Basic stages in PVC profile production are:
- Polymer pellets are fed in the hopper.
- From hopper, the pallets are flow down through feed throat and spread across the barrel by the spinning screw.
- Barrel heaters provide heating to pallets and screw movement provides the shear heating. At this movement, pallets are thoroughly mixed and have a consistency like thick bubble gum.
- After passing through the screw and barrel, pallets are fed to the die at a uniform rate.
- Molten plastic then enters the breaker plate and screen pack. The screen pack perform as contamination filter while breaker plate changes the motion of the plastic from rotational to longitudinal.
- The gear pump (located in between the extruder and the die) pumps the molten plastic through the die.
- The die gives the final shape to the molten plastic. Hollow section extrudes by placing a mandrel or pin inside the die.
- Calibrator is used to hold the molten plastic that comes out of the die in the dimensional specification until it cools down.
- Cooling unit is where the molten plastic is cooled.
- Haul off unit is used for extracting the profile at uniform speed through the water tub.
- Cutting unit cuts the profiles in desirable lengths automatically once they pass the haul off. Speed of haul-off unit and cutting unit must be in sync.
Post time: Jun-24-2022