Strength reduction of sewing threads during high speed sewing in an industrial lockstitch machine

Reports on investigations into the mechanism of sewing thread strength reduction. Results indicate that structural damage, namely, structural openness and pull‐out of fibre ends from the surface are the major cause of strength reduction and that the fibre strength reduction is found to be only marginal compared to the thread strength reduction. Cotton threads exhibit higher strength loss owing to their poor abrasion resistance. Comparatively shorter fibres in cotton threads are also found to be responsible for the higher strength reduction.