Tinning method for SMD stamp-mounting-paper diode

Abstract

The invention relates to a plating method, in particular to a tin plating method of an SMD surface mounting diode, which comprises removing oxide films on the surface of the pins of the SMD surface mounting diode with sulfuric acid solution, cleaning the pins of the SMD surface mounting diode through adopting a multi-stage back rinsing device, placing the cleaned SMD surface mounting diode into methanesulfonic acid solution with 3-5% concentration, removing the oxide films generated on the surface of the pins to expose metal crystalline structures on the surface of the pins, placing the SMD surface mounting diode into an electroplating bath which holds electroplating solution to electroplate for 1.5-2 hours, and adopting 25-35 DEG C temperature when in the electroplating, wherein the electroplating solution is mixing solution which comprises methanesulfonic acid, tin methanesulfonic acid and methanesulfonic acid additive. The invention provides a tin plating method of the SMD surface mounting diode, which can increase the product quality and electroplating efficiency, and can prevent the tin plate layer from growing tin beards.

Description

technical field [0001] The invention relates to an electroplating method, in particular to a tinning method for SMD patch diodes. Background technique [0002] In the electronics industry, diodes have become the basic components of various electronic products. Traditional diodes have a pin at each end. When using it, you need to insert the pins of the diode into the holes on the circuit board so that the diode can be fixed in the circuit. board. However, at present, electronic products such as telephones, televisions, fax machines, computers and computer peripheral products all over the world are researched and developed with thinness, lightness and smallness as their research and development goals. Multi-layer circuit board technology cannot punch holes like traditional single-layer circuit boards, so the diode volume is required to be as small as possible. In order to adapt to the trend, some people invented SMD diodes (such as SMD series SMD diodes). Chip diodes are fi...

AI Technical Summary

Problems solved by technology

The coating is easy to change color and grow tin whiskers when the product is stored for a long time

[0004] Sulfate has poor oxidation resistance within the process temperature range. When the electroplating temperature is high, it cannot inhibit the formation of tetravalent tin, and the plating solution is easily turbid and inconvenient to maintain.

[0005] Sulfate has high acidity and high corrosiveness, not only highly corrosive to components, but also very harmful to operators

In addition, the wastewater treatment of highly acidic sulfate discharge is also very difficult

[0006] Therefore, due to the defects of the performance of the plating solution itself and the problems of environmental pollution, it has been unable to meet the current product quality requirements and environmental protection requirements.

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