Precautions for transparent PET sheet:
1. The temperature of each part of the barrel of the plastic sheet and PET sheet manufacturing equipment gradually increases from the feeding part to the junction between the barrel and the molding die.
2. The temperature of the forming mold is slightly higher than the temperature of the barrel. The high temperature is controlled at 5-10°C. The temperature at both ends of the mold is slightly higher than the temperature inside the mold, and the high temperature is controlled at 5-10°C.
3. For paper feeding, the upper roller surface of the three-roller intermediate roller must be at the same level as the lower surface of the die lip. The end faces of the lip are parallel to the centerline of the middle. Roller and distance are 50-100mm.
4. The gap between the die lips should be less than or equal to the thickness of the board product, and the gap between the die lips should be slightly smaller than the gap between the two ends of the die lip.
5. The roughness R of the working surface of the roll should not exceed 0.2 pm. When cleaning the surface of the roller, do not use a hard steel knife to scrape the surface of the roller. You will also need to use a copper knife to clean any residue from the surface of the roller.
6. The height of the drum surface should be medium. The gap between the three rolls should be equal to or slightly larger than the thickness of the plate.
7. The temperature control of the forming mold must be stable. The higher the temperature, the faster the flow rate of the melt in the mold, and the lower the temperature, the slower the flow rate of the melt in the mold. If the melt flow rate is not stable, the vertical thickness of the plate product will have a large error.
8. Pay attention to the temperature of the working surfaces of the three rollers. The feed rollers should be slightly warmer and the output rollers cooler. If the temperature of the roller surface is too high, it is difficult for the slab to roll, and the surface of the product is easy to form a horizontal line. If the temperature is too low, the surface of the product becomes dull. According to this phenomenon, the temperature control of the roller surface must be adjusted in time.
9. 3 rolls run slightly faster than pushing the slab out of the die opening, with a typical speed difference of less than 10%. It is necessary to control the working speed of the 3 rollers smoothly, if the speed is too fast or too slow, it will greatly affect the thickness error of the printing plate.
10. When extruding polyolefin plastic to form a plate (sheet), the screw adopts a steep structure, the compression ratio is (3-4): 1, the melt flow rate is 0.3-2.0g/10min for HDPE, and 0.1 for LDPE. ?0.3g/10min, PP0.5?1.5g/10min. For ABS and other non-crystalline polymer resin extrusion sheets (sheets), step-by-step screw must be selected, and the compression ratio is (1.6-2.5): 1.
11. Extrusion molding of plastic plates (sheets). However, PVC, polyethylene and polypropylene resins are generally not dehumidified prior to extrusion. Extrusion of other plastics (ABS, polyamide, etc.).
Transparent PVC Sheet 
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