This paper aims to define the dominating factors having influence on the quality of the seam by sewing of fine fabrics and their optimum values.
Ten factors defining a seam's quality are chosen on the base of literary research. There was a check for concurrence of specialists' opinions, as the Spearman's coefficient of concordance was determined. A designed experiment with variation of the first three of the arranged factors was made. Mathematical models for the tensile and the aesthetical properties of the seam were devised, and also optimization made.
A classification of the properties, defining seam's quality, is made. A cause‐effect diagram of Ishikawa with aiming parameter – quality of the seam – has been developed. On the basis of a survey the factors that have a great deal of influence on it are presented. Mathematical models for seam's strength, elongation and smoothness are produced by changing the following factors: straining of the upper thread, size of the needle and load on the pressing foot are worked out. Received models are optimized.
The research was conducted using a sewing‐machine class 301. Received results and conclusions refer to seams made from base material – fabric from PES and sewing thread from 100 percent PE.
Optimum values have been established for the straining of the upper thread, the size of the needle and the load on the pressing foot by sewing of fabric from synthetic silk with mass applicable machines, needles, and sewing threads.
The research has been done in several directions: systemizing the seam's properties for evaluation of its quality and the factors defining it, inquiry into the significance of the different factors and implementation of a designed experiment. Consultations were made with a broad circle of specialists and these results are given in visual systems (schemes and graphs).
