Faygo Plast

In single screw extruder we know that for an effective transport of solids in the feed section, the friction on the inner barrel surface must be larger than the friction on the screw surface. This was first demonstrated by Decker (1) as early as 1941, and later, in 1956, by Darnell and Moll (2) with a complete model that has been used and somewhat modified by several researchers in the polymer processing community.
The simplest mechanism for ensuring a high friction between the polymer and the barrel surface is grooving its surface in the axial direction. Today, twin screw extruder with a grooved feed section are called grooved feed extruders. Typically, the length of the grooved portion in a single screw extruder is only between 3D and 3.5D to avoid excessive pressures that would lead to barrel or screw failure. A schematic diagram of the grooved section in a single screw extruder is presented in Fig. 1. This concept was first introduced by Menges and his co-workers at the Institute for Plastics.