Fraunhofer Institute for Machine Tools and Forming Technology
Fraunhofer Institute for Machine Tools and Forming Technology

Electromagnetic forming

Contact-free and fast

Electromagnetic forming (EMF) is a high-speed forming technology that can be applied for shaping as well as as for joining and cutting of sheet metal and profile-shaped workpieces made of electrically conductive materials.

In EMF the force application is realized via the energy density of pulsed magnetic fields and does not require any physical contact of tool (inductor) and workpiece. As a consequence of the force application, the workpieces are accelerated up to velocities of several hundreds of meters per second, resulting in strain rates in the magnitude of up to 10,000 s-1. The forming, joining or cutting process is typically completed within some tens of microseconds up to one or two hundreds of microseconds.

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Forming by EMF

  • Design of tool and process for EMF
  • Electromagnetically formed door handle cavity
  • Optimization of component properties by generated structuring

Joining by EMF

  • Electromagnetically joined drive shaft
  • Electromagnetically joined pipes
  • Simulation of joining by EMF
  • Magnetic impulse welding of hybrid pipes

Cutting by EMF

  • Cutting with electromagnetic pulse

  • Due to contact-free force application, sensitive, structured or coated surfaces can be processed
  • Tool wear due to tribology does not occur, application of lubricants not required
  • Environmentally friendly processes with clearly reduced cleaning effort
  • Achieving of higher deformations
  • Springback effect significantly reduced
  • No active medium required for pressure application
  • Process can be carried out under special conditions, if necessary, e.g. in a vacuum, a clean room or in radioactive environment by locally separating the control panel from the effective area
  • Process can be applied for sheet thicknesses of some tenths of a millimeter up to a few millimeters

Technology development

  • Development of manufacturing concepts
  • Feasibility studies
  • Design of electromagnetic forming processes
  • Simulation-based analysis and optimization of electromagnetic forming processes
  • Investigation of process chains and design
  • Design of joining and cutting operations

Tool development

  • Application-specific design of tool systems (inductors) and dies
  • Consideration of mechanical, electrical and electromagnetic aspects
  • Systematic design strategy for cylindrical inductors
  • Calculation of tool load
  • Selection and testing of tool materials

Product development

  • Production-oriented design of component geometries, joints, etc.
  • Optimization of component properties (stiffness, acoustics) by generating structuring
  • Consideration of process-specific advantages and limits of EMF

Machine technology

  • Pulsed power generator for electromagnetic forming PS103-25 Blue Wave (maximum capacitor charging energy 103 kJ, maximum capacitor charging voltage 25 kV, gradually adjustable capacity 25.6 -320 µF)
  • Pulsed power generator for electromagnetic forming (Siemens, maximum capacitor charging energy 100 kJ, maximum capacitor charging voltage 21 kV, capacity 450 µF)
  • Tool holder with rotatable clamping plate for positioning coils and dies
  • Flexible tool adapter for operating large tool systems, e.g. for deep drawing combined with electromagnetic forming
  • Various inductor systems (tool coils and field shapers) for specific forming, joining and cutting processes

Software

  • Finite element simulation: LS-Dyna, Ansys, FEMM
  • Planning and evaluation of experiments: Cornerstone, Origin, MathLab

Testing technology

  • Sensors for determining the inductor current for process analysis and process monitoring
  • Tactile and optical metrology for determining component geometry
  • Testing of static bond strengths by tension-compression testing