Wednesday, 22 April 2009

Blending at draw frame



Blending at Draw Frame

This method is normally used for binary blends only. The required blend proportion is adjusted by the number of slivers of each component and the hank of respective slivers.

The fleece blending is done on the blending Drawframes specifically designed for this purpose. They are fed with 16-20 slivers at the back and therefore provide a much greater flexibility as regards the blend ratios.

Advantage

- Easier to obtain uniform blend ratio.
- During opening and carding, optimum settings fro each blend component can be used for better quality of output with less damage to the fibres. 

- Easy working.

Disadvantages

- Difficult to attain random arrangement of fibres in the yarn cross section.
- Additional drawing capacity needed.
- Separate opening lines needed for each component.

Blending of Combed Cotton Sliver and Polyester

Many Indian mills resort to this practice when the humidity control or conditions of machines is very poor.

Advantages
- Produces very intimate blend
- Trouble free running and high productivity at card.
- Less yarn imperfections due to better fibre individualisation because of reprocessing of the cotton component.
- Reduced number of d/f passages.
- Lower end breaks due to fewer slubs.
-better uniformity of dyeing due to more intimate blend.

Disadvantage
- Poor tenacity and evenness in blend yarn.
- High cotton nep content in blend due to reprocessing
- Need of additional b/r and card capacity
- Slightly higher waste in b/r and carding.

Optimum Blending Method of various Blends

1. For blends like P/V , blowroom blending is effective as they need similar b/r sequence.
2. For blending of manmade stack blending method is generally used.
3. The polyester /cotton or acrylic/cotton are generally blended at d/f because cotton component needs a severe opening and cleaning action
4. Where there is a problem of running 100% polyester on card, stack blending of polyester stock and combed cotton may be resorted to.
5. In case of v/c blend, they should be blended at the draw/frame as they need quite a different opening sequence.  

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