For three different free-flowing rubber/filler-composites, based on NR/carbon black, E-SBR/carbon black and E-SBR/silica/silane, studies are conducted on the continuous manufacture of rubber compounds. A co-rotating twin screw extruder is used for mixing. An optimum screw configuration could be found for each RFC type. To minimize the time and work expense required for a formula change a common screw configuration for all three RFC types is developed. The attained compound and vulcanizate properties are at a high level. Finally, results from the continuous rubber mixing process on a production extruder are shown.