Matching wind speed and traction speed in PE shrink film production: profound impact on product performance

In the blow molding process of PE shrink film, the cooling of the film bubble is a crucial link. The cooling rate not only determines the solidification speed of the film material, but also directly affects its internal stress distribution and microstructure, which in turn affects the physical properties of the product. As the main means of adjusting the cooling rate, the size and direction of the wind speed have a decisive influence on the cooling effect of the film bubble.
Influence of cooling rate: The appropriate wind speed can quickly take away the heat on the surface of the film bubble, so that it can quickly reach the solidification point and maintain a stable shape. Too slow wind speed may cause uneven cooling of the film bubble, generate thermal stress, and even cause the film material to deform or rupture in subsequent processing. On the contrary, although too high wind speed can accelerate cooling, it may also cause the surface of the film bubble to cool sharply, internal stress concentration, and also affect product quality.
Wind speed and film bubble morphology: Reasonable adjustment of wind speed can also effectively affect the morphological stability of the film bubble. During the blow molding process, the film bubble will be affected by the combined effect of internal gas pressure and external air flow. Appropriate wind speed helps maintain uniform expansion of the film bubble and prevents it from over-expanding in a certain direction, thereby ensuring the dimensional accuracy of the product.

The pulling speed, that is, the speed at which the film bubble is stretched through the pulling device after cooling, is another crucial parameter in the production of PE shrink film. It not only determines the stretching multiple of the film material, but also affects the final size, strength and shrinkage performance of the product.
Influence of stretching effect: The appropriate pulling speed can enable the film material to obtain a good orientation structure during the stretching process, thereby enhancing its mechanical properties, such as tensile strength and tear strength. Too fast pulling speed may cause the film material to break during the stretching process, while too slow pulling speed may cause the film material to relax excessively and reduce its shrinkage performance.
Dimensional stability: Accurate control of the pulling speed is essential to ensure the dimensional stability of the product. During the stretching process, the film material will shrink to a certain extent along the stretching direction. By adjusting the pulling speed, the shrinkage rate of the film material can be accurately controlled to meet the customized needs of different customers.

In the production of PE shrink film, the matching of wind speed and pulling speed is not a simple mathematical relationship, but a dynamic, interdependent synergy. The reasonable matching of the two is directly related to the final performance of the product.
Balance of cooling and stretching: On the one hand, the cooling rate needs to be controlled by adjusting the wind speed to ensure that the film reaches a sufficient degree of solidification before stretching to prevent deformation or rupture during stretching. On the other hand, the pulling speed needs to be adjusted according to the cooling state of the film to avoid breakage caused by too fast stretching or relaxation caused by too slow stretching.
Optimize product performance: By accurately matching the wind speed and the pulling speed, the shrinkage, strength, transparency and durability of the PE shrink film can be significantly improved. For example, when producing film materials that require high shrinkage, the pulling speed can be appropriately increased while the wind speed can be reduced to promote the orientation and shrinkage of the film during stretching. When the production requires high-strength film materials, the wind speed can be increased to speed up the cooling rate while maintaining a suitable pulling speed to obtain better mechanical properties.

In the actual production process, the matching of wind speed and pulling speed faces many challenges, such as differences in raw material properties, fluctuations in the production environment, and limitations in equipment accuracy. Therefore, how to achieve accurate matching between the two through technical means has become the key to improving product quality.
Optimization of raw materials and formula: For raw materials of different properties, it is necessary to adjust their formula and process parameters to meet different production needs. For example, by adding modifiers or adjusting the molecular weight distribution, the processing performance of the raw materials can be improved to make them more suitable for specific wind speed and traction speed matching.
Control of the production environment: Maintaining the stability of the production environment is the basis for ensuring the precise matching of wind speed and traction speed. By optimizing the workshop layout, strengthening temperature and humidity control, and adopting advanced air flow management systems, the impact of the production environment on the cooling and stretching effects of the film bubble can be significantly reduced.
Improvement of equipment accuracy: The use of high-precision and intelligent production equipment is the key to achieving precise matching of wind speed and traction speed. Modern blow molding equipment is usually equipped with advanced sensors and control systems that can monitor and adjust production parameters in real time to ensure the stability and consistency of product quality.