Blowroom & Carding
Doubling buys exactly the square root of the ends. Everything worse than that was made in the drafting zone.
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The irregularity doubling does not explain
The decomposition assumes the feed ends are independent, which is the basis of the square-root rule. They are not independent if several ends come from the same card or the same can, and correlated feed is a real and common condition that makes the doubling improvement smaller than predicted - in that case the drafting-wave residual computed here is overstated, because the shortfall is being blamed on drafting. The limit irregularity is the Martindale figure for a random assembly of fibres of uniform linear density; a real fibre population has a spread of fineness, which raises the true limit slightly above the value shown. Measured CVs must be taken at the same cut length on the same instrument - a CV at 1 m and a CV at 1 cm are different quantities and cannot be combined. The drafting wave is periodic in nature and a CV alone does not locate it: use the spectrogram to identify the roller, and this figure to size the problem.
Drawframe Draft, Doubling & Drafting-Wave Decomposition — free, with the formula and a worked example, at Textile School.