Swiss plant manufacturer Apaco:
“It’s fun to work with this machine!”
The new system offers two new features: an ‘intelligent’ control system and a variable adjustment of the rollers, which achieves 85 percent additional bending moment by ‘repositioning’ the rollers.
Bending becomes child’s play
With this new technology, sophisticated shells and built-in parts can be rolled from the first sheet in series production thanks to Bendtronic. The graphically supporting software allows both single and multi-stage sheet rolling. It can be used for any type of product such as cylinders and tubes, ovals, containers or other more complex geometries up to S-shaped workpieces. These multi-radial geometries such as ovals, cushions or cups are usually real challenges for sheet metal roll operators. After the graphically supported definition of the desired geometry, the system calculates the machine settings and all steps from the flat plate to the final geometry. The operator can start rolling directly after the process simulation.
The smart control also ensures that no waste is produced when rolling individual parts or small series. “The final geometry is approached successively, whereby the first pass is only slightly larger than the required final geometry. For the second pass, you only have to measure the real geometry, enter the values in the corresponding mask and roll the workpiece to the final geometry,” Timo Wölker summarizes.
The control is based on the simulation of the material properties of the plates, the machine behaviour and the machine-plate interactions. With this, the system calculates the machine settings for the desired geometries with given material properties. The simulation model takes into account the non-linear flow behavior of the materials and thus knows in advance exactly how high the springback is for each sheet thickness. The machine behavior itself is simulated based on the roll properties, the rigidity of the system and the existing friction. The modeling of the machine-plate interaction includes the modeling of the contact points as well as the gravitational forces acting on the plate. With these calculations inside, the operator knows exactly what and how he can roll on the machine, even without much knowledge of his own. The CNC sheet metal rolling software also helps in the finishing of already rolled workpieces, making even complex multi-radius geometries easy and efficient to bend and delivering high-quality products from the first plate.
Maximization of the bending range
By using two pivot points instead of only one when adjusting the side rolls, the machine can be adjusted individually to the respective requirements. A wide bending geometry helps when bending thick-walled sheets; a narrow geometry is optimal when bending small diameters.
“The complete machine is designed so that all possible adjustments can be made without special tools and in the shortest possible time. Not only is it quick and easy to change the pivots, but thanks to a newly developed mechanism, a top roll can be changed in less than half an hour,” confirms Arben Djokaj.
The hybrid drive system HHDS, developed in-house, offers high efficiency through the use of electric motors in combination with planetary gears. In practice, this saves up to 50 percent of operating costs. In addition, the hybrid drive system enables a continuously adjustable rotation speed of 0 to 8 metres per minute, which is 60 percent more than other machines available on the market. This higher rotational speed is especially important when bending and calibrating large diameters and saves enormous maintenance costs. Long-term tests show that this type of drive can save 50 percent of maintenance costs.
Standard machine, but still flexible
But customer-specific, non-standard solutions are also possible. For example, Apaco wanted a beam to support the bent sheet metal, which, in order not to obstruct the crane, was hinged and could be easily swung out of the way.
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