DEVELOPMENT AND CHARACTERIZATION OF STITCH-BASED SENSORS

Strain sensing seams have been developed by integrating conductive sewing threads in different types of seam designs on a fabric typical for sports clothing using sewing technology. The aim was to obtain a simply integrated stitch-based sensor that can be applied on sports clothing to monitor the movements of the upper body parts of the user during exercising. Stitch types 304; 406; 602 and 605 were produced. The seams were made on a knitted fabric composed of 80% polyamide 6.6 and 20% elastane. The seams underwent stretch cycling for 10 cycles and up to 44 cycles following EN ISO 14704-1:2005 (modified), using an INSTRON tensile tester machine. The changes in the resistance of the seams with time were recorded simultaneously using Agilent meter U1273A. Sensing functionality among which is sensor gauge factor (GF), stability, drift, and reproducibility were evaluated on the promising sensor seams. The type of base fabric used, stitch type, stitch formation process (friction and dynamic forces during sewing), integrated EC thread length, and positioning of thread(s) in the fabric have a significant influence on the performance of the seams. Sensor seam 406-001comprising 2 EC yarns (Madeira HC12) and Sensor seam 304-010 comprising 1 EC yarn (Madeira HC40) turned out to be very promising and others shall be improved (sensor 602-006 with Madeira HC 40 and sensor 605-002 with a Muriel yarn).

Thread Type and Stich Density Suitable for Seams in Ghanaian Public Basic School Uniforms

Background: The serviceability of a sewn garment is influenced by the quality of its seams, which form the basic structural element. The factors that affect seam quality in garments includes, sewing thread type and stitch density. Their right choice helps with the achievement of quality seams in garments. However, the choice of suitable sewing threads and stitch densities for particular fabrics can only be determined through testing. Objective: Problems associated with poor performance of school uniforms include seam failure. The aim of the study was to determine sewing thread brand and stitch density suitable for seams for a selected fabric (79% polyester and 21% cotton) for Ghanaian public basic school uniforms. Method: A 2×3 factorial design was employed which involved two brands of sewing threads labelled Aʹ and Bʹ and three range of stitch density, 10, 12 and 14. The total number of specimens prepared from the selected fabric was 81. The parameters investigated included fabric weight, strength and elongation, seam strength, seam elongation and efficiency. The data were analysed using the Predictive Analytic Software (SPSS). Means and standard deviations of the fabric’s yarn count, weight, strength, elongation and the linear density of the sewing threads were determined. Analysis of Variance and Independent samples t-test at 0.05 alpha levels were employed in testing the hypotheses. Results: Differences for seam strength, efficiency and elongation were significant for the two sewing thread brands and the three stitch densities in both warp and weft directions of the fabric sample. The sewing thread brand B′ with stitch density 14 performed best in terms of seam strength, elongation and efficiency. Conclusion: The sewing thread brand B′ and stitch density 14 are recommended to be used for the construction of uniforms with the selected fabric to achieve quality in uniforms.

Investigation of interactions between fabric performance, sewing process parameters and seam pucker of shirt fabric

Seam pucker is a common problem in sewing. It not only affects the appearance of product, but also affects product performance. The purpose of this study is to quantify the complex dynamic interactions between fabric performance, sewing process parameters and seam pucker. In order to solve the problem of shirt seam pucker, this study selected four kinds of shirt fabrics, three kinds of polyester sewing threads, three kinds of stitch density and four kinds of seam types for experiments. Through unitary regression analysis, the subjective and objective evaluation results are consistent. Further analysis the results of objective experiment revealed that fabric performances, seams type, sewing thread and stitch densities all have impact on seam pucker. Meanwhile also find out the sewing process parameters for the four fabrics when the seam shrinkage’s were smallest, so it’s helpful for the apparel enterprises to improve seam quality. Multiple linear regression analysis of experimental results show that fabric performances has the greatest influence on seam pucker, thickness, weight and warp density of fabric properties significantly affect seam pucker. And as the breaking elongation of sewing thread increases, seam pucker also increases. Stitch densities and seam type has the least affected on seam pucker, they affect the seam pucker by changing the extension of stitch and thickness of fabric at the seam, respectively. Seam type has greater impact on fabrics that are prone to seam pucker, seam type T1 get larger seam shrinkage than T4. Finally, the complex dynamic interactions was quantified and expressed through mathematical models.

Towards One-Dollar Robots: An Integrated Design and Fabrication Strategy for Electromechanical Systems

SUMMARY To improve the accessibility of robotics, we propose a design and fabrication strategy to build low-cost electromechanical systems for robotic devices. Our method, based on origami-inspired cut-and-fold and E-textiles techniques, aims at minimizing the resources for robot creation. Specifically, we explore techniques to create robots with the resources restricted to single-layer sheets (e.g., polyester film) and conductive sewing threads. To demonstrate our strategy’s feasibility, these techniques are successfully integrated into an electromechanical oscillator (about 0.40 USD), which can generate electrical oscillation under constant-current power and potentially be used as a simple robot controller in lieu of additional external electronics.

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.

Graphene/silver nanoflower hybrid coating for improved cycle performance of thermally-operated soft actuators

Twisted and coiled actuators (TCAs), fabricated by twisting cheap nylon sewing threads, have attracted a great deal of attention for their use as artificial muscles or soft actuators. Since the dynamic behavior of a thermally-operated TCA is governed by its thermal properties, graphene and silver nanoflowers (AgNFs) were spray-coated onto the surface of an actuator to achieve enhanced heat transfer. Addition of AgNFs improves interfacial thermal contacts between graphene flakes, while pristine graphene flakes have extremely high in-plane thermal conductivity. Thus, the synergistic effect of graphene and AgNFs reduced the total cycle time of the TCA by up to 38%. Furthermore, when a pulsed current with a 40% duty cycle was applied to the TCA, the graphene/AgNF-coated TCA exhibited a threefold larger peak-to-peak amplitude of the displacement oscillation of the actuator, as compared to that of the non-coated TCA, which demonstrates that the combination of graphene and AgNFs effectively reduced a cooling time of the TCA. This work shows great potential for a simple coating of graphene and AgNFs to produce high-performance thermally-operated soft actuators.

Concerning the Application Possibility of Ultrasonic Welding of Textile Materials on the Basis of Synthetic Fibres in the Manufacturing Processes of Parachute Systems

The application possibility of ultrasonic () welding in the technological process of the canopies of braking parachute systems manufacturing for the unmanned aerial vehicles was considered. The subjects of research were parachute fabrics (100 % capron), manufactured by with different surface weight, weave and type of finish. Welding modes were chosen. The obtained welded seams had no defects and met the requirements of technical standard documentation, with the increase of the distance between the welding spots, the welding strength of the welded seam was decreased by 10–40 %. The strength of the seams at the “in shear” test is on the average 2-3 times larger than at the gripping method test. The draft of the nozzle-roll for executing the spotted welded seams was proposed. The calculations suggested that the application of the welded seams instead of sewn seams would allow the reduction of the costs for sewing threads during the manufacturing of the canopy to 50 % and the significant reduction of the labour requirement.