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Weaving Calculations · Lecture 22
Planning IV – Production Over Months
A day-by-day simulation: looms come on line one by one, stock builds up, and four shipments must be met on their dates.
Ramp-upCumulative stockShipmentsContainers
The problem
Two widths of 60×60/161×112 are to be woven for a customer: the 68" quality makes 230 m per loom per day and the 98" quality 170 m. Looms are released to the order gradually — one more every two days until all are running. Shipments are booked on 10 October, 25 October, 5 November and 30 November, and each ships in a container (a 20 ft container holds 40,000 m of 68" or 30,000 m of 98"; a 40 ft holds double). Will the stock be there on each date?
The workbook runs a daily ledger from 1 September: looms × rate = production, cumulative stock minus shipments. The sheet below does the same with a loop, so you can change the ramp, the rates or the shipment programme and see at once which shipment slips.
| A | B | C | |||
|---|---|---|---|---|---|
| 1 | 68" quality | 98" quality | |||
| 2 | Production per loom per day (m) | ||||
| 3 | Maximum looms on this quality | ||||
| 4 | Looms added: one every … days | ||||
| 5 | Looms running on day 1 | ||||
| 6 | Shipments (day number from 1 Sep: 10 Oct = 40, 25 Oct = 55, 5 Nov = 66, 30 Nov = 91) | ||||
| 7 | Shipment day | 68" (m) | 98" (m) | ||
| 8 | |||||
| 9 | |||||
| 10 | |||||
| 11 | |||||
| 12 | Result: stock on the shipment day after loading (negative = short) | ||||
| 13 | 40 | 40,040 | 18,450 | ||
| 14 | 55 | 36,440 | 18,950 | ||
| 15 | 66 | 46,800 | 22,650 | ||
| 16 | 91 | 95,800 | 35,150 | ||
| 17 | Day on which the last shipment is fully covered | 57 | 71 | ||
blue = input (edit me)grey = formula (click to see it)
With the lecture’s figures the 68" shipments are comfortably covered but the 98" quality is short for the first two shipments unless more looms are freed earlier — the planner’s choice is to delay the 68" ramp and give the 98" looms priority. Containers: 40,000 m of 68" + 30,000 m of 98" fill one 40 ft box; the 5 November lot (20,000 + 15,000) fits a 20 ft box.