Correlation between the Seam Stitch Length of the Sewing Garment and Friction Forces

Abstract

In this article the influence of the friction forces on stitch length is analysed. In the course of research, fabrics with
different mechanical and structural properties have been used. Internal friction of fabric has been assessed using resonant
oscillations. When correlating stitch length with internal friction of fabric it has been established that internal friction
influences the stitch length. With minor internal friction of fabric stitch length is unstable and may vary by up to 0.5 mm.
As internal friction of fabric increases, average stitch length stabilises or varies within the limits of 0.1 mm. In order to
assess quality of the sewing garment it is important to establish how deformation of the sewing garment changes both in
the course of sewing and when some time passes after sewing. This is the internal friction that determines relaxation
time of the sewing garment and at the same time variation of stitch length after sewing. With minor internal friction of
fabric relaxation time of the sewing garment is short (~10 min). When fabrics with higher internal friction are sewn
together relaxation time is longer (up to 60 – 240 hours). It has been established that different external forces lead to
different feeding conditions of fabric. If external friction force is minor stitch length has no tendency of constant
variation, i.e. it may either increase or decrease within the limits of 0.1 mm – 0.3 mm. If external friction force is
considerable, stitch length is higher and in the same fabric, under different directions featuring different friction force
stitch length may differ by up to 0.4 mm. The lower is the external friction force of fabric, the more considerable
decrease of the stitch length is observed when increasing pressing force. It was found as well that the higher is the
external friction force of fabric, the lower influence on stitch length variation is made by two-sided load of the sewing
garment.