Preparation work before cleaning the barrel of the plastic granulator
Before cleaning, it is necessary to master the thermal stability of the materials stored in the barrel and the materials that need to be replaced in the next step, the moulding temperature range and the compatibility between different plastics. The correct operation method should be mastered during cleaning to save time. And raw materials.
To clean the barrel of the plastic granulator by changing materials: direct material replacement method and indirect material replacement method.
Direct material change method. When the raw material and the retained material in the barrel have an expected melting temperature, the natural material change method can be used.
The operating procedures for directly replacing materials are as follows.
1. If the moulding temperature of the replacement material is higher than the temperature of the material stored in the barrel, the temperature of the barrel and nozzle should be raised to the lower processing temperature of the replacement material. Then the replacement material is added, the machine head is opened, and the machine head is directly extruded. , Until the remaining materials in the barrel are cleaned, adjust the temperature for regular production.
2. If the moulding temperature of the replacement material is lower than the temperature of the material stored in the barrel, the temperature of the barrel should be raised to make the stored material in an excellent flowing state. Then the healing power of the barrel and nozzle should be cut off, and the replacement material should be used. The cleaning is carried out under cooling, and it can be transferred to production when the temperature drops to the processing temperature to be changed.
Indirect material replacement method.
When the replacement material and the remaining material in the barrel do not have an expected melting temperature, the indirect refuelling method can be used. The operating procedures for indirect replacement of materials are as follows.
1. If the moulding temperature of the replacement material is high, and the remaining material in the barrel is heat-sensitive, such as polyoxymethylene, etc., if the plastic is decomposed, it should be cleaned in two steps, that is, first use a material with good thermal stability, such as polyoxymethylene. Plastics such as styrene or low-density polyethylene are used as transitional cleaning materials to perform transitional cleaning and then replace the transitional cleaning materials with replacement materials.
2. Separate the screw
Since the screw of the plastic granulator is relatively easy to disassemble, relatively speaking, the above refuelling method is used for refuelling. This method can save a lot of raw materials.
The basic parameters of plastic granulator screw
1. Screw diameter: the outer diameter of the threaded part of the screw. The unit is MM
2. The ratio of length to the diameter of the screw: the balance of the size of the falling apart of the screw to the diameter of the screw
3. Rotational speed range of the screw: the minimum and maximum rotational speed of the screw is in-max.
4. Motor power: the motor power that drives the screw to rotate. Unit KW
5. Barrel heating power: the electrical power used when the barrel is heated by resistance. Unit KW
6. Number of barrel heating sections: barrel heating is divided into several sections, and the temperature zone is controlled.
7. Output of plastic granulator: the production capacity of plastic granulator per unit time, unit KG/H
8. Nominal specific power: the weight of plastic products produced by the plastic granulator per hour.
9. Specific flow rate: the weight of the plastic product that the screw can produce for each turn.
10. Center height: the height from the centerline of the screw in the barrel of the plastic granulator to the bottom plane of the base.