Principle and processing technology of highway guardrail net

The process flow of dipped plastic guardrail net is as follows:

The workpiece is degreased and preheated to above the melting point of the powder coating. After being immersed in the fluidized bed, the plastic powder will adhere evenly, and then the plasticized polymer is cross-linked and leveled into a steel-plastic composite product.

The principle of dipped plastic guardrail net is as follows:
Powder dipping originated from the fluidized bed method. The fluidized bed was first used in the contact decomposition of petroleum in the Winkler gas generator. Then the solid-gas two-phase contact process was developed, and was later gradually used in metal coating. Therefore, it is sometimes still called the "fluidized bed coating method". The actual process is to add the powder coating into a porous and breathable container (flow tank) at the bottom, and the treated compressed air is sent from the bottom by a blower to stir the powder coating to achieve "flow". status”. Become a uniformly distributed fine powder.
The fluidized bed is the second stage of the solid fluid state (the first stage is the fixed bed stage, and the second stage is the air flow transport stage). On the basis of the fixed bed, the flow rate (W) continues to increase, and the bed begins to expand and loosen. The bed height begins to increase, and each powder particle is lifted up and moves away from its original position to a certain extent. At this time, it enters the fluidized bed stage. Section bc shows that the powder layer in the fluidized bed expands, and its height (I) increases with the increase of gas velocity, but the pressure (△P) in the bed does not increase, and the flow rate changes within a certain range without affecting the flow rate of the fluid. The required unit power is a characteristic of the fluidized bed, and it is this characteristic that is used to implement the coating process. The uniformity of the powder fluidization state in the fluidized bed is the key to ensuring a uniform coating film. The fluidized bed used in powder coating belongs to "vertical fluidization". The fluidization number must be found through experiments. Generally, it is enough to be able to coat. The suspension rate of the powder in the fluidized bed can be up to 30 to 50 %.