Solvent cleaning is a process of cleansing using chemical solutions so that unwanted paint, coatings, residue, oil, and grease from a material’s surface are removed. Solvents are of multiple types and each of them is suited for particular base materials.
The process of solvent cleaning is used for multiple purposes. Before giving a coating, a substrate must be free from all dirt. To take a simple example, solvent cleaning can be similar to using acetone for removing your nail polish. Various contaminant removal requires different types of solvents. Mostly, solvent cleaning is used to clean the oil left after mass production or to remove the coating incorrectly applied or damaged before the next coating was applied.
Various solvents are commercially available. The most complex solvents are usually hydrocarbon solvents like benzene and turpentine. Mostly, benzene is used in the removal of paint. Solvent cleaning also makes use of oxygenated solvents. They are affordable and simpler than the usual hydrocarbon solvents. Some common oxygenated solvents are ketones, acetates, and alcohols. Halogenated solvents are chlorinated hydrocarbon solvents.
Water is considered to be the solvent abundantly found in nature without much impact on the environment. However, the impact depends on the contaminant type that is to be removed. However, water is not categorized into the group of solvent cleaning. When water is used as a solvent for cleaning methods, it is regarded as an aqueous cleaning process, which is different from a solvent cleaning process.
While using water-based cleaning, soils such as hydrocarbons may not dissolve in the provided water baths, which shows its limited efficiency. The same happens with fluxes and oils too. You have to add chemicals and detergents to improve cleaning efficiency. The wastewater has to be pretreated as well. Another problem is that aqueous solvents may have negative reactions to the part that has to be cleaned, leading to corrosion, rust, or other damages.
Solvent cleaning is mostly executed in a vapor degreaser and makes use of specially prepared cleaning fluid. They are effective in cleaning electronic and mechanical parts that have sophisticated geometrics. The residue in solvent cleaning will be zero. It can also clean high volumes of sophisticated parts fastly. It is also ideal to clean sensitive parts that require a drying process of low temperature.
Solvent cleaning is faster and it significantly cuts down the cycle time. The cycle times are extremely high while using water-based solvents. It is mainly because the parts have to be washed, thoroughly rinsed, and then dried. These stages will have a time lag amidst them. Solvent cleaning just takes minutes or seconds to complete the process as everything will be in a contained system. The parts will be then ready for adhesion or plating.
Old cleaning solutions such as n-propyl bromide, trichloroethylene, and hydrochlorofluorocarbons had various safety and environmental issues. However, modern chemistry could overcome a lot of these challenges. Various fluids were specially created to blend sustainability with robust cleaning performance along with a high margin for the safety of workers.