The core operation conducted by plastic pipe machines is known as extrusion. In this process, dry plastic granules are fed into a hopper, where they are heated and melted within a rotating screw. The molten plastic is then forced through a die that shapes it into a continuous pipe. After exiting the die, the pipe is cooled through various methods such as water baths or air cooling systems. Finally, it undergoes a calibration process to ensure that it meets the required specifications and dimensions.