Which Finishing Line Each Quality Should Run On

How to read this sheet

The three numbers to act on are the extra-hours figures. They say which line to put an overtime shift on, and they are routinely nothing for the line everybody assumes is the constraint. Cheap capacity is what runs out; expensive capacity sits there being expensive. On the seeded plant an extra ten hours on the small old narrow stenter is worth twelve thousand and an extra ten on the new wide one is worth nothing, which reverses the order of every capital request the plant has ever written. A line that takes no metres at all is the finding, not an error. It means that at every point in the answer some other line was cheaper for every quality that would fit on it, which is a different statement from "it is slow" and a much more serious one. Before deciding anything from it, check the hours: a line with no hours entered takes no metres because it was never offered any. Where the width penalty comes from. Nothing in this sheet has a term for wasted width, because none is needed. A wide machine costs more an hour, and it makes no more metres of narrow cloth than a narrow machine does, so its cost per metre of narrow cloth is higher on its own. That is also why the answer is not separable and why a speed table cannot produce it: the cheapest line for one quality is the dearest for another, and no ranking of machines survives contact with a mixed book. What is not modelled. Changeovers between qualities are ignored, so the answer will split a quality across two lines whenever that is a rupee cheaper, and a real plan should round those splits away unless the metres are large. Sequencing within a line is ignored for the same reason - shade order, temperature order and the width order that avoids re-setting the chain are all real and all outside this sheet. Hours are taken as available rather than scheduled, so a line with hours in the period but no crew on nights will be over-loaded here. And the seconds factor is one number per machine, where in truth an old machine is bad at some things and perfectly good at others.