Controlling the Fiber Stress Distribution with Variable-Frequency Step Roll for Tunable Spun Yarn Structures

Area of Science:

• Textile Engineering
• Materials Science

Background:

• Dynamic regulation of fiber stress is crucial for composite yarn structures.
• Siro and sirofil composite yarns exhibit variable structures dependent on fiber stress distribution.

Purpose of the Study:

• To compare geometric structure and stress distribution in yarn formation using asymmetrical fiber control.
• To analyze the impact of step roll parameters on composite yarn characteristics.

Main Methods:

• Ring-spinning technology with step rolls featuring asymmetrical fiber control.
• Geometric analysis of yarn-forming triangle area.
• Yarn structure modeling and simulation.
• Systematic comparison of yarns produced with different step roll frequencies.

Main Results:

• Asymmetrical control leads to cyclic changes in helical angles and wrapping density.
• Siro yarns show periodic staple fiber distribution; sirofil yarns exhibit gradual changes.
• Step rolls with low frequency and wider grooves cause more pronounced structural variations and slight quality deterioration.

Conclusions:

• Intermittent fiber restraint due to asymmetrical control significantly impacts yarn structure.
• Step roll design, specifically groove width and frequency, directly influences composite yarn uniformity and quality.
• Optimizing step roll parameters is essential for controlling structural variations in siro and sirofil yarns.