Influence of Fiber Quality on Draftometer Measurements

Fiber-to-fiber and fiber-to-machine friction play an important role in determining textile processing efficiency and end-product quality.  A process, known as drafting, is used to control the attenuation of the fiber mass being processed in carding, drawing and spinning.  The amount of attenuation the fiber mass is subjected to can be referred to as the “draft”.  Critical draft is the draft at which drafting forces become unstable; also known as “stick-slip”.  Prior studies have shown that the break draft on ring spinning frames should be 10 percent below critical draft.  Textile processors have the option to control the stick-slip point without altering the break draft on the spinning frame by altering the twist in roving.  Critical draft can be determined through instruments such as the ITT Draftometer.  In this study, cottons of various fiber quality (length and micronaire) were converted into roving and measured on the draftometer.  Roving was produced at the recommended level of twist as well as at higher and lower levels of twist and then subjected to spinning trials to measure yarn quality and spinning efficiency.