| 摘要 |
A cutter hub and blade assembly (10) for an underwater pelletizer in which molten polymer is extruded as strands through orifices in a die plate (18). The cutter hub is rotatably driven and includes cutter blades (14) mounted at a steep angle on support arms (34) on the cutter hub and move along the face of the die plate (18) to cut the extruded strands into pellets. The cutter blade support angle on the cutter arms is 60 DEG - 79 DEG , preferably about 72 DEG to about 76 DEG and most preferably about 75 DEG . The blade cutting edge (26,28) is beveled or angled at about 40 DEG to about 50 DEG and preferably about 45 DEG to the opposed planar surfaces of the blade. The included angle between the blade cutting edge and the die face is at least about 20 DEG . The inclination of the cutter blade support angle in combination with the blade cutting edge angle in accordance with the invention provides a clean cut of the pellets and enables faster blade grinding when seating new blades to the die face. The steep blade inclination also enables a larger number of cutter blades to be supported from a cutter hub and reduces "tracking" of the blade cutting edge toward the cutter hub center as the blade edges wear down. |
