Vaporizing Foil Actuators (VFA)
In this technique, electrical energy stored in a capacitor bank is released through a switched circuit (illustrated to the right) that contains a thin metal conductor, such as a wire or foil (pictured below). When the energy deposition rate into the conductor is very high, it can be heated above its energy of sublimation before it has time to melt. This, the conductor vaporizes directly into a gas that expands rapidly. The result is a high-pressure pulse that, when physically constrained, can be harnessed as a tool to drive workpieces.
The VFA tool is small, light, and agile, adaptable with little retooling for a wide variety of small-scale impulse-based metalworking applications, pictured to the right. Such applications are elaborated upon in the Impulse-Based Metalworking section.