Thermoforming
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PP Extruded Sheet/Plate Uneven Thickness
Problem Phenomenon
Large transverse thickness deviation of PP sheet; after winding, one side is high and the other low, with wall thickness out of control in subsequent '2079851475616104458 or cutting.
Cause Analysis
Improper die lip gap adjustment, uneven melt pressure and temperature distribution in the die, and haul-off speed fluctuation all cause transverse thickness deviation; uneven die thermal expansion or local material buildup also causes uneven discharge.
Solution
①With an online thickness gauge, closed-loop adjust the gap via die lip adjustment bolts (or automatic die); ②stabilize melt temperature and die zone temperatures; ③stabilize haul-off speed; ④regularly clean die flow channels and die lip buildup; ⑤check die heating uniformity.
Key Takeaway
PP sheet thickness relies on the three-in-one stability of 'die lip + melt temperature + haul-off', preferably with thickness closed-loop; for transverse deviation, first use the thickness profile to locate which die lip section has the problem, then adjust targetedly—don't randomly adjust bolts overall.
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