Golden Rule 1

What Lycra® decitex to use?

A fabric's elasticity is determined by its elastic, open construction. Lycra ® is used simply to given the fabric prefect recovery. Without Lycra® the fabric would stretch and "bag". The right Lycra ® decitex choice is based on final fabric weight

Golden Rule 2

What yarn count to use?

The right choice of rigid yarn count is based on the fabric elasticity you want to achieve. Example: if I am looking for an elasticity of 20% in the weft, I should choose weft yarns with a count of 20% lower then my control fabric (rigid). This is because once the open, elastic construction produced on the loom has been pulled bake into shape by Lycra ®, the rigid yarn is forced into a tighter space , it will swell up and if it does not have enough room to move (because it is too course) it will produce an unwanted "orange peel" effect .

 

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Golden Rule 3

What width to use on the reed?
(For a weft stretch fabric)

A Lycra ® fabric has to have an open construction to allow it to be elastic. The elasticity of the fabric is due largely to the difference the maximum reed width and the fully relaxed, closed fabric construction you achieve once Lycra® has come into play and the fabric has been properly relaxed and finished.

There is no alternative for the weaver than to carefully calculate the reed width and the rigt number of yarn ends.

Determine the reed and number of ends in reed with the following formulas:

Remember, as a general guide, a one way elastic fabric with 2% Lycra® content that has less than 20% elasticity risks not being "felt" by the consumer in wear. More than 40% elasticity and the garment risks bagging at elbows and knees . More than 35% elasticity is not needed in an outerwear garment. The weaver needs to tailor his fabric to the consumer needs and the boil off test helps him do so.

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Golden Rule 4

Boil off test: why?

Always perform a boil off test on your sample, before moving into bulk production.
1 meter of full width greige fabric, boil freely in water in a large pan for 1/2 an hour . Dry flat.
(Add detergent to remove any size and enzymes if Lyocell is used)
This text gives very important parameters to the weaver and the finisher,

A) Maximum fabric weight
B) Maximum fabric elongation
C) Maximum dimensional stability
D) Minimum fabric width

Remember, as a general guide, a one way elastic fabric with 2% Lycra® content that has less than 20% elasticity risks not being "felt" by the consumer in wear. More than 40% elasticity and the garment risks bagging at elbows and knees . More than 35% elasticity is not needed in an outerwear garment. The weaver needs to tailor his fabric to the consumer needs and the boil off test helps him do so.

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Golden Rule 5

How to use the parameters obtained from the boil off test?

Theoff test is t starting point for the development of a new fabric with Lycra®, for the weaver and the finisher. It's important to know these parameters before starting the production.

The data collected tells me that

1) I can finish (heat set) the fabric to a width equal to the one after the boil off + 10/15%(maximum)

2) If I want to lower the elasticity / elongation I need to put more yarns per cm in warp, to the construction

3) If I want to achieve a fabric with a slightly higher width… I should not stretch it during finishing but re-design the fabric construction