How it works ?
Generally speaking, dry ice blasting is a combination of 3 effects:
Kinetic effect:
When dry ice particles hit a surface at the speed of sound, the contaminant cracks.
Thermal effect:
The low temperature of dry ice (-78.5 ° C) makes the contaminant fragile, it peels off: the bond between the coating and the underlying surface is reduced.
Explosive effect or sublimation:
Dry ice is projected using compressed air and dry ice blasting machines.
Dry ice penetrates into the cracked and peeled contaminant, and immediately sublimes (change from solid to gaseous state in a ratio of 1 to 400): an “explosive effect” occurs and blows the contaminant off the surface.
By blasting dry ice particles onto hard contaminants such as paint, varnish… the process produces a compression wave between the coating (contaminant) and the substrate (surface). This wave has sufficient power to break the cohesion and detach the contaminant, which by gravity ends up on the ground.
For malleable or viscous contaminants like oil, grease or wax, the cleaning action is a process comparable to high-pressure cleaning. As the particles hit the surface, they are compressed and flattened, producing a high-speed 360 ° spray that cleans surfaces.
​
​
Does dry ice cleaning damage the surface?
The decohesion or detachment of the contaminant takes place at a certain energy threshold. When the decohesion threshold is lower than the damage threshold, you can clean without danger. When it is higher, you might damage the surface.
The hardness of dry ice is comparable to that of chalk.
Since the majority of parts cleaned with COâ‚‚ are production equipment (cast iron, steel, stainless steel, aluminium) there is no damage. You can also clean more fragile substrates (surfaces) such as plastics, electronic boards, monuments, copper, fabrics, etc.
A preliminary test will make it possible to define the feasibility of the dry ice cleaning project.
Example of application not recommended:
Stripping a marine-grade varnish on soft wood (pine, fir): the pressure necessary to loosen the varnish from the wood.
​
What kind of applications has dry ice cleaning proven to be very effective?
The advantages of cleaning in place and the sublimation of the blasting media makes dry ice cleaning very effective in industries/applications including:
General Maintenance of Machines & Production lines • degreasing chains • cleaning conveyor systems • renovating printing presses • cleaning of glue modules (paper industry) • paint stripping • removal of resin • control panels and fans • …
Automotive & Aerospace Industry • removing weld slag from robots • cleaning tyre moulds • reconditioning motor blocks • cleaning engine parts • …
Plastic and Foundry Industry • cleaning of injection moulds • cleaning of extrusion moulds • cleaning of casting moulds • foundry core boxes • …
Food Industry • cleaning of tanks & silos • cleaning of industrial ovens • cleaning of forms (pastry, waffles, …) • cleaning of production lines (chocolate, …)
​
​
What happens to the contaminant?
The contaminant can be solid, viscous or liquid (paint, carbon deposit, glue, grease, sugar, ink, dirt, …). Solid contaminant will be blown away during blasting and fall down close by. Viscous or liquid contaminant will loosen and pulled forward by the blasting air force. The operator can direct the contaminant in a certain direction. In specific cases the contaminant is removed in a controlled way with an extraction system.
​
​
How does dry ice blasting compare to other methods?
Sandblasting works like a chisel, but dry ice blasting works like a spatula. The sand cuts or chisels the contaminant, while the dry ice lifts it after loosening it.
In addition, sandblasting generates a lot of dust, and it is generally not possible to clean in place.
​
The advantages of dry ice blasting as compared to other blasting methods with sand or grit are:
Time saving
Cleaning in the production environment
No need to strip down the production machines
Short or no production stop
Fast cleaning method Powerful but less aggressive
Leaves the base material intact
Suitable in food industry
Pellets do not conduct electricity
Environmentally friendly
Generates no additional waste
No decontamination nor disposal of blasting media needed
​
​
What kind of applications are not suited for dry ice cleaning?
There are three categories of applications where dry ice cleaning is not the right technique:
The base material is too soft and can be damaged by the high impact of the pellets. Examples are soft wood and some softer plastics.
Thick coatings of very hard material that have a strong bond with the underlying material. Examples are baked-on enamel on cast iron, some primers on car parts, …
Soft contaminants, like oil, tend to splatter and may require special procedures or collection system.