With progress in electronics and the introduction of the flux vector drive using complex control algorithms, AC drives are now equal to or better than DC drives for most applications.
Most extrusion screw designers often do not design the feed section with the same rigor as other sections. This is odd since nothing goes through the screw that doesn’t first go through the feed section.
Changing levels of regrind can result in unstable output. If not set up properly, a melt pump can add to this instability—the opposite of the intended effect.