Rieter

Fiber transfer factor

Index

Reference to the forces exerted by the teeth in the carding disposition will show that, all other things being equal, it is a matter of chance on which tooth tip the fiber will remain caught.

Such a random result is not acceptable everywhere. The doffer, although it is in the carding disposition relative to the main cylinder, must be able to take up a portion of the fibers. This is only possible if the doffing conditions are improved by the following:

  • An increased tooth density in the doffer clothing (no longer used with rigid wire clothing).
  • A clothing supporting the carding capacity, by using a greater carding angle for the doffer clothing and thus obtaining an increased drawing-in component E.
  • Maintaining the catching effect of the clothing by frequent sharpening.
  • Keeping the doffer clothing clean and receptive by continually withdrawing the web.
  • A very narrow setting between main cylinder and doffer.
  • Assisting transfer of fibers by special air-circulation conditions in the convergent space between the main cylinder and the doffer.

Even with these measures, the odds in favor of transfer are not even 50:50.

According to Artzt and Schreiber  [11], the transfer factor with rigid wire clothing is only 0.2-0.3.

This means that, on average, a fiber rotates from three to five times with the main cylinder before it passes to the doffer. The effect is caused by the strong adherence of the fibers to the main cylinder, the fibers being drawn into the main cylinder clothing during continual movement past the flats.