Rieter

The quality of the combing operation in forward and backward feeding

Index

From the preceding section it will be seen that with forward feed not only will shorter fibers be passed into the combed sliver (E - S instead of E), but also the quality of the combing operation itself must be different. Consider a fiber having a trailing end laying just in the bite of the nippers: During the forward movement of the nippers, with forward feed, this fiber passes into the combed web without any change, because the feed roller pushes it out of the nippers. In backward feed combing, this fiber will stay in the feedstock, because no feeding occurs during forward movement of the combs; the fiber is then nipped while projecting with the hook inside the nippers and combed once again. Therefore, if backward feed is used, the  circular combs rake through the fibers more often, so the quality of the combing operation is increased. This shows up in the elimination of impurities and neps. However, the difference is hardly detectable in modern high-performance machines of the latest generation.