Test 3 Flashcards
what system does not make roving?
Woolen system
anytime you ring spin you need what?
Roving
what does roving come after in the yarn process?
Drawing
why do we need roving?>
To reduce the size
why can’t we have more than a 40 tex draft when ring spinning?
will create variability in the yarn
how do snarls form?
needs to have tension or will wrap around itself
why do we lay in roving?
we need to arrange the coils of each layer right next to each other so we dont have roving wrapping around other roving
what is building in roving?
regulates the length of the layers on the bobbin to form a properly shaped bobbin
why is the flier hollow on one side in roving?
so you can feed the roving down it to support the rover so the extra forces aren’t impacting it
what is the flier responsible for in roving?
putting in twist
why does the flier speed stay constant in roving?
to put in the correct amount of twist
Where does the twist run from?
Back up to the front roll
flyer and bobbin rotate….
in the same direction
bobbin speed is _ than flyer speed
greater
the difference in the bobbin and flyer speed causes
the roving to wind on the bobbin
why does the bobbin move up and down inside the flier?
to make sure we are laying the coils in the proper position
why do we shape the bobbin in roving?
so roving doesn’t get trapped in layers below
what will happen if the wind on velocity isnt constant?
roving will break
how does the rubbing frame work?
two aprons rub together to entangle the fibers
what is different about worsted roving?(3)
bigger rollers, double apron drafting, can get slip draft
what is slip draft?
fibers slip through draw zone,
What holds fibers together with twist?
the force that acts towards the center which increases friction to hold the yarn together
Twist density =
turns per length
what is the helix angle
angle of wrap
what does the helix angle affect?
amount of force in yarn because it is generated by how much twist is put in yarn
small angle of wrap = _ twisted, feels _
lightly, softer
large angle of wrap= _ twisted, _ tension in yarn
high, more
What does TM talk about?
influence of angle wrap
8 influences of twist on yarn properties
hand absorbency luster flexural abrasion resistance special effects contraction strength
how will low twist affect hand, absorbency, luster, flexural endurance
feel softer, more absorbent, more luster, more flexible,
what does a change in contraction cause?
change in yarn count and linear density
assumptions of strength in twist
yarn is made of unbreakable staple fibers and assume we have a continuous filament yarn
what is optimum twist?
maximum strength in the yarn, max twist that allows max strength
short fibers have a _ coherence curve than w long fiber
lower
5 effects of reducing fiber length
- short fibers need more twist to reach strength
- short fibers give lower strength
- short fibers give harder hand
- short fibers give less luster
- short fibers require a higher cost of conversion
5 factors that influence effective staple length
- fiber fineness
- fiber crimp
- fiber finish
- fiber cross sectional shape
- fiber stiffness
why do we do yarn winding
transfer yarns on better suited packages
what is the goal with yarn winding?(5)
large fault free package, no thin and thick, needs to unwind easily, may wax yarn to reduce friction for knitting, efficient package
what is the average number of bobbins put on a package
20
what are the two types of packages?
cheese and cone
what speeds do cheese packages need to work at?
high speeds
what type of yarns are mostly used on cheese packages?
filament yarn
which type of package has more problems with winding packages?
cone
what are cone packages mainly used for?
knit packages
What does the preclearer do?
senses and cuts out thick and think spots
What does the tensioner do?
keeps tension in yarn
winding can increase what?
hairiness because of running over the metal parts
what is the purpose of the split drum?
determines where the yarn ends up on the pakcage, goal to space yarn out and make sure it is not on top of each other
3 problems in winding?
neps
irregularity
hairiness
how do ribbions and patterns form?
traverse shift is too small and yarns wind right on top of each other
how do budgles form?
due to the outer layer of yarns putting pressure and squeezing the inner layers, poor tension control
what is clearing?
remvoing thick and thin spots that are predetermined
what is splicing?
joining the yarn ends together, dont want it to create thick or thin spots, we normally end up with something a little thicker
what does waxing a yarn do?
modifies yarn friction so it wont abrasive as easily
what do link winders do?
they are connected to the spinning frame and rolls doff into winders, they mske it easier to track packages
what do we do to staple yarns when they are twist lively?
twist yarns together in opposite direction than normally twisted
Twisted yarns together =
plied yarns.
twisted plied yarns togethr =
ropes
twist ropes together
cables
why is multifold done? (6)
done to improve regularity, increase strength, get balanced yarn, reduce hairness, imporve extensibility, produce speical effects
liveliness is a function of (3)
time
amount of twist
finish
reduce liveliness (2)
slash w heavy starch
steam
why is ring spinning expensive?
because of all the processing you have to go through for labor
what can we use in ring spinning
any fiber type
ring spinning can make what
any yarn size
why does ring spinning need drafting?
to reduce size
why does ring spinning need twist
to make yarn strong
fiber orientation in roping is what and cohesion
not good and cohesion is not very strong
why do we use a false twist spindel?
near the front roll to help hold it together so it wont draft there
where does the traveler sit
on the ring
where does the bobbin sit
on the spindle
bobbin speed _ spindle speed
=
belt turns forcing _ to turn forcing _ to turn
spindle and bobbin
what is the drive belt connected to
a master cylinder
what limits the amount of yarn on a package
the size of ring
why is ring spinning sloe
due to travelor speed
yarn oulls _ around the _
travelor, ring
in ring spinning twist happens becasue of what
the spindle
difference between traveler and spindle speed
traveler is a little less than spindle speed ( ab 100 rpm difference)
in ring spinning dront roll speeds is what
needs to stay constant
in ring spinning fyler and spindle speed needs what
to stay constant
the travelor speeds needs to what in ring spinning
change
in ring spinning if bobbin increase, travelor has to what
increase
2 biggest problems in end breaks
high tension and high variability in yarn
things that affect high tension in ring spinning (6)
yarn speed, yarn size, traveler speed, traveler weigh, ring size, surface area of ablloon
with high tension in ring spinning what are the 3 things we change to help fix it
control size of balloon, changhe traveler weight, change yarn speed
why is balloonless spinning used in woolen yarns q
to reduce the likelihood that yarn will break
how does balloonless spinning work?
collapse the balloon by putting a crown on top of the spindle and it forces yarn to run through the crown and collapse arounf spindle
why do we wax bigger rings
its more likely that the traveler will burn up and fly off
3 major problems with ring spinning
speed
size of yarn package
cost
pros to rubbing (3)
easier to set up
faster
easy to use
pros to roving (2)
better cohesion and better package size
can keep working w rest of bobbins if one breaks
similarities of roving and rubbing (2)
same yarn quality and both widely used
5 roving objectives
draft twist profuce roving lay build
what is necessary with ring twisting?3
tension control, twisting in opposite direction single twist, end break detectors
ring twisting process
ring spinning
wing and clear
twist on ring frame
rewind from ring tube
how does two for one twisting work
the package does not turn, the twist happens from the rotation of a disc, 1 rotation inserts 2 turns of twist in the yarn
obliquity efffect
ordered to disordered state, adding twist
oe: strength goes down w _
twist
