The screw is the heart as well as the key component of the twin screw extruder machine, which determines its production efficiency, plasticizing quality, dispersion of the filler, melt temperature, power consumption, etc. The following is to introduce the cleaning steps of the screw in the twin screw extruder machine:
1. Choose the right heating device
Fire burning or fire roasting is the most common and effective method used in plastic processing companies to remove the plastic fixed to the screw of the twin screw extruder machine. But never use acetylene flame to clean the screw.
Correct and effective method: Clean the screw with a blowtorch immediately after use. The heat distribution of the screw is still uniform because the screw still has the heat generated during processing.
2. Choose the right detergent
Commodity economy is highly developed today, and there is no lack of various screw cleaners (screw cleaning materials) on the market. For most of them, the price is not cheap, and the using effect varies greatly. Whether using commercial detergents depends on different manufacturers and production conditions. Plastic modification processing enterprises can also use different resins to do screw cleaning materials according to their own production conditions, which can save a large sum of money for the companies.
3. Choose the right cleaning method
The first step to clean the screw of laboratory twin screw extruder is to turn off the feeding board, that is, to close the feeding port at the bottom of the hopper. Then reduce the screw speed to 15 to 25r/min and maintain this speed until the melt flow stops at the front end of the die head. All heating zones of the barrel shall be set at 200°C. As soon as the barrel reaches this temperature, cleaning should be started immediately. Depending on the extrusion process (the die head may need to be removed to reduce the risk of excessive pressure in the front end of the extruder).
Cleaning must be done by one person: The operator watches the screw speed and torque from the control panel, as well as the extrusion pressure to ensure that the system pressure is not too high. During the whole process, the screw speed should be kept within 20r/min. In the application of low pressure die head, first do not remove the die head for cleaning. When the extruder is completely converted from the processed resin to the clean resin, stop the machine immediately and remove the die head, and then restart the screw (rotating speed within 10r/min) to allow the residual cleaning resin to flow out.
4. Use the right cleaning tools
Correct and proper tools and cleaning materials should include: Heat-resistant gloves, goggles, copper scraper, copper brush, copper wire mesh, stearic acid, electric drill, tube ruler, and cotton cloth.
The cleaning resin on the screw can be cleaned with the copper scraper and copper brush. After the cleaning resin on the exposed screws has been cleaned, use the screw extraction device to push forward 4 to 5 screw blocks and continue to clean. This process is repeated, and eventually most of screws are pushed out of the barrel.
A steel tool such as a steel screwdriver, scraper, or skid bar should never be used to clean the screw because steel can damage the surface of the screw.
KEYA Twin Screw Extruder