Siro Yarn
The development of Siro spun technology by Dieter Plate and colleagues from the Division of
Textile Industry in the 1970s was an important innovation for the global wool textile industry.
The original patents were taken out in 1973, 1974 and 1976 and for his role in this development
Dieter Plate was awarded a CSIRO Medal for Research Achievement in 1986, the Sir Ian
McLennan Achievement for Industry Award in 1988, the Warner Memorial Medal of the Textile
Institute in 1990 and the Wool Foundation Eliza Forlonge Medal in 1993.
Traditionally, two-fold yarns are used for worsted weaving, because twisting binds the surface
fibres into the structure of the yarn and makes it more resistant to the abrasive forces that occur
during weaving. The essence of Siro spun is the combination of spinning and doubling in the one
process. At the same time the productivity of the Spinning Frame is effectively doubled. Fabrics
produced from Siro spun yarns have a smoother handle than those produced from the traditional
two-fold yarns, which made them particularly suitable for the light-weight, 'Cool Wool' fabrics
being introduced to the trade at the time by the International Wool Secretariat (IWS).
The development was commercialized in 1980 by a consortium comprising the Melbourne
engineering company Warren, Brown and Staff, IWS and CSIRO. Siro spun spindles had been
installed in Australia, Britain and Germany before the systems formal release in 1980. Twelve
years after its commercial release the net world profit from Siro spun was estimated to be $8
billion.
Siro yarn is a process of spinning – which actually claims a yarn name “Siro Yarn”. This process
are able to produce directly weavable two ply (2 ply) siro yarn at the ring spinning machine. So it
eliminates the usual twisting process. In this process two parallel rovings are placed through the
drafting system and they only combined once they have passed the nip point of the front top and
front bottom rollers. The process resulted in two-fold ply yarn which is known as “SIRO
YARN”. Siro yarn is a twisted single yarn, or we can say twists absorbent yarn.
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Production process:
With the siro spun process, a special spin-twisted yarn can be produced directly on the ring
spinning machine. In this process, two rovings are led in parallel through the drafting system,
separated by two specially developed condensers, and drafted separately.
The twist is introduce as for a normal single yarn by means of ring and traveler. The roving
strands, which are drafted parallel, are combined after passing the front rollers at the exit from
the drafting system, with some twist being produced in the individual strands right up to the nip
point. Once past the front roller of the drafting system, the two strands are combined producing a
twofold like yarn. The yarn has uni-directional twist like a singles yarn but the fibers are bound
sufficiently for the yarn to survive weaving.
Half weight single yarn sections are avoided by breaking the second strand if the other one
breaks. A mechanical yarn break detector located below the drafting system continuously
controls the yarn path of both single yarns throughout the spinning process. If one of the two
strands breaks, the special yarn break detector falls in the opposite direction, blocking the twist
so that the second strand breaks, thus ensuring that only perfect Siro ply yarn runs onto the
bobbins.
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Benefits or characters of Siro Yarn:
• High yarn strength in terms of CLSP
• Smooth yarn surface
• Excludes separate twisting process
• High quality 2 ply folded single yarn with its unique quality
• Low hairiness
• Less neps
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• Low Imperfections
The system has some major advantages:
• The cost of two-folding is eliminated and the productivity per spindle of the ring frame is
effectively doubled.
• Fabrics produced from Siro spun yarns have a smoother handle than those produced from
the traditional two-fold yarns.
• It eliminates the usual twisting process for doubling.
• The siro yarn can be produce at a significantly lower cost than conventional yarn, part of
this cost saving is passed to the fabric producer and thus to garments manufacturer.
• An independent analysis in 1992 by the Australian Bureau of Agricultural and Resource
Economics (ABARE) research estimated the world net profit from Siro spun at that time
to be just over $8 billion, and the profit to Australia at $974 million
End uses: The end use of Siro yarn is in the shirt manufacturing, socks manufacturing, weaving,
knitting and sweater industry. Siro spun is especially suited to the production of lightweight,
trans-seasonal 'cool wool' fabrics.
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