Introduction:
During warp calculation in weaving, the following formula will be found useful for determining various particulars required in practice. They have all been derived from the fundamental formula,
Count = Number of hanks per lb.
1. Total number of ends in cloth,
= Number of ends per inch in cloth × cloth width + extra ends for selvedge
Or,
= Number of ends per inch in reed × width of warp in reed + extra ends for selvedge
2. Length of warp yarn in yds in cloth,
= Tape length in yds × number of ends
3. Total length of warp yarn in hanks ,
Total number of ends × Tape length in yds
= ………………………………………………
840
4. Tape length in yds,
Count of warp yarn × weight of warp yarn in lbs × 840
= …………………………………………………………….
Total number of ends
5. Length of cloth in yds,
Count of warp yarn × weight of warp in lbs × 840
= …………………………………………………………………….. – (up-take)
Total number of ends
6. Total length of warp yarn in metres ,
= Total number of ends × Tape length in metres.
Or,
= (Cloth length in metres + warp regain%) × Total number of ends.
7. Weight of warp in lbs,
Total length of warp yarn in hanks
= ………………………………………….
Count
Or,
Total number of ends × Tape length of warp in yds
= ……………………………………………………
840 × Count
8. Weight of warp in kg,
Count in tex × Total length of warp yarn in metres × Total number of ends
= …………………………………………………………………………………………
1000 × 1000
9. Count of warp yarn,
Total length of warp yarn in hanks
= …………………………………………………..
Weight of warp in lbs.
Or,
Total number of ends × Tape length of warp in yds
= ………………………………………..............………
840 × Weight of warp in lbs.
10. Count of warp yarn in tex,
Weight of warp yarn in kg × 1000 × 1000
= …………………………………………………..............
Total number of ends × Tape length of warp in metres
Example 01:
Calculate the total length and weight of warp in 100 mrtres of cloth having 3648 ends. The regain of warp is 10%. The count of the warp yarn is 20 tex.
Solution:
Total length of warp in metres,
(Cloth length in metres + regain% of warp) × total number of warp ends
= (100 + 10%) × 3648
= 110 × 3648
= 401280 metres
= 401.28 kms.
So, Total length of warp is 401.28 kms.
Now,
Weight of warp in kg,
Total length of warp yarn in km × count in tex
= ………………………………………………………………..
1000
401.28 × 20
= ………….
1000
= 8.0256 kg
So, the Weight of warp is 8.0256 kg. (ANS)
Example 02:
Calculate the length of cloth you would produce from a weavers beam containing 100⅓ lbs of warp. The total number of ends in the warp is 3000 and the count of the warp yarn is 40s. allow ⅓ lb as waste and 5% up-take of warp in weaving.
Solution:
Actual warp available is,
= 100⅓ - ⅓
= 100 lbs.
Now,
Length of cloth in yds,
Count of warp yarn × weight of warp in lbs × 840
= …………………………………………………………………….. – (up-take)
Total number of ends
40 × 100 × 840
= …………………………. – 95%
3000
= 1064 yds.
So, Length of cloth in yds is 1064 yds.(ANS)
