PI has 4 decades of experience with piezo ceramic actuators in motion control applications in industry and research. Currently PI employs more than 100 people fully dedicated to piezo ceramic research, development and production. Extensive knowhow and the most modern equipment make for the unique flexibility and worldwide leadership in piezo matters.
PI piezo actuators not only show an optimal combination of travel and stiffness, but are also designed for maximum lifetime under actual operating conditions in industrial environments.
Download the latest PICMA® actuator Lifetime Test Results
Maximum lifetime means highest possible reliability. PI’s awardwinning, patented PICMA® actuators are manufactured at PI's Piezo Ceramic Facility and are based upon the newest technology which reduces the failure rate by a factor 10 compared to conventionally designed multilayer actuators.
Long Term Tests Prove DC Reliability
PI’s monolithic ceramic-encapsulated design provides better humidity protection than conventional polymer-film insulation. Diffusion of water molecules into the insulation layer is greatly reduced by the use of co-fired, outer ceramic encapsulation (fig. 2). Humidity is the main influence on the longterm reliability in low-dynamics or quasi-static operation modes, where the piezo actuator is supplied with a DC voltage to maintain a position for a long time.
Comparative tests with both PICMA® and conventional multilayer piezo actuators have proven the positive effects of the ceramic encapsulation. While polymer-coated piezos typically only survive 30 days of continuous operation - PICMA® actuators are still working after more than 4 years!
Continuous Dynamic Operation
Here, the well-known lifetimelimiting factors of conventional designs are humidity, crack formation inside the ceramic leading to rising leakage currents and delamination of electrodes under extreme dynamic conditions.
PI reduces the cracking probability by a special patented design where segmented slots take care of excessive tensional stresses. Furthermore, the special electrode design ensures excellent, stable, electric contact even after billions of cycles. More Information on Lifetime Testing.
PICMA® multilayer piezo actuators show no significant decrease in displacement even after many billions of cycles.
Long-Term Test under Cryogenic Conditions
To suit an application requiring 10 years minimum lifetime under cryogenic conditions, accelerated lifetime tests with PICMA® piezo actuators have been successfully performed. Inserted in a cryogenic bath of liquid nitrogen (75 K), the piezo is placed in a vacuum chamber (2 • 10-3 mbar) and subjected to dynamic operation at 90% of the maximum voltage range (>105 V) with an operating frequency up to 1000 Hz. After one month of continuous operation there were no degradations in piezo performance to be measured, neither mechanic concerning the displacement, nor electrical concerning electrical capacitance or resonant frequency. (Dr. Bosotti et al., University of Milano, Italy, 2005)
Large Operating Temperature Range , Optimum UHV Compatibility - Minimum Outgassing
Another advantage of fully ceramic-encapsulation PICMA® actuators is the extended operating temperature range, up to 150 °C, a huge improvement over the 80 °C limit common for other, polymer-insulated, monolithic actuators. The heat generation in dynamic operation is proportional to the operating frequency. Thus, a higher operating temperature allows for higher operating frequencies and duty cycles. Additionally, the lack of polymer insulation and the high Curie temperature make for optimal ultra-high-vacuum compatibility (no outgassing / high bakeout temperatures, up to 150 °C).
PICMA® award-winning multilayer piezo actuators feature full-ceramic insulation
PICMA® piezo actuators (lower curve) compared with polymer-insulated multilayer piezo actuators. PICMA® actuators are insensitive to high humidity in this test. In conventional actuators, the leakage current begins to rise after only a few hours — an indication of degradation of the insulation and reduced lifetime.
Results of an accelerated DC-lifetimetest of PICMA® actuators compared to conventional actuators (100 V DC, room temperature, 90% R.H.). The expected MTTF (Mean Time To Failure) for PICMA® is 80 years (700 000 hrs of continuous operation). All of the polymer-insulated samples have failed after 1,600 hrs (MTTF 805 hrs = 1 month)
AC tests were performed for 4.0 x 109 cycles at 8 samples PICMA® 5x5x18 using a 116 Hz-sine wave excitation (1.0 x 107 cycles per day) at a unipolar operating voltage of 100 V, 15 MPa preload. Control measurements were taken every 109 cycles. There was no significant decrease in displacement.