Many customers do not know how to clean the plastic extruder after it has been used for a period of time, which takes a lot of time. If it is not handled properly, it will even damage the screw. Due to the characteristics of plastic materials, carbon deposits will decompose at a certain temperature, which is not easy to be carried out when attached to the screw. Another reason is that in actual production, an extruder will not always make only one product. It often needs to change color and materials. At this time, it is also necessary to clean the screw, barrel, head and other positions. So, how to clean more quickly and effectively?
How to clean screw properly:
1.Non-dismantling cleaning method
A: Using “Resin” cleaning method
Generally used in the new equipment of the cleaning machine or extruder after a period of time, due to part of the material remaining in the screw or barrel above the glue, the material extrusion speed is slow, and color variety color difference is large. The usual method is to replace the post-production material or degraded material, carefully clean the screw, barrel, head and die without damaging the screw. By using the chemical cleaning method, The active components of the product are activated at a certain temperature to remove these pollutants by decomposing the structure of high molecules and pigment molecules in the equipment. It also has a good cleaning effect for some “dead corner” positions.
B: Using “Non-resin material” cleaning method
In the actual production process, it is also widely accepted to use materials with certain friction and easy to crush, such as rice, corn, sawdust, toilet paper or newspaper, etc. to clean the screw. After the extruder is heated to the normal extrusion temperature, the friction generated by these substances between the screw and barrel is used to remove the resin gelation attached to the surface of the screw and the barrel. However, it is worth noting that after cleaning with this method, it is necessary to open the screw and barrel to check the cleaning condition. Under normal circumstances, it is also necessary to clean the machine again with resin cleaning material before the production of formal products.
2. Adopted the suitable heating-device
Using fire or fire baking to remove the plastic fixed on the screw is the most common and effective method in plastic processing, but acetylene flame must not be used to clean the screw. The temperature of acetylene flame can reach 3000℃. cleaning the screw with acetylene flame will not only destroy the metal characteristics of the screw, but also significantly affect the mechanical tolerance of the screw.However, it is easy to produce black spots by burning.
3. Adopted the suitable clean method
The first step to clean the extruder is to close the discharging port at the bottom of the hopper; According to the different extrusion process, the cleaning must be realized by one person: the operator observes the screw speed and torque from the control panel and the extrusion pressure to ensure that the system pressure is not too high. Firstly, do not remove the die head for cleaning. When the extrudate is completely converted from processing resin to cleaning resin, stop the machine immediately and remove the die head, and then go in to make the residual cleaning resin flow out. Then reduce the screw speed to 15-25r / min and continue this speed until the melt flow at the front end of the die stops flowing.
How to clean barrel properly:
1. When preparing the barrel for cleaning, the barrel temperature is also set at 200°C.
2. Screw the round steel brush into a drill pipe and use it as a cleaning tool on the electric drill. Then wrap the steel brush with a copper wire mesh.
3. Before inserting the cleaning tool into the barrel, sprinkle some stearic acid into the barrel, or sprinkle stearic acid on the copper wire net of the cleaning tool;
4. When the copper wire mesh enters the barrel, it starts the electric drill to rotate it, and artificially makes it move forward and backward until the movement becomes no resistance;
5. After the copper wire mesh is removed from the barrel, use a bundle of cotton cloth to wipe back and forth in the barrel to remove any cleaning resin or fatty acid residue; After several such back and forth wipe, the cleaning of the barrel is done. The thoroughly cleaned screw and barrel are ready to be assembled for the next production.
On the premise of adopting effective methods, regular repair and maintenance of equipment can largely avoid failures and ensure the economic benefits of equipment operation.