The Complexity of Screw Geometry

A twin screw extruder is not a simple combination of two single screws. In addition to the nuclear space between twin screw and barrel, there are side gap, the tetrahedron gap and calendaring gap. Mating-type twin screw extruder can be divided into full meshing engagement and a part one and the entire mating type can be further subdivided into conjugate and non-conjugated type. It is interrelated among different geometric parameters, such as screw diameter, screw head, screw edge width, the center distance. Due to the different geometric parameters, the horizontal spiral flow channel slot of twin screw extruder can be opened. It is geometric complexity that can distinct single screw extruder and twin screw extruder fundamentally.