Measurement Of Bowing
Bowing in the fabric can be calculated by using following formula
(B /A) x 100=%
B=maximum distance between curvature width of fabric A=Width of fabric in mm
so for example if
maximum distance between curvature width of fabric =20
Width of fabric in mm= 1500 mm
then the bow is – (20 / 1,500) x 100 = 1.3%.
Where possible, rental launderers need to aim for a bow of below 1% to avoid customers complaining about edge creases along the closed end of a duvet – in some cases, the creases will be down the sides, depending on the cut.
Skewing is the condition in which the filling yarns in a fabric do not lie perpendicular to the warp yarns throughout the width of fabric is called as “skewing”.
Measurement Of Skewing
fig. Schematic diagram of a fabric contains skew faults.
Referring to the diagram,
the percentage of skewing is given by following formula
(C /D) x 100
then the skew is (30 / 2,000) x 100% = 1.5%.
Rental launderers need to aim for a maximum skew of 1% if at all possible, to avoid problems with twisted edges on duvets and pillow cases or with sheets that go off the square.
Causes Of Skews & Bows
- Fabric can become skewed during its manufacture if it is placed on the stenter guide pegs in such a way that the weft yarns are not perpendicular or at right-angles to the direction of travel.
- Even if the fabric is correctly aligned on the stenter, problems can still occur if the parallel stenter drive pegs do not run at precisely the same speed as each other,
- Fabric will become bowed during manufacture if it is wound under high tension and the pull on the middle is greater than that at the outer edges. The problem will be worse if the selvages are thicker than the main body of the cloth.
Removal Machine Of Skew & Bow
- After heat setting in the stenter machine, bowing problem is solve by compactor machine.
- In the compact machine, there is a device name “Mahlo” which can straight the weft yarn and solve the skewing bowing problem.