The Effect of Bottom Front Roll Run-Out in Spinning on Yarn Quality and Processing Performance

Abstract

Measurement of bottom front roll run-out at every spinning stand position in a typical mill indicates that only a small percentage of the stands have run-outs that are exces sively high. It was found also that square neck jointed rolls in the two plants studied have higher roll run-outs than screw neck jointed rolls. A reasonable explanation for this is that the square neck jointed rolls generally receive rougher handling. since con siderable force is required when separating or putting together the sections of the rolls on the spinning frame. Periodic irregularities are introduced in the yarn by eccentric bottom front rolls which lower the quality of the yarn being produced. With increases of bottom front roll run- out from 0.000 in. to 0.010 in., the following properties of 31 1 warp yarn were affected to the extent shown: As the roll run-out increased, the pattern on yarn appearance boards became more dis tinct. Analysis of the yarn properties indicated that yarn quality was appreciably lowered at bottom front roll run-outs in excess of 0.0055 in. A study of the processing performance of the yarn produced at various bottom front roll run-outs indicates that yarns produced at high roll run-out positions are more difficult to process in spooling and weaving. In this study, there was an increase of 12% in the number of breaks in spooling as the bottom front roll run-out increased from ranges of 0.000-0.003-0.006 in. and higher. With these same ranges of roll run-outs, warp stops in weaving increased 48% when the weavability of the yarn produced at low roll run-out positions was compared with yarn produced at high roll run-out positions in spinning. The appearance grade of 80 X 80 print cloth, woven with filling yams produced at various roll run-out positions, was found to decrease with increases in bottom front roll run-outs. All graders that ranked the fabrics selected the fabric having the highest roll run-out as being the worst fabric in the group. However, no correlation was found be tween the appearance grade of 110 X 58 broadcloth woven with warp yarn produced at different bottom front roll run-outs in spinning.