EVA halogen-free sheet extruder

What are the precautions for halogen-free sheet extruder and plastic sheet extruder?
The mold temperature is slightly higher than the barrel temperature. The temperature is controlled above. The temperature at both ends of the mold is slightly higher than the temperature in the mold. The temperature is controlled at -.
The upper roller surface of the middle roller of the three-roller form of sheet insertion should be on a horizontal plane with the lower plane of the mold lip, and the lip end surface should be parallel to the center line of the middle roller.
The gap between the mold lips should be slightly less than or equal to the thickness of the plate product. The gap between the mold lips should be slightly smaller than the gap between the two end mold lips.
Note that the roughness r of the three-roller working surface should not be greater than. When cleaning the roller surface, do not use a hard steel knife to scratch the roller surface. Use a copper knife to clean the remaining material on the roller surface.
The roller surface should have some medium height. The gap between the three rollers should be equal to or slightly larger than the thickness of the plate. The temperature control of the mold must be stable. When the temperature is high, the flow rate of the melt in the mold becomes faster; when the temperature is low, the flow rate of the melt in the mold becomes slower. Unstable melt flow rate will cause large longitudinal thickness errors of plate (sheet) products.
Pay attention to controlling the working surface temperature of the three rollers so that the temperature of the film entering roller is slightly higher and the temperature of the film exit roller is slightly lower. If the roller surface temperature is too high, the slab will not easily come off the roll, and the surface of the product will easily produce horizontal lines. If the temperature is too low, the surface of the product will be dull. According to this phenomenon, the roller surface temperature control must be adjusted in time. The operating speed of the three rollers is slightly higher than the extrusion speed of the slab from the die mouth. Generally, the speed difference does not exceed %. The working speed of the three rollers must be controlled smoothly. Too fast or too slow running speed will have a great impact on the thickness error of the plate.
When polyolefin plastics are extruded to form plates (sheets), the screw adopts a mutation structure. The compression ratio is (-): the melt flow rate is: D.~./D.~./.~./. For non-crystalline polymer resin extrusion molding plates (sheets), the gradient screw compression ratio should be (.1.):.
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