Thanks to the benefits of dry ice, cryogenic cleaning is increasingly used in the automotive sector for the preparation of plastic surfaces prior to painting.
In this application, dry ice is used with a particle size ranging from 50 to 300 microns and is known as “carbon dioxide snow” or snow blasting.
The System
The cryogenic cleaning system consists of a control unit containing all the equipment required for the control and regulation of liquid CO₂ and compressed air.
The liquid CO₂ is fed through the blasting gun with an ejection speed of approximately 520 m/s.
Inside the nozzle, there is an expansion chamber where the liquid CO₂ partially transforms into solid and partially into gas. The solid phase is dry ice in the form of flakes, which is projected onto the plastic component to be cleaned using dried and oil-free compressed air.
The entire system is housed inside a negative-pressure cabin equipped with an extraction and filtration system. Outside the system, a cryogenic storage tank for liquid CO₂ (-20°C at 20 bar) and a CO₂ conditioning unit are installed. This unit transforms the liquid CO₂ from cold to warm conditions (10/15°C at 50 bar). The CO₂ injected into the expansion and blasting nozzle is therefore at room temperature.
The kinetic action of the carbon dioxide snow, the rapid sublimation of the flakes, and the thermal shock generated by their low temperature combine to clean the component and activate the plastic surface for the subsequent painting process.
L’operazione è estremamente veloce: si trattano circa 2 m2/min (la dimensione paraurti anteriore e posteriore di una berlina media), in 1 minuto circa. L’operazione di pulizia è gestita da un robot antropomorfo a 6 gradi di libertà programmato con le varie ricette di preparazione per i singoli manufatti.
The cleaning system is designed to operate continuously 24 hours a day, 6 days a week. It can, of course, be customised according to the customer’s cleaning requirements, component dimensions, and production needs.L’impianto di pulizia è progettato per lavorare 24 h su 24 per 6 giorni la settimana in continuo. Ovviamente può essere personalizzato secondo le esigenze di pulizia, di dimensione dei manufatti e di produzione del cliente.
