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How to solve the black spots of plastic particles during plastic granulation?

Jan. 13, 2020

The problem of black spots in the granulation process of Plastic Granulator is a common failure phenomenon, especially in colored and light-colored products. It is often during the final large-scale production process that there is no problem in product performance and color. However, after a period of time, I will receive customer complaints and requests for returns. At this time, the problem of tangled black spots is too headache. As a Central Plastic Granulator Suppliers, share with you.

In order to effectively avoid the harm of carbonization of plastic products, the most important thing is how to effectively prevent and minimize the losses. We need to understand the nature of carbonization and be good at applying effective methods to solve and prevent carbonization of plastic products, all of which require our strict control.

Plastic Granulator

Plastic Granulator

To quickly clean the carbides in the plastic granulator, you need to use a harder plastic or its return material plus white mineral oil to clean it. The temperature should be increased by 10 ~ 15 ℃. At the same time, the plasticizing capacity of the plastic by a small plastic granulator should be considered. For large and medium-sized plastic granulators, it can be cleaned with ultra-high molecular weight plastic or its return and white mineral oil. Ultra-high molecular weight plastic large and medium-sized extruder plasticizing, ultra-high molecular plastic or return material and white mineral oil cleaning. Because the ultra-high molecular weight plastic has good rigidity, when the temperature is high, the cleaning object will be softened and easily fall off, which is conducive to the carbide being carried out by the plastic melt. During the cleaning process, the plastic granulator is repeatedly switched between low speed and high speed. If the motor load has a margin, during the operation, it can be repeatedly stopped and restarted multiple times to further improve the cleaning effect. When the carbides (black spots) in the melt are significantly reduced, they can be cleaned with plastic commonly used for flattening until they are clean, and gradually adjusted to the appropriate temperature, normal production can be achieved.

Because the equipment is a metal structure, the thermal expansion coefficient of plastic is very different. The adhesion of the carbonized plastic to the metal decreases, and it is easy to separate from the inner wall of the barrel, the inner wall of the head and the screw of the plastic recycling machine. Mixed into the plastic melt, making the inner and outer walls of the product more black spots, prone to quality problems such as perforation or leakage. After a long period of time after shutting down, turning on the machine after heating, many black spots of various sizes are prone to appear The quality requirements of the products cannot be met, and the carbides remaining in the machine after thermal degradation are these black spots. Generally, the washing method is to continuously extrude the plastic and remove the plastic melt for washing, and the washing time is up to 3-5 hours. If the original ultra-high molecular weight plastic is carbonized, and the production of primary-color products, it will increase the difficulty of washing the machine, resulting in longer washing time and higher cost. Our company also has Medium-speed Granulator on sale, welcome to consult.


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  • Add: Ningbo Economic & Tech Development Zone, Xiaogang, Beilun, Ningbo, China