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Weaving Calculations · Lecture 18
Sizing Cost Analysis
Relating sizing cost per kilogram to warp count across many articles, and forecasting the cost of a new count with linear and quadratic trends.
RegressionFORECASTTrend lineCost per kg
Why sizing cost rises with count
Finer warps have more ends per kilogram and more surface to coat, need higher size add-on and run slower on the sizing machine, so the cost of sizing one kilogram of warp climbs steeply with Ne. The lecture tabulated the sizing cost of 41 articles against their warp count and fitted a trend to it. A representative selection of those points is loaded below — type your own figures over them.
| A | B | C | D | E | F | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Warp Ne | Rs / kg | Warp Ne | Rs / kg | Warp Ne | Rs / kg | |||||
| 2 | |||||||||||
| 3 | |||||||||||
| 4 | |||||||||||
| 5 | |||||||||||
| 6 | |||||||||||
| 7 | Fits (least squares over the 15 points) | ||||||||||
| 8 | Forecast at Ne | ||||||||||
| 9 | Linear slope | 0.1450 | Intercept | 3.3256 | Linear forecast | 9.13 | |||||
| 10 | Quadratic a (x²) | (0.00008) | b (x) | 0.1492 | c | 3.2833 | |||||
| 11 | Quadratic forecast | 9.12 | |||||||||
blue = input (edit me)grey = formula (click to see it)
The lecture’s full table gave a linear FORECAST of 9.15 Rs/kg at Ne 40 and a quadratic trend 0.0027x² + 0.0172x + 4.4432 → 9.45. The quadratic fits the upward curve better; a linear trend under-estimates the cost of fine counts and over-estimates coarse ones. One double-pick article at 11.64 Rs/kg was an outlier and excluded.
Trend lines from the lecture
Original lecture material
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