Active Shims for Nanometer Resolution and Long-Term Stability: Adjusting with Piezo-Based „Shims“

The piezo-based shims are built into the machine during its construction; they are available – in exactly the same way as other piezo actuators from the same manufacturer – in virtually any shapes and sizes. The static gap at the actuator can be set by applying voltage. PI provides an easy-to-use power supply for this adjustment process together with the matching control. After adjusting, the desired position remains stable without power and the power supply can then be disconnected. In the case of standard products, the maximum displacement is 35 µm; but skillful combination of the active shims makes it possible to adjust in up to six axes.

The ability to adjust at inaccessible locations has been simplified considerably, even more so because piezo-based shims can hold heavy loads of several tons. If required, active shims can also be combined with classical piezo actuators, e.g., for dynamic vibration compensation. Typical applications include for example, readjusting the focal plane during a measuring or scanning process as well as controlling a laser beam in measuring technology or materials processing.