Floating particles in the cleanroom concentration, high performance filters can be used to reach the zero level, the actual production site due to contact with dust and substrate operator and machine, mechanical parts surrounding transport material dust, in the manufacture of goods surrounding particles raised slightly, resulting in a clean surface element particle pollution.
The following four basic principles should be observed in the cleanroom to prevent particulate pollution:
One, do not carry
There are no means of carrying particles in a cleanroom.
1) before the operator enters the cleanroom, the machine and parts should be cleaned before they are put into the room.
2) in the cleanroom, people in the dressing room should wear dust-free clothes, hats, shoes, gloves and masks with special conductive fiber material without dust and static electricity.
3) through the use of high speed clean air to remove particles attached to the surface of clothes, the dust chamber can be entered.
4) machines and materials into the cleanroom, should as far as possible in the sealed state into the clean room maintenance room with ultrapure water to clean, the air shower room shower before entering the clean room.
5) a closed safety helmet and a small fan with filter exhaust must be worn on the waist in the dust free room.
Two. Do not produce
At the same time, the dust amount of the second major pollution sources - the manufacturing platform should be controlled at the same time. As the objects are moving, the friction and contact stripping will cause dust, and the particles will occur when the objects are moved. Therefore, in order to minimize the amount of dust to reach the minimum, the following countermeasures should be taken.
1) reduce the action form of contact peeling dust.
2) use the material with small wear and dust;
3) the use of small dust in the lubricating oil;
4) the principle of non - contact work of air - pressure floating is applied to the machine.
Three, not reserve
The cleanliness of the cleanroom can be maintained if "no particles are carried into the workshop". But in reality, the frequent entry and exit of people and goods and the braking of the machine are impossible to have complete cleanliness in the vast undustless room. It is therefore very important that the "non reserve" technology be applied quickly in the filter to remove the particles that have occurred. The normally occurring particles will stay on the surface of the surrounding objects based on the gravity and the electrostatic adsorption. Sudden vibration and unstable airflow can make these accumulative particles rise again in the air and increase the risk of pollution of major particles.
Four, exclude / remove
In the machine which can not avoid many particles, in order not to produce particles in the dust-free chamber, we should do the external exhaust directly, that is, the so-called partial exhaust. The countermeasures are as follows: the introduction of exhaust gas amount is necessary, but will be accompanied by a large amount of energy consumption. So it can't be said to be an absolute ideal. Therefore, as far as possible, we should exhaust the volume as much as possible, and not only go to the dustless outdoor air, but we should adopt the strategy of returning the air after removing particles to the cleanroom chamber.
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