The Influence of Stitch Density and of the Type of Sewing Thread on Seam Strength
Having in mind the complex problems of technological process of sewing, as well as general demands for seams produced in garment production, this research should contribute the development of sewed seams breaking forces. Thus, many measurements of seam breaking forces have been conducted. These measurements enable us to define optimal strength of seam strength that improves the compliance of sewed seams parameters. This paper deals with the influence of the thread type and stitch density on the seam strength. The breaking forces and elongations at break were determined by the standardized method (SRPS 2062) and fabric (tape method) according to SRPS EN ISO 13934-1. Fabric samples used for seam testing were sewed by seam (1.01.01) and stitch type 301 with stitch densities 3, 4 and 5 cm. Optimal seam strength (130.9 Ncm) on the fabric T71, and at the same time the highest strength, has been noticed at the samples with seam line in weft direction with stitch density 5 cm, sewed with polyester thread 20x2 tex count, while on fabric T71 that value is 115.9 Ncm. According to obtained results, it can be concluded that stitch density (3 cm ÷ 5 cm) and the type of sewing thread (cotton and polyester, K1 ÷ K5) have great influence on defining seam sttrength, their inconsistency may lead to great differences in seam behavior.
Effect of cyclic loading on the car seat’s seams
The purpose of this work is to find out the influence of thread type, extension ratio and number of cycles to decrease in strength due to stress. In this study four different ratio of spun polyester and polyamide threads are used to sew the textile material (used for car seat cover) by a lockstitch sewing machine. The measuring system simulation of cyclic load has been used. The tensile load, which corresponding to 20 %, 30 %, 40 %, and 50 % of the breaking extension of seam, acting on the experimental specimens with different type of was calculated. Based on the results of experimental measurements, which were closer to the real using conditions of seat covers, it can be stated that with increasing number of cycles, the strength due to the influence of the stress were decreased.
An experimental study of needle heating in sewing heavy materials using infrared radiometry
This paper presents an experimental study on needle heating in sewing heavy materials such as upholstery fabrics. In the experiments, infrared (IR) radiometry, high speed line scanning IR radiometry, and high speed IR radiometry are used to obtain thermal images of the needle during sewing. In particular, IR radiometry was used in lower speed sewing (approximately 500rpm). High speed IR and high speed line scanning IR radiometry were used for medium speed sewing (1,000‐2,000rpm). Using Taguchi’s design of experiment method, the effects of various factors are studied including needle conditions (sharp or blunt), sewing speeds, number of stitches per inch, material being sewn, and thread tension. It is found that even with air vortex cooling the needle may still reach high enough temperatures that may affect the sewing quality and even cause thread breakage. This was confirmed via a thread tensile testing experiment. An empirical model of the mean needle temperature is also proposed and tested.