Fraunhofer Institute for Machine Tools and Forming Technology
Electromagnetic forming (EMF) is a high-speed forming process particularly suited for processing workpieces made of highly conductive materials, such as aluminum or copper. The force application is contactless, utilizing Lorentz forces, making it exceptionally surface-friendly and suitable for forming pre-coated semi-finished products. The process can compress and expand tubular and profile-shaped workpieces, as well as form flat and three-dimensionally preformed sheets. Induction coils and single-sided forming dies or mandrels serve as tools. A capacitor is discharged through the coil, generating a damped sinusoidal current pulse. This time-dependent current induces a corresponding magnetic field and a counter-current in the electrically conductive workpiece. The interactions between the magnetic field and the current produce Lorentz forces, which deform the workpiece at extremely high speeds (up to several hundred meters per second) within microseconds.
Unlike other high-speed forming processes, electromagnetic forming does not require hazardous materials such as explosives or a working medium. This makes the process particularly user-friendly and environmentally friendly, eliminating the need for cleaning steps and reducing production costs. Additionally, unlike conventional drawing processes and high-speed forming with accelerated tools, the tooling coils for electromagnetic forming can be used more flexibly for different component geometries. This allows for cost savings, especially in variant production, and simplifies tryout processes.
In addition to forming, the technology can also be used for joining, both through force and form closure (crimping) and through material bonding (magnetic pulse welding), as well as for cutting. Different manufacturing operations, such as forming and punching for small to medium-sized components, can be performed simultaneously in a single electrical discharge process. Larger components can be realized by combining EMF with other technologies for local post-forming of geometrically demanding details and component areas, or through sequential or incremental manufacturing approaches.
Advantages of the Process
- Combined Processes:
- Elimination of manufacturing steps by combining forming, cutting, and joining in one process.
- Contactless Force Application:
- Surface-friendly force application.
- No Tool Wear:
- No wear due to tribology.
- Environmentally Friendly:
- Clean process without lubricants or working media.
- Improved Formability:
- Enables higher degrees of deformation with significantly fewer wrinkles, necking, and springback compared to conventional processes.
- Flexible Tool Use:
- Flexible use of tooling coils for different component geometries.
- Suitable for Aluminum:
- Particularly well-suited for processing tubes, hollow profiles, and sheets made of aluminum alloys.
- Automation:
- Very simple and easily automatable process.