Development and Future of Circular Knitted Fabrics.
New functional yarns, new fashions,
new areas of application.
Flowing and feather-light knitted fabrics are a big selling item world-wide. The smoothness and elasticity convey wearing comfort, snugness and a unique textile feeling of wellness. These excellent wearing properties are achieved by the use of synthetic yarns, as well as mixtures - especially micro-fibres with plated elastomers.
In the meantime, these materials have attained a dominant use for underwear and sportswear in particular. Also, the elastomer-plated fabrics achieve a soft, clinging optical effect with excellent wearing properties in combination with cotton
The use of these so-called filament yarns - that means synthetically manufactured yarns - in addition or in place of natural yarns - has also increased considerably with the improved flexibility provided by circular knitting machines. Plating with elastomers is meanwhile a standard procedure, however, new developments continue all the time.
Fashion increasingly uses these new yarns to create new patterns, structures and optical effects merely from the yarn itself. Colour and glitter effects are very popular with international fashion designers. And there is already talk of clothing being made of precious metal fibres - as a fashion gag, but also to shield individuals from damaging electro-smog.
But the processing opportunities for new yarns also open up new areas of application for circular knitted fabrics if one thinks of the interior of cars, for example. The market for technical textiles especially is becoming more interesting for the circular knitting industry, which a look into the near future clearly reveals.
Special yarns made of polymers and metals can be used in mesh fabrics in the areas of filter technology or in the electrical or electronics industries, for example, for shielding cables. A further big field of application could be that of environmental protection with so-called geo-textiles, if one thinks of reinforcements and safeguards for embankments of rivers or slopes to protect against boulders or surface erosion or even landslides.
The processing of metallic yarns, for example, based on steel or copper, or even alloys such as brass, is already possible on circular knitting machine. Corresponding trials by Mayer & Cie. have been very successful.
However, the specific material properties of synthetic yarns and, of course, to an even greater extent those of metallic yarns correspondingly puts new demands on circular knitting machines.
Factors which influence the yarn feed of new yarns.
These new functional yarns are, however, much more aggressive than cotton yarn, for example. This places corresponding demands on practically all parts which come into contact with the yarn, from the creel to the feeder and the thread guide to the needles. For the tubes of the creels the synthetic plastic material is replaced by aluminium.
The functioning of the yarn supply via storage feeders in order to avoid different yarn tensions is also dependent upon the types of yarn used. In order to be able to match up to the increased requirements of the new yarns, the surfaces of the thread wheels have an anodised coating, just as the metallic parts of the thread in-feed and out-flow - as well as the thread guides - are powder-coated with ceramic.
The needles are also subject, of course, to higher wear and tear and needle manufacturers will have to react correspondingly to this in the future.
The use of metallic yarns is still in the experimental phase and thread guides, needles and cam parts will have to be continuously optimised for these knitting processes in trials. It is an important fact, however, that it is already possible today to knit pure metallic mesh fabric, which Mayer & Cie. has already been able to demonstrate in corresponding tests.
The matter of the "kink."
Normally, the knitted fabric is wound as a tube, whereby "kinks" or crease edges can arise, which can mean a higher cutting loss when synthetic yarns are used.
In order to avoid this cost factor, solutions were sought in order to achieve removal of the fabric without crease edges. Different approaches were not very satisfactory, so that an open width device was developed in the circular knitting machine. But also by solving the "kinking" problem new problems were created due to imprecise cutting and, in particular, to fabric takedown which was not free of distortion.
Perfect open width from Mayer & Cie.
The open width device without any distortion was first presented by Mayer & Cie. at the TECNO TMA fair in Bologna in early summer of 2001. This small technical revolution could be achieved by the intelligent combination of electronics and mechanical engineering. The electronic fabric takedown EPA allows a positive takedown, which on the one hand guarantees an even takedown over the entire width of the fabric and also allows even winding. The values for the EPA can be set on the display and can therefore also be replicated at any time.
By simply setting the respective yarn and fabric width the fabric distortion and centre creases can be excluded. The values can be read off on the scale and can be used again for repeat orders.
In order to cut the material carefully and precisely, Mayer & Cie. uses a self-sharpening blade. This open width device can also be used for conventional winding of tube knitted materials and the change-over can be easily done by personnel.
There are also different frame sizes for the open width device, just as there are for standard frames - these are matched to the cylindrical diameter of the machine, whereby the maximum fabric width is between 2,200 mm and 2,750 mm.
Depending on their size, Mayer open width devices work on a continuous operating basis at speeds up to 33 rpm. In this way, a high level of machine output and productivity can be maintained, flexibility and economy are clearly improved when single as well as double machines are used with open width devices.
The fact that more than 300 MCT machines with open width devices have been sold since the first launch just over a year ago shows that the market has been waiting for such a technological concept.
Transport problems solved.
Because of the very broad diameter, transport as well as fitting of the open width devices was a problem. Special transporters and quite often not inconsiderable structural changes were and still are a logistical and cost factor for many open width devices which are available.
Mayer & Cie. has therefore also found an excellent solution for this problem for its open width devices. The device can be reduced to the width of a standard frame for transport purposes with effortless ease and thereby adjusts to the size of a conventional container.
Win in the future.
Just as new technologies open up new applications and opportunities in many areas, which were not thought possible a few years ago, this also applies in circular knitting. And this development has a momentum of its own with an accelerating tendency.
For this reason, engineers have to continuously develop machine designs still further, in order to open up these opportunities to the circular knitted products of the future. As a circular knitting machine manufacturer, Mayer & Cie., which has always placed major emphasis on achieving strong development results and will continue to do so, intends to help shape this future decisively and be able to offer its customers a large piece of the future in this way.
[ 01.01.2003 ]
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1.: A look into the future: A wrap, knitted from metallic yarn on a Mayer & Cie. circular knitting machine.
2.: Positive storage feeder CONI SEP with anodised coated thread wheel.
3.: The friction and thereby the wear of the needles can be considerably reduced using the relative technique with flat cam angles and absolutely positive needle guidance. Furthermore, the needles run quietly and free of vibrations.
4.: Precise cutting without damage to fabrics with self-sharpening blade.
5.: No fabric distortion across the material width using simple, replicable settings.
6.: Even fabric takedown - even wind-on across the entire fabric width.
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