ROJTRICOT storage feeder for high-precision yarn delivery

12 Dec '08

4 min read

Warp knitting is a complex process, in which the relationship between all the processing sequences has a decisive effect on the efficiency of the process and the quality of the fabrics produced. The principles of feeding the yarn to the knitting point are extremely important for the quality of the fabric. This is why this process is constantly being improved and revamped.

The yarn must run with a high degree of precision from the warp beams; it should reach the processing point at an exact tension and should not be damaged in any way by the processing sequences. If necessary, the delivery of individual yarns can be specified by experienced specialists.

This is a particular requirement on warp knitting machines with parallel weft insertion. When using high-performance production machines, all 24 or 30 weft yarns taken-off from the weft-yarn creel must be inserted absolutely uniformly over large fabric widths – and this applies to every type and count of yarn.

Synthetic yarns, either in the form of monofilament yarns, twisted or untwisted multifilament yarns, or textured yarns, must lie as perfectly in the fabric as wool or cotton yarns do. Furthermore, increasingly more technical, special yarns have to be processed efficiently and accurately.

If weft stripes are formed during insertion of the yarns, the fabric will fail the quality criteria. There are many reasons for undesirable stripiness, but they can often be traced back to the yarn package. Irregularities in the yarn being delivered, such as different package diameters, differences in the package build, or irregular yarn finishes, can no longer be compensated for by simple braking systems.

The efficient operating principles of storage feeders can help to solve these problems. The yarn lengths, which are processed by the operations of the weft laying-in device, are first taken off from the package, wound individually onto a storage device, and delivered at the same tension as required.

MEMMINGER-IRO GmbH is one of the most well-known manufacturers of storage feeders. This company, which specialises in yarn-feed technology, has been supplying high-quality products to knitting companies for more than 40 years – including KARL MAYER.

The ROJTRICOT storage feeder – a common feature of warp knitting machine with weft insertion facility KARL MAYER Malimo uses the ROJTRICOT storage feeder from Memminger-IRO most frequently on its warp knitting machines with parallel weft insertion. This high-precision yarn delivery system was optimised especially to cater for these types of machines.

This device is especially suited for use with high yarn speeds. It has a stationary spool body to prevent undesirable, additional yarn twisting and has a switch for setting the rotational direction for S- or Z-twist yarns. The spool body also has a device for transporting and controllably separating the yarn windings, which is an important requirement when processing difficult yarns.

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