The industrial cleaning consists in the preparation of the surface toward further specific treatments, or the last finishing step before packing and sale.
In detail, the industrial cleaning is a process composed of one or more operations for removing any kind of contaminants (organic and/or inorganic) from the surface of industrial components according the required cleaning degree. It is a combination of chemical and physical actions and interventions (mechanical, thermal and electrical), which have a precise function in the cleaning process.
The following phases are part of the industrial cleaning process:
Pre-cleaning
Cleaning
Rinsing
Drying
The cleaning agents that are normally used in surface treatments for the removal of contaminants could be divided into two groups of chemical products:
- Detergents, products generally in aqueous solutions with a chemical-physical action on the contaminant provoking its detachment from the surface and preventing redeposition;
- Solvents, products that che interagiscono con il contaminante, consentendone la solubilizzazione.
A clearer distinction is a classification of the agents used on metals surface treatment:
- Solvent cleaning (no water);
- Aqueous cleaning (detergents in water);
- Mixed cleaning solution (mix of solvent and detergent).
In the surface treatment of metals, it is very important to know exactly the nature and behaviour of the surfaces that will be involved in the process of cleaning of metals, in respect of substances used to clean them. This will allow to optimize the choice of the working cycle and of products necessary to wash the metals.
Each material has, with regard to these substances, a proper reactivity that must be known to the user in order to avoid, or control, the possible chemical attack of the surface by the substances during the processes of degreasing metals. This chemical attack, if uncontrolled, can lead to the fragility of the surface of the material or to its consumption for removing material during the washing of metals.
In this regard, cleaners have to follow specific requirements:
- Good ability for removing contaminants;
- Good penetrating power, for eventual cavities and/or interstices of the part;
- Good chemical stability, to avoid undesired reactions during the cleaning process, to avoid eventual corrosions of the machine;
- Low environmental impact.
Why ultrasonic cleaning?
The ultrasound are composed by sound waves with a frequency beyond the limit of human hearing, that is more than 16000 Hz. The diffusion of such waves in the cleaning liquid originates compressions and rarefactions that generate the phenomenon of cavitation, in other word the formation of millions of small bubbles that are made and destroyed at a very high speed. These formation and implosions of the micro-bubbles, or empty cavities, make the cleaning through their high pressure (beyond 1000 atm)and the attack to the impurities at a molecular level.