New line concepts for increased performance, reduced energy consumption and the production of special films
Increased working widths and higher line speeds are decisive parameters for increased performance. In recent years Brückner has repeatedly set new standards in these areas, including BOPP lines with 10.4 m working width and speeds of over 500 m/min and BOPETlines which are 8.7 m wide and also operate at speeds of over 500 m/min.
An improved layout for high-speed lines
At the K 2013 Brückner Maschinenbau will be introducing lines for the manufacture of high-quality BOPP films which can achieve working speeds significantly higher than the previous525 m/min. It is not just the speed that is decisive, but parameters such as availability and efficiency of the line, ease of operation and process stability have also been optimised. To this end Brückner has developed a new, innovative platform:
- The centrepiece is the new transport systemin the transverse direction orienter(TDO) with increased operating stability at high speeds. This is achieved, for example, through:
o A new geometry for more efficient power transmission
o The use of new polymer materials with lower friction values and reduced need for lubrication
- A new longitudinal stretching unit (MDO) with automatically adjustable contact rolls ensures stable production conditions at high speeds and a reproducible film quality
- An even moreefficient water removal in the area of the chill roll
- The new low-vibration winding unit with an optimised contact roll guarantees high-quality winding and hence good quality film
BOPET lines for packaging films
Nowadays, BOPET lines by Brückner operate at speeds of over 500 m/min. At the K Brückner will be introducing a number of new developments which will improve still further the film quality and the operating stability and efficiency of the installations through the systematic development of the integrated approach:
- The pinning of the film to the chill roll is further optimised by a completely new automatic control system. Standard materials can be processed at high speeds without additives such as pinning agents.
- Brückner’slongitudinal stretching unit with the unique “two-gap-stretching” has been fitted with innovative adjustmentsfor a closed power flow. The result is top film qualities at speeds of over 500 m/min – even for special applications such as very thin films.
- A newly designed low-vibration transport systemin the transverse direction orienter (TDO) ensures optimal stability during operations in the high-speed range and therefore a longer lifetime.
Reduced energy consumption
High Speed Extrusion
In all lines, Brückner continues to optimise constantly the possibilities for energy savings, thereby achieving a reduction of the energy consumption required for film production by 30% compared with the 1990s. In line with this trend Brückner will be presenting the new “HSE” high speed extrusionsystem at the K’13.
The development of the fast-running HSE single screw extruder – especially as co-extruder for film stretching lines – aimed to achieve the performance of several larger conventional machines with considerably smaller screw diameters. This offers the user a number of advantages compared with conventional extruders with the same throughput performance. The HSE extruder requires a smaller installation area, weighs much less, is easier to operate and less expensive to service. With regard to energy consumption a small extruder also provides advantages because it has lower radiation and convection losses. The direct drive also contributes to the lower energy consumption, because there are no energy losses resulting from the reduction gear.
Simultaneous stretching: the new LISIM generation
The high flexibility of Brückner’s linear-motor-driven simultaneous lines (LISIM) permits the production of films with characteristics which cannot be achieved using sequential technology. A total of ten such lines have been in operation since 1998, designed for film thicknesses of up to 400µm.
The new LISIM generation is specially designed for top-quality thinner films of between 0.5 and 75µm, includingpolyamide packaging films or ultra-thin BOPP and BOPET capacitor films. The new, less expensive system for the simultaneous stretchingof thinner films demonstrates considerably higher energy efficiency in the stretching oven – regarding the drive power as well as the ventilation system performance inside the stretching oven.
LISIM SLC: Sensorlesscontrol
Brückner’s patented simultaneous stretching technology is based on linear motor-driven individual clips, holding the film during the stretching process. This permits the plant operator a high degree of flexibility throughthe individual operation of each clip.
Through precise analysis of the current and tension, the sensorless regulationSLC (Sensorless Control) ensures that the stretching unit registers the load level of each individual clipat all times. Thus the power levels can be reduced to therequired minimumin real time. In this way the power taken up, and hence the energy consumption, can be reduced by 40%. This represents an enormous financial advantage for the film producer and of course also reduces emissions.
Furthermore, the line operator can pinpoint with great precision the forces to which the film is subjected. This provides him with precise knowledge of the stretching process and therefore permits optimisation compared with the mechanical process.
Lines for specialty films
Battery separator films
The new process for the manufacture of high-quality battery separator films (Evapore), developed and patented by Brückner, has met with a positive reception on the market. Several orders for productionlines have already been placed. Further development is now focused on continuing to expand the product range of Brückner lines for battery separator films. Brückner will be presenting its latest results at the K:
- Reduction in film thickness, in order to increase the power density of batteries, thereby reducing the construction volume
- Processing of new materials in order to improve the temperature stability of the separator films – important in electrically powered vehicles – e.g. UHMWPE (ultra-high-molecular-weight polyethylene)
Further new developments in specialty film lines
Brückner Maschinenbau will also be presenting new concepts at the K for
- High-quality simultaneously stretched polyamide films
- Extra-thin capacitor films under 3µm film thickness
- Technical and optical films (BOPET thick film up to 400µm)
- PP multi-layer films (5, 7, 9 layers)