How does no-clean flux ensure that the surface of the circuit board is clean and free of residue after welding?
Publish Time: 2025-04-16
In the modern electronic manufacturing industry, welding is the key link to connect electronic components and circuit boards. As an important auxiliary material in the welding process, the performance of flux directly affects the welding quality and the cleanliness of the circuit board surface. As a new type of environmentally friendly product, no-clean flux has received widespread attention and application due to its characteristics of no need for cleaning after welding and clean and residue-free circuit board surface.1. Composition and design of no-clean fluxThe main components of no-clean flux include activator, film former, wetting agent, solvent, etc. Among them, the activator is the core component of the flux, which can remove oxides on the metal surface during welding and promote the wetting and spreading of the solder. The film former can form a protective film after welding to prevent oxidation and corrosion of the solder joint. The wetting agent can improve the wettability of the solder and make the solder joint fuller and smoother. The solvent is used to dissolve and disperse other components to form a uniform flux solution.The design idea of no-clean flux is to minimize the residue on the surface of the circuit board after welding. Therefore, in the formulation design, a system with low solid content, halogen-free, rosin-free or low rosin will be used. Low solid content means that the flux volatilizes more components and leaves less residue during the welding process. Halogen-free avoids the corrosion and contamination of circuit boards by halogen ions. Rosin-free or low rosin reduces the carbonization residue of the flux during the welding process.2. Mechanism of action of no-clean fluxDuring the welding process, no-clean flux quickly removes oxides on the metal surface through its active ingredients, allowing the solder to smoothly wet and spread on the metal surface. At the same time, the film-forming agent forms a protective film after welding to prevent the solder joints from being eroded by oxygen and moisture in the air. The wetting agent improves the wettability of the solder, making the solder joints fuller and smoother, and reducing the generation of pores and voids.Because no-clean flux uses a system with low solid content, halogen-free, rosin-free or low rosin, it volatilizes more components and leaves less residue during the welding process. These residues are mainly organic solvents in the flux and a small amount of non-volatile active ingredients. They are non-polluting and non-corrosive to the surface of the circuit board, and can evaporate or solidify naturally in a short time.3. Advantages of no-clean fluxEnvironmental protection: no-clean flux does not need to be cleaned after welding, which reduces the emission of wastewater and exhaust gas and reduces pollution to the environment.High efficiency: no-clean flux can significantly improve welding efficiency and quality, reduce solder joint defects and defective products.Economic efficiency: no-clean flux does not require a cleaning process, saves the cost of cleaning equipment and cleaning agents, and reduces production costs.Reliability: no-clean flux has less residue after welding, does not corrode or pollute the circuit board, and improves the reliability and stability of electronic products.Through its unique composition design, mechanism of action and advantages, no-clean flux ensures that the surface of the circuit board is clean and residue-free after welding. This not only improves welding efficiency and quality, but also reduces production costs and pollution to the environment.
