## Tuesday, 1 September 2009

### Warping Calculations for Warp Knitting

The warping Length of Small Yarn Packages
When small yarn cones or leftovers are used in warping operation,these cones can be used efficiently if the warping length is precalculated.
The weight of the yarn on the cones is measured (in case of varying weights,the lowest should be used since it will run out first).The length of the yarn on the cone can then calculated by the formula
as follows :

I = w x 1000 /tex
for example : the length of the 100 tex yarn weighing 250 g is :

250 x 1000 /100 = 2500 metres

To calculated the weight of certain length of the yarn when the tex is known,the following formula is used:

w = I x tex / 1000
for example : the weight of the yarn on the warp beam containing 27.000 km of 7 tex yarn is :

27000 x 7 / 1000 = 189 kg

The dtex unit is such a variation.The unit can be defined as the weight in decigram  (dg) of the 1000 metre long yarn or filament (or the weight in gram of 10000 m length of the yarn).
To calculate the different parameter in different situations,the following formula are used :

dtex = w x 10000 / I

I = w x 10000/ dtex

w = I x dtex / 10000

According to the number of warp sections which required,the warping length of  is deducted.
For example : 42 inch wide of warp beam are to be warped for 168 inch tricot machine for production of lock knitt constructions (run-in ratio of 1.38 : 1).
I the creel ,the required number of 77 dtex cones are accommodated each weighing 1 kg ( net weight of the yarn).The yarn length per cones is :

1 x 10000 / 77 = 129.87 km , the number of section beams for each guide bar is : 168 / 42 = 4
According to the run-in ratio,the length of the warp on the front of beam should be 1.38 times longer than the yarn length of the back beam section can thus be considered as one unit while lenght  of the warp on the front section as 1.38 units.The number of units which required is :

4 x 1 + 4 x 1.38 = 9.52 units

he length for each unit is :

129.87 / 9.52 = 13.64 km

so that maximum warp length available for the back beam sections is 13.64 km and the available length  of  the front sections is 13.64 x 1.38 = 18.83 km.Thus the correct length of the yarn to be warped on each section can be pre-calculated for maximum usage of available yarn.