The screw extruder is an important component in the spunmelt production line. It uses an electric heating device, which is installed outside the sleeve of the extruder. Since the process requires different temperatures at different positions, the sleeve is often divided into multiple (5 to 7) independent heating sections according to the length of the sleeve, starting from the inlet section of the screw to the discharge head. , the temperature of each heating zone is set in an incremental manner. The melt temperature during spinning is determined based on the type of raw materials, running speed and product performance requirements. There are four main factors that affect the temperature control of the screw extruder. Let’s introduce the four factors below.
Four major factors affecting the temperature control of screw extruder
01 Melting point of raw materials
The higher the melting point of the polymer, the higher the working temperature of the screw extruder, and it should be higher than the melting point. For example, in a spunbond system, when using PP raw materials, the melt The temperature is 220~250℃; when using PET raw material, the melt temperature is about 270℃.
02 Flow characteristics of raw materials
Melt during spinning Temperature is also related to the flow characteristics of the feedstock. Generally, the higher the fluidity of the raw material, the slightly lower melt spinning process temperature required.
03 Screw extruder models
The same polymer raw material can be used in different When used on different models, the temperature setting values will be quite different. For example, the melt temperature of some tubular drafting production lines will be 20 to 40°C higher than that of slit drafting production lines.
04 Spinning process
The melt temperature of different spinning processes differs even more. In the melt-blown production line, the commonly used screw extruder melt temperature setting value (such as PP melt temperature) is about 50°C higher than the melt temperature of the spunbond production system.
In order to prevent the melt temperature from being too low or the melt not yet Starting the machine in a completely molten state may cause equipment damage. Generally, screw extruders and spinning heating systems are equipped with low-temperature protection functions. That is to say, the screw extruder cannot start operation until the temperature of the melt has not reached the set value and the predetermined holding and balancing time has passed.