Calculation Of Regain, Tape Length, Reed Width and Loom Pick in Weaving
Regain:
Regain is estimated from the warp length on a sample cloth. The usual procedure for a grey cloth is to cut the cloth of a convenient length. Then a warp thread is taken out from the cloth and straightened out without unduly stretching it. The length of the thread is then measured and from it the regain is calculated out.
Example 01:
A cloth was cut to a length of 10 cms. And the average length of straightened warp threads was found to be 10.8 cms. Calculate the regain of warp of that cloth.
Solution:
Regain,
10.8 – 10
= ………………… × 100
10
= 3%
Thus for 100 yds of cloth 108 yds of warp will be required.
The regain of weft of a grey cloth can be found out in the same manner.
Tape length or Cut length:
This is the length of warp required to weave a definite length of cloth.
Tape length = Up-take + Required length of cloth
100 + regain% of warp
= ……………………………… × Required length of cloth
100
Tape lengths are marked on the warp during slashing.
Example 02:
Calculate the tape length for 20 yds of grey piece, whose regain of warp was found to be 6%.
Solution:
Tape length,
100 + regain% of warp
= ……………………………… × Required length of cloth
100
100 + 6
= ………………. × 20
100
= 21.2 yds
= 21 yds 7 inches.
Reed width:
In the case of grey cloth the reed width can be found out by measuring the regain of weft as described before. But in the case of cloth which has been bleached or dyed and passed through different processes of finishing the contraction in width cannot be ascertained by the above method. In this case, the following formula should be maintained.
Reed width,
100 + regain%
= ………………….. × Cloth width
100
When we have ascertained the regain percentage of contraction of weft, we shall have to find out the count of the reed to be used. This can be easily found out,
Reed count × Reed width = Number of ends per inch in cloth × Width of cloth
Therefore,
Reed count,
Number of ends per inch in cloth × Width of cloth
= ………………………………………………………………
Reed width
Loom Pick:
Owing to the contraction of warp during weaving, picks per inch in the cloth are higher than the picks inserted per inch of warp on the loom. Therefore, to ascertain the number of picks to be inserted per inch of warp on the loom. To get a certain number of picks in an inch of cloth, the following process should be followed-
Loom Pick × Tape length = Picks per inch in cloth × Length of cloth
Therefore,
Loom Pick,
Picks per inch in cloth × Length of cloth
= …………………………………………………….
Tape length
