Circular Knitting
Two per cent of slippage is two per cent of fabric weight, banded at one machine revolution.
— %
Delivery shortfall against the wheel circumference
The model assumes the feeder wheel is the delivery reference and that loop length scales directly with delivered yarn, which holds for a positive feeder controlling supply but not for a tension-controlled or negative feed, where loop length is set by yarn tension against the cam and this calculation does not apply. Measured delivery must be taken over many revolutions; a single revolution cannot be measured to the precision the arithmetic implies. Slippage is not a fixed property of a feeder - it rises with downstream tension, so a reading taken at one machine speed or fabric take-down setting does not transfer to another. The feeder-to-feeder spread is entered as a range rather than derived, and it needs measurement across a representative sample of feeders rather than the two that were easiest to reach. Fabric weight here is the greige figure at the stated stitch density and will move substantially through relaxation and finishing.
Positive Feeder Slippage, Loop Length Error & Barre Spacing — free, with the formula and a worked example, at Textile School.