The extruder screw is the key component of the extruder and the heart of the plastic extruder. Due to the need of assembly, there is a matching gap between the extruder screw and the extruder barrel. Since this matching gap is in the diameter direction of the screw, it is also called a diameter gap or an assembly gap. And this fit clearance is an important parameter related to the working performance of the extruder.
1. Resin cleaning method
This method is to use resin, such as polyester resin or epoxy resin cleaning machine. This method is generally used in the cleaning of new equipment or after the extruder has been used for a period of time, because part of the material remains on the extruder screw or extruder barrel to gel, the material extrusion speed becomes slow, and when the color difference of the color change variety is large, you can use this method. After the resin cleaning machine, use the resin to be produced, add appropriate external lubrication and calcium powder to further clean the machine. When the extrudate is considered clean, it can be officially put into production.
2. Non-resin cleaning method
This method uses materials such as rice, corn, sawdust and toilet paper, which have a certain friction and are easy to crush. When the extruder is heated to the normal extrusion temperature, the friction between these materials and the screw and barrel is used to remove the resin glue attached to the surface of the screw and barrel. Experience has shown that the shell of rice has high hardness and high friction. In contrast, the cleaning effect is ideal. After cleaning the machine with this method, it is necessary to open the extruder barrel to check the cleaning condition. Under normal circumstances, it is necessary to clean the machine with the resin cleaning material formula according to the above method before the production of the formal product can be carried out.
3 Manual cleaning method for disassembling screw and barrel
This method is to manually or automatically push out the extruder after the extruder is heated to working temperature to push out the screw to remove easily removed materials while it is hot. After cooling, it is put into an organic solvent tank containing cyclohexanone and soaked. When the molten deposit attached to the screw swells, the deposit is manually removed. The soaking time of the screw depends on the amount of attachment and the thickness of the gel. In order to reduce the use of solvents and facilitate the sealing of the container, use steel pipes or stainless steel pipes that are slightly thicker than the screw diameter, and one end of the welded seal can be used as a soaking tank. For safety reasons, the container for immersing the screw must be stored in a cool place away from fire and power sources. At the same time, the container must be sealed to prevent the solvent from evaporating, and a safety mark must be attached.
If the machine needs to be cleaned thoroughly, the extruder barrel can also be manually or solvent wiped to remove the glue attached to the inner wall of the barrel after it is opened while it is hot.
