Effect of different parameters on stitch shape and thread consumption

The present work is aimed at studying the effect of fabric compressibility, feed rate and thread tension on the shape of lockstitch and the amount of thread consumed per stitch. Images of different possible stitch shapes have been captured by varying these parameters, and it is found that stitch shape may be rectangular, elliptical, elongated elliptical or circular, depending on the interaction between these parameters. Then, Box-Behenken design of experiment is applied to study the effect of these parameters on the amount of thread consumed per stitch. The contribution% of all the parameters affecting thread consumption is calculated and it is found that the feed rate has highest contribution (92%) followed by thread tension (2.18%) and fabric compressibility (1.53%). From this study, it can be concluded that the prediction of thread consumption in lock-stitching process is only possible if the geometry of the stitch is correctly assumed which varies due to the variations in feed rate, fabric compressibility and thread tension