Rieter

General

Index

Rotor spinning machines produce packages ready for sale, which can be used immediately in downstream processing without any detour via the winder. Waxing devices and quality monitoring sensors at each spinning position and cylindrical package formats from 2° to 4°20 (USA 3°51) ensure that the most suitable cross-wound packages can be provided for any stage of downstream processing - knitting, weaving, yarn dyeing or doubling.

Almost all rotor spinning machines nowadays produce packages with a traverse of 150 mm (6˝), which results in the following package formats, depending on the winding unit of the different types of machine:

  • cylindrical packages: max. diameter 350 mm; max. package weight up to 6 kg;
  • conical packages (2° - 4°51’): max. diameter 280 mm; package weight depends on package density.

The high package weights reduce handling costs in the spinning mill and downstream processing as well as capital costs for empty tubes.

Two main advantages are cited for cross-wound packages from the rotor spinning machine as compared with those from the winder:

  • the number of piecings in the rotor spinning package is only 2-3% of the number in the winder package since, in rotor spinning, a continuously spun yarn is wound up as it is produced, whereas the winder package is made up of yarn from small cops with a mass of 60-120 g, joined together by corresponding splices;
  • winding is carried out at speeds of up to 350 m/min, as compared with 1 400 m/min in the winder; this gives a better package build, and the yarn lengths on the individual packages can be kept more uniform; admittedly, however, a larger balloon is generated when unwinding yarns from rotor spinning packages.

The following requirements must be fulfilled by packages of yarn from modem rotor spinning machines:

  • package density as uniform as possible from one package to another;
  • the same yarn length on all packages; this will be achieved exactly with individual length-measuring devices;
  • adaptable winding density attainable by means of adjustable yarn tension and above all by a variable angle of intersection of the windings in the package;
  • packages free of patterning zones;
  • yarn waxing where necessary;
  • formation of an accessible yarn reserve on the tube so that, during unwinding, the thread end can be knotted to the start of the yarn on the next package to be unwound before the package runs out; this enables stoppages to be avoided at package change in further processing.