In the SMT electronics manufacturing process, PCBA or circuit board / circuit board water-based cleaning process, how do we balance water-based cleaning and material compatibility issues?
Water-based cleaning needs to be controlled from the cleaning process. The requirements and material factors that affect the cleaning process include circuit density, component height, flux residual composition, reflow temperature, and number of heats before cleaning. Component materials that may be severely affected by the cleaning process include copper-clad layers, surface coatings, plastic parts, components, labels, device identification, metal alloys, coatings, unsealed components, and adhesives. The preparation of components and assembly materials (chemicals used in the process, including cleaning and surface pretreatment processes) can be severely affected by the assembly cleaning process. Chemicals used in processes that may affect the effectiveness of the cleaning process include SMT solder paste, SMT solder flux, wave solder bars, wave solder flux, tin wire for rework, flux, or any other that must be removed during the cleaning process. substance.
Key material compatibility considerations when designing a cleaning process are component, assembly materials, cleaning agents, impact energy applied in the cleaning process, expected process time, temperature, and equipment design. Cleaning factors that may affect the cleaning process include the cleaning agent, the liquid concentration of the tank, the amount of flux introduced, the cleaning equipment, the spray pressure, the fluid flow rate, the speed, and the process temperature. These same factors can affect material compatibility. Since the contaminants accumulated in the tank may come from incompatible materials, it may be necessary to consider the interactions that occur depending on the time of use of the tank.
To ensure the reliability of PCB components, it is required to understand the raw material properties and characteristics of manufacturing electronic components and components. When selecting fluxes, pastes, adhesives, substrates, cleaning materials, conformal coating materials, and other common interconnect materials, identifying the potential negative impact of the cleaning process on the appearance quality or even the entire component structure is fundamental to successful engineering design. in principle. The actual performance of the material can be different from theoretical or expected performance under different conditions. Material properties vary from batch to batch and may affect material compatibility. Factors affecting the actual performance of the material such as cleaning agent, cleaning time, cleaning temperature, amount of cleaning, and impact energy should be tested to understand the interaction between the materials.