Variations to this decades-old mixing section are widely used, but processors should carefully analyze these designs and not assume they will perform better.
Reusing scrap is a necessary evil. But be aware of the negative impact scrap has on properties and extrusion efficiencies. Start by developing a regrind-usage program.
Polymers shrink and orient. Sometimes orientation is unbalanced, resulting in misshaped parts. But there are steps beyond tweaking the die that can mitigate these effects.
At least not for longer than a few minutes. The thin film that’s captured between the screw flights and barrel wall supports the screw and acts as a lubricant. Without it, galling can occur.