What are the types of traction systems for Dalian blown film units?

As an important equipment in the modern plastic processing industry, the blown film unit has continuously improved and expanded its technical level and application scope. With the advancement of technology and changes in market demand, blown film units will continue to develop towards high efficiency, energy saving, intelligent control, multifunctionality, and environmentally friendly materials, providing more advanced and reliable solutions for the production and application of plastic films.

The blown film unit is widely used in various fields such as packaging, agriculture, construction, electronics, etc. In the field of packaging, various specifications of plastic packaging bags, cling film, shrink film, etc. can be produced; In the field of agriculture, it is used to produce agricultural film, greenhouse film, etc; In the field of construction, waterproofing membranes, insulation films, etc. can be manufactured; In the field of electronics, we can produce packaging films for electronic components.

What are the types of traction systems for Dalian blown film units?

Classified by traction method

Upward traction: The traction device is located above the blown film unit. After being extruded from the die, the foam is inflated upwards and then pulled by the traction roller above. This method is suitable for producing films with larger widths and thicknesses, which can cause the film to naturally sag under the action of gravity, facilitating the cooling and shaping of the film, and improving its quality and stability. The common three-layer co extrusion rotary traction blown film machine often uses the upward traction method.

Lower traction: The traction device is located below the blown film unit. The film bubble is extruded from the die and first inflated downwards, and then pulled by the traction roller below. The downward traction method occupies a small area and has a relatively low equipment height, making it suitable for producing thin films with small widths and thicknesses. It is widely used in some small blown film units.

Classified by the structure of the traction roller

Rubber roller traction: The surface of the traction roller is made of rubber material, which has good elasticity and friction, and can effectively clamp the film to prevent it from slipping during the traction process. Meanwhile, the rubber roller causes minimal surface damage to the film and is suitable for pulling various types of films, such as LDPE, LLDPE, and other plastic films.

Steel roller traction: The traction roller is made of steel material with high surface hardness and strength. Steel roller traction is suitable for pulling thick and high-strength films, such as HDPE films. In some high-speed blown film units, steel rollers are also used for traction in order to withstand high traction tension. In addition, the surface of the steel roller can be treated with chrome plating to improve its wear resistance and corrosion resistance.

Wheel traction: composed of two opposing rollers, the traction of the film is achieved by adjusting the pressure and speed between the two rollers. The wheel traction structure is simple, easy to operate, and can effectively control the traction speed and tension of the film. It is commonly used for traction of film products such as drip irrigation tapes.

Track traction: Adopting a track type structure, the film is pulled by the movement of the track. The contact area between the track traction and the film is large, and the traction force is uniform, which can effectively prevent deformation and uneven stretching of the film during the traction process. It is suitable for occasions with high requirements for film quality, such as producing high-precision packaging film. However, the track traction structure is relatively complex and costly.

Classified by driving method

Motor driven traction: By driving the traction roller to rotate through the motor, the film is pulled. The motor drive method has the advantages of wide speed range, high control accuracy, and stable operation, and can accurately adjust the traction speed and tension according to production needs. Common types include AC motor drive and DC motor drive. Nowadays, the application of variable frequency speed regulation technology is becoming increasingly widespread, which can further improve the energy-saving effect and control performance of motors.

Torque motor driven traction: The torque motor has the characteristic of automatically adjusting the output torque within a certain range, and can automatically adjust the traction torque according to the tension changes of the film, maintaining the stability of the film tension. This driving method is suitable for situations that require high tension control of thin films, such as in the production of some composite films and stretch films.

Classified by special functions

Rotating traction: The traction device can rotate around a certain axis, causing the film to continuously change direction during the traction process, thereby improving the mechanical properties and thickness uniformity of the film. Rotary traction is commonly used in multi-layer co extrusion blown film units, which can effectively improve the barrier properties and comprehensive performance of the film, and is widely used in packaging fields such as food and medicine that require high film quality.

Correction traction: Equipped with a correction device, it can detect the position deviation of the film in real time and automatically adjust the position or speed of the traction roller to keep the film on the correct running track at all times. The correction traction system can improve the quality of film winding and reduce the generation of waste, which is particularly important in high-speed blown film and wide film production. Common correction methods include photoelectric correction, ultrasonic correction, etc.

The extruder is the core component of the blown film unit, responsible for heating and melting plastic particles and extruding them through molds. Extruders are usually composed of screws, barrels, heating devices, driving devices, etc. The design and material selection of screws have a significant impact on the performance of extruders, and common screw types include single screw and twin-screw.

With the continuous advancement of technology, blown film units are constantly developing in terms of automation, production efficiency, film quality, energy conservation and environmental protection. For example, adopting advanced control systems to achieve automated operations and precise control; Developing efficient cooling technology and traction systems to improve production efficiency and film quality; Apply energy-saving heating devices and motors to reduce energy consumption. At the same time, in order to meet environmental requirements, the blown film unit is constantly exploring the production technology of biodegradable plastic films.