Similarities:
Both of parallel twin screw extruder and conical twin screw extruder have the transmission mechanism to push forward the plastic compulsorily. The two kinds of extruders also have the nicer ability of mixed plasticization and dehydration. In addition, they have the similar adaptability of molding process for the material and plastic.

Differences:
1. Diameter
Parallel twin screw extruder has the same diameters but there is a difference between diameters of the small end and big end of the conical twin screw extruder.
2. Concentric distance
Parallel twin screw extruder has the same concentric distance but there is an angle between the two axes of the conical twin screw extruder.
3. Length-diameter ratio (L/D)
The L/D of the parallel twin screw extruder means the ratio of the screw’s effective length to the outside cycle of the screws. But the L/D of the conical twin screw means the ratio of the screw’s effective length to the average value of the diameters of small and big end.