Rieter

Introduction

Index

The ring spinning machine was invented by an American named Thorp in 1828, and Jenk – another American – added the traveler rotating around the ring in 1830. In the intervening period of more than 170 years the ring spinning machine has undergone considerable modification in detail, but the basic concept has remained the same. For many years any noteworthy further development hardly seemed possible, yet a significant process of evolution took place during this time. The productivity of the ring spinning machine has increased by 40% since the late nineteen-seventies. This has been achieved by:

  • using smaller rings and cop formats
  • introducing piecing in the winding department
  • substantial improvements in rings and travelers.

The degree of  automation has also been increased significantly. As this process of evolution is not yet complete, the ring spinning machine will continue to be the most widely used spinning process in short staple spinning, since it has considerable advantages over the new spinning processes:

  • it can be used universally, i.e. any material and any yarn count can be spun on it
  • it produces yarn with optimum properties (especially as regards structure and tenacity)
  • it is uncomplicated and easy to control
  • know-how for handling the machine is old, well established and accessible to everyone
  • it is flexible with regard to volume (blend and batch sizes).

New spinning processes therefore often find it difficult to make a substantial breakthrough (with the exception of rotor spinning, and most recently air-jet spinning). Due to their many inherent limitations, the new processes are only ever to be found in sub-segments of the market, usually in the coarser yarn sector. The current renaissance of the ring spinning machine is due to the fact that these inherent features have been clearly recognized by specialists. However, the ring spinning machine can only hold its own position in the long run if the ring spinning process can be automated further and spinning costs substantially reduced, since this machine is a major cost factor in a spinning mill, as the graph produced by Rieter shows (Fig. 2).

Improvements can be achieved primarily by:

  • further development of rings and travelers
  • using automated take-off devices (doffers)
  • reducing the ring diameter, which enables the rotation speed of the spindle to be increased while traveler speed remains unchanged. For example, cost savings of some 7 US cents/kg of yarn are achieved by using a 42 mm ring instead of a 48 mm ring, despite a slight decline in efficiency. However, reductions in ring diameter presuppose the use of doffers on the ring spinning machine (except when wage costs are very low) and piecers on the winder. The slub-free length is then of little importance.
  • increasing machine length, which reduces the machine price
  • reducing ends down frequency, in which the new data collection systems and new drive systems can be of great assistance
  • improving roving quality, since the causes of at least 50% of all ends down on the ring spinning machine are to be found in the preparatory machines
  • combining the ring spinning machine and the automatic winder into a production unit
  • roving stop motions, primarily for reducing waste and preventing laps; they could perhaps enable operations to be maintained with fewer personnel during certain working periods
  • automation in the fields of roving bobbin transport and roving bobbin change.

Altogether, these can make the ring spinning machine a very attractive proposition again. Technological relationships are explained in detail in " Technolog of Short-staple Spinning".

Fig. 1 – Ring spinning machine

Fig. 2 – Cost structure in a typical ring spinning mill