SPINNING METHODS DISCUSSED

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OE SPUN YARNS - VS RING SPUN YARNS - COMPARISONS ( PART 2 )

Further to our publication on Linkedin we would like to let our readers know more about  insights and further developments concerning spinning technologies, in particular to a revolutionary development in OE spinning - and the application and trial of a new spinbox.

Quote :


On Tue, Jan 29, 2013 at 5:02 PM, we wrote:

 
RE: DECIMATION OF RING SPINNING
 
In a message dated 27/01/2013 07:14:45 GMT Standard Time, aheneghana@gmail.com writes:
Dear Mr. Parker

We appreciate your comments and elaborations in your email given.

May we take this opportunity to comment on our LinkedIn group : Textiles Engineering group :

http://www.linkedin.com/groups/This-has-come-my-inbox-100140.S.208467389

Thanking you

sincerely

Heinz Rainer

africasiaeuro.com
Dear Mr. Rainer,
 
1) I explain that the new spin-box device is longer than the rotor spin-box and needs the production of a Subassembly Unit to enable the Schlafhorst Autocoro to be retrofitted with the new spin-box; as well as simplifying the Autocoro's travelling robot.
This is what is called the Pre-production Development Stage.
Severe physical injuries to 3 key staff in a car accident 2 years ago on 7 January 2011 forced the postponement of the Pre-production Development Stage until the end of November 2012 - nearly a 2 year delay.
Retrofitting older Schlafhorst Autocoro is the cheapest option for the new spin-box to enter the market.
A new open-end spinning machine would require about 2 years and some 3,500 CAD/CAM component drawings at a cost of about £2.5 million; and after 2 years one only has a set of drawings.
Retrofitting older Schlafhorst Autocoros has the drawback that both the winding head and the fibre opening device are only capable of commercially operating at a maximum yarn delivery speed of 200 metres per minute.
2) I understand that using 100% cotton fibres, modern rotor spinning machines can spin at a yarn delivery speed of 200 metres per minute, but the necessarily reduced rotor diameter to spin at over 100 metres per minute, twists the fibres so tightly together that the yarns are wire-like and fabrics can need chemical softening.
 
I also understand that using cotton fibres blended with polyester (man-made) fibres, rotor spinning can have operating problems at yarn delivery speeds over 80 metres per minute, because the polyester (man-made) fibres have a tendency to melt on the rotor causing a commercially unacceptable number of yarn-end breaks.
 
I know that fabrics woven or knitted from Rotor yarn have a much harsher feel than fabrics woven or knitted from Ring yarn.

OE yarn microscopy

So much so, that I am led to believe that some 30 years ago around 1983, Marks & Spencer banned the use of Rotor yarns in any St. Michael brand garments worn next to the skin of private parts.
 
I understand that Airjet technology can spin at a yarn delivery speed of 400-500 metres per minute; but only when using 100% man-made fibres.
I also understand that the Airjet technology is commercially useless for cotton fibres and I am led to believe that Airjet yarns - just like Rotor yarns - no matter the higher productivity will never be able to compete with soft-handle Ring yarns in 90% of the worldwide fabric market.
Schlafhorst, Rieter, Murata, Marzoli, and Savio tried to join in with the technology's lengthy R&D programme. Project documentation proves that they were all turned down.
 
Your yarn spinning firm is one of many in the world. However, it may be useful going forward if proper commercial interest is shown and, most importantly, subsequent forensic due diligence on your firm's financial stability is satisfactory.
Please don't expect any secrets, nor any detailed technical information unless it can be ascertained that your yarn spinning firm will be useful in going forward.
In response to above letter we have following observation:

All statements made by  above are relative. No warranty as to authenticity can be made. In addition some discrepancies are noted, which will be discussed..

In respionse to :

1) Rotorshafts are supposedly longer than hitherto applied ones. This could have several reasons, I am not sure to which model of Autocoro the writer refers to. In case of Tangetial belt drives, a longer shaft will have better heat dissipation due to extended cooling surface. Higher speeds are directly proportional to higher deliveries - and as such require higher Rotor rotation, thus a longer shaft will dissipate heat faster. This seems the only plausible reason. If on the other hand a wider Rotor is used - a hypothesis , then a longer shaft will mean underlying supporting discs are wider in diameter (a pre requisite at higher Rotorspeeds due to higher gravity forces.
If on the other hand Aero bearings are in use - or other than roller bearings with supporting discs, in such case a longer rotorshaft will have more mass - and as such requires more kinetic energy  amounting in higher energy consumption. It is not clear which type of bearing / Rotor / supporting disc , and axial bearing is used here. In comparison Rieter has been successfully applying their Aero bearings for well over a decade now.
Without clear defintion no final explanation can be given.

Disclaimer : No Warranties provided. The aforementioned yarn spinning technology is not officially known, nor do we have any liason with persons who are mentioned. We can not accept responsibility as
to authenticity. The name Schlafhorst Autocoro is a registered Trademark.
Illustration shows microscopic photography of OE yarnswith significant yarn wrappers in first picture, and missing in second picture. we can not verify the source and authenticity of these pictures.

2) Correct is : Higher curcumferential speeds of rotors compact yarns and at 120- 130000 RPM this can become a problem. The question is : In order to achive significant delivery speed increase one must apply higher rotational speeds in  case of OE spun yarn. This is so far the only possibility to reach a higher production rate on OE. In finer counts the number of fibers in the crossection in the yarn are a parameter which can not be overlooked. In order to maintain the minimum number of fibers in the crossection attention on rawmaterial is paramount.

In case of PES fibers higher rotorspeeds will pose a problem of thermofixing if rotors are overheated due to friction of tangential belts or axial bearings. If PES fibers are blended with Cotton the natural wax content (oil) will create a barrier and lubricant to aid spinning at higher speed to a certain degree.
OE spun yarns do have a significant characteristic which manifest in form of wrapper fibers. On the attached miscroscopic photography such wrapper fibers are non visible. This is a phenomen which has to be closer investigated. The structure on picture 2 show a clear disctincton from picture 1. Fibers seem more parallel.  Wrappers are almost absent.

We shall continue to follow developments and our efforts will include observations and opinions from machinery manufactuers in this sector.

africasiaeuro.com


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