The Cheapest Bale Laydown That Still Meets the Specification

How to read this sheet

Read the relaxation column before anything else. It is the only place in a spinning mill where the cost of a quality line is written as a number, and the pattern is nearly always the same: one line is carrying the entire cost and the rest are met with room to spare. Arguing about the free ones is free in both senses. Take the binding one to whoever wrote the specification and ask what half a point is actually worth in the yarn, because on the seeded floor half a point of short fibre is two hundred and seventy thousand rupees a laydown and the answer may well be that it is worth it - but it will be an answer rather than a habit. What the sheet is not saying. The cheapest mix that meets the specification on paper is not automatically the mix to run. Blending behaviour, contamination history, how a lot opens in the blowroom, and whether a supplier will still be there next month are all real and none of them is in an HVI report. Treat the answer as the floor price of the quality you have written down, and the difference between it and what you actually pay as the price of everything the sheet cannot see. Why there is a cap on any one lot. Without it the arithmetic returns two lots, because a linear programme has no reason to use more, and two lots is not a mix - it is a shade break waiting for the day one of them runs out. The cap is what makes the answer a laydown, and because it costs money the sheet prices it rather than pretending it is free. What is not modelled. Bales are treated as divisible, so the answer will ask for 2,857 kilograms of something that comes in 170 kilogram bales; round it and re-run rather than arguing with it. Quality is averaged linearly, which is right for micronaire, length and strength and wrong for anything that behaves like a threshold - a single contaminated lot is not diluted by the seven around it. Nothing here values consistency across laydowns, which is what a mixing plan is actually for, and a mill that re-solves this sheet from scratch every week will produce a technically cheap mix and a dyehouse in revolt.