Page 45 - April-May-2017

influence is of the two yarn structures,
ring and rotor.

Yarn quality
The quality criteria of the ring yarn shows
that the spindle method gives somewhat
better yarn results than the stripper
method. With rotor yarn, no evident
differences between the two harvesting
Influence of the mechanical harvesting methods are detectable.

method on ring and rotor yarn up to Knitted fabric comparisons
The knitted fabrics made of rotor yarn
have a far better evenness than those
the end productuality made of ring yarn. This means that the
influence of the end spinning system on
the knitted fabric quality is far higher than
In a joint cooperation between the Cotton Institute of costs, lower fuel consumption and higher harvest the influence of the harvesting method.
South Africa and Rieter, the two commonly used yields, which, however, can increase the proportion of Nevertheless, the positive influence of the
methods of mechanical cotton harvesting were immature fibres. Also known is that the cotton spindle method, at least with one farmer,
compared with each other. The comprehensive test harvested with the stripper picker exhibits a higher is recognisable even in knitted fabric
and its results are available in a special print. Here seed coat content. made of rotor yarn.
are a few interesting extracts from the project.

Cotton is still the dominant staple fibre. In Africa 1.4
million tons of cotton were produced 2013. That
corresponds to about 5 % of global production. In
South Africa, approx. 9 000 tons of cotton are
harvested annually.

Test conditions
Two different methods of cotton harvesting were each
examined at two different farmers. The comparison Knits from rotor yarn, 100% cotton, Ne 24, 4.2 αe.
was carried out through to the knitted fabric, whereby The cotton harvested by the spindle method (left) contains fewer trash particles than the
cotton harvested by the stripper method (right).
carded ring and rotor yarns with various counts were Fibre length Comprehensive information in
spun. Not only the yarns and knitted fabrics were The fibre length, in particular short fibre ratio and the special print
tested but also interim products, to be able to better mean fibre length, have a strong influence on the The special print includes the complete,
interpret the effects on the yarn and the knits. yarn unevenness. Across the process line, a mean comprehensive data and detailed
staple 1 to 2 mm longer is seen with the spindle explanations and background
Mechanical harvesting methods method compared to the stripper method. Thus, as information. It can be ordered under
Today there are two common mechanical methods far as evenness is concerned, a positive result in the rieter-link@rieter.com. Electronically, the
for harvesting cotton – the spindle method and the yarn and in the knitted fabric is also to be expected. special print can be downloaded with the
stripper method. Also decisive here is, however, how great the given QR code.

QR code for scanning and downloading the special
print. http://bit.ly/CottonHarvest_SA3011v1
The mechanical cotton harvesting methods currently in use are the
spindle and the stripper methods.
Author: Har ald Schwippl
They differ in productivity and quality. The stripper Head Technology - After Sales
method has many advantages – lower investment
Across the process stages, the spindle method exhibited a 1 – 2 mm longer mean staple. harald.schwippl@rieter.com