Roller pressure distribution on twisted strands during drafting

Drafting is a critical process in spinning that attenuates slivers or strands into yarn and influences the final yarn quality. Roller pressure is key to controlling fiber movement within the strand during drafting. However, previous studies have mainly concentrated on roller pressure in non-twisted strands, leaving the effects on twisted strands unexplored. This study develops a geometric model to analyze the roller pressure distribution in twisted strands during drafting and establishes a mechanical calculation model for further analysis. A thin-film pressure sensor was used to measure the pressure distribution and validate the calculation model. The results indicated that the maximum deviation between the calculated and measured values was 9.58%, confirming the accuracy of the model in predicting pressure distribution on twisted strands held by the roller nip. Additionally, this study investigates how linear density and twist factor influence strand compression properties. Increasing strand linear density promotes uniform pressure distribution, while a higher twist factor leads to stress concentration and elevated compressive stress. Understanding roller pressure distribution is essential for accurately predicting fiber interactions and movement during drafting, ultimately aiding in yarn quality assessment.