New spinning processes have been available in a practicable form for almost forty years, and yet by far the largest amount of short-staple yarn is still spun on conventional machines. These are mostly developments dating from the period 1760 - 1830, in particular:
- mule spinner;
- flyer spinning machine;
- cap spinning machine;
- centrifugal spinning machine;
- pot spinning machine;
- and ring frame.
The mule spinner operates according to a discontinuous spinning method. It has gradually been replaced by the ring spinning machine even in its last domain, the wool spinning mill. Flyer, cap, and centrifugal spinners have been mostly confined to the worsted spinning mill; only a few still remain in use. The flyer spinning machines used in bast-fiber spinning represent exceptions. Even pot spinning is hardly used in today’s woolen mills.
Accordingly, most yarn is now produced on the ring frame. Ring spinning has been able to supplant almost all other conventional spinning methods and has proved very resistant to inroads by the newcomers. This can be attributed mainly to its:
- universal applicability, and
- yarn quality.
As regards yarn quality, ring spinning has recently made a remarkable step further ahead with the introduction of compact spinning (see The Rieter Manual of Spinning, Volume 4 – Ring Spinning).
However, there are also problems associated with the ring spinning machine. For one thing, this machine is difficult to automate. For another, ring frame productivity is currently limited by traveler speed (around 45 m/s), yarn tension in the balloon and spindle speed (around 25 000 rpm), and major improvements above these levels are not easily imaginable. Only the search for new solutions therefore offers the prospect of basic advances in the spinning field in future. This search began on a broad front at the end of the 1960s.
The main problems of the new spinning processes are:
- yarn character differing from that of ring-spun yarn, which still represents the basic standard for comparison;
- characteristics occasionally bordering on the unusable;
- difficulties in maintaining consistently uniform yarn characteristics;
- greater demands on the raw material;
- market segments limited to:
– a narrow count range;
– specific raw material types;
– specific end products;
- a high level of process know-how; and
- expenditure on repair and maintenance.
However, compared with ring spinning, they offer the following advantages:
- high production rates;
- elimination of processing stages;
- a considerable reduction in:
– personnel and
– space; and
- relative ease of automation.
Advantages of this kind are persuasive for yarn producers, particularly the economic benefits of new methods of spinning, and some of the new spinning processes have therefore in fact achieved more or less broad acceptance in the market. These systems have to be taken into account in the near to medium term for several fields of use, even if these processes may still have some drawbacks.
However, the machine builders, research institutes, and several independent inventors offer such a large range of already operable, semi-developed, and downright utopian possibilities for spinning yarn that it is not always easy to keep a grasp of the full spectrum. This problem is made still worse by the lack of standardized terminology. Sometimes, the generic designation of a spinning system is used, e.g. „open-end spinning“, sometimes the name of the process itself, e.g. „friction spinning“, sometimes the trade mark of the manufacturer, e.g. „Dref“. The quantity of available literature is enormous. Unfortunately, however, it is difficult to find a simple, succinct overview. This volume is therefore intended to provide the spinning specialist with this overview and to present the spinning principles in general terms.