Rieter

Changes in demand and in the processing possibilities

Index

Fig. 70 – The total market for short staple yarns today

Fig. 71 – The total market for short staple yarns in future

Up to now combing has been employed for (Fig. 70):

  • medium counts to improve running behavior in downstream processing and yarn quality;
  • really fine counts, as the number of fibers in the cross section of these yarns is very small, and each short fiber is an interference factor here.

Combing somewhat coarser counts has not been very popular to date. It was too expensive. In the near future, however, spinning mills will be forced to give more attention to this type of combing. This is due to changes in customer markets, in the cotton market, and the availability of improved processing facilities. The latter will allow combing to penetrate into areas where the material has only been carded to date (Fig. 71).

In this respect we need to bear in mind an aspect that has already been mentioned, namely the need for more intensive utilization of our material:

  • by optimized raw material employment;
  • by better treatment of it on all machines;
  • by reduction of waste and
  • by upgrading (very important).

The main arguments in favor of upgrading are:

  • increasing demands on the end product;
  • increasing demands on the yarns in further processing, e.g. when working with carded yarns in knitting mills about 70% of the processing problems can be traced back to the yarn;
  • compensating for expensive raw material by improving a cheaper cotton through semi-combing.

Upgrading is all the more interesting, as the biggest improvements in quality arise when combing in the range of 8 to 10% noil, as shown in Fig. 12.

A very interesting field of application can be rotor spinning. Compared with ring-spun yarns, rotor-spun yarns have some disadvantages in quality. Some improvements can be achieved by upgrading the raw material. For example:

  • reduction of impurities in the yarn;
  • better parallelization of the fibers in the yarn; and thus
  • higher strength;
  • smoother feel of yarn and end product.

Besides these quality parameters, operating behavior on the rotor machine also improves due to the additional extraction of trash at the comber.