a cutter blade driving and positioning control structure formed of a rotary drive , a transmission unit , a sliding unit , a linear motor and a cutter unit and used in a plastic pelletizing machine for making plastic pellets is disclosed . the rotary drive provides a rotary driving force for driving the transmission unit to rotate the cutter unit . the linear motor is adapted to reciprocate the transmission unit , moving the cutter unit back and forth rapidly with minimized energy consumption .