A quantitative assessment of seam strength and efficiency across various seam types in shoe upper leathers

In shoe manufacturing, needle holes left on leather after seams are opened or removed, either during production or subsequent use, render the leather unsuitable for reuse. This issue leads to considerable waste of expensive raw materials, increased production costs, and adverse effects on sustainability in the leather industry. Addressing this challenge is crucial to improving both manufacturing efficiency and environmental sustainability. This study investigates the influence of four commonly used seam types, lapped seams (LSa and LSb) and superimposed seams (Ssa-Closed and Ssa-Open), on the seam strength and efficiency of upper leathers used in shoe production. The choice of seam type significantly affects the mechanical performance, durability, and overall quality of the final product. Experimental testing revealed that the lapped seam (LSa) exhibited superior durability when applied to upper leather. Moreover, statistically significant differences were identified among the tested seam types, underscoring the critical role of seam selection in optimizing product integrity and longevity. By selecting seam types based on their mechanical properties, manufacturers can enhance product durability, reduce material waste, and promote sustainability. The findings of this study provide valuable insights for improving the efficiency and environmental impact of leather product manufacturing.