Key Installation Points: ABA Blown Film Machine

As core equipment for producing three-layer functional films with ABA structure, its installation specifications directly determine film layer thickness uniformity, mechanical properties and production stability. Installation shall strictly follow the workflow: pre-installation preparation → core system positioning → precision calibration → connection & commissioning. Key points are specified below:

First, pre-installation preparation, the foundation to avoid rework. The site must meet load-bearing requirements. The total weight of the main unit and co-extrusion system generally ranges from 5 to 15 tons. The ground shall be hardened with bearing capacity ≥10 tons per square meter, and horizontal deviation controlled within 0.05 mm/m, calibrated longitudinally and transversely via precision level gauge. Power and fluid supporting facilities shall comply with standards: three-phase five-wire power supply with voltage fluctuation within ±5%, and rated power matching heating and load demands of the machine. Compressed air shall be dried and degreased with stable pressure of 0.6–0.8 MPa. Cooling water temperature shall be lower than 30°C, with sufficient flow for die and barrel cooling. Conduct inspection upon delivery for key components: check that screws and barrels of three extruders for outer A layers and middle B layer are free of collision damage; co-extrusion distributor flow channels are smooth without scratches; die sealing surfaces remain intact; thermocouples, heater bands and other accessories are complete.

Second, precise positioning of main unit and co-extrusion system, critical for consistent layer thickness. The three A/B extruders shall be arranged in parallel with identical center height, to prevent pressure difference of melt inside the distributor and uneven core layer flow. Adopt laser alignment instrument to ensure the connecting centerline of three extruders coincides with die axis within a tolerance of 0.2 mm. Anti-vibration rubber pads shall be fitted under anchor bolts to absorb operational vibration and avoid positioning shift that affects layer thickness ratio during running.

Third, core calibration of die and air ring, which directly governs bubble stability. Flow channels of the ABA three-layer co-extrusion die must be aligned; coaxiality deviation of upper A layer, middle B layer and lower A layer channels shall be limited within 0.1 mm; otherwise core layer offset and film delamination will occur. The dual-lip air ring must be concentric with the die, with annular gap uniformity deviation ≤0.1 mm. The distance between air ring and die lip is adjusted to 20–50 mm (fine-tuned according to film thickness), ensuring even cooling air distribution and eliminating thickness fluctuation caused by bubble oscillation. Meanwhile, calibrate the temperature control system of each die section; thermocouple accuracy shall reach ±1°C to avoid poor melt plasticization due to uneven heating.

Fourth, connection and pre-commissioning of auxiliary systems. Screen changers, traction units and winders shall be coaxial with the main machine, and traction rollers parallel to extrusion direction to guarantee flat winding. Online thickness gauges and tension sensors require on-site calibration, with tension control accuracy of ±2 N to prevent loose winding or hard rolls. Inspect tightness of screw cooling and barrel heating systems to eliminate risks of melt leakage and cross-flow.

Fifth, no-load and loaded commissioning. Run under no-load condition for 30 minutes first, check all motors for abnormal noise, and conduct air tightness test for melt channels with compressed air. Then feed raw materials for trial extrusion, adjust rotation speed of each extruder to match layer thickness ratio, stabilize melt pressure and eliminate cross-flow and uneven distribution. Gradually increase load, regulate air ring airflow and traction speed.

After the film bubble stabilizes, fine-tune extruder parameters via online detectors to achieve thickness deviation ≤±2% and meet film performance requirements. Every calibration record shall be kept throughout standardized installation procedures to lay a solid foundation for stable long-term production.