Effects of Passive Shed Unbalancing on Weaving Resistance

Abstract

Weaving of high sett fabrics is difficult due to high Weaving Resistance encountered. Various passive methods have been used in the past, however, little information is available on what can be achieved. In this paper an account is given of the effects of passive shed unbalancing on weaving resistance or Beat-Up Force (BUF) on a narrow fabric loom. The narrow loom was fitted with constructed BUF and warp tension measuring devices. The fabric sett, shed geometry and timing were varied in this experiment. Experimental results show that the effect of dividing the total warp tension unequally between two sheets, during beat-up by raising the position of an extra-roller at the back of the loom is to reduce substantially the pressure between the warp and weft threads. Thus, the inter-yarn friction forces brought about a reduction in WR. A reduction of between 15-52 % in BUF was achieved over the narrow range used depending on the degree of shed unbalance and other loom settings. This enables or facilitates weaving of high weft sett fabrics close to or exceeding construction limits as given by setting theories.