3. Extrusion

3.1 Extruders

The extruder consists of (figure 2 ):

• of a screw, made up of different sections;

• a geared motor unit driving the screw ;

• a sleeve or cylinder around the screw ;

• a heating and temperature control system (heating collars) distributed along the length of the sheath;

• fans for cooling the sheath;

• probes that measure sheath temperature and enable closed-loop control of...