Weaving Productivity
The cause with the most stops is not usually the cause with the most minutes.
— %
Before scheduled changeovers and set marks
Efficiency here is the stop-driven figure only: scheduled changeovers, beam gaiting, style changes, waiting for a weaver and planned maintenance are excluded, so it will always read higher than posted machine efficiency. Mean repair times are treated as constants per cause, which is right for totalling minutes and wrong for predicting any individual stop - the distributions are strongly right-skewed and the tail often carries a third of the time. The three causes here are the standard first cut; a monitoring system that separates weft break from weft feeder, or warp break from drop-wire fault, will produce a sharper Pareto and should be used where available. Lost metres assume the loom would otherwise have run at full speed on the same construction, which overstates the recoverable portion slightly because some stops occur during periods the loom would have been stopped anyway. Contribution per metre, not selling price, is the correct value to apply: the variable cost of yarn not woven is not incurred.
Loom Stop Cause Pareto, Lost Metres & Annual Cost — free, with the formula and a worked example, at Textile School.