A geometrical model of stitch length for lockstitch seam

Abstract

A geometrical model has been proposed for prediction of thread consumption based on original cross- section of lockstitch seam for woven fabric. The developed model has been used to calculate the thread consumption during the process of stitching. The stitch length equation is obtained in terms of feed rate, thickness of fabric, machine rpm, thread diameter and position of the cross-over point between needle and bobbin thread in a stitch. Some experiments are carried by changing the parameters such as thickness, tension of needle thread and feed rate with high gsm denim fabric on JUKI lockstitch machine. The needle and bobbin threads length per stitch is also calculated. A new model is therefore proposed for the calculation of stitch length in seam balance as well as in any other conditions, depending on the position of needle and bobbin thread cross-over point. To predict the thread consumption in a lock stitch seam, a dynamic analysis of the stitching process is needed.