Karl Mayer’s innovation in weft insertion

The new Biaxtronic® CO from KARL MAYER MALIMO was launched in September. The company has combined the key components of its RS MSUS-V machine with biaxial technology and developed a biaxial machine featuring weft insertion in line with the courses.

A great deal of potential lies in exploiting synergistic effects as the latest development from KARL MAYER MALIMO shows. This textile machinery manufacturer, which specialises in technical textiles, has combined the key components of its RS MSUS-V machine with biaxial technology and developed a biaxial machine featuring weft insertion in line with the courses. This new innovation is known as the Biaxtronic® CO.

Compared to the conventional version, this new composite machine offers an improved cost:benefit ratio and advantages in terms of its operation and maintenance. But above all, the quality of the product has changed an important advantage, particularly for the Chinese wind turbine market. There, manufacturers of multiaxial structures for the blades of wind turbines want a construction containing weft yarns that are not pierced during the knitting process.

General textile characteristics
As with all stitch-bonded biaxial textiles, the fabrics produced on the Biaxtronic® CO are made up of zero inlays and weft yarns and, if required, an additional base web, such as a chopped glass strand mat or a nonwoven. The two reinforcing yarn systems are inserted absolutely straight and parallel at angles of 0 and 90¦ and fixed in place by stitches. This avoids variations caused by the construction, which lead to loss of strength and undesirable stretching with woven fabrics. Most machines on the composites market operate on the basis of weft insertion that is not in line with the courses but, with this new technology, the weft yarns are inserted in line with the courses. The weft yarns are not pierced or damaged. On the one hand, this enables higher strength levels to be achieved when using conventional materials. On the other hand, new yarn combinations can be used for the same strength values, e.g. a heavy zero inlay layer with very thin weft yarns with defined spaces between the yarns.

Technical features
The Biaxtronic® CO is available in working widths of 100´, 101´ and 102´. The gauges available as standard are E 5, E 6, E 7 and E 10. The standard features also include the KAMCOS® system, an N-drive with a maximum of three pattern discs, an operating interface with 12.1´ touchscreen monitor, and a warp beam frame with one or two warp beam positions. An electronically controlled yarn let-off drive is available for each mounted warp beam. The maximum flange diameter of the sectional warp beams is 32´. The zero inlays are delivered via electrically driven delivery rollers from creels (Figs. 2 3). The tried-and-tested MSUS system is responsible for weft insertion: the weft laying device draws 24 reinforcing yarns from the weft creel and inserts them into the hooks of a transport chain (Fig. 4). A complementary laying device runs ahead of the weft laying device, which ensures that all the yarns are taken off at the same tension and speed. The yarn layers are fed to the knitting point via the transport chain.

The knitting elements are also similar to those of a weft-insertion warp knitting machine, and include a compound needle and closing wire bar, knock-over sinker bar, zero inlay bar, counter retaining bar with support rail, and one or two ground guide bars for stitch formation (Figs.5). Every yarn is tied-in in a stitch at the knitting point to bond the structure of the textile.

An electronically controlled 3-roller system is responsible for take-down of the final reinforcing textile. The panel fabric can be cut into strips by a cutting mechanism located in front of the batching unit. It can<