PREVIOUS TEST Flashcards
why is roving necessary?
to reduce size, sliver is too big to come straight our of the drawframe and go immediately to spinning
what are the 5 actions in roving?
- Drawing: reduces size
- twisting: add cohesion/strength
- make roving: wind on a package
- laying: make sure there is not gaps
- building: properly shaped bobbin
what is balloonless spinning
we deflate the balloon and put a crown on-top of the spindle, the yarn goes through the crown and the crown forces the yarn to collapse around the bobbin without going too far out
8 influences of twist on yarn properties
- hand
- luster
- abrasion resistance
- absorbency
- special effects
- flexural endurance
- contraction
- strength
in ring spinning, the amount of tension on the yarn is due to what 6 factors
- yarn size
- yarn speed
- travelor speed
- travelor weight
- surface area of balloon
- ring spinning
what 3 things characterize twist in short staple yarns?
- twist angle
- twist direction
- s or z twist
list the 5 effects of reducing staple length
- short staple needs more twist
- not as strong
- more expensive
- less luste
- harder hand
T or F: In worsted spinning rings and travelers are sometimes lubricated to reduce friction and temp
T
T or F: in ring spinning, end breaks are a result of too little tension in the yarn and high yarn variability
F
T or F: ribboning in winding is due to the traverse shift being too large
F
T or F: in 2 for 1 twisting the second turn of twist is inserted as a result of the package turning
F
T or F: woolen ring frame spinning uses card roping
T
T or F: rubbing frames run about twice as fast as roving frame
T
T or F: in ring spinning the spindle speed lags behind the travelro speed to casue winding to occur
F
T or F:In the production of roving for producing woolen yarns single zone drafting and a slip-drafting system are used
F
T or F:in winding of roving onto a package, as the bobbin speed increases the flyer speed must also increase
F
T or F: the goal in splicing is to have the yarn diameter after splicing be no more than twice the original yarn diameter
F
list the 3 tyoes of irregularity in drawn sliver that are related to machine defects or poor maintence
- roller speed variation
- fiber slip
- roller nip movement
T or F: in open end spinning the rotor design and size is selected based on fiber type and desired production speed
F
T or F: compact spinning is a modification to the rotor spinning machine which allows for better twisting of edge fibers to create a stronger yarn
F
T or F: air jet yarns have a parallel core of cotton fibers held together by abdns of polyester wrapper fibers
F
T or F: ring spun yarns are stronger than open end spun yarns
T
T or F: tow to top changes filament yarns into baled fibers
F
T or F: edge crimping as a texturing method was not very successful because of the difficulty in getting large denier filaments to curl
T
T or F: fasle twist can be used to create both stretch and bulk yarns
T
T or F: it is possible to extrude, draw and texture filaments in a one step process
F
T or F: one reason for wanting new spinning methods was the fact that ring spun bobbins were too large for efficient shipping
F
T or F: coarser air-jet yarns were determined to be stronger than finer air-jet yarns
F
T or F: stacked disc fricition twisters used rubber bushings to genereated false twist yarns
F
T or F: compact spinning allows a reduction in twist level while maintaining the yarn strength
T
T or F: converting is a term used to describe the process of changing continuous filaments into staple fibers sliver
T
T or F: in stretch breaking the tow is wrapped around the rolls to enhance fricition and reduce slippage
t
T or F: stuffer box textured yarns are used in artificial turd becasue it gernerated a buckled crimp
F
T or F: vortex spun yarns are more hairy than ring spun yarns
F
T or F: simultaneous and sequential draw0texturing both use POY as the input material
T
T or F: in compact spinning the twist triangle is enlarged so that more fibers are incorporated
F
T or F: yarns textured using gear crimping maintained their crimp better than edged crimped yarns
T
T or F: oepn end spun yarns are more even than ring spun yarns
T
T or F: twist transference is used in the production of compact yarns to help hold the fibers together
F
T or F: the guillotine method of cutting filament tow is used by most filmament staple producers becasue it is a simple procedure
F
T or F: staple textured yarns can be produced from fully drawn yarns, partially oriented yarns and low orientation ayarns
F
T or F: bulk and hairiness of a yarn can be changed by the type of navel used in open end spinning
T
T or F: tight spots are untextured areas due to poor tension and teist contol
T
are open yarns stronger or weaker than ring spun yarns and why?2
weaker because of bridge fibers and poor fiber orientation
are open end yarns more or less even than ring spun yarns and why?3
more even because more doubling in lay in, no roving, and can chose amount of drawing processes
do open end yarns have more or less elongation than ring spun and why?1
greater because of bridge fibers
do open end yarns have a better hand than ring spun and why? 1
harsher hand than ring spun bc shorter fiebrs
do open end yarns more or less bulky than ring spun yarns and why? 1
more bulky bc bridge fibers
are open end yarns more or less hairy than ring spun and why? 1
more hairy bc bridger fibers
6 attributes that were consider inportant for the ideal spinning system?
- good quality yarns
- spin from sliver
- fast
- cheaper
- produce large fault free packaages
- flexible in fiber and yarn types
6 process phases in open end spinning
feeding drafting fiber transport twisting yarn removal winding
7 process steps in texturing
- input fully drawn yarn
- heat above tg
- deform the yarn
- cool below tg
- reverse the deformation
- relax the yarn which is optional
- wind onto a package
methods for feeding fibers in short staple fibers 3
incline
feed hooper
horizontal
things to control with gridbars 3
air flow
distance
mounting/cleaning angles
properties of air texturing 4
more bulky
higher mositure absorption
heat insulation
more elastic
whihc is more bulky and has more elongation false twist or air tecturing
false twist
intermingling
process where filament which may have been tectured are condolidation
co-mingling
where several yarns are combined and consolidated
torque balancing
using a torque jet to eliminate any residual torque liveliness from a textured yarn
how to eliminate residual toruqe in false teist textured yarn 2
combine z and s textured yarn through intermingling
use a detorque jet after 2nd heater
5 properties improved by combing
luster strength hand be more even along the length improve spin limit
