Right choice of the size of sewing thread and the number of joint stock should be based on the difference of the density, thickness and weight of the sewing material. The shoe fabric as an example, the single yarn strength is greater than the sewing yarn of a single fabric (or thread) strength requirements, so the yarn fineness should be larger than the single yarn or thread in the fabric of fineness and similar, while also taking into account the suture fineness and fabric appearance to adapt in addition, according to the different parts of sewing sewing products of their own requirements, and fabric structure and joint structure changes, to choose the suitable sewing thread of different specifications and fineness.
Specifications of the sewing thread are represented by the number of single yarn or monofilament and the number of joint shares. Such as 14.8 x 3 polyester line, x 3 (150 D 167 x 3) polyester filament, it marks the strength of thickness, and the application range of the line, because the line thickness specifications of different lines, its strength is not the same. When sewing, if the thickness specification line improper selection, will also directly affect the sewing effect, such as sewing shoes uppers, such as line selection fine, will be produced because of suture strength is not enough the seam strength, or because I don't have the matching needle skipping fault.
But because the money is relatively tight and sewing seam joint is smooth, not easy to cause the seam shrinkage, the stitch is not easy to wear, but also beneficial to improve the sewing efficiency. To sum up, in sewing, we should choose the thickness and size of sewing thread reasonably according to the thickness and properties of sewing materials and sewing process requirements, which is an essential condition for ensuring the sewing effect.