Compressed air pressure for blow molding

In the blow molding process, the compressed air pressure typically ranges from 0.2 to 1.0 MPa. The specific value needs to be dynamically adjusted according to the type of plastic, the temperature of the parison, the structure of the product and the process requirements. The oil-free water-lubricated air compressor has become the key equipment to ensure the quality of blow molding by providing clean oil-free compressed air. Its technical characteristics and pressure control logic are as follows:

1. pressure range of the core basis

for

1. most processes in conventional blow molding scenarios
   use a pressure of 0.3 to 0.5 MPa to balance drying efficiency and pattern integrity. For example, purging after the positive photoresist is developed, it is necessary to quickly remove the residual developer through this pressure range, while avoiding the generation of water marks.

2. Precision structure requires
   a low pressure of 0.1~0.2 MPa to prevent photoresist edge peeling or pattern distortion caused by high pressure airflow for grooves or nano-scale patterns with aspect ratio> 10. For example, in an EUV lithography process, low pressure nitrogen can reduce micron-sized particle adsorption.

3. Special process adaptations
   require higher pressure (e. g. 0.6~0.8 MPa) to ensure uniform gas flow coverage, or reduce nitrogen consumption by 20% ~ 30% through pulsed purging (e. g. 0.5 seconds start-stop, cycle 2 seconds) while maintaining drying efficiency.

   1. of

      2. Oil-free Water Lubrication Air Compressor for

   Cleanliness ensures
   that the oil-free water-lubricated air compressor eliminates oil content through water film lubrication, and the oil content of the output gas is extremely low (≤ 0.003 mg/m & sup3;), which meets the strict requirements of blow molding on air quality and avoids surface defects or performance degradation caused by oil pollution.

4. Pressure stability
   This type of equipment uses permanent magnet frequency conversion technology to adjust the speed in real time to match changes in gas demand. For example, when the pressure fluctuation is detected to exceed ± 0.02 MPa, the system automatically starts the standby compressor or adjusts the opening of the pressure reducing valve to ensure the stability of the blow molding pressure.

5. part of the equipment in the multi-stage pressure gradient design
   adopts the combination of the main nozzle (0.4~0.5 MPa) and the auxiliary annular micropore (0.2~0.3 MPa) to form a laminar boundary layer through the pressure difference, accelerate the peeling of the liquid film while reducing eddy current interference, and improve the drying uniformity by more than 30%.

   1. 3. Key Considerations for

   Plastic characteristics and parison state
   low melt viscosity, easy deformation of plastics (such as LDPE) need lower pressure (0.2~0.4 MPa), and higher melt viscosity of plastics (such as HDPE) or thick-walled parison need higher pressure (0.4~0.7 MPa).

6. Product structure complexity
   Large volume products (such as G10.5 glass substrate) need higher pressure (0.4~0.5 MPa) to ensure the uniformity of airflow coverage; Three-dimensional structures (such as TSV through holes) need low-pressure pulse purging to avoid uneven drying caused by airflow vortex.

7. Cleanliness and particle control
   The purity of compressed air should be ≥ 99.999 (5N grade) to prevent impurities from contaminating the photoresist. The oil-free water lubrication air compressor can effectively isolate external particles through a closed water circulation system, and cooperate with a terminal filter (such as a 0.01μm filter element) to ensure that the cleanliness of the purge gas meets the requirements of Class 1 clean room.