According to the theory of plastic melting, the extruder screw for blow molded film is divided into three stages: feeding stage, melting stage, and homogenization stage. At the end of the feeding section and the beginning of the melting section, according to the melting theory, its temperature should be the viscous flow temperature. The adhesive flow temperatures of various blown film resins are PP: 164-175 ℃, PE: 105-135 ℃, and PA: 195-210 ℃, respectively.

A plastic film blowing machine that can process plastic particles into plastic films through a series of processes. Throughout the entire operation process, a frequency converter is used to control the operating speed of the motor in each processing step to control the thickness and other process parameters of the film. In the frequency conversion control of the plastic film blowing machine, other steps are relatively easy to control, and simple speed regulation can meet the process requirements, What is difficult to control is the frequency conversion control of the traction and winding parts, which directly affects the usability and automation level of the equipment, and is related to the quality of plastic film products. For plastic film traction and winding, speed control, position control, and torque control can be used.

Key points for controlling the extrusion temperature of Dalian plastic blow molding machine

1. The temperature of the blown film process varies for different types of resins.

2. The same type of resin has different types and melt indices, and the blowing process temperature is different. Those with higher indices have better flowability and lower temperatures.

3. The same resin, blown film with different thicknesses, and the process temperature are also different. For thick films, the process temperature can be slightly higher.

4. The temperature of the mouth can also be slightly higher, which is beneficial for reducing viscosity and improving productivity.

The control difficulty of plastic blow molding machines lies in the high degree of synchronization of rotational speed, therefore a series of measures are needed to ensure synchronous and synchronous stopping. At the same time, due to the flexibility requirement of actual tension, it is necessary to have a certain range of small self adjustment while ensuring high synchronization. The entire control system requires the frequency converter to have high sensitivity, high-speed pulse input/output ports, fast slope following, frequency superposition and switching performance.