Underwater pelletizer and cutting system therefor

In an underwater pelletizing system having an extruder extruding a polymer through an extrusion die, the die having a cutting face facing away from the extruder, a cutting system comprising:

• a) a rotatable cutting assembly bearing a plurality of cutting knives;
• b) a drive shaft attached to the cutting assembly for rotating it, the drive shaft driven by a drive motor;
• c) motorized cutting assembly adjustment means for adjustably moving the drive shaft axially toward and away from the cutting face of the die, thereby moving with it the cutting assembly along its rotational axis;
• d) a load measuring system associated with the motorized cutting assembly adjustment means to measure the contact pressure between the cutting assembly and the cutting face of the die;
• e) a control system for coordinating communication between the measuring system and the motorized cutting assembly adjustment means and for providing instructions to the motorized cutting assembly adjustment means to move the drive shaft toward or away from the cutting face of the die;
• and
• f) a frame, wherein said drive motor is carried on a carriage mounted on and movable relative to said frame and wherein said motorized cutting assembly adjustment means comprises a servomotor for reciprocating said carriage linearly relative said frame.