The Riele: Manualeffipinning
`Volume 1
`
`- -
`U- T- l
`- -
`
`Werner Klein
`
`The Rieter Manual of Spinning
`
`1u'nlume '1— Teehnelngyr of Short—staple Spinning
`
`0001
`
`Bedgear2008
`
`Fredman v. Bedgear
`IPR2017-00351
`
`0001
`
`Bedgear 2008
`Fredman v. Bedgear
`IPR2017-00351
`
`

`

`Publisher
`Rieter Machine Works Ltd.
`
`(opyrlght
`moi-u by Rieter Machine Works Ltd.,
`Klosterstrasse 20. CH-BtiOEi Wintherthur,
`www.rieter.com
`
`Part of this content provided by The Textile Institute. Used by permission.
`
`Cover page
`Cotton plant
`
`Available Volumesl'Edition:
`
`Volume 1 - Technology:r of Short-staple Spinning
`ISBN 13 3-95231T3-l-4 1' ISBN 13 978-3-95231T3-1-0
`
`Volume 2 - Blowmom 8. llIarding
`ISBN 13 3-952317’3-2-2f15BN 13 9?B-3-95231T3-2-?
`
`Volume 3 - Spinning Preparation
`ISBN 13 3-95231?3-3-OIISBN 13 978-3352318345:
`
`
`
`Volume ti - Ring Spinning
`[SEN 13 3-95231Y3-4-9HSBN13 9T8-3-95231ra-4-1
`
`Volume 5 - Rotor Spinning
`ISBN 13 3-95231T3—5-i" i' ISBN 13 9?8—3—95231?3—5—8
`
`Volume 6 — Alternative Spinning Systems
`ISBN 13 3-95231T3-6-5 ,1' ISBN 13 9?8-3-9523l?3-6-5
`
`Volume 1' - Processing of Man-Made Fibres
`ISBN 12] 3-952311’3-76 ,I' ISBN 13 9T8-3-9523li3-Y-2
`
`Collectors Edition - all Volumes (Vol. 1-?)
`ISBN 13 3-95231T3-Uv6 1' ISBN 13 978-3352317303
`
`0002
`
`0002
`
`

`

`The Rivtcr Manual Ul Sninrinfi. Volume I . Technology at Shetl‘flaolc Sninnl-mt
`
`13
`
`Fiber fineness influences primarily:
`- spinning limit:
`. yarn strength:
`- yarn evenness:
`
`- yarn fullness:
`- drape ofthe fabric:
`- luster:
`- handle:
`
`- productivity of the process.
`
`Productivity is influenced via the end-breakage rate. the number
`of turns per inch required in the yarn {giving improvement of the
`handle}. and generally better Spinning conditions. In the produc-
`tion of blends. it must be borne in mind that, at least in conven—
`
`tional ring spinning processes, fine fibers accumulate toa greater
`extent in the yarn core and coarser fibers at the periphery.
`Blending of fine cotton fibers with coarse synthetic fibers would
`produce a yarn with an externally synthetic fiber character.
`
`1.2.2. Specification of fineness
`
`It'lfith the exception of wool and hair fibers. fiber fineness can-
`not be specified by relerence to diameter as in the case of steel
`wire. because the section is seldom cirwlar and is thus not
`
`easily measurable. As in the case of yarns and fibers, fineness
`is usually specified by the relation ofmass [weight] to length:
`5
`o‘
`tear: —ma5 {g}
`or other = —mfl${9':
`fength (km)
`irm
`
`Whereas for man-made fibers dteit is used almost exclu-
`
`sively. the Micronaire value is used worldwide for cotton,
`The fineness scale is as follows:
`
`MicWiLLIE
`
`FINENESS
`
`upto 3.1
`
`i very fine
`
`
`
`Conversion factor: dtr-ur = Mic :- 0.3984
`[heavily dependent on degree of maturity].
`
`it should be remembEred. howiaver. that the Micronaire value
`
`does not always represent the actual fineness of the fibers.
`Owing to the use of the air-throughflow method for measur-
`ing the Mi value. for example. a low average value is obtained
`where there is a high proportion of immature fibers. and this
`does not correspond to the true value for the spinnable fibers.
`
`1. RAW MATERIAL A5 A FAETOR
`
`INFLUENCING SPINNING
`lCharacteristics of the raw material
`
`1.1.
`
`Raw material represents about 50 - "f5 '36 of the manufactur-
`ing cost of a short-staple yarn. This fact alone is sufficient
`to indicate the significance of the raw material for the yarn
`producer. The influence becomes still more apparent when
`the ease in processing one type of fiber material is com—
`pared with the difficulties. annoyance. additional effort.
`and the decline in productivity and quality associated with
`another similar material. But hardly any spinner can afford
`to use a problem-free raw material because it would nor—
`mally be too expensive.
`Adapting to the expected difficulties requires an intimate
`knowledge of the starting material and its behavior in pro-
`cessing and subsequent stages.
`Optimal conditions can be obtained only through mastery
`of the raw material. Admittedly. however. the best theoreti—
`cal knowledge will not help much if the material is already
`at the limits of spinnability or beyond, Excessive economy
`in relation to raw material usually does not reduce costs
`and often increases them owing to deterioration of process-
`ability in the spinning mill.
`As an introduction to the subject of raw material. the fol-
`lowing pages will sketch out several relationships which
`are important for the yarn producer. Dnly cotton will be
`dealt with here. Man-made fibers will be dealt with sepa-
`rately in another volume.
`
`1.2. Fiberlineness
`1.2.1. The influence of fineness
`
`Fineness is normally one ofthe three most important
`fiber characteristics. A multitude of fibers in the cross-
`
`section provide not only high strength but also better
`distribution in the yarn. The fineness determines how
`many fibers are present in the cross-section of a yarn
`of given thickness. Additional fibers in the cross-sec—
`tion provide not only additional strength but also better
`evenness in the yarn.
`About thirty fibers are needed at the minimum in the
`yarn cross-section. but there are usually over 100.
`One hundred is approximately the tower limit for
`almost all new spinning processes. This indicates that
`fineness will become still more important in the future.
`
`0003
`
`0003
`
`

`

`The Rivtcr Manual of Spinning. I-'t:-lurI'II.'
`
`I . "thud“! cistern-stool: solnnI-na
`
`“9
`
`11.3. Fiber disposition
`
`The yarn buyers expect that the yarn they receive is (besides
`other quality features} even in structure and appearance.
`However. an even yarn is achievable only by fulfilling some
`preconditions. These preconditions are very easy to explain.
`but very hard to obtain: in every yarn cross-section of the
`Iwhole yarn length there should always be:
`- the same number of individual fibers:
`- the same number of fibers of every group of the same
`quality parameter lie. length. Fig. 1+9 afb]. fineness.
`thickness. etc.
`
`
`
`Fig. 49 — The ideal arrangement offibers ofdil‘lerent lengths in the yarn
`a. the distribution within the yarn strand;
`ti. the length grnups extracted group-wise from the strand.
`
`11.1%. The order of fibers within the yarn
`
`Also expected is that the yarn has optimal strength.
`Nowadays yarns obtain their strength. almost without
`exception. from twisting. Therefore the strength is. beyond
`doubt. highly dependent on the height of the twist. but also
`on a large area ol fiber-contact, and that again means for
`the fibers:
`
`- high degree ofstretching-out (straightening);
`- highest attainable degrea of paralleliSm;
`- binding-in of the whole fiber. including if possible both
`fiber ends, into the yarn structure.
`
`Furthermore. in yarns which have not been produced by
`using adhesives. the helical winding of all. or at least some
`(wrap yarns] of the fibers is of decisive importance. since
`ultimately the stability and strength of the structure are
`derived from the pressure towards the interior exerted by
`fiber windings. which are created by thetwist.
`One reason for the lower strength of rotor-spun yarn relative
`to ring—spun yarn is the lower degree of parallelization and
`the lower degree of straightening (fiber hooks} of the fibers
`in rotor-spun yarn.
`
`7. YARN FORMATION
`7.1. Assembly of fibers to make up a yarn
`11.1. Arrangement of the fibers
`
`The characteristics of a yarn are strongly dependent upon
`the characteristics of its fibers. but they are equally depend-
`ent upon the structure of the yarn itself. The following fac-
`tors are especially significant:
`- the number of fibers in the yarn cross—section;
`. fiber disposition:
`- fiber alignment;
`. position of the fibers in the strand {e.g. long fibers
`inside. short outside);
`- binding—in [fully or only partly bound—in):
`- overall structure;
`- twist.
`
`11.2. Number oi fibers in the yarn cross-section
`
`This determines. among other things. strength, evenness,
`handle. insulating capacity. thread-breakage rate. and the
`spinning limit of the raw material. Accordingly, there are
`lower limits to the numberoffibers in the cross-section.
`
`as follows {for normal conditions}:
`
`33 fibers
`
`Cotton yarns
`ing-spun yarn:
`carded
`F5 fibers
`
`Synthetic fiber yarns
`
`I
`
`.
`
`
`
`
`otor—spunyam:
`
`
`rug-spun yarn:
`
`
`
`Icarcled
`
`100 fibers
`
`50 fibers
`
`. 100 fibers
`
`rotor-spunyar .
`: carded
`
`
`The spinning limit can then be calculated approximately
`by transposition of the equation:
`
`TEXyou:
`
`fur.-
`tee .,
`
`J'T‘-
`’
`
`to ive
`g
`
`tex
`
`W'" = r1r 2' texfiw
`
`where ”I is the number of fibers. However, this formula does
`not take into account other parameters. such as fiber length.
`coefficient of friction. etc., which also affect the spinning limit.
`If it is desired to ascertain the average fiber fineness
`in a blended yarn. the following formula can be used:
`
`to
`
`prxtea +p. Hex
`
`100
`
`=—‘’ '
`
`Falter
`
`where p represents the proportion offibers as a percentage.
`and the index it represents one component and the indexythe
`other.
`
`0004
`
`0004
`
`

`

`5E}
`
`The clic'tt'r Manual of Snin'n'ns .VoliJ'nc 1 .Technolon o‘f Short-slash Spin-tins
`
`Looking at the first two items. the Following operations are
`responsible for imparting this order:
`- Carding [the high degree of longitudinal orientation
`obtained on the main cylinder is, however, nullified to
`a large extent by the doffer}.
`- Combing (here. however. parallelizing is a side-effect.
`which is not always desired to this extent].
`- Drafting [this is the most usual method of imparting
`order. since each drafting of the fiber masses is accom-
`pa nied by straightening].
`- Floating of individual fibers in a strong air current
`(for example, in the feed tube of the rotor-spinning
`machine).
`- Deliberate collection of fibers. e.g. in the rotor.
`
`11.5. The positions of the fibers in the yarn structure
`11.5.1. Ring-spun yarns
`
`Owing to the twist. all or some of the fibers take up the
`required helical disposition. The number of fibers affected
`by the twist. and the degree of winding. are strongly depen-
`dent upon the spinning process. in ring-spun yarns, twist-
`ing takes place from the outside inwards. At the periphery
`[the outer sheath .4. Fig. 50], owing to the greater degree
`of winding, the fibers have a lesser inclination, to = angle
`between the fibers and the axis of the yarn} than in the
`interior of the yarn {the core 8]. Since the fibers become
`steadily less tightly wound towards the core. ring-spun yarn
`may be said to have sheath—twist. Under loading. the outer
`layers will tend to take the radial forces and the inner lay-
`ers will tend to take the axial forces. However. by increasing
`pressure inwards. the radial forces reinforce atrial resistance
`to sliding apart of the fibers.
`
`Ring-spun ‘I’arri
`
`Open-End ‘I'arn
`
`
`
`classic
`
`. compact
`
`. rotorspun
`
`. fricllon spun
`
`/-l .,
`
`4
`
`P:
`
`a
`
`Fig. 50 — The twist structure in ring-spun yarn [22]
`
`Accordingly. fully twisted yarns with sheath-twist have high
`tensile strength but are not so resistant to abrasion. Under
`abrasion the outer. highly tensioned fibers are destroyed.
`Since these fibers hold the yarn together, the strand loses
`its cohesion. Hairiness on the yarn surface is mainly caused
`by protruding shorter fibers.
`
`7.1.5.2. Open-end spun yarns
`
`In contrast to ring spinning. twisting during rotor spinning
`takes place from the inside outwards. The rotating. brush-like
`open yarn end (C, Fig. 51] first catches fibers in the core and
`then with further rotation gradually takes up fibers towards
`the periphery. In the interior, where the fibers cannot avoid
`the twist, the strand becomes more compact but also some-
`what harder. On the other hand. towards the eitterior, com-
`
`pactness and hardness fall off to an increasing degree, since
`here the fibers are able partially to avoid twisting-in.
`
`hit-let 'i'arn
` et spun. two nozzles.
`vortex spun. one nozzle
`false twist process
`
`:
`
`
`
`
`Wrap 'i'arn
`filament wrapped
`
`less parallel.
`parallel without twist
`parallel.
`less parallel.
`parallelwithouttwist
`:parallelwithouttwist
`
`
`
`
`helical
`
`helical
`: helical
`
`
`
`Er %of fibers twisted
`
`
`parallel.
`f more random.
`ess parallel.
`a;attest;a;""“""'""
`2sagapasta
`helical
`around core in spllals
`.
`helical
`_
`lesslinnsted
`around core in spirals
`
`
`
`
`
`
`
`
`
`
`
`medium
`very good
`good
`- very good
`
`
`
`compact
`compact
`very compact,
`compact
`
`
`rnund
`
`
`
`
`so i!
`medlum to had
`handle
`
`
`noticeable
`hairiness:
`low to medium
`very low
`
`
`
`
`
`
`Table at — Shows roughly the differences in structure arislng from the spinning process
`{see also Fig. Sci}
`
`- medium
`
`-
`
`compact to
`
`Fiber disposition:
`in the core
`parallel.
`
`helical
`
`in the sheath
`parallel.
`
`; helical
`Fiber orientation:
`
`parallelism:
`compactness:
`
`good
`compact
`
`0005
`
`0005
`
`

`

`The thcr Manual Ul Spinrirlfi
`
`I-'t',|urrII.'
`
`t
`
`. Technology ol Shurl‘flaole Snmnl-M.
`
`51
`
`\\
`
`A further disadvantage of the loose outer layers is their sensi-
`tivity to axial rubbing. Since these open layers are not firmly
`secured in the core. they tend to accumulate in small knots
`during passage ofthe yarn over edges. guide elements. etc. As
`far as possibler open-end spun yarns should not be rewound.
`
`1232222232"-B 222
`
`N
`c 1a..
`_-="';=_==_=T-_——:=.
`
`?.1.5.3. Wrap yarns
`
`Fig. 51 — Bindlng-in oi the fibers in open-end splnning
`
`
`
`Fig. 52 - Yarn iorniation in the rotor
`
`Typical characteristics of this so-called core-twist are there-
`fore a harder handle accompanied by a lower strength
`than is obtained with sheath—twist. since the outer layers
`have relatively little twist and can thus contribute little
`to strength. However. abrasion-resistance is often better.
`Removal ol outer fibers due to abrasion has little effect.
`since these fibers dict not create much strength anyhow.
`In rotor—spun yarns. this outer layer exhibits other peculiar—
`ities. One of these is the presence of wrap fibers. These are
`fibers which fly directly onto the fully created yarn as the
`rotor passes under the feed passage. By the further rota-
`tion of the yarn in the rotor they are wrapped around the
`already spun yarn like the band on a cigar. This is atypical
`characteristic of rotor-spun yarn.
`Another peculiarity is a thin outer layer of fibers with
`hardly any twist, or even with twist in the reverse sense.
`This arises from the false twist between the navel [Fig 52, T]
`and the binding—in zone {A}. In the latter. during each rota-
`tion of the rotor. new fibers join on to the already well
`twisted fiber strand. These latecomers receive only a [rac-
`tion ofthe desired twist level. Ilthis low twist is lessthan
`the false-twist effect. the fibers are twisted in the reverse
`
`sense during cancellation of the false twist [reverse twist—
`ing} at the navel, and are thus wrapped around the other
`fibers with reverse twist.
`
`0006
`
`IWrap yarns consist for the most part of fibers arranged in
`parallel without any twist (Fig. 53). These form the very
`thick core. Synthetic filament or staple fiber of the same
`kind as the core material is wrapped around this core but
`forms a small proportion of the fiber material. It the thread
`is wrapped with filament. it will have high strength. since
`the fibers themselves are stretched out and arranged paral-
`lel and are pressed closely together. The filament also con-
`tributes some of the strength. Accordingly. for a given yarn
`strength. Fewer fibers are required in the cross-section.
`
`___.
`-:_
`
`‘-
`
`_._.-__
`
`.-—-
`
`_.
`
`ra-
`
`_.....__
`
`_..
`::__‘_ '
`
`_
`
`—_-:
`
`Fig. 53 - Bundled yarns (wrap yarns)
`
`11.5.13. Air-jet Yarns
`
`If. the core fibers are wrapped only with fibers of finite
`length (staplefibers). as in false—twist spinning (air—jet
`spinning and Dref 3}. then the yarn strength is lower than
`that of ring-spun yarn because the relatively short fibers
`cannot hold the structure of the yarn together in an optimal
`fashion. A minimum fiber length is required for production
`of such threads. At present. therefore. the false—twist pro-
`cess is suitable mainly for the spinning of man-made fibers,
`blends of cotton and man-made fibers. or combed cotton.
`
`Airiet spinning systems using one nozzle. like vortex-spun
`allow higher percentages of wrap fibers. resulting in better
`yarn properties and higher productivity.
`
`7.1.6. Yarn structure
`
`One aspECt of structure is the visual appearance. created
`solely by the peripheral layer of the yarn. and a second
`aspect is the internal and external make-up. Yarn structures
`are very variable. The difierences are partly deliberately
`caused. depending on the intended use of the yarn, but for
`the most part they are predetermined by the means avail-
`able. For example. it is difficult to produce a yarn equiva—
`lent to a ring-spun yarn by the new spinning processes
`
`0006
`
`

`

`TtIt' “ticlt'r Manual of Spin'n'ng .VoIU'IIc 1 .Tothnolon of Short-slant: sate-tins
`
`— and the ring-spun yarn still represents the standard of
`comparison [Table It}.
`The yarn structure is dependent primarily upon the raw
`material. spinning process, spinning unit, machine,
`machine settings, twist, etc. The structure can be open or
`closed; voluminous or compact: smooth or rough or hairy:
`soft or hard; round or flat; thin or thick, etc.
`But yarn structure is not simply appearance. It has
`a greater or lesser influence on:
`- handle:
`
`- strength;
`- elongation;
`- insulating capacity:
`- covering power:
`- ability to resist wear, damage, strains, etc.:
`- resistance to abrasion;
`
`- ability to accept dye:
`- tendency towards longitudinal bunching of fibers:
`- wearing comfort. etc.
`
`Ring yarn
`
`'
`
`Ell. E. rotor yarn
`
`Wrap - spun yarn Mir-gel - yarn
`
`G. E. friclion yarn
`
`Fig. 551 - Differences in the yarn structure for various spinning processes
`[drawings without attention to hairiness)
`
`7.2. Fiber migration
`
`Owing to their different characteristics. the fibers take
`up different positions in the body of the yarn. Grouping
`arises mostly during drawing. Thus. long fibers are often
`located in the core, since they exhibit more cohesive fric-
`tion. and therefore higher resistance to the draft. and
`remain in the interior. Short fibers are often found on
`
`the yarn exterior. This tendency is reinforced by fiber
`migration (wandering of the fibers}. since the fibers do
`not always stay in the positions they first take up. For
`example. if any traction of power {even minimal} acts on
`the yarn. highly tensioned fibers of the outer layers press
`inward wholly or partly [the fiber ends, for example}.
`In doing so. they press out the lower-tensioned fibers
`
`0007
`
`from the interior. Migration takes place from the sheath
`to the core and vice versa. Such migration is, of course,
`most prevalent during yarn formation but still occurs after
`yarn formation is completed. |u'r'hen the smallest forces are
`exerted on the yarn. e.g. during bending, tensile loading,
`etc.. the persisting tensions in the fibers constituting the
`yarn lead to continuation of the process of fiber migration
`even after the completion of yarn formation. For example.
`the short fibers work their way to the surface and are then
`partly rubbed off. Moreover, some fibers in the body ofthe
`yarn lose their helical dispositions during fiber migration:
`this effect is more prominent the shorter the fibers and the
`more random their arrangement.
`In addition to its dependence on length. fiber migration is
`dependent upon degree of elasticity, stiffness, fineness,
`crimp. etc. Short. coarse. stiff fibers move out towards the
`sheath while long. fine, flexible fibers move towards the
`core. Strongly crimped fibers are also found predominantly
`in the sheath. since they can exert greater resistance to
`binding-in. Fiber migration should be adequately taken into
`account in determining the composition of blends.
`
`Impartingstrength
`13.
`7.3.1. Possibilities for imparting strength
`
`In order to obtain strength in the yarn. which consists of
`individual fibers of relatively short length. the inherent
`strength of one fiber must be made wholly or partly trans-
`ferable to another. In principle. there are two alterna-
`tives: adhesives and twist.
`
`Total exploitation of the inherent strength of the fibers
`can be achieved only by using adhesives, as was done, for
`example, in the Twilo process. The adhesive effect can be
`produced by means of adhesive substances or adhesive
`fibers [polyvinyl-alcohol fibers). Since this process can be
`used only for a small market segment. twisting of the fiber
`strand remains the sole possibility for imparting strength.
`even for the future.
`
`The extension of the fibers that arises during twisting
`leads, via the associated fiber tension, to increased pres-
`sure directed towards the yarn interior. i.e. to an increase
`in the frictional forces between the fibers and thus finally to
`the desired, immensely strong coherence of the body of the
`yarn (Fig. 55).
`Fiber strands that are not held together by adhesives can—
`not completely exploit the inherent strength of the individ-
`ualfibers.
`
`Staple fiberyarns held together by twist have a degree of
`exploitation between 25 as and T0 as (normally 3[} - SO ‘56}.
`Possibilities available for producing the required twist are
`true twist, false twist and self-twist l[as in the Repco process].
`
`0007
`
`