What Is A Blown Film Machine?

A A blown film machine is a plastic processing device that heats and melts plastic particles, which are then blown into thin films. At its core, it converts plastic particles into uniform melt, which is then blown into tubular film坯料 (thin film billets) with high-pressure air, which are then cooled, molded and coiled to produce finished films.The following is explained from four aspects: working principle, core components, application field and technical classification.
Principles of work
Plastic Plasticization: Plastic particles enter the the extruder tube from the hopper and are pushed forward along the tube by a rotating screw. The plastic pellets are heated by a heating ring outside the barrel, while the shear heat from the screw rotation gradually melts the pellets into an even melt.
Film Extrusion: The plasticized melt is pushed into the die head by screws and squeezed through the annular gap between the die and the mandrel to form tubular thin film blank.
Expansion and cooling: Tubular film billets extruded from the die head are rapidly cooled and molded with cold air blown from the air ring above the die head. At the same time, a certain amount of compressed air is introduced into tubular thin film billet, which inflates radial to reach the required film width and thickness.
Traction and coiling: The cooled and shaped film is pulled from the die's head by a coiling roller, conveyed upward at a certain speed, and eventually coiled.
Core Components
Extrusion System: comprised of motor, screw and barrel, responsible for the conveyance, melting and extrusion of plastic particles.
Die Head: determines the shape and size of the film and is a key component of the extrusion system.
Cooling System: mainly composed of cooling air ring and blower, responsible for cooling and forming film.
Haul-off System: includes reel and guide rolls, is responsible for reel and transport film.
Electrical control system: such as frequency converters, PLC controller, etc., responsible for automatic control and parameter adjustment of equipment.
Application areas
The film produced by blow-dryer has the characteristics of excellent barrier properties, freshness, dampness, antifreeze, oxygen isolation and oil resistance. It is widely used in the following fields:
Food packaging: such as fresh fruit, meat products, kimchi, fresh milk, liquid beverage packaging.
Daily Necessities Packaging such as supermarket shopping bags,保鲜袋 (plastic bags), garbage bags, etc.
Agrofilm: such as greenhouse films, mulch films, etc..
Industrial applications: such as production of waterproof, moisture-proof, sound-proof materials.
Technical Classifications
By Extrusion Method: can be divided into single screw and twin screw blow film machine. Single-screw film blower has simple structure, low cost and is suitable for small-scale production. Twin screw film blower has good plasticization effects and high production efficiency and is suitable for large-scale production.
By Film Application: can be divided into agricultural blown film machines, packaging blowing machine and industrial blown film machines. The films produced by the agricultural blower are mainly used in agricultural mulch and greenhouses; the films produced by the packaging blower are used in the packaging of food and household goods; and the films produced by the industrial blown film machines are used in various industrial applications.
By Material Type: can be divided into PE blowing film machine, POF blown film machines, PVC blown film machines. PE blown film machines is suitable for the production of low density polyethylene (LDPE) and high density polyethylene (HDPE) films, POF blown film machines is suitable for the production of multilayer coextruded multilayer co-extruded polyolefin heat-shrinkable films, and PVC blown film machines is suitable for the production of polyvinyl chloride (PVC) films.