Size Pick-up Percentage Calculator

The formula

This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.

How the result is derived

Step by step, from the values you type to the figure on screen.

1. A sized sample and an unsized sample of the same yarn are dried to constant mass and weighed.
2. The difference is the size solids deposited on and in the yarn.
3. Expressing it against the unsized weight gives pick-up, the figure every size recipe is specified in.
4. The percentage is scaled to the beam to give the solids the size box must deliver, and the sized beam weight that will come off it.
5. The deviation from target is reported because size pick-up is a control variable, not a measurement to be admired.

What each input means

Where to read each value on the floor, the unit it must be in, and the range the tool accepts.

What the tool returns

The headline figure and every supporting value it is built from.

Worked example

Substituting

One point above target on a 1,500 kg warp is 15 kg of extra size solids — bought once in the size kitchen, then removed again at desizing, with the effluent load that implies.

How to use it

1. Work through the input groups in order — Oven-dry Weights and Batch. The defaults are a realistic case, so you can change one value at a time and watch what moves.
2. There is no calculate button. Every figure recalculates as you type or drag, which is what makes this usable for a what-if sweep rather than a single answer.
3. Read Size Pick-up in the dark results panel — that is the headline figure, expressed in %.
4. Check the supporting rows underneath (Deviation from Target, Size Solids on Warp, Sized Warp Weight and Size Added per Sample) before acting on the headline — they are where an implausible input usually shows itself first.
5. Reset to defaults returns every field to the reference case, which is the quickest way to check whether a surprising result came from the tool or from an input you had changed earlier.

Where this is used

• Sizing control — confirming the size box is delivering the recipe, on the beam rather than in the tank.
• Recipe make-up — converting a target percentage into the kilograms of solids for the batch.
• Weaving troubleshooting — under-size shows as warp breaks and hairiness, over-size as shedding, dust and brittle yarn.
• Desizing and effluent planning — the size that went on must come off, and it arrives at the effluent plant as COD.

Reading the result

Typical bands and what each one is telling you.

Assumptions and limits

• Typical pick-up: 8-12% for medium cotton warps, 12-16% for fine or high-sett constructions, under 6% for filament. Check on the beam, not just at the size box.
• Every input is bounded to the range normal practice occupies (Unsized Dry Weight 0.1 to 100000 g, Sized Dry Weight 0.1 to 100000 g and Target Pick-up 0 to 30 %, and so on for the rest). Those bounds are guard rails against typing errors, not a claim that the formula fails one unit outside them.
• The calculation is deterministic: the same inputs always give the same result. It carries no allowance for machine condition, operator skill, ambient conditions or lot-to-lot material variation unless an input above explicitly represents one.
• Nothing is sent anywhere. The maths runs in your browser, so the numbers you type never leave the page.

Standards and further reading

• ASTM D3775 and mill practice: size pick-up is quoted on the oven-dry basis unless stated otherwise.
• ISO 6741-1 — oven drying to constant mass, the method behind both weights.

Questions people ask