Effect of Different Sewing Parameters on Lockstitch Seam Strength for Denim Fabric

Abstract

Seam strength plays a very important role in acquiring the desired quality seam which ultimately defines the quality of any clothing. The paper is aimed to study the strength of seam produced from denim fabric, how different sewing parameters like sewing thread type, type of seam, seam direction as well as the density of stitches influence the strength of seam, and it is observed that they have direct effect on lockstitch seam strength of denim fabric with various degree. For research denim fabric with 3/1 weaves structure and three different sewing threads namely 100% cotton spun with 14tex linear density, 100% polyester spun with 24tex and 60tex linear density were used. Seam class used for the research was superimposed seam prepared with two layers, SSa and three layers, SSb. The samples were made by stitching with lockstitch sewing machine both in warp and weft way. Three different stitch densities were used to sew the samples and they were-7, 9 and 11 stitches per inch. The strength of the produced seams was tested on a universal strength tester machine-the titan tensile strength tester. Test was performed according to ASTM D5034 test method. The outcome of the research shows that seam type, seam direction, thread types, and stitch density have direct effect on lockstitch seam strength of denim fabric with various degrees. Higher seam strength was obtained for the SSb type seam produced in warp direction with coarser sewing thread (60tex) and 11 stitches per inch (SPI). The influence of independent variables on the seam strength was assessed statistically using a multivariate variance analysis (ANOVA) with the help of SPSS software and it was found that they effect significantly. Regression analysis was done to develop the regression equation to predict lockstitch seam strength before production process.