Twin Screw Extruders

The first twin screw extruders for polymer processing were developed in the late 1930s in Italy. Roberto Colombo developed the co-rotating twin screw extruder, and Carlo Pasquetti developed the counter-rotating twin screw extruder. Early twin screw extruders had a number of mechanical problems. The most important limitation was the thrust bearing design. Because of the limited space, it is difficult to design a thrust bearing with good axial and radial load capability. The early thrust bearings were not strong enough to give the twin screw extruders good mechanical reliability.