What should be paid attention to when operating plastic sheet equipment?
Release time：
2022-05-13 15:32
(1) The temperature of each section on the barrel of the plastic sheet equipment gradually increases from the feeding section to the junction of the barrel and the forming mold.
(2) The temperature of the forming die is slightly higher than the temperature of the barrel. The temperature is higher than 5---10℃. The temperature on both sides of the mold shell is slightly higher than the temperature in the mold shell, and the temperature is controlled at 5-10 °C.
(3) In the way of sheet feeding, the upper surface of the middle roller of the three rollers should be on a level surface with the lower plane of the lip of the die; the inner hole of the lip is parallel to the axis of the middle roller, with a distance of 50~100mm.
(4) The gap of the die lip should be slightly less than or equal to the thickness of the board product, and the gap in the middle of the die lip should be slightly lower than the die lip gap on both sides.
(5) Note that the surface roughness R of the three-roller working table surface should not exceed 0.2pm. When removing the roller surface, it is not allowed to scrape the roller surface with a hard kitchen knife, and a copper knife should be used to remove the finished product from the roller surface.
(6) The roller surface should have some medium relative height; the gap between the three rollers should be equal to or slightly larger than the thickness of the plate.
(7) The temperature control of the forming mold should be stable. When the temperature is high, the flow rate of the wear-resistant material in the injection mold becomes faster; when the temperature is low, the flow rate of the wear-resistant material in the injection mold slows down. Unstable flow rate of wear-resistant material will lead to large vertical thickness deviation of plate (sheet) products.
(8) Pay attention to the temperature of the working surface of the three rollers. It should be that the temperature of the feeding roller is slightly higher, and the temperature of the filming roller is slightly lower. The temperature of the roll surface is high, the billet is not easy to come off the roll, and the surface of the product is easy to cause longitudinal striations; the temperature is slightly lower, and the surface of the product is not glossy. According to this situation, the roll surface temperature control should be adjusted immediately.
(9) The running speed of the three rollers is slightly higher than the extrusion speed of the billet from the die mouth, and the general speed difference is not more than 10%. The speed of the three-roller operation should be controlled stably. Too fast or too slow operation speed will have great harm to the wall thickness deviation of the plate.
(10) When the isoprene rubber plastic extruded sheet (sheet) material, the screw adopts a sudden change structure, the engine compression ratio is (3-4): 1, and the melt flow rate is: HDPE0.3~2.0g/10min , LDPE0.1~0.3g/1Omin, PP0.5~1.5g/10min. ABS and other amorphous polymer epoxy resin extrusion forming plate (sheet) material, should use gradient lead screw, the engine compression ratio is (1.6-2.5): 1.
(11) Extrusion of plastic sheets (sheets), except that polyethylene, high-pressure polyethylene and polypropylene resins are generally not dehumidified before extrusion, other plastics (such as ABS, acrylic resin, etc.) Dehumidification and drying should be carried out before extrusion. Otherwise, it should be extruded with an exhaust pipe type extruder.
plastic sheet,equipment
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