3. How does plasma work?
In the low-pressure plasma technology, gas is excited by energy supplied in a vacuum. This results in energetic ions and electrons, as well as other reactive particles, which constitute the plasma. Surfaces can then be effectively altered. There are three plasma effects:
Micro-sandblasting: The surface is removed by ion bombardment.
Chemical reaction: Chemical reaction of the ionized gas with the surface.
UV radiation: UV radiation breaks down long-chain carbon compounds.
The effect of the plasma changes by varying the process parameters such as pressure, power, process time, gas flow and composition. Several effects can therefore be achieved in a single process step.
Plasma removes release agents (including silicone and oil) from the surface. These are chemically attacked by e.g. oxygen and converted into volatile compounds. The release agents, or their residues, partially evaporate due to the vacuum and the surface heating. The release agent molecules are broken into smaller molecular fragments by the energetic particles in the plasma and can therefore be extracted. In addition, a "micro-blast effect" is created on an atomic level.
On freshly produced items, as well as on stored products, there are usually invisible deposits such as grease, oil, silicones, moisture and oxidation layers. To flawlessly coat these surfaces, they must be PWIS-free (PWIS = paint-wetting impairment substances), which can be achieved by plasma cleaning.