Blow molding film processing wholesale generally follows this workflow:
Hopper feeding one material → plasticizing extrusion → blowing and stretching → air ring cooling → V-shaped clamp → traction roller traction → corona treatment → film winding
However, it is worth noting that the performance of blown film processing in bulk has a significant relationship with the production process parameters. Therefore, during the blowing film process, it is essential to strengthen control over process parameters, standardize operational procedures, and ensure the smooth progress of production, as well as obtain high-quality film products. In the production of polyethylene blown film processing in bulk, the following process parameters must be controlled effectively:
Extruder temperature
When extruding low-density polyethylene (LDPE) film in blow molding, the extrusion temperature is generally maintained between 160℃ and 170℃, and the head temperature must be uniform. Excessive extrusion temperature can cause resin decomposition, making the film脆，especially reducing the longitudinal tensile strength significantly; whereas, too low a temperature results in poor resin plasticization, preventing smooth expansion and stretching, leading to lower film tensile strength, poor surface gloss and transparency, and even the appearance of wood grain patterns and unmelted crystal nuclei (fish eyes).
2. Blowing Ratio
Blow-up ratio is one of the key control points in the blowing film production process for wholesale film manufacturing, referring to the ratio between the diameter of the film bubble after blowing and the diameter of the unblown tube ring. The blow-up ratio represents the lateral expansion multiple of the film and, in essence, is a form of lateral stretching that exerts an orientation effect on the plastic molecules. As the blow-up ratio increases, it enhances the lateral strength of the film. However, the blow-up ratio should not be too high, as it may lead to unstable film bubbles and an increased likelihood of creases. Therefore, it should be appropriately coordinated with the draw ratio. Generally speaking, the blow-up ratio for low-density polyethylene (LDPE) film should be controlled between 2.5 and 3.0.
Blow molding wholesale products generate pollutants.
During the blow molding processing and wholesale manufacturing, plastic pellets generate a small amount of organic waste gases due to high temperatures, with the main component being non-total hydrocarbons.
