The extruder screw of the film blowing machine is divided into three sections: feeding section, melting section and homogenizing section. Next, let us have a detailed understanding for you.
1. Temperature requirements of the feed section: At the inlet of the feed section, it is hoped that the temperature can be low to avoid the resin sticking to the feed port. In addition, the resin of the feed section will be tightened from time to time, and the air will be discharged backward from the feed port. According to the different structure of the equipment, although the inlet does not stop the electric heating, the inlet temperature is about 50-90 degrees after the cylinder heat transfer, so the temperature of the feed section is determined, the inlet temperature is 50-90 degrees, and the end is equal to the melting point or the viscous flow temperature. In this section, the temperature can be determined as a proportional linear temperature rise.
2. Melting section temperature requirements: At the beginning of the melting section, the temperature reaches the viscosity flow temperature before melting. For crystallized resin, the viscosity flow temperature is equal to the melting point temperature, and then the melting layer is tightened and increased continuously, and the temperature is increased continuously, so that the length of the resin molecular chain is different, so that the polymer with different thermal motion energy is melted successively. Therefore, after determining the temperature at the end of the melting section, The rest of the segment can be determined to be linearly heated.
3. Temperature requirements of the homogenization section: In the homogenization section, mainly remelting homogenization and quantitative constant pressure constant temperature output melt, the temperature of this section can be kept constant, or the temperature at the end of the melting section can be slightly increased (about 2-5 degrees). When blowing film, the temperature through the probe part is required to be low, but not lower than the viscous flow temperature, in order to facilitate the lifting of film and normal blowing film, when the melt comes out of the die, should have a certain viscosity, so as to avoid film rupture or collapse, generally speaking, it is about 10-30 degrees lower than the end of the homogenization section, the temperature drop from the homogenization section to the touch mouth can also be regarded as an isothermal drop.
