A step on automatic sewability evaluation and seam control on an overlock sewing machine

摘要

This paper presents a contribute to the quantification of the sewability of different materials and a proposal for the automatic control of the seams in order to obtain quality seams. A system is used on an overlock sewing machine, enabling the acquisition, monitoring and storage of the variations of the most important variables involved in the set-up of the stitch formation. The knowledge of the absolute reference values of each variable on different sewing conditions, enable to establish the relationships between thread tension on the threads involved in the stitch formation and its consumption and the quality of the seams, resulting in the definition of factor designated by Stitcheck. This factor is related with the quality of seam and is than used to control and guarantee the on-line set-up of the sewing machine. The knowledge of the behaviour of the thread tension variation with the pre-tension force applied to each thread allows also the on-line detection of defects or non-ideal seams.