Loom Sley Acceleration Profile & Frame Loading

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 4 inputs are read from the form on every keystroke: Sley Stroke, Reciprocating Sley Mass, Connecting Rod Ratio and Loom Speed.
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 Peak Inertial Force together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Peak Acceleration, Peak Acceleration, Back Dead Centre Force, Alternating Force and Oscillation Frequency — 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

The tool loads with this case already solved — the Peak Inertial Force shown above is its answer. Change one value and the difference from this baseline is the sensitivity of the result to that variable.

How to use it

1. Work through the input groups in order — Mechanism and Running Speed. 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 Peak Inertial Force in the dark results panel — that is the headline figure, expressed in kN.
4. Check the supporting rows underneath (Peak Acceleration, Peak Acceleration, Back Dead Centre Force, Alternating Force and Oscillation Frequency) 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 Peak Inertial Force before a trial is booked, so machine time and material in Textile Machinery Kinematics & IoT Analytics are committed against a calculated figure rather than an estimate.
• Costing and quotation — Peak Inertial Force 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 Sley Stroke) shows how much of the gap in Peak Inertial Force each variable explains.
• Teaching and study — the accepted ranges bracket normal Textile Machinery Kinematics & IoT Analytics practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Assumptions and limits

• Only the first two harmonics of slider-crank motion are included, which is standard practice and adequate for the peaks, but a real cam-driven sley follows whatever profile the cam designer chose and can differ substantially — particularly in jerk, which the harmonic approximation understates and which is what actually cracks brackets. The reciprocating mass must be the effective mass referred to the sley, including the appropriate share of the swords and rod, not just the reed and race. Inertial force is also only one of the loads on the frame: beat-up resistance from the fabric and shedding forces arrive at the same time and are calculated separately.
• Every input is bounded to the range normal practice occupies (Sley Stroke 20 to 400 mm, Reciprocating Sley Mass 2 to 300 kg and Connecting Rod Ratio 2 to 12 L/R, 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.

Questions people ask