The concentration of floating particles in the clean room can be easily reached to zero level by using a high-performance filter. The actual production site is dusty by the operator, the machine, the peripheral machinery, and the dust of the parts that are in contact with the substrate. A small amount of fine particles are raised around the manufactured product, which causes particle contamination on the clean surface of the component.

How to prevent particle pollution in a clean room? The following four basic principles should be observed:

First, do not bring in

The methods of not carrying particles in a clean room are:

1) Before the operator enters the clean room, the machine and parts should be cleaned before being carried;

2) Those who enter the clean room should wear clean clothes, caps, shoes, gloves, masks, etc. with special conductive fiber materials that do not dust or generate static electricity in the locker room.

3) After passing through the air shower, high-speed clean air is used to remove the particles attached to the surface of the clothes before entering the clean room.

4) Before the machine and materials are brought into the clean room, they should be brought into the clean room front room as much as possible after being cleaned, and then wiped with ultra-pure water, and then enter the clean room after being blown through the air shower.

5) In the clean room, wear a closed helmet and a small fan with a filter attached to the waist.

Second, does not happen

While controlling the largest source of pollution - the amount of dust emitted by people in the clean room, it should also control the amount of dust generated by the second largest source of pollution. As the article moves, the friction and contact peeling will cause dust, and the particles will also occur when the object moves. Therefore, in order to minimize the amount of dust generated, the following countermeasures should be taken:

1) reduce the action pattern of contact peeling and dusting;

2) Using a material that is small in abrasion and dust;

3) using a small lubricating oil;

4) The non-contact working principle of the air compressor floating on the machine.

Third, no reserve

If the "no-carry" technology can be completely implemented, the cleanliness in the clean room can be maintained. However, in reality, the frequent influx of people and articles and the instigation of the manufacturing machine are impossible to have complete cleanliness in the vast clean room. It is therefore very important that the "no reserve" technique is quickly applied in the filter to remove the particles that have occurred. Usually, the particles that have occurred will stay on the surface of the surrounding object depending on gravity and electrostatic adsorption. Sudden vibrations and unstable airflow can cause these accumulated particles to rise again in the air, increasing the risk of significant particle contamination.

In the highest-grade clean room, from the ceiling to the ground, the air completely removing the particles must flow vertically downward at a speed of 0.3-0.4 m/s. This is the value calculated by completely exchanging indoor air and completely filtered air in about 10 seconds. At the same time, the flow of air must also have precise control. In particular, it is necessary to ensure that the flow path of the airflow is unobstructed, because if there is an obstacle in the circulation path, the air vortex is easily generated to form a trapped area of ​​the air, so that the microparticles that have occurred in the vicinity cannot be quickly eliminated and drifted in the clean room for a long time. Some of them will adhere to the surface of peripheral equipment and cause pollution.

Controlling the airflow prevents the accumulation of particles, but the accumulation of particles on the charged surface cannot be prevented.

In order to prevent adhesion of particles due to electrostatic adsorption, a conductive material having a charged degree of several tens of volts or less is usually used in a clean room. For the charging of the manufactured product itself, the conveying form and the contact part material having a small degree of charging are used, and the static elimination device is used to remove electricity.
Fourth, exclude / remove

In a machine that cannot avoid the occurrence of a large amount of fine particles, in order to prevent the generation of fine particles in the clean room, the external exhaust operation is directly performed, that is, the so-called local exhaust. The countermeasure against the exhaust gas is as follows: It is necessary to introduce the same amount of external air, but it is accompanied by a large amount of energy consumption. Therefore, it cannot be said that it is an absolutely ideal countermeasure. Therefore, as much as possible, while compressing the amount of exhaust gas, it is not only to exhaust the dust-free outdoor, but also to take measures to recirculate the air after removing the particles into the clean room.