A pipe extrusion line consists of a number of pieces of
equipment. An extruder converts the polyethylene raw
material to a continuous tubular melt by extrusion through
an annular die. The molten pipe then proceeds through a
sizing or calibration device (which fixes its dimensions) to
a cooling trough. After being cooled, the pipe passes via a
haul-off to handling equipment for cutting into final lengths
or coiling. Printing devices may also be inserted into the
line to mark the extruded pipes with specific details