Baumüller supplies a precisely controllable drive system for the newly developed electric powder press from Maschinenfabrik Lauffer
How is it possible to produce complicated geometries in metal, carbide, or ceramics economically, quickly, and efficiently? By using electric powder presses like the E-Line 12. This press enables the production of high-quality components in the narrowest tolerance fields, generally eliminating the need for downstream mechanical processes.
High-precision parts, such as indexable inserts, are used in cutting tools, milling machines, and lathes. These parts always have the task of removing a uniform amount of material from the workpiece. The aim here is to increase the service life of the indexable insert. This allows the user to machine as many workpieces as possible with the same insert before it has to be changed.
Extensive process knowledge for ideal results
With more than 10,000 systems on the market, Maschinenfabrik Lauffer based in Horb am Neckar in southwestern Baden-Württemberg, Germany is one of the world’s leading manufacturers of both hydraulic and electric presses and automated systems in the fields of lamination and composite technology, plastics and wrapping technology, and forming and powder technology.
In 1872, Johann Martin Lauffer laid the foundation for Lauffer’s successful future with the foundation of a mechanical workshop and forge in Mühlen am Neckar. At first specializing in the maintenance and sale of agricultural machinery, Lauffer produced the first self-designed water hydraulic press in the 1920s. Today, thousands of machines and systems worldwide are proof that top quality and extensive process knowledge are what it takes to succeed in the market.
In order to eliminate downstream mechanical processes, such as grinding the sintered precision parts, Lauffer looked for a solution that could produce high-precision parts in as few work steps as possible. The goal was to increase the production rate of the machine – while maintaining the quality of the end product.
To achieve the productivity targets that it set for itself, Lauffer relies on an efficient drive system from Baumüller in addition to optimized mechanics for its E-Line series of electric presses. The solution consists of four water-cooled DST2-135 high-torque motors, motors from the DSC1 and DSD2 series, and a b maXX 5300 air-cooled modular system.
How the electric press works
The machine operates according to the following principle: The sinter powder is fed by the filling shoe and compacted in a multi-stage process to influence the density distribution. Software developer Nicolas Goeing explains the reason for this step: “It’s not the force that’s decisive, but the density. That’s why we operate the press with position control. The press force is an indirect indicator that the density is within the defined adjustment range.” This step is followed by a random weight check. The filling level is automatically fine-tuned and readjusted to compensate for changes in bulk density. The load on the part is then reduced, i.e. the press force is lowered to about 10 percent so that the loading force acts to push the finished part out of the die. The gripper sucks in the part with compressed air and conveys it onwards with the removal device. This is usually a graphite sintering plate. The parts then enter the sintering furnace, where they shrink by 30 to 40 percent as the density of the component increases.
With 12 tons of press force, the E-Line 12 electric powder press has an output of up to 22 parts per minute. The press can therefore produce up to 1,320 high-precision parts per hour.
Low inertia for increased dynamics
Four water-cooled DST2-135 high-torque motors are used in the press. The motors enable space-saving integration into the machine. The four drives generate high torques that produce a high press force via the spindles, making them ideally suited for the production of precision parts such as high-precision indexable inserts.
The two compact servomotors DSC1-045 and DSD2-045 are responsible for stripping excess material and for the movement of the gripper.
The drive electronics are also kept very compact: The b maXX 5300 modular system controls the main and auxiliary drives very precisely. The combination was optimally matched to the E-Line 12 electric powder press. “The EtherCAT connection to the servo drives allowed us to significantly reduce our cycle times. In addition, we considerably reduce the amount of necessary wiring thanks to the integrated safety and FSoE connections of the Baumüller converters,” stresses software developer Lothar Vöhringer. Baumüller also took charge of the drive dimensioning and initial commissioning of the powder press. Work is currently underway on further drive optimizations using the ProSimulation simulation tool.
The efficient automation of the powder press is made possible by the CNC control unit, which was specially developed by Lauffer, and by the intelligent “Powder Wizard” responsible for tool development, program sequence optimization and quality assurance. A special highlight is the 3D simulation of the pressing process. The software allows the convenient, safe, and reliable operation and monitoring of each pressing process.
In the development of the E-Line 12 electric powder press, Maschinenfabrik Lauffer cooperated with Baumüller as drive specialists.
“What’s special about our partnership is that we achieve close cooperation in the design and very fast and very good support from expert Baumüller employees.”
Lothar Vöhringer, software developer at Lauffer Pressen
The E-Line 12 electric powder press is compact, fast, and extremely precise. It has an outstanding positioning and repeat accuracy of less than 1 μm. Its innovative mechanical design significantly shortens the power flow. The powder press allows very good synchronization, even under partial load. The machine has excellent performance thanks to its low cycle times and high press forces. This enables it to produce a wide range of high-precision parts. The close, cooperative partnership between Maschinenfabrik Lauffer and Baumüller has brought forth a compact drive system that benefits from high dynamics, precise control, and a space-saving drive concept.
Drive systems from Baumüller are also used in Lauffer’s C-Line hydraulic powder press system. Presses with a tonnage of 320 t have already been implemented. A new concept with a servo pump direct attachment is currently in development for a press with 800 t.