With EvoTape, the process for manufacturing tapes has literally been revolutionised, and depending on the configuration, the systems output can be increased by up to three-fold, writes Jens Weinhold of Oerlikon.
The technology used for manufacturing tapes has remained the same for many years now. Although minor optimisations have been achieved with regards to the production speed, there have been no quantum leaps in the technology. For this reason, there has been very little replacement investment over the years.
However, the broad range of applications for tape yarns ensures constant growth, hence making new investments due to expanding capacities the norm.
The application possibilities for extruded tapes range from carpet backing fabrics, textile packaging via agricultural textiles and all the way through to the increasingly coveted area of geotextiles.
In addition to systems and yarn quality, the operational expenditures are a very considerable decision making criterion for investors in view of ever-growing pressure on margins. Traditionally, Oerlikon Barmag extrusion systems are high-end with regards to the quality of the systems, the process and the yarn. To this end, the focus during the development of a new systems concept for tapes was on production costs and energy consumption.
Efficient tape extrusion with the EvoTape concept
With the EvoTape, a process for manufacturing tapes has been developed that has literally revolutionised the process used to date, depending on the configuration, the systems output can be increased by up to threefold. The EvoTape operates with a cold pre-drawing process. In the subsequent, second drawing stage, the tapes are ‘lighter’; they take on the heat from the hot-air oven more easily. These two drawing stages result in superior process stability, reaching the same tenacity values with higher speeds or superior properties at the same speed.
The splitting of the drawing process also ensures a low overall draw ratio. As the cut width of the overall drawing is defined, this is also reduced. Consequently, more tapes can be manufactured, which—in addition to the higher process speed—increase the system’s output. Overall, the specific energy consumption per kg of output is therefore considerably reduced.
Cost advantages as a result of greater process stability
A further argument for the new EvoTape concept is its superior process stability: the changed process reduces tape breakages compared to conventional processes. Furthermore, the lower temperature transfer – for example during hot-air drawing – simplifies additional string-up of torn tapes.
WinTape – more output, less waste
Higher speeds reduce the package running time. This, in turn, requires an automatic winder. The automatic WinTape precision winder supplements the EvoTape concept in the take-up stage. Electronic crossing angle(s) ensure(s) perfect package build with optimum quality for the downstream further processing.
As the tapes dwell in the yarn guide during package transfer, automatic take-up of folded tapes is possible. Further plus point: with two parking positions for full packages, the system configuration for carpet backing fabrics can operate for 24 hours without package transfer, hence simplifying shift work.
Furthermore, identical package running lengths, which are common in an automatic take-up concept, reduce waste. Operating the WinTape in conjunction with the EvoTape systems opens up further benefits offered by the new precision winder: production waste occurring during package transfer can be directly routed back to the extruder.
EvoTape concept is available for many processes
Following the successful market launch for manufacturing tapes for carpet backing fabrics, the EvoTape process is now also revealing its strengths for other products. The focus of the development work over the past few months has been on the verification of speed potentials and a lower overall draw ratio for further products: to this end, the new concept currently offers solutions for the manufacture of carpet backing, agricultural textiles and geotextiles.
The system configuration for carpet backing generates the familiarly high and, above all, homogeneous tape quality at simultaneously considerably higher process speeds. The EvoTape offers a process speed of 400 m/min: by contrast, extrusion systems for carpet backing used to date operate at a speed of 320 m/min, while systems manufactured before 2010 produce at just 180-280 m/min. To this end, the considerably superior productivity of the new EvoTape system in conjunction with the WinTape take-up unit provides yarn producers with a significant expansion in capacity without substantial additional space requirements.
In this application configuration, the energy savings amount to up to 50 per cent compared to equipment manufactured during the 1980s and 1990s, which is a quite permissible comparison for a system lifespan of 30 years and more.
The potential is particularly apparent in the case of baler twine: here, it is – in addition to higher process speeds – above all the reduction of the overall draw ratio that is significant.
With this, it is possible to virtually double the output compared to established processes. While the titers of carpet backing fabrics lie between 300 and 1500 dtex, the titers for baler twines start at 20,000 dtex and goes as far as 70,000 dtex and more. Instead of tape widths of between 0.9 and 2.5mm and thickness ranging from 35 to 45 µm, tapes with widths of between 20 and 90 mm and thicknesses of between 75 and 100 µm can be manufactured. The tapes are profiled or fibrillated and are twisted in the downstream process and wound onto tubeless packages.
The focus of the process is on high tenacities for the yarn and high tenacities for the knots when tying off the bales. To achieve the high tenacities desired, the tapes are drawn at a ratio of 1:12 in currently common standard processes. The high draw ratios mean that in the case of products with 70,000 dtex, for instance, only 3 to 4 tapes can be run in parallel on the system.
With EvoTape, these draw ratios can be reduced to one seventh or one eighth. Lower draw ratios simultaneously also mean cutting narrower tapes, hence allowing more tapes to fit on the godets. The output of the system is virtually doubled in conjunction with the speed increase from 250 to 350 m/min: from 500 kg/h (common market standard) to up to 1,000 kg/h (EvoTape / WinTape concept). To this end, the new systems concept saves space, handling and – above all – energy. Energy consumption of just 0.4kWh/kg is a further decisive argument for the EvoTape / WinTape solution.
Geotextiles And EvoTape process also showcases its advantages for geotextiles and agricultural textiles. Here, high tenacities are achieved with lower overall draw ratios as well. For some applications, the addition of LDPE as a ‘drawing aid’ can be dispensed with, additionally securing a reduction in raw material costs for this process.
The benefits of the concept are also available for manufacturing sacks and big bags: the EvoTape 800 and the WinTape mini have been developed especially for the production of tape yarns, which are round woven in the downstream process. Tapes with a minimum thickness of 25 µm are manufactured at a take-up speed of 800 m/min and a denier range of between 400 and 2,500 dtex. With this, the Evo-Tape 800 in conjunction with the WinTape mini system are the ideal solution for small circular-woven sacks.
EvoTape & WinTape – the perfect duo
In an age in which investment decisions are also influenced by sustainability considerations, the EvoTape/WinTape concept has set a new standard. More output with up to 25 per cent less energy consumption, around 20 per cent fewer operating staff and no waste during package transfer when manufacturing non-preparation tapes as a result of immediate recycling – these are just a few of the advantages offered by this optimally tailored duo. Furthermore, a fast return on investment (ROI) makes the new tape system from the Chemnitz-based Oerlikon Barmag experts for extrusion technology a real alternative.
With the EvoTape/WinTape duo, the tape market now has a concept that is also a prudent replacement investment as a result of its immense efficiency. The concept only unveils its full potential as a duo of perfectly coordinated components: here, high extrusion process speeds can only be efficiently realised with an automatic winder. Conversely, although connecting an automatic winder to a standard extrusion system makes sense, it is unable to reveal its entire performance spectrum.
In terms of tape quality, the EvoTape & WinTape combination makes no compromises: the familiarly superlative product quality promises tape manufacturers a position within the high-end market.
For further information:
Oerlikon Barmag, Zweigniederlassung der, Oerlikon Textile
Tel: +49 371 23 88 240 | Fax: +49 371 85 21 42 Email: email@example.com