The mechanism of sewing damage in knitted fabrics

An investigation is reported in which penetration of the sewing needle in fabric was recorded by using a high-speed video technique. Photographs show that the sewing needle penetrates the fabric structure at different positions during sewing. On the basis of a simplified knitted structure, the mechanism of sewing damage is analysed. This analysis establishes that sewing damage in a knitted fabric is affected by the yarn structure and properties, fabric construction, and sewing conditions. During needle penetration in the sewing of garments, the fabric will be liable to damage by a number of factors or a combination of them, namely, an increase in the yarn modulus, coefficient of friction (yarn to yarn and yarn to needle), needle size, and yam-tension or yam-compression modulus. Sewing damage will be reduced with an increase in the size of the throat-plate hole and/or the loop size of the fabric structure. The effects of needle points, yarn twist, and yarn tension are also analysed in cases in which the sewing needle hits the yarn of the fabric, and the importance of ball-point-shaped needles for combating needle damage and the influence of yarn twist are demonstrated.