A jack of all trades in the world of hydraulic presses
Langzauner GmbH has been designing and building presses since 1936. Today, the Austrian company is the leading international producer of presses for manufacturing skis. At the Composites Europe trade fair in September 2011, Langzauner presented a methodological paradigm shift rivaled only by the industry's movement from the screw press to the hydraulic press. Using variable speed hydraulic drives, their newly developed laboratory press sets new standards in precision while also reducing energy consumption significantly. B&R's single-source compact control technology eases development and assembly for the manufacturer and simplifies operation for the end user.
A surprising number of the products we use every day has passed through a press at some point along the way. "This trend has risen sharply with the increasing popularity of composite materials," states Michael Laufenböck, marketing specialist at the machine manufacturing company Langzauner, headquartered in the Austrian town of Lambrechten. Founded in 1924 with an initial focus on sawing and sanding machines for wood and metalworking, the company began manufacturing presses in 1936. While early production dealt primarily with screw presses for veneer production, Langzauner has also been building hydraulic presses for composite materials since the 1970s. "When it comes to presses for manufacturing skis, we are the undisputed world market leader," explains Laufenböck with justifiable pride. "Over the last two decades, we have also been manufacturing components for the aerospace and automotive industries."
Upgraded technology to increase flexibility
While order quantities for these segments are not particularly high, suppliers must be able to quickly and easily react and adapt to changing requirements. In addition, the demands for precision are extraordinarily high not only for the parts themselves, but for the individual forming steps as well. "This was also reflected in the technical specifications for our upcoming series of presses, particularly in regard to the hydraulics," reports Gerhard Mayrhofer, the mechatronics engineer heading up Langzauner's Electrical Engineering department. "Control technology was a central aspect from the very beginning since some of today's market requirements are nearly impossible to achieve using the separate hydraulic controllers of the past."
A turning point in the development of the new product series was the decision to move away from the conventional solution that uses proportional valve technology for the hydraulic unit. "The traditional method not only contributes to energy waste with a pump that runs at constant full capacity, it also involves extremely complicated control elements," states Mayrhofer. "Not only that, but the proportional control valves are not exactly cheap and are far from being maintenance-free." Rather than accept these disadvantages, he chose to go with a variable speed hydraulic drive, where an internal gear pump – driven by a servo motor – always generates just the amount of pressure needed at any given moment. "All we use now are cost-effective, maintenance-free switching valves," explains Mayrhofer. This brings several advantages. "We no longer need an extra controller on the hydraulics side because we're now able to handle all open and closed loop control tasks electrically," he says. On top of that, there's also the energy savings of over 70% and a noise level that can barely be perceived.
Faster development with libraries
The first machine in this new generation is a laboratory machine. Unlike most series production machines specified for a narrow range of applications, practically all the parameters and functions in this machine can be configured individually – from the pressing power and the closing speed to the strength and duration of heating. The newly designed laboratory press is the first of its kind available on the market that is capable of handling all pressing techniques including RTM, prepreg and injection molding. This places extremely high demands on both the controller and usability. "The real challenge has to do with the control algorithms themselves, however" explains Mayrhofer. "This is where B&R's development environment, Automation Studio, really helped us out. We were able to implement all of the control-related tasks, including the hydraulics, in record time thanks to the native software libraries." It was this approach that allowed Langzauner to proceed from initial development in February of 2011 to a fully mature machine in September, sending shockwaves through the industry.
User friendliness as priority #1
The technicians at Langzauner were able to utilize the extensive features offered by their automation software to completely revamp the user interface and provide their customers with significantly more options. In the past, it was only possible to define and save parameters. They are now able to easily put together entire programs from predesigned modules using pull-down menus and store them for later use. Up to 1,000 such programs can be saved as CSV files on the nonvolatile memory card and transported via USB flash drive.
Eliminating unnecessary hardware
The new hardware is pretty straightforward: Control tasks are handled primarily by a Power Panel PP480 with a 15" touchscreen, which also records operating data to CSV files – a function that used to require a separate computer.
"Last but not least, B&R's perfectly harmonized hardware and software products enabled us to develop this jack-of-all-trades among hydraulic presses within record time, which brought throngs of visitors to our exhibition stand at the Composite Europe trade fair," reports Laufenböck happily. Mayrhofer adds, "The fact that Automation Studio already provides all of the libraries needed for the latest variable speed hydraulic motion control technology shortens our development time dramatically."
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