Small Film Blowing Machine: Complete Molding Principle from Plastic Pellets to Film

Film blowing is a classic process for converting plastic pellets into continuous film. A small film blowing machine fully replicates the entire industrial film blowing process. It is mainly designed for polymer laboratories and new material R&D companies, used for formulation debugging and film sample preparation. It helps R&D personnel quickly verify material blow molding performance and effectively reduces R&D material costs.

The entire film blowing process consists of six continuous stages: melting and plasticizing, tubular extrusion, bubble inflation, air-ring cooling, haul-off and flattening, and automatic winding.

Melting and Plasticizing: Plastic pellets are fed into the hopper and enter the screw barrel. The barrel is heated in zones, and combined with the shear heat generated by screw rotation, solid pellets melt into a uniform plastic melt. A cooling device is installed in the feeding zone to prevent premature heating and sticking of materials. A reasonable screw L/D ratio ensures sufficient plasticizing of various raw materials, making it suitable for micro-scale experimental trials.

Tubular Extrusion: The screw pushes the melt to an annular die, where it is extruded through the die gap to form a high-temperature tubular parison.

Bubble Inflation: Compressed air is introduced into the tubular parison, and the air pressure inflates the parison outward into a cylindrical bubble. By adjusting the inflation pressure, extrusion speed, and haul-off speed, the bubble width and film thickness can be controlled. For materials with good toughness, ultra-thin film samples can be produced.

Air-Ring Cooling: The air ring outputs uniform cold air to rapidly cool the bubble. The polymer melt solidifies and takes shape, ensuring the film's appearance, toughness, and light transmittance.

Haul-off and Flattening: The cooled bubble passes through a collapsing frame and is folded and flattened. Haul-off rollers pull it forward at a constant speed, and together with the inflation pressure, the film thickness is regulated in both directions.

Automatic Winding: The flattened film is fed into the winding mechanism and neatly rolled up, directly producing film rolls ready for performance testing.