Before using a plasma cleaner, read this article first

The operating process of a plasma cleaner is as follows:

(1) The workpiece to be cleaned is loaded into the vacuum chamber of the plasma cleaner and fixed in place. The operating unit is started and pump-down begins, until the vacuum in the chamber reaches a standard vacuum level of about 10Pa. Pump-down generally takes about 2min.

(2) The plasma cleaning gas is introduced into the vacuum chamber and its pressure is maintained at 100Pa. Depending on the material being cleaned, gases such as oxygen, hydrogen, argon or nitrogen can be selected.

(3) A high-frequency voltage is applied between the electrode in the vacuum chamber and the grounding device, causing the gas to break down; the gas is ionized through glow discharge and plasma is generated. The plasma generated in the vacuum chamber fully envelops the workpiece being treated, and cleaning begins. Cleaning typically lasts from several tens of seconds to a few minutes.

(4) After cleaning, the high-frequency voltage is switched off and the gas and vaporized contaminants are exhausted. At the same time, air is admitted into the vacuum chamber and the pressure is raised to one atmosphere.

Plasma is generated mainly by electrons striking neutral gas atoms, dissociating them to produce plasma. However, the nucleus of a neutral gas atom binds its outer electrons with a certain energy, which we call the binding energy. An external electron must have more energy than this binding energy to be able to dissociate the neutral gas atom, but such external electrons often lack sufficient energy and cannot dissociate neutral gas atoms.

Therefore, we must supply external energy to give the electrons energy so that they are able to dissociate the neutral gas atoms. A simple way to supply energy to electrons is to apply a DC voltage across parallel electrode plates. Electrons between the electrodes are attracted and accelerated by the positively charged electrode and accumulate energy as they accelerate. When an electron's energy reaches a certain level, it is able to dissociate neutral gas atoms.