Extrusion & Post
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Die head pressure fluctuation of general-purpose polyethylene extruder
Problem Phenomenon
The die head pressure gauge reading fluctuates greatly, and the pressure is unstable.
Die head pressure fluctuation directly causes extrudate dimensional fluctuation and surface defects, and is an important indicator of extrusion instability.
Cause Analysis
（1）The screw output is uneven, and the melt pressure fluctuates
（2）The filter screen is blocked or broken
（3）The die head temperature fluctuates greatly, and the melt viscosity changes
（4）The breaker plate is deformed or improperly installed
（5）The raw material contains many impurities, frequently blocking the filter screen
Solution
（1）Stabilize the screw speed and barrel temperature to ensure uniform output
（2）Regularly replace the filter screen and establish a replacement cycle
（3）Stabilize the die head temperature, and control the fluctuation within ±3°C (within the range of 160-260°C)
（4）Check the breaker plate, replace it if deformed, and ensure it is installed in place
（5）Sieve the raw material before use, and install a magnetic frame on the hopper to remove impurities
Key Takeaway
Die head pressure fluctuation is caused by unstable output or filter system problems, and the extrusion parameters need to be stabilized and the filter system maintained.
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