Cutting and drawing unit for the high-speed loading of knitting machines
Technical textiles such as agricultural textile nets for straw bales, vegetable packing for onions, potatoes and zucchini as well as shade and hail protection nets, are all made from flat tape yarn on knitting machines.
The manufacturing process requires that the knitting machine be afforded a reliable material feed, which guarantees robust film thickness, durability and a steady knitting-machine feed speed.
The ISO cutting and drawing unit’s in-line system integration is the most cost-efficient manufacturing method for planar textile production. A reason for this is that the specific requirements placed on the yarn characteristics can only be met by directly linking the yarn feeding and finishing processes.
Rubberised rollers in the finely-tuned ISO cutting and drawing unit architecture enable a high level of torque transmission. As such, yarn processing speeds of up to 85m/min are achieved.
The gauge of the film tapes is also incredibly narrow: in the manufacture of net tube packing, for example, yarn gauges of around 0.5-0.7 mm in width and only approx. 0.016 mm in thickness are processed.
The focus of the machine concept centres on the drawing of the primary polyolefin film to make monoaxially-oriented flat tape yarn. On passing the heated comb and drawing unit, the tapes are stretched to consequently achieve their impressive strength.
Normally situated behind the machine, the yarn feed system feeds the tapes precisely as required into the knitting machine. First the tape width is set. Then the film is pulled from the film roll and monoaxially drawn within a drawing zone to between 2.7 and 12 times its size. Coordinated to the respective consumption rate, the output tapes then run into the knitting machine.
The modular design makes the ISO system exceptionally flexible. Thanks to the dual construction, the feeding speed of the two conveyed feeds can be independently selected. Hard-chrome-plated drive lines cater for a minimum of wear and a long machine service life.
To produce a high number of yarns, a number of modules are brought together to form one functional block. The width of subsequent machines, the number of guide bars, fine tuning of the machine and selected tapewidth upon entry into the knitting machine determine the required number of ISO cutting and drawing unit modules.