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Notices of plastic sheet extruders

Zhangjiagang Sansu Machine Co.,Ltd | Updated: Jan 25, 2018

(1) the temperature of each section on the machine barrel of the plastic sheet production equipment begins from the feeding section to the temperature of the connection between the cylinder and the molding mold.


(2) the molding mold temperature is slightly higher than the barrel temperature. The high temperature is controlled at 5---10 C. The temperature at both ends of the die is slightly higher than that in the mold, and the temperature is controlled at 5-10 degree C.


(3) in the form of film, the upper roller surface of the three roller middle roller should be on a horizontal plane with the lower lip of the die lip, and the lip end face is parallel to the center roll of the middle roll, which is 50~100mm apart.


(4) the lip and mouth gap of the mold should be slightly less than or equal to the thickness of the plate products. The middle gap of the die lip should be slightly less than the gap between the two sides of the die lip.


(5) pay attention to the roughness of the three roll working face R should not be more than 0.2pm. The cleaning roller surface without scratch hard steel roller surface, should use copper knife roller surface cleaning residue.


(6) the roll surface should have some middle height; the gap between the three rolls should be equal to or slightly greater than the thickness of the plate.


(7) the molding mold temperature control should be stable.  When the temperature is high, the flow speed of the melt in the mold becomes faster and the flow speed of the melt in the mold is slow when the temperature is low. The unsteady flow velocity of the molten material will cause a large error in the longitudinal thickness of the plate (sheet) products.


(8) pay attention to control the temperature of the working face of the three roll, the temperature of the roller should be slightly higher and the temperature of the out roll is slightly lower. The roll surface temperature is high, the slab is not easy to roll off, and the surface of the product is easy to produce cross grain; the temperature is low and the surface of the product is not glossy. According to this phenomenon, the temperature control of the roll surface should be adjusted in time.


(9) speed slightly higher than the three roll slab extrusion speed from the mold opening, three roller speed control to work smoothly, has a great effect on the thickness error of the running speed is too fast or too slow for the board.


(10) when polyolefin plastics are extruded into sheet metal, screw structure should be selected, and ABS and other non crystalline polymer resin extruded sheets should be selected with gradual screw.


(11) extrusion of plastic sheet (sheet), except for polyvinyl chloride, polyethylene and polypropylene resin before depressing before general extrusion, some other plastics, such as ABS and polyamide, should be dehumidification and drying before extrusion. Otherwise, the extruder should be extruded by the exhaust type extruder.