Rieter

Number of drawframe passages

Index

Only one  drawframe passage should be employed after combing. Two passages not only increase the cost, they also cause a deterioration in quality. Owing to the high  degree of parallelization, the adherence of the fibers in the sliver is so low that false drafts can be induced, for example when the sliver is pulled out of the can behind the  roving frame. However, the drawframe that performs the one remaining drafting operation should then be fitted with a short-term autoleveler.

Combers with four-fold doubling (8 combing heads, 2 delivery heads) usually require two drawframe passages after combing. This is unfavorable, not only due to the higher costs associated with it, but also because of the deterioration in quality that can result.

With the new generation of combers, i.e. eight-fold doubling (8 combing heads, 1 delivery), one drawframe passage can usually be eliminated because of the good suppression of the piecings.