Relationship between drafting force and morphological structure of fiber bundles during the combing process

Abstract

Drafting force during the combing process exhibits periodic variations and considerably affects fiber bundle morphology and unevenness (CV_m) of combed sliver. To address the inefficiency and limited accuracy of conventional methods for evaluating the morphological unevenness of fiber bundles (U_F), an online device was developed to measure drafting force during combing process. Meanwhile, unevenness of periodic drafting forces (U_T) was proposed to evaluate periodic fluctuations in drafting forces. This study investigated the influence of lap weight on drafting force, fiber bundle mass, and the quality of combed slivers, and evaluated the accuracy of U_T in representing U_F. The results showed a good linear relationship between drafting force and fiber bundle mass, with both demonstrating unimodal trends during drafting. Increases in lap weight resulted in higher drafting force and fiber bundle mass, with maximum values observed at the 24th division. Further, U_T and U_F exhibited a good linear relationship, indicating that U_T effectively reflects the periodic fluctuations in fiber bundle morphology. As lap weight increases, U_T, U_F, and CV_m of combed slivers decrease and later increase. Using the JSFA2186 comber and based on the combing process utilized in this study, the optimal lap weight for long-staple cotton was found to be 75 g/m, which yielded the lowest U_T (4.53%), U_F (4.25%), and CV_m of combed sliver (6.28%). For medium-staple cotton, a lap weight of 81 g/m yielded the lowest values (4.66%, 4.52%, and 6.76%, respectively). This study establishes a theoretical foundation for developing auto-leveling devices and advancing the development of smart combing machines.