Processing Machinery
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Improper processing temperature window selection for metallocene linear low-density polyethylene metallocene linear low-density polyethylene (variant: startup commissioning scenario)
Fenómeno del problema
Unreasonable barrel or head temperature settings lead to poor material plasticization quality, degradation or incomplete melting.
Temperature window selection directly affects melt quality and final product performance.
Especially during new machine commissioning or initial startup, this problem is more prominent and requires focused attention.
Análisis de la causa
(1) Temperature setting is on the low side; high melt viscosity results in insufficient plasticization
(2) Temperature setting is on the high side; material thermal degradation reduces molecular weight
(3) Unreasonable temperature distribution across sections; feeding section temperature too high or plasticizing section temperature too low
(4) Material grade differences and MFR changes are not considered
(5) Ambient temperature changes are not adjusted in time
(6) During new machine commissioning or initial startup, process parameter fluctuations or equipment condition changes aggravate this problem
Solución
(1) Reasonably set the temperature range according to metallocene linear low-density polyethylene characteristics: 190-260°C
(2) Barrel temperature gradually increases from the feeding section to the homogenizing section, but does not exceed the upper limit temperature
(3) Regularly calibrate actual barrel temperature with a thermometer or infrared temperature gun
(4) Test MFR for each batch of raw material and fine-tune temperature as needed
(5) Establish standardized process parameter cards to reduce human operation differences
(6) And do a good job of parameter recording and archiving; pay special attention to parameter stability during new machine commissioning or initial startup
Conclusión clave
Temperature window selection is the foundation of processing and needs to be reasonably set according to material characteristics and actual operating experience.
In different production scenarios, targeted preventive measures need to be taken.
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