Removing Water Spots and Water Droplets
Removing water spots and water droplets from precision parts is a specialized niche in the world of precision cleaning. In many manufacturing environments, aqueous cleaning is used for gross, general cleaning. Among the final process steps, the excess water can be removed with powerful air knives and/or heat. However, occasionally the water removal process does not achieve the required quality. In these instances — photonic devices are a common example — “solvent drying” is used to remove the water, any residual contamination, and to prevent water spots from forming. Removing water spots and water droplets requires a solvent that either (a) is hydrophobic (does not mix with water) and is of sufficient density that it can displace the water, which is called displacement drying, or (b) the solvent is hydrophilic and absorbs the water into the solvent. These are two entirely different methods with different chemistries and costs. Absorption works well when the quantity of water is small; displacement cleaning is a better option for very wet applications.