Influence ofthemechanicalharvestingmethod on ring and rotor yarn up to the end product

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In a joint cooperationbetweentheCotton Institute ofSouthAfrica and Rieter, thetwocommonlyusedmethodsofmechanicalcottonharvestingwerecomparedwitheachother. Thecomprehensive test and itsresults are available in a specialprint. Here are a fewinterestingextractsfromtheproject.

Cottonisstillthe dominant staplefibre. In Africa 1.4 milliontonsofcottonwereproduced 2013. Thatcorresponds to about 5 % ofglobalproduction. In SouthAfrica, approx. 9 000 tonsofcotton are harvestedannually.

Test conditions

Twodifferentmethodsofcottonharvestingwereeachexaminedattwodifferentfarmers. Thecomparisonwascarriedoutthrough to theknittedfabric, wherebycarded ring and rotor yarnswithvariouscountswerespun. Not onlytheyarns and knittedfabricsweretested but also interim products, to beable to better interpret theeffects on theyarn and theknits.


Todaythere are twocommonmechanicalmethodsforharvestingcotton – thespindlemethod and thestrippermethod (Fig. 1).

Theydiffer in productivity and quality. Thestrippermethod has many advantages – lowerinvestmentcosts, lowerfuelconsumption and higherharvestyields, which, however, canincreasetheproportionofimmaturefibres. Alsoknownisthatthecottonharvestedwiththestripperpickerexhibits a higherseedcoatcontent (Fig. 2).


Thefibrelength, in particularshortfibre ratio and meanfibrelength, have a strong influence on theyarnunevenness. Acrosstheprocess line, a meanstaple 1 to 2 mm longerisseenwiththespindlemethodcompared to thestrippermethod. Thus, as far as evennessisconcerned, a positive result in theyarn and in theknittedfabricisalso to beexpected. Alsodecisivehereis, however, howgreatthe influence isofthetwoyarnstructures, ring and rotor (Fig.3).


Thequalitycriteriaofthe ring yarnshowsthatthespindlemethodgivessomewhatbetteryarnresultsthanthestrippermethod. With rotor yarn, no evidentdifferencesbetweenthetwoharvestingmethods are detectable.


Theknittedfabrics made of rotor yarnhave a far betterevennessthanthose made of ring yarn. Thismeansthatthe influence ofthe end spinning system on theknittedfabricqualityis far higherthanthe influence oftheharvestingmethod. Nevertheless, the positive influence ofthespindlemethod, at least withonefarmer, isrecognisableeven in knittedfabric made of rotor yarn (Fig. 4).


Comprehensiveinformation in thespecialprint

Thespecialprintincludesthecomplete, comprehensive data and detailedexplanations and background information. Itcanbeorderedunder This email address is being protected from spambots. You need JavaScript enabled to view it. . Electronically, thespecialprintcanbedownloadedwiththegiven QR code (Fig.5).


Source: TIS 26815





Fig.1  Themechanicalcottonharvestingmethodscurrently in use are thespindle and thestrippermethods.

Fig. 2  Thecottonharvested by thespindlemethod (left) containsfewertrashparticlesthanthecottonharvested by thestrippermethod (right).

Fig. 3  Acrosstheprocessstages, thespindlemethodexhibited a 1 – 2 mm longermeanstaple.

Fig. 4  Knitsfrom rotor yarn, 100 % cotton, Ne 24, 4.2 αe.

Fig. 5  QR codeforscanning and downloadingthespecialprint.



Harald Schwippl

Head Technology

After Sales


This email address is being protected from spambots. You need JavaScript enabled to view it.

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