Now, imagine a fibre B coming out of the front nipping point
at a distance d from fibre A. It suffers the same fate so to speak. It will
also be unable to cross the downstream edge of the slot and will align itself closely to fibre
A, as they move to the end of the slot.
Thus, a fibre bundle having a certain width upon leaving the
front nipping point, and with the individual fibres neither parallel nor
stretched, is transformed into a bundle where the fibres are perfectly parallel
and close to each other.
Naturally, the two effects complement each other, but it is
obvious that the second effect is several orders of magnitude larger than the
first one; also only the second effect stretches the fibres at the same time. As
may be imagined, there is a complicated relationship between the optimum angle α, the
suction pressure and the properties of the various fibres.
If the compacting system allows V0, the speed of
the perforated means to be varied relative to the speed of the front roller,
the stretching of the fibres may be controlled further.
Much of these important details are not yet understood well
theoretically, and as so often in spinning one must rely on experience, and
one finds surprises every once in a while!
About the Author:
The author is the Managing Director of Spindelfabrik Suessen
GmbH.
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