Autoleveller Systems on Cards
topic
Card autolevellers measure sliver linear density continuously using a sensing element at the card trumpet and apply corrective speed changes to the feed roller within 0.5 seconds, correcting long-term sliver weight variations above 5 metre wavelength to within plus or minus 1 percent coefficient of variation of sliver count, compensating for chute feed density variations and cylinder loading changes during production.
Role
Maintains sliver linear density consistency that is fundamental to subsequent yarn count consistency and fabric weight uniformity, with card autolevelling being the first closed-loop control in the spinning preparation sequence that prevents raw material variability from propagating as count variation through drawing, roving, and spinning stages into the final yarn and fabric.