Warping and Sizing Calculations.
In getting an order passed through a weaving shed the first point, after calculating the particulars for each piece or cut, is to get the length for warping and sizing. In the case of an order for 3750 pieces of the before-mentioned dimensions, the total length of warp is calculated thus—38 yards for one piece × 3750 = 142,500 yards, allowing nothing for waste in length, as the tension on the yarn in process will stretch it sufficiently to allow for that, and perhaps a little more. At the warping mill the length is taken in wraps of 3564 yards, subdivided into teeth of 27 yards. In this case, four wraps or 14,256 yards would be taken to a set of back beams; therefore, this order would be run in ten separate sets.
The number of back beams for the sizing machine is proportioned to the capacity of the warping mill—say five beams, the length on each beam must be 14,256 yards, and the total number of ends on the beams equal to the ends in the piece—say 5 at 456 each = 2280.
To Calculate the Counts of Yarn after Warping.—Divide the length by the weight and 840. A beam weighs 301lb., carrying 504 ends, each 14,256 yards long—
(14,256 × 504)/(301 × 840) = 28·41’s.
Having 375 pieces to make from the set of beams, which will probably weigh about 1300lb. for 30’s twist, to this add 25 per cent. for size =
(1300 × 325)/100 = 325
1300
——
1625
Divide by 375) 1500 (4lb. 5oz.
——
125
16
——
2000
4lb. 5oz. being about the size required (vide page 150).
Actual Size.—To find the size actually put on the yarn, subtract the weight of the unsized yarn less waste from the sized yarn—e.g.,
1639 Actual sized weight.
1300
——
339 = Weight of size.
1300) 33900 (26·07 per cent. actual.
2600
———
7900
7800
——
100
Counts after Sizing.—
(14256 × 2280) / (1639 × 840) = 23·61’s
To Calculate the Percentage of Waste.—Multiply the waste made by 100 and divide by the weight of yarn used. If eleven skips of twist, weighing 3189lb., make 33lb. of waste—
3189 ) 3300 ( 1·034 per cent.
3189
———
11100
9567
———
15330