How to determine FFU configuration in PCB electronic clean workshop?
Why does the PCB clean workshop need to be partitioned to determine the configuration?
PCB electronic clean workshops are different from single clean level workshops. PCB production includes multiple processes such as inner layer exposure, drilling, outer layer wiring, solder mask, molding, and testing. Different processes have different sensitivity to particles. The exposure area is the most sensitive to particles, the drilling area will generate dust, and the requirements for the auxiliary area are relatively loose.
If the entire workshop determines FFU according to the same configuration, the exposure area may be underprotected and the auxiliary area may be over-configured. Therefore, the FFU configuration of the PCB clean workshop should be determined by partition. First, clarify the cleanliness level and air flow requirements of each process, and then calculate the number and layout of FFU.
Aili Industrial has complete production capabilities in FFU supporting areas in the electronics industry and can provide partitioned configuration solutions based on PCB workshop layout. For the basic structure of the FFU machine, you can refer toAili Industrial FFU fan filter unit。
How does the cleanliness level correspond to the process?
The cleanliness level of the PCB workshop should be determined based on the characteristics of the process. The inner exposure room usually requires higher cleanliness, corresponding to ISO Class 5 or ISO Class 6, and stricter particle control -6. The drilling operation area will generate dust, and is usually equipped with local exhaust and clean air supply, corresponding to ISO Class 6 or Class 7. The outer circuit, solder mask and molding area can be appropriately relaxed-6。
Different levels correspond to different ventilation times. The air change frequency of ISO Class 5 areas is usually designed at a higher value, and the air change times of ISO Class 6 and Class 7 areas are successively lower. The specific value should be determined based on the project process requirements and design specifications.
After the partitions are clear, the FFU requirements can be calculated separately for each area.
How to calculate the quantity using the ventilation rate method
The number of air changes method is a commonly used method for calculating the number of FFU in non-unidirectional flow areas. The basic formula is: the required number of FFU is equal to the workshop volume multiplied by the number of air changes, and then divided by the air volume of a single FFU.
The workshop volume is calculated based on length, width and height. The number of air changes is determined according to the cleanliness level and process requirements. The air volume of a single FFU is based on the actual working air volume, not the maximum air volume on the nameplate.
For example, an ISO Class 6 PCB area may have between 50 and 100 air changes per hour -1. Assume that the area volume is 500 cubic meters and the actual air volume of a single FFU is 1,000 cubic meters per hour. Calculated at 60 times per hour, the required number is approximately 30 units. This is only a preliminary calculation value and needs to be revised in conjunction with the layout.
Which areas is the wind speed method suitable for?
For areas requiring one-way flow protection such as exposure areas, the wind speed method can be used for calculation. The wind speed method is based on the protection area multiplied by the target wind speed, and then divided by the air volume of a single FFU.
PCB exposure areas usually require vertical unidirectional flow protection, and the target wind speed is generally between 0.3 and 0.5 meters per second -4. If the protection area is large, more FFUs need to be deployed to maintain continuous coverage.
The wind speed method is suitable for key protection areas, but it needs to be confirmed whether the FFU arrangement can form a uniform unidirectional flow. There may be weak airflow areas at the splicing boundaries between multiple FFUs and around the lamps, which need to be considered during layout.
How to cooperate with airflow organization
The airflow organization of the PCB workshop needs to cooperate with the process equipment. The exposure area can use FFU plus raised floor air return to form a vertical one-way flow. In the drilling area, local exhaust can be set up near the equipment, and FFU provides clean air supply to bring dust to the exhaust path.
The return air path should avoid being blocked by equipment or materials. If the return air is not smooth, airflow dead zones may form in local areas, affecting particle control.
For areas with limited space or dense equipment, you can refer toUltra-thin FFU and70mm ultra-thin EFU understands compact configuration solutions.
How to choose filtering configuration
Different areas of the PCB workshop have different requirements for filtration efficiency. The exposure zone may require higher efficiency filters, and the auxiliary zone may use conventional configurations. The filter efficiency rating should be determined based on the cleanliness level and process sensitivity.
Different filters have different resistances, which will affect the FFU operating point. When configuring partitions, you should check whether the air volume and static pressure of FFU in each area meet the requirements.
How to consider control methods
The FFU in the PCB workshop can be connected to the group control system and set different speeds or operating modes according to regions. The exposure area requires stable air supply, and the auxiliary area can reduce the rotation speed during non-production periods.
If the project requires partition control, you can refer toFFU/EFU group control touch screen controller andFFU computer group control system understands the control scheme.
Issues that should be confirmed in advance during project communication
During the PCB clean workshop FFU configuration stage, it is recommended to confirm the following with the FFU manufacturer and designer: cleanliness level requirements for each process; area divisions and boundaries; number of air changes or target wind speed; workshop volume and ceiling height; return air path and return air outlet location; filtration efficiency requirements; control methods; whether partition debugging is required.
If you are planning a PCB clean workshop FFU solution, you can visitAili Industrial FFU fan filter unit to learn about the complete machine configuration, you can also contact Aili Industrial to obtain support for air supply solutions in the PCB industry.
in conclusion
The FFU configuration of the PCB electronic clean workshop needs to be determined based on the cleanliness level, number of air changes, workshop volume and air flow pattern. Different processes have different requirements for cleanliness, and the configuration should also be considered in different areas. The air exchange rate method is suitable for non-unidirectional flow areas, and the wind speed method is suitable for unidirectional flow protection areas such as exposure areas. The airflow organization and filtration configuration need to be coordinated with the process equipment.
Aili Industrial has complete production capabilities in FFU supporting areas in the electronics industry and can provide partitioned configuration solutions based on PCB workshop layout. If you need to know more about PCB clean workshop FFU configuration, you can visitAili Industrial FFU fan filter unit , you are also welcome to contact Aili Industrial for project support.
