Blowroom & Carding
A drawframe blend is quantised. One end down is a blend change, not a stoppage.
— %
By mass, from ends and linear densities
This is a two-component blend by mass at the creel. Three or more components follow the same arithmetic but are not covered by the two-component form here. The calculation assumes both components pass through the machine with equal waste, which is close enough for a drawframe but not for a blend struck earlier in the line - differential fibre loss between polyester and cotton through blowroom and carding is real and moves the delivered ratio away from the fed one. Blend is on an as-received mass basis; if the two components are at different moisture regains, the dry-mass ratio differs from the ratio computed here, and a cotton-polyester blend weighed on a humid day is the classic case. Verify the finished blend by chemical analysis rather than trusting the creel arithmetic.
Drawframe Creel Blend Ratio, Quantum & End-Down Shift — free, with the formula and a worked example, at Textile School.