Theoretical output at the efficiency entered. Unplanned stoppages and defect running time reduce this further.
Production in weight is really a yarn-consumption calculation. Every loop consumes one stitch length of yarn, so counting loops per hour and converting to weight gives output directly.
The 10⁹ divisor handles three unit conversions at once: millimetres to metres, tex (grams per 1000 metres) to grams, and grams to kilograms.
A 30-inch, 24-gauge single jersey machine running 96 feeders at 25 RPM, stitch length 2.8 mm, 30s Ne yarn (19.7 tex), at 85% efficiency:
This calculation assumes every kilogram produced is saleable. It is not. Fabric knitted after a needle breaks or a lycra end drops is still counted as production by the machine, still consumes yarn and machine hours, and is still discovered only later at the inspection table. On a floor running at 85% mechanical efficiency, the effective yield can be materially lower once downgraded rolls are subtracted.
Production in weight comes from the total yarn consumed. Multiply needle count by machine RPM and feeder count to get loops per minute, multiply by stitch length for yarn length, then convert length to weight using the yarn's tex value. Finally apply your machine efficiency percentage.
Needle count equals pi times the cylinder diameter in inches times the gauge in needles per inch. A 30-inch, 24-gauge machine has roughly 3.1416 × 30 × 24 = 2,262 needles.
Efficiency accounts for yarn breaks, doffing, cleaning, style changes and maintenance stops. Well-run circular knitting floors typically run 85–92%. If you are unsure, 85% is a realistic planning figure. Anything quoted above 95% usually excludes planned stoppages.
The calculation gives theoretical output at the efficiency you enter. The gap is almost always unplanned stoppage: yarn breaks, needle damage, lycra breaks and — most expensively — time spent knitting fabric that will later be downgraded. Defect running time is production that costs yarn and machine hours but yields nothing saleable.
Yes, directly. Higher gauge means more needles per inch, so more loops per revolution and more yarn consumed per minute. But finer gauge normally pairs with finer yarn, so the two effects partly cancel in weight terms while changing fabric character substantially.
Divide courses produced per hour by courses per inch, then convert inches to metres. The calculator reports both weight and length so you can plan against either a kilogram target or a metre target.
A machine that has been knitting a hole for forty minutes is running at 100% mechanical efficiency and producing nothing of value. Knit-I detects the defect as it forms and halts the machine — converting hours of scrap into metres, and making your real yield match your calculated one.
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