Rieter

General

Index

Any new spinning process launched on the market can only be successful if it fulfills certain criteria for economic benefits and can claim advantages over an established spinning system in at least one of these criteria, such as:

  • higher quality of the product manufactured;
  • higher productivity of the system as a whole;
  • lower costs of the production process in relation to the quantity produced (labor, energy, capital);
  • greater flexibility of the process, i.e. a wide range of yarn products can be manufactured or a wider range of raw materials can be used.

If these criteria are applied to the many spinning processes brought out in recent decades, it is clear why most of these processes were unable to establish themselves, i.e. soon disappeared again. Only rotor spinning and – with some qualifications – air-jet spinning, albeit with a limited range of yarns, can be said to fulfill the aforementioned criteria.

When considering the economics, higher productivity certainly ranks first with rotor spinning. Rotor-spun yarns have always established themselves in the past where they could be produced more cheaply than ring-spun yarns, while at the same time meeting the requirements of the end product. This will continue to be the case in future. In the course of development the economically relevant factors have intensified to the extent that the break-even point compared with the established ring-spinning process has been moved in the direction of increasingly fine rotor-spun yarns.

If productivity takes first place in terms of the success of rotor spinning, the conclusion should not be drawn that even a single yarn manufacturer today would be prepared to sacrifice yarn quality for lower manufacturing costs. Yarn quality and economy are not only not mutually exclusive, they are necessary prerequisites for each other! In contrast to ring-spun yarn, significant quality improvements have been achieved in recent years while continuously increasing rotor speeds and delivery speeds.

The following aspects have contributed significantly to the economic success of rotor spinning versus ring spinning:
  • elimination of the roving frame passage and the lower number of drawframe passages for many applications (refer to section Drawframes);
  • elimination of the cost-intensive rewinding process due to direct processing of rotor-spun yarns;
  • elimination of the doubling process (for some applications) by using single rotor-spun yarns instead of doubled ring-spun yarns;
  • cards and drawframes for the rotor spinning process can be operated 30%-50% faster;
  • lower energy consumption due to the shorter spinning process; savings can be up to 30%;
  • material flow in a shorter spinning line is simpler and therefore easier to organize; the throughput time is shorter;
  • increased productivity in the spinning mill due to delivery speeds up to 10 times higher, lower ends down rates and higher machine efficiency compared with ring spinning;
  • use of shorter and therefore less expensive cottons, especially for manufacturing coarser yarns; no compromises may be made as regards raw material quality for spinning finer count yarns;
  • increased productivity in downstream processing due to large package formats and longer, defect-free yarn lengths, and the resulting improved running properties of the yarns.