Development of a Miniaturized, Electromagnetically Actuated Punch

The production of micro-components in high quantities by means of cutting plays a central role in the area of metal forming. Generally, these components are manufactured with mechanical high speed presses with modified drive kinematics which provide stroke rates of up to 4,000 strokes per minute (spm) and punching forces of up to 2,000 kN. Depending on the application, this may result in a significant oversizing both in terms of maximum cutting force and size of the punching machine. This leads to higher production costs due to increased space and energy consumption which could be improved by a better adaptability of the machine to the process. To fulfill both requirements, a prototype of an electromagnetically driven punch machine with highly efficient resonance drive and miniaturization potential is proposed in this paper. Electromagnetic actuators induce oscillations of a mass-spring system at its resonance frequency by storing potential energy in the system’s springs. An advantage of the resonance propulsion is that only magnets with low nominal force are needed, since only small forces are necessary during the swing-up. The resulting oscillation frequency can be adjusted for the given task by using a modular concept with exchangeable springs. After discussing the concept and essentials, the requirements and constraints are pointed out. Subsequently, a model of the system is created and an energy based bang-bang control concept is implemented utilizing model based filter techniques. Based on the simulation results a test rig was built and obtained measurements were compared to the simulation data. The test rig provides stroke rates up to 2,000 spm and cutting forces up to 20 kN. A prototype, which will be able to achieve higher stroke rates and cutting forces will be part of future work.Copyright © 2015 by ASME