Poor Film Printability

Inappropriate ink Choose the right ink Improper use of additives Reduce the amount of additives Use the appropriate surface lubricant Insufficient corona treatment Increase the treatment voltage or wattage Reduce the take-up speed Narrow the gap of the electrode Raise the electrode treatment temperature Air humidity too high Reduce the air humidity

Non-uniform Film Speed

Unstable die head temperature Check the heater function is normal Check the thermocouple position is correct Die head throughput fluctuations Adjust the die gap Regular cleaning of die head, screw and hilter Non-uniform cooling air volume Check air ring for dirt buildup or breakage Adjust air ring position Check whether air pipe is damaged The air flow in the factory is too fast Do not let outdoor air directly enter the factory Extruder throughput instability Cool down the hopper throat to avoid plastic blocking Replace the strainer meshes of Filter to avoid blocking Matter of the formula

Insufficient Film Strength

Blow-up ratio Use a smaller die head to increase the blow-up ratio Improper die design or scratches Clear die impurities Fix scratches on the die head Avoid seams by design Material cracking Change the material Turn down heating temperature Inappropriate raw material formula Select raw materials with suitable Melt Index (MI) Select compatible additives Uneven gels mix Use screw with a greater L/D Adjust the melt temperature Use multi-layer strainer meshes for filter, or reduce the die gap, to improve back pressure

What Materials Can Be Used in Blown Film Die Heads?

Blown film die heads are commonly used for: HDPE LDPE LLDPE MHDPE PP Multilayer co-extrusion materials Different die head designs are optimized for different resin flow characteristics and film applications.

What Is the Difference Between HDPE and LDPE Die Heads?

HDPE die heads are designed for high-pressure blown film production and are commonly used for shopping bags and grocery bags. LDPE die heads are suitable for low-pressure blown film applications and are widely used in food packaging, agricultural films, and flexible packaging. The flow channel design, air volume requirement, and cooling configuration are different between HDPE and LDPE systems.

How Does an Air Ring Work in Blown Film Extrusion?

An air ring delivers uniform airflow around the molten film bubble to cool and stabilize the film during extrusion. The air ring directly affects: Film thickness consistency Bubble stability Cooling efficiency Optical film quality Production speed

What Is the Difference Between Single Lip and Dual Lip Air Rings?

Single lip air rings provide basic cooling performance and are suitable for standard film production. Dual lip air rings provide more stable airflow distribution and better cooling efficiency, making them ideal for high-speed and high-quality blown film production.

Why Is Film Thickness Uneven During Blown Film Production?

Uneven film thickness may be caused by: Improper die head adjustment Unstable air ring airflow Incorrect temperature settings Poor raw material quality Bubble instability Damaged die lips Regular maintenance and precision die head design help improve thickness uniformity.

How Often Should a Die Head Be Cleaned?

The cleaning frequency depends on production volume and raw materials. Generally, manufacturers should clean the die head: During material changes After carbon buildup When black spots appear During routine maintenance Proper cleaning improves film quality and extends die head service life.

What Does a Screen Changer Do in Plastic Extrusion?

A screen changer filters contaminants and impurities from molten plastic before extrusion. Benefits include: Better film quality Reduced black spots Improved die protection More stable extrusion pressure Longer equipment life