invention a vertical axis version shown in fig1 uses a conical surface to control the motion of the fibers passing through the machine as shown in fig1 a conventional fluffer is comprised of a generally conical housing 1 having an inlet 2 and an outlet 3 for receiving and discharging pulp fiber respectively a pin rotor 4 is shown which is also generally conical in section and is mounted for rotation within the housing 1 on a shaft 5 which extends through the housing the rotor is further provided with a plurality of pin like projections 6 which extend from the rotor to a point proximate the internal wall of the housing pulp fibers enter the machine through inlet 1 where they are then caused to be spun about the circumference of the machine by the combing action of the rotor 4 and pins 6 in a vertical machine the centrifugal force of the pulp fiber mat 7 acting against the conical surface 8 causes the downward motion of the pulp fiber mat due to gravity to be retarded this conical surface also can be used to provide a means of traversing the pulp fibers through a horizontal machine for a given rate of rotation of the pulp fiber.