Uniform Pressure Actuator Captures Industrial Interest
Traditionally, sheet metal forming is done at very slow speeds by pairs of massive tools that stretch and bend metal sheets into desired shapes. While this approach has served well for many decades, research in electromagnetic metal forming is creating great advances in sheet metal forming technology.
Glenn Daehn, professor of materials science and engineering, developed and advocates a very different approach for forming sheet metal. His design calls for uniform acceleration of the metal sheet to about 300 miles per hour, then crashing it into a form-die, enabling the metal to pick up the shape and fine detail from the die.
This unconventional approach to metal forming is enabled by the uniform pressure actuator, a recently patented metal forming tool developed in Daehn’s lab. This actuator can uniformly accelerate an aluminum sheet to about 300 mph over the distance of about one-eighth of an inch. This allows the material to be formed, surface textured, surface hardened and even sheared or perforated, all in one extremely quick operation. Also, the metal can bestretched to much greater limits than with traditional low-speed forming, enabling the use of higher strength materials and/or more complex component designs.
There is significant industrial interest in Daehn’s invention. Initial inspiration came during a visit to General Motors, where GM engineers John Bradley and Paul Krajewski asked whether electromagnetic metal forming would be useful to form fuel cell bipolar plates. At the time, the premise was not a good match for electromagnetic forming, because with current actuators, pressure is either uneven or coils have very low efficiency.
But since then, Daehn’s team member Manish Kamal completed his doctoral thesis on the design and use of the uniform pressure actuator. GM is evaluating its use for manufacturing fuel cell bipolar plate, and American Trim Corp. is working on the commercial development of the actuators for a range of purposes.
High velocity metal forming can improve other processes in addition to the forming of flat sheets. In collaboration with external partners including EWI (Edison Welding Institute), Daehn’s work is leading to applications for electromagnetic forming that include impact welding, high performance crimp joining, metal cutting and precision dimensional calibration for high strength steel and aluminum components.
