1.Disassembly and cleaning
First, remove the screw barrel from the equipment.
Then use a special cleaning agent, solvent or high temperature hot water to soak and scrub.
For stubborn dirt, you can use a wire brush or sandpaper to gently wipe, but be careful to avoid scratching the surface.
2.Direct cleaning (no disassembly)
Use plastic raw materials or cleaning materials for extrusion cleaning. For example, materials such as polyethylene (PE) or polypropylene (PP) are used to bring the residual material out by rotating the screw at high temperatures.
Special screw cleaning materials can also be used, which usually have good decontamination and dissolution capabilities.
3.Chemical cleaning
Using a specific chemical cleaning agent, fill the cartridge according to the instructions.
Let the cleaning agent stay in the barrel for some time to fully dissolve the dirt.
The cleaning agent and dirt are then removed by extrusion.
4.Heat cleaning
The barrel is heated to a high temperature to soften or scorch the remaining material.
It is then removed by rotation and extrusion of the screw.
1.Safety first, avoid burns and chemical damage.
2.Choose the appropriate cleaning method and cleaning agent according to the material of the screw barrel and the material processed to avoid damage.
3.After cleaning, dry the barrel thoroughly to prevent rust.
For example, if previously processed is a heat-sensitive material, such as PVC, because of its easy decomposition residues, it may be more suitable to use chemical cleaning or direct cleaning with new PVC raw materials at low temperatures. For some ordinary plastics, such as PE and PP, the method of heating cleaning combined with the extrusion of plastic raw materials may be sufficient.
1. Check appearance
Look directly at the inner surface of the screw and barrel to see if there are traces of residual material, stains or discoloration.
Tools such as a flashlight or an endoscope can be used to assist in viewing areas that are difficult to see directly.
2. Sampling test
A small sample of residual material is taken from the barrel for analysis.
For example, chemical analysis is performed to determine the presence or absence of components of previously processed materials.
3. Trial production testing
Pilot production of a small batch of products.
Observe the quality of the products produced, such as color, transparency, impurity content, etc., to meet the requirements.
If the product quality is good and not affected by residual materials, it usually means that the screw barrel is cleaned.
4. Smell judgment
Smell close to the mouth of the cylinder to see if there is a special smell of residual material.
5. Temperature detection
Monitor the temperature distribution of the barrel during and after cleaning to ensure that the temperature is uniform and that there are no locally overheated or undercooled areas, which may indicate residual material impeding heat transfer.
6. Pressure detection
Monitor pressure changes during extrusion or injection molding. If the pressure is stable and within the normal range, it means that the flow channel of the barrel and screw is smooth, and there is no blockage or resistance caused by residual materials.
For example, after cleaning the screw barrel used to produce white plastic products, small batches of white products can be piloted. If the color of the product produced is pure, there are no stains or spots, then to a large extent, it is cleaned. Or after processing the screw barrel with a strong odor of plastic before cleaning, by smelling the odor, if you do not smell the special odor before, you can initially judge the cleaning effect is better.
