Aqueous or Solvent? Industrial Cleaning Technology and which is best
There are many industrial cleaning technologies available, the choice between aqueous (water-based) and solvent cleaning depends on several factors, including the type of contamination being cleaned, the type of material being cleaned, and the desired end result. Below are different technologies with their advantages and disadvantages.
Aqueous Cleaning
Ultrasonic Cleaners
Single tanks or complete cleaning lines with cleaning, rinsing and drying stages. The benefit is its versatility for various kinds of applications and contaminations (polar/inorganic contaminants with acid detergents, non-polar/organic contaminants with alkaline detergents).
Advantages of ultrasonic cleaning:
- Many delicate components can be cleaned with this non-abrasive method, ensuring no damage
- Removal of most contamination, down to the smallest dimensions is achieved in ultrasonic cleaning following the correct process
- Typical cleaning cycles range from 1 to 10 minutes, however, some applications can take considerably longer
- Removes a wide range of contaminates, including machining oils & coolants, fingerprints, dust, rust, pigment, dirt, burnt carbon, and flux
- Cleans hard-to-reach areas, such as blind holes and crevices
- Very user-friendly machines with simple operation & typical systems require basic servicing
Disadvantages:
- Achieving a spot-free finish with an aqueous process typically requires several stages. As the systems are modular, an aqueous cleaning line's overall footprint can be much larger when compared to single-chamber solutions.
- Depending on the process, water must be purged and refreshed to maintain water quality, ensuring repeatable results. High water waste and use expected on large systems are to be expected, but we do have smart solutions to minimise water use and waste.
Closed rotary aqueous spray washers
Typically used for maintenance cleaning, a good solution for removing large amounts of heavy contamination, the combination of the mechanical jet spray combined with the correct cleaning detergent can provide an effective solution single-stage solution for components which just require a visually clean and no surface treatment. A good option as a pre-wash before ultrasonic cleaning.
The disadvantages are:
- Typically, not a complete cleaning solution, Impossible to reach difficult surfaces like holes and cavities
- Parts not completely rinses & dried
- Difficult to offer different detergents for various kinds of contamination, multiple stages are required to remove certain contamination.
Aqueous Cleaning Advantages
- Environmentally friendly: Aqueous cleaning solutions are typically less toxic and more biodegradable than solvent-based cleaners.
- Safe for use on most materials: Aqueous cleaners are suitable for cleaning a wide range of materials, including plastics, metals, and ceramics.
- Effective in removing oils, greases, and other water-soluble contaminants: Aqueous cleaning solutions are often used to remove oil, grease, and other water-soluble contaminants.
Aqueous Cleaning Disadvantages
- May not be as effective in removing certain types of contaminants: Some contaminants, such as certain adhesives, are not readily soluble in water and may require a solvent-based cleaner.
- Slower cleaning times: Aqueous cleaning may take longer than solvent cleaning to achieve the same level of cleanliness.
Solvent Cleaning
Open or enclosed vapour degreasers
Immersion cleaning systems originally used with solvents banned nowadays (Trichloroethylene, Freon, nPB ) are now used with low boiling solvents (Methylene Chloride, HFE, etc). They are vertical systems with open tanks for boiling and immersion, a vapour rinse zone, and a cooling zone for drying).
The disadvantages are:
- Higher cost of solvent
- High volumes of solvent waste disposal
- Open tanks with an important volume of solvent evaporating in the working area, even for the automatic enclosed machines (these machines are not sealed and the solvent is very volatile)
- Operator in touch with solvent in the maintenance phases (filters change for
- Difficult to provide the rotation due to the difficulties in manufacturing big sizes for this kind of vertical process
- Not suitable at all for polar/inorganic contaminants (salts, emulsions)
Vacuum chamber parts washers
In completely closed and sealed systems, no solvent vapour is able to escape into the working area, used under vacuum conditions to improve cleanliness and reduce working temperatures.
The disadvantages are:
- Not all manufacturers produce state-of-the-art machines, with complete vacuum conditions, complete distillation and contaminant separation.
- In comparison with aqueous cleaning, it can be harder to clean polar/inorganic contaminants (salts, emulsions). The system must be specified correctly with additional features to ensure optimal results.
Solvent Cleaning Advantages
- Effective in removing a wide range of contaminants: Solvents are often used to clean a wide range of contaminants, including oils, greases, and adhesives.
- Faster cleaning times: Solvent cleaning is often faster than aqueous cleaning in removing certain types of contaminants.
Solvent Cleaning Disadvantages
- May not be safe for use on certain materials: Some solvents can be harmful to certain materials, such as plastics and composites.
- Potentially hazardous to the environment and to operators: Solvents are often toxic and flammable, and proper ventilation and handling is required to minimise exposure.
- May require additional treatment steps: Solvents may require additional treatment, such as distillation or disposal, before they can be safely released into the environment.
In conclusion, the choice between aqueous and solvent cleaning depends on the specific application and desired end result. Aqueous cleaning is a safer, more environmentally friendly option, but may not be as effective in removing certain types of contaminants. Solvent cleaning is faster and more effective in removing a wide range of contaminants, but may not be safe for use on certain materials and can be hazardous to the environment and operators.
