Three screw extruder granulation machine granulator appear black spots how to do

What about the black spot of the three screw granulator granulation? In the process of pumping, it is a common problem to meet the black spots of the particles, which will teach you how to deal with the problem of black spots in the process of plastic granulation, which is caused by the problem of the plastic granulator, the problem of raw materials, or other factors.

The appearance of black spot in the process of plastic granulation is a common failure phenomenon, especially in color and light color products, especially in the final production process, it is found that the product performance and the sensory product color are all right, but after a period of time, the customer complaint "the product qualification rate is too low" "There are black spots, asking for returns" and so on, and this time entangled in the question of why there will be black spots, so many friends have a headache.

In order to avoid the harm of carbonization to plastic products as far as possible, the key is to prevent effectively and minimize losses. In order to understand the essence of carbonization, we should be good at using effective solutions, and we need to strictly control every link in the solution and prevention of carbonization of plastic products.

To quickly clean the carbide inside the machine, it is necessary to use some hard plastic material or its return material to wash with white mineral oil, and the temperature is appropriately raised 10~15 degree C. At this point, the plasticizing capacity of the small extruder should be considered. Large and medium extruders that can plasticized ultra-high molecular weight plastics can be washed with ultra-high molecular weight plastics or their recycled materials and white mineral oil. Because the hardness of the super high molecular weight plastic is better and the temperature is high, the cleaning object will be softened, so it becomes easy to fall off, and it is good for the carbide to be taken out of the plastic melt. During the cleaning process, the speed of the extruder is repeatedly switched between low speed and high speed. If there is a residual load on the motor, it can repeatedly stop and restart the extruder several times during the operation so as to further improve the cleaning effect. When the carbide (black spots) in the melt is obviously reduced, the replacement of the usual plastic is cleaned until it is cleaned, and it is gradually adjusted to the appropriate temperature, then it can be produced normally.

In the actual production of plastic products, the intake port is generally isolated before the three screw granulator is shut down, the plastic melt in the extruder and the head of the machine is excluded, the temperature of each area is closed, and then the power supply is closed. Because the plastic melt has strong adhesion to the metal, it is impossible to completely eliminate it at a time of stopping. Finally, there will always be a thin layer of plastic melt firmly attached to the extruder's barrel and the inner wall of the machine head and the screw. After the shutdown, the equipment is cooled and cooled for a long time in the process of high temperature. Retention, obvious thermal deterioration, gradually yellow and zoom into carbide. According to the conventional stopping method, no effective sealing measures have been taken at both ends of the head and the inlet of the inlet, resulting in the oxidation of the air into the machine and the aggravation of the residual plastic heat deterioration in the machine, which provides favorable conditions for carbonization.

Because the equipment is metal structure, the thermal expansion rate of the plastic is different from that of the plastic. The adhesive property of the carbonized plastic is reduced. It is easy to fall off the inner wall of the inner wall of the machine barrel of the three screw granulator, the inner wall of the machine head and the screw. It is mixed into the plastic melt, which makes the inner and outer wall of the products more black, and it is easy to wear holes or leakage and so on. Multiple quality problems, after a long time shutdown, heating and reopening the machine, plastic products easy to appear a lot of large and small black spots, can not meet the quality requirements of products, these black spots are the residual plastic in the machine after the carbide. Usually, continuous washing with plastic is used to remove the washing method of plastic melt with black spots for washing. The washing time is up to 3-5 hours. If the original use of ultra high molecular weight plastic cup carbonization, and the production of raw products, it will greatly increase the difficulty of washing machine, will make the washing time longer, the washing machine cost is higher.