The effect of short fibre and neps on Murata vortex spinning

More documents

Recommendations

Info

Yarn hairinessYarn hairiness is significantly affected by <strong>short</strong><strong>fibre</strong> <strong>and</strong> the trial results follow a similar patternto the yarn tenacity <strong>and</strong> evenness results. BothMZ <strong>and</strong> DZ treated cotton, which had relativelylow levels <strong>of</strong> <strong>short</strong> <strong>fibre</strong>, had the lowest hairinessvalues in both yarn counts, while AS <strong>and</strong> MHcotton produced the highest hairiness values inboth yarn counts (see Figure 8).Fibre lossFibre loss at the MVS twist zone due to thevacuum around the base <strong>of</strong> the stationaryspindle will be an important issue in themarketability <strong>of</strong> Australian cotton to MVSspinning mills. Fibre losses, expressed as apercentage <strong>of</strong> the total input weight, weresignificant <strong>and</strong> greater for the cottons exposed todry storage <strong>and</strong> excessive heat during ginning.Figure 9 illustrates the <strong>fibre</strong> loss for each yarncount due to each gin treatment. As expected,MZ cottons lost less <strong>fibre</strong> while cottons subject toharsher treatments — for example AS <strong>and</strong> DHcotton — lost more <strong>fibre</strong>. Different nozzlegeometry <strong>and</strong> pressures can be used to reducethese figures although alteration <strong>of</strong> suchspinning parameters may cause significantchanges in yarn properties.Spinning breaksSpin breaks are defined as the number <strong>of</strong> breaksper hour per spinning frame. Sixty breaks perhour is considered the cut <strong>of</strong>f if a spinningefficiency <strong>of</strong> above 90 per cent is to be achieved.Spinning breaks for Ne 30/1 yarn were similarfor all gin treatments. <strong>The</strong> high end-break ratewith the DZ treatment was attributed to thecondition <strong>of</strong> the sliver (see Figure 10).Spinning breaks increased when the yarnbecame finer with all Ne 40/1 yarn exceeding 60breaks per hour per machine. But the MZtreatment had the lowest number <strong>of</strong> end breaks(64) while the DH treatment had the highest(96). <strong>The</strong> high number <strong>of</strong> breaks is evidence thatNe 40/1 may <strong>effect</strong>ively be the spin limit forcarded Australian cotton <strong>and</strong> that to efficientlyspin finer counts, combing may be required.
FABRIC QUALITYNe 30/1 yarn from each gin treatment wasknitted into single jersey fabric. <strong>The</strong>se sampleswere then subject to a pilling resistance test.MVS fabrics are generally highly resistant toabrasive damage <strong>and</strong> pill formation, <strong>and</strong>consequently retain a fresh appearance evenafter many launderings.All fabrics in this trial were rated as having no orlittle pilling.CONCLUSIONSTreatment <strong>of</strong> seed cotton before <strong>and</strong> duringginning, especially with respect to <strong>fibre</strong> moisture<strong>and</strong> drying temperatures, has significant <strong>effect</strong>son <strong>fibre</strong> quality. Dry seed cotton <strong>and</strong> hot air inthe gin lead to high <strong>short</strong> <strong>fibre</strong> content, <strong>short</strong>erstaple length, increased <strong>neps</strong> <strong>and</strong> reducedstrength. <strong>The</strong>se properties have adverse <strong>effect</strong>son both the quality <strong>of</strong> spun yarn <strong>and</strong> theefficiency with which the yarn can be spun.With MVS yarn, higher <strong>short</strong> <strong>fibre</strong> contents leadto greater <strong>fibre</strong> loss around the MVS twist zone,which translates directly into lost production forthe spinning mill.High <strong>short</strong> <strong>fibre</strong> also contributes to poorer yarntenacity, poorer yarn evenness, higher levels <strong>of</strong>imperfections, higher yarn hairiness <strong>and</strong> lowerspinning efficiency. Conversely, elevated neplevels in <strong>fibre</strong> did not translate into higher yarnimperfections, because <strong>neps</strong> are removed at thetwist insertion point during MVS spinning.In terms <strong>of</strong> grade <strong>and</strong> trash content, the cottoninvestigated in this study would normally bedescribed as a high quality growth. But for MVS(<strong>and</strong> ring) spinners the control cotton (AS) couldonly be described as being <strong>of</strong> reasonable quality.<strong>The</strong> AS treated cotton performed worst in almostall yarn quality indicators.MVS spinners require better lengthcharacteristics to achieve the desired quality intheir yarns. <strong>The</strong> results from this study showthat cotton treated with more moisture <strong>and</strong> lessheat in the gin performed better on MVS interms <strong>of</strong> yarn quality, spinning efficiency <strong>and</strong>raw material cost savings.
Page 3: subjected to extended pilling tests
Page 8: This study was funded by the CRDC <

The effect of short fibre and neps on Murata vortex spinning

Create successful ePaper yourself

Delete template?

Save as template?