STUDY REGARDING THE STITCHING STRENGTH OF MATERIALS USED FOR FOOTWEAR UPPERS MANUFACTURING

Abstract

The shoes manufacturing implies the use of various types of leathers, leather substitutes and fabric. The sewing plays a very important role in shoe making, having an impact both in terms of functionality and outlook. One of the most important indicators of the sewed products quality is seam strength, which is influenced by a series of technological parameters such as: the shape of the needle’s top, the needle’s diameter, the seam thickness, the number of seams, the gauge of the thread, the type of seam and the material type. This paper studies the stitching strength of the full grain leather and full grain leather shiny surface used for footwear uppers, in order to improve productivity and seam quality.The experimental researches obtained for the stitching strength allow calculating the weakening coefficient of the material in the process of sewing (a= 0.33-0.48). The “a” coefficient is dependent on the stitch density, the shape of the needle’s top and the joined materials. In terms of stitching strength, the results indicate that the full grain leather obtains higher values than the full grain leather shiny surface.

Keywords

• Leather
• Stitch strength
• needle
• stitch density
• open seam
• lapped seam