Thread consistency

Thread consistency is understood as deviations in diameter from the average linear density of sewing threads and embroidery threads. The number of defects is recorded in relation to a defined length. Thread consistency directly influences sewing performance. A distinction is made between disruptive defects, i.e. those that hinder the sewing process, and non-disruptive defects. Thread consistencyis particularly important for the qualitative assessment of spun threads and core spun threads, as these, due to their construction, exhibit sporadic irregularities and thick spots even under optimal manufacturing conditions.

For optimum thread consistency, a smooth production process from the spinning mill to the finished thread is essential. AMANN examines both the consistency of the yarns used and the threads themselves. This quality feature is tested and monitored in the laboratory and during production.

An Elcometer is used for laboratory testing, which mechanically scans the sewing threads with a probe and detects defects (diameter deviations of a specified size). Defects are cut out and displayed on defect cards.
The faults are divided into fault classes. These are linked to the various causes that lead to the formation of thick and thin spots. They can be caused in the spinning or twisting process, by nubs, impurities, fibre deposits, loops, knots or poor splice points.

Thread consistency is checked during production using optical sensors on the winding machines. Unlike in laboratory testing, defects are not cut out but simply recorded as part of quality control. This allows goods with an excessive number of defects to be identified and separated.