STUDY ON DRAFTING FORCE (I)

Abstract

1. The measurement of the force generated during drafting the slivers or rovings would be a valuable imformation for drafting conditions (drafting ratio, roller setting etc.) and sliver constructions (twist and fibre arrangement in a sliver). For this purpose we developed an instrument for measuring drafting force (Fig. 1).In figure 2 the main part for measuring is shown. The front rollers A1A2 are mounted in the cradle which is suspended from a framework by a shaft B. The torsion due to drafting force is only picked up by the magenetic strain meter M which is clamped along two edges: along one edge to the cradle H1 and along the other edge to external frame H2 (Fig. 3).2. The force required to draft ravings of rayon staple is investigated at small drafts. Results obtained are as following:a) In a certain small draft the maximum drafting force is recognised, which in turn decreases with the increase of the distance between the front and back rollers (Fig. 6).b) Generally drafting force dependents on the distance of roller setting when drafting ratio is constant (Fig. 7, 8).c) The relation between drafting ratio, roller setting and drafting force is represented by the 3 dimensional surface (Fig. 9), which is formulated by equation (6).