relatively large, and the The control accuracy of the hot air leveling device is strictly required. At the same time, it is understandable that during the hot air leveling process, the excess tin on the surface of the circuit board is taken away by the hot air to form tin particles that diffuse in the air. The tin production environment causes pollution and is not conducive to the personal health of the production environment. On the other hand, tin particles may be oxidized or polluted in the air and fall back into the hot tin pool to pollute the tin liquid in the hot tin pool, thereby affecting tin spraying. process stability

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