Influence of the Sewing Conditions on the Amount of Needle Penetration in Two-ply Fabrics (Interlining and Outer Fabric) using Blind-stitch Sewing Machine.

The behavior of needle penetration in blind stitch sewing was examined in the case that interlining (upper fabric) is seamed together with outer fabric (bottom fabric). The amount of needle penetration in the upper fabrics, l1 becomes larger with the increase in the fabric thickness (TM1 + TM2) and the rise in ridge forming disc, where TM1 and TM2 are thickness of upper and bottom fabrics respectively. The amount of needle penetration in the bottom fabric, l2 becomes smaller with the increase in the fabric thickness TM1. It was found that the multiple regression equations of l1 and l2 can be obtained using the position of ridge forming disc, TM1, TM2, bending rigidity and crimp ratio of woven fabric along the sewing direction (warp or weft direction). As for the sewing direction, it was observed that the amount of needle penetration becomes larger in the bias direction in comparing with the warp and weft direction. And a master curve which shows directional effect was obtained. It was shown that the amount of needle penetration predicted by the results mentioned above agreed well with the actual values.