A twin-screw extruder having a novel fractional element has been invented that can provide different tip angles. The twin-screw extruder is suitable for processing thermo plastic, thermo set and other material. It has a barrel with two parallel intersecting bores, two sets of co-rotating fully intermeshed extruder elements that are linked to each other in non rotary manner forming continuous chain, each element operating in one of the bores and each screw being provided with multi lobbed elements that has special geometry.