An Approach to Seam Strength Prediction Using Residual Thread Strength

Owing to a high amount of stress, seam failure in workwear fabrics makes the fabric unsuitable although the fabric strength is high. It is therefore important to predict the seam strength to ascertain the performance of the garments during use and determine the required thread strength and stitch density to match the required seam strength. In all of the earlier predictive equations, seam strength is predicted from thread strength and stitch density along with some multiplicative factors. During the sewing process, a substantial loss in needle thread strength occurs; therefore, the thread becomes weaker than expected after incorporation into the seam. In this paper, the effects of various machine and process parameters are studied on thread strength loss and seam strength. The seam strength is predicted from the loop strength after considering the loss in thread strength. It is observed that higher seam strengths are observed when stronger threads are used for sewing. Loss in thread strength has a significant influence on the seam strength. Seam strength can be predicted using stitch density and thread loop strength, by considering the loss in thread strength during the sewing process. A closer match between predicted and experimental seam strength is possible.