Work on the screws immediately after use while they are […]
Work on the screws immediately after use while they are still hot, or put the screw shaft assembly back in the extruder to heat the shafts and elements together. Allowing the elements time to heat up slowly is always better. The idea is then to remove the screw tips and slide off a portion of the screws onto a raised table or cart right at the end of the machine.
As compounders move from one job to the next, time is money. Twin-screw compounding extruders are all designed with removable elements whose position on the screw shaft is designed to optimize the process. And when the run ends and it’s time to move to the next one, these screw sets need to be removed and swapped out for a new set.
How quickly and efficiently that essential task is carried out has direct impact on the bottom line.If the shafts must be removed from the machine and heated with a torch, please use caution and heat evenly all the way around the element. Do not let the elements change color! This can affect the metallurgy. Warm them instead of burning them.
Use a rosebud acetylene torch and be patient. While the elements are hot, use a punch made from wood or hard plastic to push the elements from the shaft.For difficult-to-remove elements, an impact hammer is a noisy device, but works very well at breaking loose stuck screw elements. The steps outlined above still need to be followed for screw removal.
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