Yarn Faults And ClearingIt is still not possible to produce a
yarn without faults for various reasons. Stickiness of cotton can
contribute to the formation of thick and thin places. Fly
liberation in Ringframe department is one of the major reasons for
short faults in the yarn because of the fly gets spun into the
yarn. Hence it is not possible to have fault free yarn from
ringspinning, it is necessary to have yarn monitoring system in the
last production process of the spinning mill. As physical principle
for electronic yarn clearing the capacitive and the optical
principle have established. Both principles have their advantages
in specific applications.Depending upon the rawmaterial, the
machiery set up, production and process parameters, there are about
20 to 100 faults over a length of 100 km yarn which do not
correspond to the deisred appearance of the yarn. This means that
the yarn exhibits a yarn fault every 1 to 5 km. These faults are
thick and thin faults, foregin fibres and diry places in the
yarn.The yarn faults which go into the woven or knitted fabric can
be removed at very high costs or can not be removed at all.
Therefore the yarn processing industry demands a fault free yarnThe
difference between frequent yarn faults and seldom occuring yarn
faults are mainly given by the mass or diameter deviation and size.
These faults are monitored by classimat or clearer installation on
windingEach yarn contains, here and there, places which deviate to
quite a considerable extent from the normal yarn corss-section.
These can be short thick places, long thin places , long thick
places or even spinners doubles. Eventhough such events seldom
occur, they represent a potential disturbance in the appearance of
the fabric or can negatively influnece subsequent processing of the
yarn.Short thick places are those faults which are not longer than
approximately 8 cms, but have a cross-sectional size approx. twice
that of the yarn. These faults are relatively frequent in all spun
yarns. To an extent they are the result of the rawmaterial (
vegetable matter, non-seprated fibres, etc). To a much larger
extent, these faults are produced in the spinning section of the
mill and are the result of spun in fly. Short thick places are
easily determinable in the yarn. In many cases, they cause
disturbances in subsequent processing. Once they reach a certain
size( cross-section and length) , and in each case accoridng to the
type of yarn and its application, short thick place fults can
considerably affect the appearance of the finished product.Long
thick places are much more seldom-occuring than the short thick
places and usually have a length longer than 40cms. In some cases,
their length can even reach many meters. Their cross sectional size
approx. + 40% to +100% and more with respect of the mean
cross-section of the yarn. Long thick places will affect the fabric
apperance. Faults like spinners doubles are difficult to determine
in the yarn, with the naked eye. On the other hand, they can
produce quite fatal results in the finished product. A spinners
double in the warp or in yarn for circular knitting can downgrade
hundreds of meters of woven , or knitted fabric.Thin places occur
in two length groups. Short thin places are known as imperfections,
and have a length approx. three times the mean staple length of the
fibre. Their frequency is dependent on the rawmaterial and the
setting of the drafting element. They are too frequent in the yarn
to be extracted by means of the electronic yarn clearing.Long thin
places have lengths of approx. 40cms and longer and a
cross-sectional decrease with respect to the mean yarn
cross-section of approx.30 to 70%. They are relatively
seldom-occuring in short staple yarns, but much more
frequently-occuring in long staple yarns. Long thin faults are
difficult to determine in the yarn by means of the naked eye. Their
effect in the finished product however, can be extremely
serious.The quite extensive application of electronic yarn clearing
has set new quality standards with respect to the number of faults
in spun yarns.It is therefore necessary to evolve a method of yarn
fault classification before clearing the faults in winding. The
most important aspect is certainly the determination of the fault
dimensions of cross-sectional size and length. With such a
cross-section and length classification and by means of the correct
choice of the class limits, the characteristic dimensions of the
various fault types can be taken into consideration, then a
classification system will result which is suitable primarily for
satisfying the requirements of yarn clearing and yet allows, to
quite a large extent, for a selection of the various types of
faults.Types of Electronic Yarn ClearersElectronic Yarn Clearers
available in the market are principally of two types -capacitive
and optical. Clearers working on the capacitive principle have
mass'as the reference for performing its functions while optical
clearers function with diameter' as the reference. Both have their
merits and demerits and are equally popular in the textile
industry. Besides the above basic difference in measuring
principle, the basis of functioning of both the types of clearers
are similar if not exactly same. Since most of the other textile
measurements like, U% / CV%, thick and thin places etc., in various
departments take into account mass as the reference parameter, the
functioning of the capacitive clearer is explained in some detail
in the following sections.Functioning PrincipleThe yarn is measured
in a measuring field constituted by a set of parallely placed
capacitor plates. When the yarn passes through this measuring field
(between the capacitor plates), an electrical signal is produced
which is proportional to the change in mass per unit length of the
yarn. This signal is amplified and fed to the evaluation channels
of the yarn clearing installation. The number and type of
evaluation channels available are dependent on the sophistication
and features of the model of the clearer in use. Each of the
channels reacts to the signals for the corresponding type of yarn
fault. When the mass per unit length of the yarn exceeds the
threshold limit set for the channel, the cutting device of the yarn
clearer cuts the yarn.Yarn Clearer SettingsThe yarn clearer has to
be provided with certain basic information in order to obtain the
expected results in terms of clearing objectionable faults. The
following are some of them -A. Clearing LimitThe clearing limit
defines the threshold level for the yarn faults, beyond which the
cutter is activated to remove the yarn fault. The clearing limit
consists of two setting parameters - Sensitivity and Reference
Length.i. Sensitivity - This determines the activating limit for
the fault cross sectional size.ii. Reference Length - This defines
the length of the yarn over which the fault cross - section is to
be measured. Both the above parameters can be set within a wide
range of limits depending on specific yarn clearing requirements.
Here, it is worth mentioning that the reference length' may be
lower or higher than the actual fault length'. For a yarn fault to
be cut, the mean value of the yarn fault cross-section has to
overstep the set sensitivity for the set reference length. B. Yarn
CountThe setting of the yarn count provides a clearer with the
basic information on the mean value of the material being processed
to which the clearer compares the instantaneous yarn signals for
identifying the seriousness of a fault.C. Material NumberBesides
the yarn count there are certain other factors which influence the
capacitance signal from the measuring field like type of fibre
(Polyester / Cotton / Viscose etc.) and environmental conditions
like relative humidity. These factors are taken into consideration
in the Material Number'D. Winding SpeedThe setting of the winding
speed is also very critical for accurate removal of faults. It is
recommended that, instead of the machine speed, the delivery speed
be set by actual calculation after running the yarn for 2-3 minutes
and checking the length of yarn delivered. Setting a higher speed
than the actual is likely to result in higher number of cuts.
Similarly a lower speed setting relative to the actual causes less
cuts with some faults escaping without being cut. In most of the
modern day clearers, the count, material number and speeds are
monitored and automatically corrected during actual running of the
yarn.Fault ChannelsThe various fault channels available in a latest
generation yarn clearer are as follows: 1. Short Thick places
2. Long Thick Places
3. Long Thin Places
4. Neps
5. Count
6. SpliceThe availability of one or more of the above channels
is dependent on the type of the yarn clearer. Most of the modern
clearers have the above channels. Besides detection of the various
types of faults, with latest clearers, it is also possible to
detect concentration of faults in a specific length of yarn by
means of alarms(cluster faults).Contamination ClearingDetection of
contamination in normal yarn has become a requirement in recent
times due to the demands by yarn buyers abroad. Therefore, some of
the optical yarn clearers have an additional channel to detect the
contamination in yarn. This is mostly used while clearing cotton
yarn. The various facilities available in the yarn clearers
nowadays enable precise setting and removal of all objectionable
faults while at the same time ensure a reasonably high level of
productivity.
WindingRing spinning produces yarn in a package form called
cops. Since cops from ringframes are not suitable for further
processing, the winding process serves to achieve additional
objectives made necessary by the requirements of the subsequent
processing stages.Following are the Tasks of Winding Process
Extraction of all disturbing yarn faults such as the short, long
thick ,long thin, spinners doubles, etc Manufacture of cones having
good drawing - off properties and with as long a length of yarn as
possible Paraffin waxing of the yarn during the winding process
Introduction into the yarn of a minimum number of knots Achievement
of a high machine efficiency i.e high produciton level The winding
process therefore has the basic function of obtaining a larger
package from several small ring bobbins. This conversion process
provides one with the possibility of cutting out unwanted and
problematic objectionable faults. The process of removing such
objectionable faults is called as yarn clearing'Practical
experience has proven that winding alters the yarn structure.This
phenomenon does not affect yarn evenness, but affect the following
yarn properties Thick Places Thin Places Neps Hairiness Standard
Deviation of Hairiness Winding TensionIf winding tension is
selected properly, the following tensile properties are not
affected Tenacity Elongation Work- to- break But excessive tension
in winding will deteriarate the above said tensile
properties.Characterestics Of Bobbin Formation Stretch Length It is
the length of the yarn deposited on the bobbin tube during each
chase (one up and down movement of ringrail ) of ring rail. The
length should be around 3.5 to 5 meters. It should be shorter for
coarser yarns and longer for fine yarns. Winding RatioIt is the
ratio of the length of yarn wound during the upward movement of the
ring rail and the length wound during the downward movement of the
ringrail. Bobbin TaperThe ratio of the length of the upper taper of
the cop (bobbin with yarn) to the diameter of the bobbin must be
1:2 or greater. Winding SpeedIt depends upon the following factors
Count Type of Yarn, (type of fibre, average strength and minimum
strength) Type and Charactersitics of Bobbin Package Taper Final
Use of Package The best winding speed is the speed which allows the
highest level of production possible for a given type of yarn and
type of package, and with no damage whatsoever to the
yarn.(abrasion and breaks due to excessive tension)Winding
ProductionIt depends upon the following factors Winding speed Time
required by the machine to carry out one splicing operation Bobbin
length per bobbin( both bobbin weight and tpi to be considered,
because TPI will affect the bobbin length). This decides the number
of bobbin changes The number of faults in the yarn and the clearer
settings, this decides the clearer cuts Count The number of doffs.
It depends upon the doff weight. Higher the doff weight, lower the
number of doffs The time taken for each doff either by the doffer
or by an operator Down time due to red light. It depends upon,
number of red lights, number of repeaters setting for red lights,
clearer settings like off count channel, cluster setting which will
result in red lights and others Bobbin rejections, it depends on
weak yarn, wrong gaiting, double gaiting, bobbin characteritics
etc. Following are Some of the Winding Package Defects which will
result in complaints Yarn Waste in the Cones This is due to loose
yarn ends that are wound on to the cone Stitch, Drop Over, Web Yarn
is visible on the small or on the big side of the cone either
across the side , around the tube, or going back in the cone
Damaged Edges or Broken Ends on the Cone The yarn is broken on the
edges or in the middle of the cone. Ring Formation The yarn runs in
belt formation on to the package, because it is misguided Without
Transfer Tail The desired transfer tail is missing or too short
Ribbon Formation Pattern or ring formation are made by the drum
when rpm are staying the same Displaced Yarn Layers yarn layers are
disturbed and are sliding towards the small diameter of the cone
Misguided Yarn The yarn is not equally guided over the hole package
Cauliflower On the smaller side of the package, the yarn shows a
wrinkle effect Soft and Hard Yarn Layer Some layer of yarn are
pushed out on the small side of the cone Soft and Hard Cones Great
difference in package density from one winder head to anotherA
bobbin change occurs when yarn on the bobbin is fully exhausted
during winding. But if a bobbin is changed with yarn still left on
it, we call it Rejected Bobbin'. The quantity of yarn on the bobbin
may vary from full bobbin to only few layers of yarn.The Various
Reasons of Bobbin Rejections are as follows:1. Bobbin Quality Long
Tail End Kirchi/Lapetta Deshaped Bobbin Overfilled Bobbin Bottom
Spoiled Bobbin Ring Cut Bobbin Soft Bobbin Sick Bobbin2. Bobbin
Feeding in Magazine Presence of under-winding and back-winding
while feeding the bobbins in the magazine leads to rejection3. Top
Bunch Transfer Failure Top bunch position is lower with respect to
bobbin tip. Blowing device does not come down to concentrate blow
at the bobbin tip. Very few numbers of coils at the bobbin tip.
Removal of top bunch due to fault in cutter at the bobbin
preparatory or any other reason. Very few numbers of coils at the
top bunch.4. Fault in Winding Unit, Splicing Failure5. Yarn Quality
High degree of objectionable fault Count variation High Hairiness
BobbinBobbin Quality Checking for Best WindingWhenever there is a
count change in ring frame, the cop quality should be checked.
Proper quality of cop ensures higher winding efficiency. The cop
quality is checked as per the following parameters:1. Bobbin
Parameters2. Cop Content : Depending on the spindle lift and ring
diameter, the cop content (in gms) should be checked3. Diameter of
the Cop : The Actual cop diameter' must be checked against Standard
cop diameter'. The standard cop diameter depends on the ring
diameter. Standard Cop Diameter = Ring Diameter - 3mm.4. Back
Winding : The number of back winding coils should be around 1.5 to
2.5 and the maximum length of back winding should not be more than
80cms5. Under Winding : The number of under winding coils should be
around 2 to 3 and the maximum length of back winding should not be
more than 20cm. As the under winding and back winding increases,
more time is wasted to open them up before feeding in the magazine
and also hard waste is increased.6. Top Clearance : The clearance
from bobbin tip to yarn body of a full cop should be approx 10 mm.
If the top clearance is too less, it may cause slough off at the
start of the bobbin unwinding7. Bottom Clearance : The clearance
from bobbin bottom to yarn body of should be approx. 10mm. If the
bottom clearance is too less, it may cause bottom spoiled bobbin8.
Yarn Length per Chase : The length of yarn per chase should be
around 3.5 to 5.5 m. If the length is too long, it may lead to
slough of during high speed unwinding.9. Bobbin Hardness : The
bobbin hardness should be around 50 to 55. Soft bobbins results
slough off. Besides the above mentioned points, the cops should be
also checked for long tail end, deshaped bobbin, kirchi &
lapetta, ring cut, overfilled and bottom spoiled bobbin to ensure
high production efficiency in winding.Due to the ever-increasing
emphasis on better quality of yarn for the competitive market and
process performance, the normal parameters of yarn tenacity,
unevenness and imperfections are not adequate to completely define
today's quality. Besides the above mentioned traditional
parameters, so many factors influence the performance of the yarn
in the subsequent process such as process parameters in ring
spinning & cone winding, work procedures in ring spinning &
cone winding and ambient conditions. So to attain the expected
quality for any applications such as weaving or knitting, one
should focus mainly on the fault free feed material preparation
because it contributes more than any other factor. Best winding
capabilities can be achieved through best bobbin quality.A high
degree of yarn quality is impossible through knot, as the knot
itself is objectionable due to its physical dimension, appearance
and problems during downstream processes. The knots are responsible
for 30 to 60% of stoppages in weaving.Splicing is the ultimate
method to eliminate yarn faults and problems of knots and piecing.
It is universally acceptable and functionally reliable. This is in
spite of the fact that the tensile strength of the yarn with knot
is superior to that of yarn with splice. Splicing is a technique of
joining two yarn ends by intermingling the constituent fibres so
that the joint is not significantly different in appearance and
mechanical properties with respect to the parent yarn. The
effectiveness of splicing is primarily dependent on the tensile
strength and physical appearance. Splicing satisfies the demand for
knot free yarn joining: no thickening of the thread or only slight
increase in its normal diameter, no great mass variation, visibly
unobjectionable, no mechanical obstruction, high breaking strength
close to that of the basic yarn under both static and dynamic
loading, almost equal elasticity in the joint and basic yarn. No
extraneous material is used and hence the dye affinity is unchanged
at the joint. In addition, splicing enables a higher degree of yarn
clearing to be obtained on the electronic yarn clearer.Splicing
technology has grown so rapidly in the recent past that automatic
knotters on modern high speed winding machine are a thing of the
past. Many techniques for splicing have been developed such as
Electrostatic splicing, Mechanical splicing and Pneumatic splicing.
Among them, pneumatic splicing is the most popular. Other methods
have inherent drawbacks like limited fields of application, high
cost of manufacturing, maintenance and operations, improper
structure and properties of yarn produced.Pneumatic SplicingThe
first generation of splicing systems operated with just one stage
without proceeding to trimming. The yarn ends were fed into the
splicing chamber and pieced together in one operation. Short
fibres, highly twisted and fine yarns could not be joined
satisfactorily with such method. Latest methods of splicing process
consist of two operations. During the first stage, the ends are
untwisted, to achieve a near parallel arrangement of fibres. In a
second operation the prepared ends are laid and twisted
together.Principle of Pneumatic SplicingThe splicing consists of
untwisting and later re-twisting two yarn ends using air blast,
i.e., first the yarn is opened, the fibres intermingled and later
twisted in the same direction as that of the parent yarn. Splicing
proceeds in two stages with two different air blasts of different
intensity. The first air blast untwists and causes opening of the
free ends. The untwisted fibres are then intermingled and twisted
in the same direction as that of parent yarn by another air blast
Structure of SpliceAnalysis of the longitudinal and transverse
studies revealed that the structure of the splice comprises of
three distinct regions/elements brought by wrapping, twisting and
tucking / intermingling. Yarn WrappingThe tail end of each yarn
strand is tapered and terminates with few fibres. The tail end
makes a good wrapping of several turns and thus prevents fraying of
the splice. The fibres of the twisting yarn embrace the body of the
yarn and thus acts as a belt. This in turn gives appearance to the
splice.Yarn TwistingThe two yarn ends comprising the splice are
twisted around the body of the yarn, each yarn strand twists on the
body of the yarn on either side of the middle of the splice. The
cross-section of this region distinctly shows the fibres of the two
yarn strands separately without any intermingling of the
fibres.Yarn Tucking / Yarn InterminglingThe middle portion of the
splice is a region (2-5 mm) with no distinct order. The fibres from
each yarn end intermingle in this splice zone just by tucking. The
studies on quantitative contribution of splice elements showed that
intermingling/tucking contributes the most to the strength of
splice (52%), followed by twisting (33%) and wrapping (about 15%).
The lower strength of the splice is attributed to the lower packing
coefficient of the splice zone. Spliced yarn has a lower breaking
elongation than normal yarn. Breaking elongation is mainly affected
by intermingling. Wrapping and twisting provides mainly transverse
forces. The absence of fibre migration gives lower breaking
elongation to splice.Effect of Variables on the Properties of the
Spliced yarnSeveral studies have been conducted on the effect of
various variables on the properties of the spliced yarn.Effect of
Fibre Properties and Blend Fibre properties such as torsional
rigidity, breaking twist angle and coefficient of friction affect
splice strength and appearance. The lower torsional rigidity and
higher breaking twist angle permit better fibre intermingling.
Higher coefficient of friction of fibres generates more inter-fibre
friction to give a more cohesive yarn. Thus, these properties of
fibre contribute to better retention of splice strength. In blended
yarn, usually the addition of polyester to other fibre blend like
P/W, P/C both for ring and rotor spun yarn increases splice
strength.Effect of Yarn FinenessSeveral studies on cotton,
polyester and wool report that coarser yarns have higher breaking
strength but a moderate extension. The coarse yarn cross section
contains more fibres and provides better fibre intermingling during
pre-opening, hence the splice is stronger than that of finer
yarns.Effect of Yarn TwistAn increase in the twist significantly
increases the breaking load and elongation, even at higher
pneumatic pressure. This could be due to better opening of the
strands at higher pneumatic pressure. Splicing of twisted ply yarn
is more complicated than single yarn due to the yarn structure
having opposing twists in the single and doubled yarns. Twisted
yarns also require a relatively longer time for complete opening of
the yarn ends.Effect of Different Spinning MethodsYarn produced
with different spinning methods exhibit different structure and
properties. Therefore, these yarns show significant differences in
splice quality. The ring spun yarn lent best splicing but the
potential of splicing is affected by the spinning conditions. The
breaking strength percentage of ring spliced yarns to a parent yarn
is 70% to 85% for cotton yarn. However, the breaking strength and
extension of splice vary with fibre and yarn properties. Rotor spun
yarns, due to the presence of wrapper fibres, make it difficult to
untwist and the disordered structure is less ideal for splicing.
The breaking strength retention varies from 54% to 71% and is much
lower compared to the splice of ring spun yarns. In case of
friction spun yarns, the highest relative tensile strength obtained
at the spliced joints can be above 80%, but a number of splicing
failures occurs due to unfavourable yarn structure. The
air-jet-spun (MJS) yarn and the cover spun yarn are virtually
impossible to splice. Only very low tensile strengths and
elongation values can be attained due to the inadequate opening of
the yarn ends during preparation of the splicing. The coefficient
of variation of these properties is also generally high.Effect of
Opening PressureA study on 50/50 polyester cotton, 25 tex ring spun
yarn shows a rise in tensile strength up to a certain opening
pressure. However, long opening time deteriorates the strength. An
increase in pressure up to 5 bar caused release of fibre tufts and
fibre loss from the yarn ends in P/C blend which is due to
intensive opening, but beyond this pressure, drafting and twisting
in the opposite direction may also occur.Effect of Splicing
DurationWith a given splicing length, when the splicing is extended
for a long period of time, the breaking strength of the spliced
yarn and also their strength retention over the normal value of the
basic yarn increases because of increased cohesive force resulting
from an increased number of wrapping coils in a given length. The
effects are more pronounced at higher splicing lengths. It is
desirable however, that splicing duration be as short as possible.
The splicing duration alone has no conclusive effect on elongation
properties of splice yarn. It has also been observed that, for
maximum splice strength, different materials require different
durations of blast. These are between 0.5 to 1.8 seconds. Effect of
Splicing LengthStudies on splicing of flyer and wrap spun yarns
spun with different materials, showed that regardless of the
splicing material, the breaking strength and strength retention of
both yarn types increase with the splicing length because of the
increased binding length of the two yarn ends. Elongation at break
and retention of elongation of both flyer and wrap spun spliced
yarns increase with the splice length. Compared to the splicing
duration, the splicing length has more pronounced effect on the
load-elongation properties of the spliced yarn. It can be therefore
be stated that the splices made on longer lengths and for longer
period of time have more uniform strength.Effect of Splicing
ChamberThe factors like method and mode of air supply and pressure
along with type of prism affect the splicing quality. It was
observed that irregular air pressure has advantages over constant
pressure for better intermingling in the splicing chamber, which
varies with different staple fibres, filament yarns, and yarns with
S and Z twists. It is not possible to make a general comment
regarding potential of the splicing chamber due to the multiplicity
of factors influencing splicing.Comparison of Dry and Wet
SplicingThe comparative studies on dry and wet splicing with water
showed that the breaking load retention for wet spliced yarns are
significantly greater than dry spliced yarns. In fact, wet splicing
is more effective for yarn made from long staple fibres and for
coarse yarn. This may be due to higher packing coefficient
resulting from wet splicing.Assessment of Yarn Splice QualityThe
two important characteristics of a splice are appearance and
strength. Although quality of splice can be assessed by methods
like load-elongation, work of rupture, % increase in diameter and
evaluation of its performance in down stream process etc., the
appearance can be assessed either by simple visual assessment or by
comparing with photograph of standard splice.
What is Ply Yarn / What is Plying / Plying DefinitionFor sewing
threads as well as for some speciality industrial yarns , it is
necessary to ply (to double or fold) the yarns to give them a
smoother and less hairy character.Doubling improves the evenness
and plying balances torque if carried out correctly and binds some
of the hairs on the component yarns.PlyingPlying is a process used
to create a strong, balanced yarn. It is done by taking two or more
strands of yarn that each have a twist to them and putting them
together. The strands are twisted together, in the opposite
direction than that in which they were spun. When just the right
amount of twist is added, this creates a balanced yarn, which is a
yarn with no tendency to twist upon itself. Almost all store bought
yarns are balanced, plied yarns.A two-ply yarn is thus a yarn plied
from two strands, a six-ply yarn is one from six strands, and so
on. Most commercial yarns are more than a two ply. Embroidery floss
is generally a six ply yarn.Plying YarnRegular plying consists of
taking two or more singles and twisting them together, the opposite
way. This can be done on either a spinning wheel or a spindle. The
most important thing to remember though is that the twist must go
the opposite direction. If in spinning the single the wheel was
spinning clockwise (which is called a "Z" twist, as on any given
side the fibres appear to cross diagonally in the same direction as
the diagonal of a "Z"), in order to ply it the wheel must spin
counter-clockwise (an "S" twist). This is because otherwise you are
not balancing the twist, just twisting it more. The concept is
similar to when a heavily twisted piece of yarn is folded, and it
twists up on itself. It is most common for singles to be spun with
a "Z" twist, and then plied with an "S" twist.Novelty YarnsMany
novelty yarns make use of special plying techniques to gain their
special effects. By varying the tension in the strands, or the
relative sizes of the strands, or many other factors different
effects can be achieved. For example, when a soft, thick strand is
plied against a tightly twisted thin strand, the resulting yarn
spirals. Another example is boucl, which is a yarn where one strand
is held loosely and allowed to make loops on the other yarn while
plying.