Generally, in the normal production state, the materials enter the feeding section and compression section. Because the temperature difference between the newly entered extruder and the set temperature is too large, and the shear heat effect is not obvious, it mainly depends on the heating ring to provide a large amount of external heat. Therefore, the heating ring needs to work without stopping, so these two sections are called the heating area. The heat is mainly provided by the combined action of external heating and screw shearing, calendering and friction.
After the melt enters the melting section and metering section through the compression section, it has been basically plasticized, and even there is excess "shear heat". The purpose of temperature control at this stage is not to further heat supply, but to timely implement "cooling" when the melt is "over temperature" to transfer the excess heat.
When the melt enters the confluence core and die, the shear heat effect no longer exists because the melt has begun to change from spiral variable speed motion to linear uniform motion when it reaches the confluence core. When the melt reaches the die along the specified flow path of the confluence core, it will also consume some heat. In order to ensure that the melt moves evenly along the dovetail channel of the die, it is necessary to supplement appropriate heat. Therefore, the temperature of the die is set slightly higher, so it is called "insulation area".