Warp Calculation Formulas in Weaving

Introduction:
During warp calculation in weaving, the following formula will be found useful for determining various particulars required in practice. In this article we will discuss warp calculation formulas in weaving with problems, solutions, and examples They have all been derived from the fundamental formula, Count = Number of hanks per lb. 

Warp Calculation Formulas in Weaving
Fig: Warping Machine in Weaving

Different Formulas of Warp Calculation in Weaving

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 metres of cloth having 3648 ends. The regain of the 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 the 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, the Length of cloth in yds is 1064 yds. (ANS)

Author of this Article:
Mayedul Islam
Assistant Chemist 
Ha-Meem Group, Tongi, Gazipur, Bangladesh
Email: mayedul.islam66@gmail.com

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