Rieter

Batt thickness (weight)

Index

The self-cleaning effect of the batt exerts a considerable influence on the combing operation. This effect arises from the retaining power of the fibers relative to impurities, which depends not only on the disorder of the fibers but also on their quantity. A thick batt always exerts greater retaining power than a thin one. At least up to a certain level, the clamping effect of the nippers is also better with a higher batt volume. Adversely, a thick batt always exerts a heavy load on the comb and this can lead to uncontrolled combing. In this case, the fiber farthest from the  circular combs (upper side of the nipped web) may escape the combing operation, since the combs are no longer able to pass through the whole of the layer.

The unfavorable effect of overloading the comb is greater than the favorable effect of the retaining power of the sheet. A compromise must therefore be struck between quality and productivity. Depending on staple length (and Micronaire value), the ideal batt weight lies between 72 and 80 ktex for short and medium staple cotton, and between 64 and 74 ktex for long staple cotton > 1 1/4 (Fig. 10).

Fig. 9 – Batt weight in relation to staple length

Fig. 10 – Batt weight in relation to fiber mass (Micronaire value and number of fibers in the cross section are decisive)