Yarn Waxing Add-On, Disc Life & Friction Reduction

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. The 8 inputs are read from the form on every keystroke: Wax Add-On, Wax Disc Mass, Wax Price, Winding Speed, Yarn Linear Density, Package Weight, Unwaxed Friction Coefficient and Friction Reduction Achieved.
2. Each value is checked against the accepted range in the input table below. A value outside its range stops the calculation rather than producing a misleading figure — the results blank out and a message appears.
3. The validated values are substituted into the expression above, which resolves Wax Disc Life together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Yarn per Disc, Wax Consumed, Wax per Package, Wax per Kilometre, Waxed Friction Coefficient, Wax Cost per Kilogram, Yarn Wound per Drum and Add-On — come from the same pass, so they always describe the same case as the headline figure.
5. Results are rounded for display only. The full-precision value is used throughout the chain, so reading a rounded intermediate figure back into the tool by hand can shift the last digit.

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

Half a cent of wax per kilogram of yarn buys a 45% cut in friction. It is one of the cheapest interventions anywhere in the chain, and skipping it does not save money - it stops the knitting machine.

How to use it

1. Work through the input groups in order — Waxing and Winding & Friction. 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 Wax Disc Life in the dark results panel — that is the headline figure, expressed in h.
4. Check the supporting rows underneath (Yarn per Disc, Wax Consumed, Wax per Package, Wax per Kilometre, Waxed Friction Coefficient, Wax Cost per Kilogram, Yarn Wound per Drum and Add-On) 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

• Process planning — establishing Wax Disc Life before a trial is booked, so machine time and material in Spinning, Winding & Yarn Package Engineering are committed against a calculated figure rather than an estimate.
• Costing and quotation — Wax Disc Life is an input to the cost sheet, and quoting from a worked number rather than a remembered one is what keeps a margin intact.
• Troubleshooting — when the floor result drifts from plan, entering the measured values (starting with Wax Add-On) shows how much of the gap in Wax Disc Life each variable explains.
• Teaching and study — the accepted ranges bracket normal Spinning, Winding & Yarn Package Engineering practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Reading the result

Typical bands and what each one is telling you.

Assumptions and limits

• Add-on is the input here rather than a prediction: actual transfer depends on disc composition, contact pressure, yarn speed, yarn hairiness and ambient temperature, and it is measured by solvent extraction from the waxed yarn rather than calculated. Wax is applied for knitting and is normally omitted for weaving yarn, where it interferes with sizing adhesion. The friction figures are indicative of the effect being sought and are not derived from the add-on - the relationship between the two is non-linear and saturates, so doubling the wax does not halve the friction again. Disc life assumes continuous running and even transfer across the disc, which wear patterns do not always give.
• Every input is bounded to the range normal practice occupies (Wax Add-On 0.1 to 6 g/kg, Wax Disc Mass 20 to 600 g and Wax Price 0.5 to 30 /kg, 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 D3108 - Coefficient of Friction, Yarn to Solid Material, the measurement this targets.
• ASTM D3412 - Coefficient of Friction, Yarn to Yarn.
• ISO 2062 - single-end breaking force, which waxing should not affect.

Questions people ask