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PE film is commonly used in packaging fields, with the function of protecting goods, food as well as materials during storage or transportation. Currently, the film extrusion and blowing process also uses modern machinery systems such as: extruder combination, blower combination and winding system, but we cannot avoid problems and errors in the process. PE film blowing process. In the article below, EuroPlas will explain common problems in the PE film blowing process as well as suggest things to note when PE film blowing. Refer now!

1. Overview of PE film production

PE film is a product made from original PE plastic beads. PE is classified as a thermoplastic, it is white and slightly transparent. Basically, PE plastic is non-conductive, insulating and waterproof.

This is the most important material in the production of PE film. Currently, PE film production methods have been greatly improved to meet the strict needs and standards of the market. PE film is produced from two main methods: blowing method and rolling method. In this article, EuroPlas will mention the PE film blowing process.

Basically, the PE film blowing production process will have 7 steps, specifically as follows:

• Step 1: PE plastic granules will be mixed with plastic additives (if any). Plastic additives depend on the specific requirements of each industry and customer.

• Step 2: The mixture between PE plastic and plastic additives will be transferred to the extruder and begin the heating stage from 200 - 280 degrees Celsius. After that, the molten mixture will be filtered through a metal mesh to ensure thorough removal of impurities and remaining non-melting components.

• Step 3: Manufacturers conduct general inspection of the molten mixture before it is put into the rim mold to form thin plastic tubes.

• Step 4: Let the plastic pipes rest for 5 - 10 minutes, manufacturers will inflate them through the air vents on the body of the plastic pipes. PE film products are gradually shaped and stabilized in size.

• Step 5: Manufacturing enterprises use a high-speed cooling system combined with a high-speed air ring surrounding the plastic pipe roll. Cooling will make the mixture easier to shape.

• Step 6: The entire above mixture will be put into a high-capacity roller to flatten. The flattening process needs to be done evenly and with the right force to ensure the best quality of the product.

• Step 7: Finally, after the PE film has been flattened, it will form a double film, which can be kept intact or cut into two single films and then put through rolling cans to roll up.

Although the PE film blowing process is carried out according to a strict process with modern machinery and equipment, manufacturers cannot avoid technical problems. Refer to the next section for more detailed information!

2. Common probles during film blowing process

EuroPlas mentioned above that technical errors during the production of raw materials are inevitable, including the PE film blowing process. We will introduce to you 6 common problems when blowing PE film and their causes. As follows:

2.1. Poor dispersion and mesh clogging

  This situation occurs when the manufacturer uses inappropriate taical. The degree of filler dispersion is arranged as follows: HDPE > LLDPE > LDPE and they will affect the heating and blowing process of the mixture.

Besides, using expired fillers to mix with PE plastic also negatively affects the quality of PE film and can cause serious damage during the production process.

To minimize this situation, manufacturers need to reduce the melt temperature or increase the extruder barrel temperature. In addition, we need to regularly check, maintain and periodically clean the PE plastic film blowing system. Because they not only ensure product quality but are also safe for users' health as well as reduce risk costs.

2.2. Fish eye membrance

If you see many thin spots on the PE film and the surface is wrinkled, this is a sign of fish skin damage to the PE film. This condition occurs when the raw material contains too many substances that are vaporized or decomposed into volatile substances under processing conditions (usually steam). They will directly affect the aesthetics as well as mechanical properties of PE film.

To overcome the fish skin problem in PE film, the manufacturer should increase the melting temperature and the mold activates the heater. Besides, plastic processing additives (PPA) are also an effective choice to combine with PE plastic in the film blowing process.

2.3. Extrusion head residue

This situation often occurs after long periods of use and without regular inspection, maintenance and cleaning. If the extruder head is clogged with residue or impurities, it will affect the machine's ability to disperse temperature during the process of melting the plastic mixture. This also affects the formability of the material in a short time and product quality is inevitably degraded. Besides, the residue collects a lot of excess impurities that can affect consumers' health.

To solve this situation, the simplest way is to periodically check and clean the extruder. Additionally, manufacturers need to perform maintenance according to industry schedules and steps. After each PE film blowing session, you can generally check the motor system of the extruder and other machines. 

2.4. Membranes are not uniformed

A sign of this condition is when the surface of the PE film appears wrinkled or has long lines. In addition, if observed with the naked eye, the size of the PE film will not be uniform

Film inhomogeneity occurs due to the use of incompatible materials (usually due to too high a filler ratio) or due to contamination. To overcome the problem of inconsistent PE membranes, it is essential to accurately identify the source of contamination and remove it as soon as possible.

Immediately after identifying the source of contamination and eliminating them, manufacturers will clean the entire PE film blowing machine system as well as change the appropriate filler type.

2.5. Membrane streak condition

Uneven and rhythmic movement of shafts and tubes will easily cause stripes or wrinkles to appear on the PE film. At this time, the PE film has stretched and its thinness has also increased, so the quality will no longer remain the same as the original.

Other causes may be that the glue is too thick or the pressure is inappropriate, and the transmission speed is uneven between the rubber rollers and the electric roller. The immediate solution that manufacturers can apply is to adjust the guide tube, reset the speed and distance of the rollers, and raise the drying temperature.

3. Things to keep in mind when blowing PE film

After accurately identifying common problems when blowing PE film, we also need to grasp important notes during the production of this product to ensure optimal costs and sustainable profits for enterprise. EuroPlas will send you 5 important notes during the PE film blowing process, specifically as follows:

The mold is the part that can affect the thickness of the PE film. If the gap is uneven or misaligned, the thickness of the PE film will be uneven and substandard.

Temperature is also an equally important factor that can directly impact the entire PE film blowing process. The temperature of heating PE film ranges from 200 - 280 degrees Celsius. If the temperature is too high or too low, the finished product quality is below average and does not meet market expectations.

For example, if there is not enough heat, the plastic will not melt completely, the high viscosity will make it difficult to blow the film, and the resulting film is often gelled. If the plastic is overheated, it will burn, creating a film with many black spots.

Besides, the manufacturer can influence the thinness and thickness of the PE film through the pulling speed. If the pulling speed is faster, the PE film will be thinner. In addition, two factors about air flow that manufacturers need to pay attention to during the PE film extrusion process are air flow in the bubble and cooling air flow.

The expansion coefficient becomes larger if and only if the gas flow in the bubble is larger. Meanwhile, the larger the cooling gas flow will lead to the balloon cooling faster and the crystallization ability of the PE film will be significantly reduced. Basically, the mechanical properties will not be sustainable according to standards. However, the clarity of the PE film will be improved.

4. Introducing EuroPlas

Plastic in general and PE plastic in particular are the most important materials involved in the PE film blowing process. Choosing a reputable plastic supplier has never been easy for manufacturers. It's no exaggeration to say that EuroPlas is the perfect solution for you - the leading masterbatch manufacturer based in Vietnam.

Masterbatch products at EuroPlas are researched and designed by a team of industry-leading experts, and can specifically serve the film blowing process. Our product line includes color masterbatches, additive masterbatches and filler masterbatches that can enhance the performance and appearance of blown film products.

EuroPlas focuses maximum on production techniques, quality raw materials as well as commitment to partners and customers nationwide. Overall, EuroPlas offers a wide range of products including colored resins and plastic additives that can contribute to improving the performance of the PE film blowing process.

5. Conclusion

This article has sent you common problems in the PE film blowing process along with their causes and solutions. Please continue to follow EuroPlas to update articles about the market and quality plastic products as soon as possible!