Effect of Different Sewing Parameters on Lockstitch Seam Strength for Denim Fabric

Seam strength plays a very important role in acquiring the desired quality seam which ultimately defines the quality of any clothing. The paper is aimed to study the strength of seam produced from denim fabric, how different sewing parameters like sewing thread type, type of seam, seam direction as well as the density of stitches influence the strength of seam, and it is observed that they have direct effect on lockstitch seam strength of denim fabric with various degree. For research denim fabric with 3/1 weaves structure and three different sewing threads namely 100% cotton spun with 14tex linear density, 100% polyester spun with 24tex and 60tex linear density were used. Seam class used for the research was superimposed seam prepared with two layers, SSa and three layers, SSb. The samples were made by stitching with lockstitch sewing machine both in warp and weft way. Three different stitch densities were used to sew the samples and they were-7, 9 and 11 stitches per inch. The strength of the produced seams was tested on a universal strength tester machine-the titan tensile strength tester. Test was performed according to ASTM D5034 test method. The outcome of the research shows that seam type, seam direction, thread types, and stitch density have direct effect on lockstitch seam strength of denim fabric with various degrees. Higher seam strength was obtained for the SSb type seam produced in warp direction with coarser sewing thread (60tex) and 11 stitches per inch (SPI). The influence of independent variables on the seam strength was assessed statistically using a multivariate variance analysis (ANOVA) with the help of SPSS software and it was found that they effect significantly. Regression analysis was done to develop the regression equation to predict lockstitch seam strength before production process.

Event-Driven CNC Modularized Sewing Platform

With ever increased demand for quality and productivity, modern industrial sewing machine is becoming very complex and requiring sophisticated control. This paper presents a control platform that can be used for all kinds of lockstitch sewing machines. This event-driven control platform can support various kinds of sewing operations, from simple lockstitches, to X-Y lockstitches, as well as thread cutting. The key to the control platform is the precision cooperative control. First, for each motion axis, both the position and the velocity must be precisely controlled. In addition, the multi-axis motions must be synchronized to achieve high accuracy stitches. In order to increase the machine flexibility and decrease variety, a generalized and modularized sewing platform is proposed in this paper. It can be assembled with common lockstitch sewing machine and achieve several kinds of sewing functions. This platform module has independent driving capability to fulfill special movement and the communication ability to collaborate with other modules. Besides the modularized mechanism, the reusable and reconfigurable control system is the key point. For industry sewing machine, the important functions are the single-axis precise control and multi-axis cooperative control. In the X-Y moving platform, the closed-loop stepper motor system is adopted for each axis to obtain precise speed and position control. On the other hand, the cooperative control between modules is realized by event-based control method which uses a time-independent parameter to avoid the uncertain time-delay. To verify the system, the corresponding experiments are taken. And the results satisfy the requirements very well.

Tensile Properties of Sewing Thread and Sewing Needle Temperature at Different Speed of Sewing Machine

Needle heatup is a big issue for apparel industry especially for automobile industry seat covers where a lot of synthetic materials are used which get damaged by needle heat at high speed of sewing machine,in this article thermocamera and thermocouple are used to measure the precise temperature of needle eye and then 100% polyester 35x3 Tex thread is taken for sewing,the lockstitch sewing machine is run at 1000rpm,2000rpm and 3000rpm respectively and the both methods are used to obtain the accurate needle temperature and finally thread tensile properties are measured before the sewing and taking out the thread from the seam precisely to get the tensile properties of thread after 10,30 and 60 seconds of continuous stitching,the article is very helpful in predicting the exact temperature of needle in lock stitch machine and getting the damage to thread by the needle heat at different speeds and different stages of sewing process.