Title: The Application of a Piezoelectric Actuator for Forming Surface Micro-Geometries (SMG’s). By: Baharozan Mohid Supervisor: Prof Raj Balendra

Introduction Piezoelectric actuator was used for the construction of the tool-system in the creation of surface micro-geometries (smg’s) with a depth of 1 to 15 microns gives a promising results. To produce such accurate smg’s, very accurate displacement and consistent performance of the piezoelectric actuator is require. Therefore, loss of performance after long-term operation should be taken into account. Nevertheless In the recent research

2.Conduct performance trials on different prescriptions of piezo-actuators Introduction (cont…) Research Objectives Research Aim To define the decay characteristics of piezo-actuators in the view of design and develop the auto-compensation methodology 1.Design and develop test equipments for establishing the decay characteristics evaluations of piezo-actuators

What is Piezo-Actuator? Fig. 1: Photograph of Piezo-Actuator manufactured by Noliac A/S

Piezo-Actuators Characteristic Fig. 2: Graph of Displacement Vs. Force: Piezo-Actuator Characteristic D i s p l a c e m e n t [ m i c r o n s ] Force[N] U o Blocking Force, F max U 2 U 1 3 U=0V External Spring Characteristic curve Free Stroke U o > U 1 > U 2 > U 3

Characteristic Decay Phenomenon of Piezo- Actuators Characteristic decay as a function of time is usually called “degradation” or “ageing”. The term “fatigue” has been used by numerous researchers to describe the loss of performance of piezoelectric materials, which is due to electrical or mechanical loading. Definitions

Characteristic Decay Phenomenon of Piezo- Actuators (Cont.) “ Piezoelectric materials are commonly made from poled devices, which can readily dipole by applying high electrical field, and mechanical stress ”. [Dr Markys G Cain, at. el (1998)].

Characteristic Decay Phenomenon of Piezo- Actuators (Cont.) “The loss of performance of piezoelectric actuator is usually logarithmic and manufacturers will quote the lost of performance in terms of percentage loss per decade”. [B. Andresen Noliac A/S, Kvistgaard, Denmerk)].

The Technique of Degradation Evaluation of Piezo-Actuator Measurement of Capacitance Measurement of Free Stroke Measurement of Blocking Force Force/Displacement Characterisation

Measurement Methodology Fig. 3: Measurement flow of decay characteristics of Piezo-Actuators Force/Displacement characteristic measurement Capacitance Measurement Long-Term Cyclic Test for specific number of cycles Measurement Flow

Measurement Methodology (cont….) Fig. 4: Test equipment setup for establishing the decay characteristics of Piezo-Ceramics Test Equipment

Characteristic Measurement Measurement Methodology (cont…) Fig. 5: The steps of characteristics measurement

Results Capacitance as a function of number of cycles 5 X 5 X 20mm 3 SCMAS/S1/A/005/0,020/200/025/01000 : 5 X 5 X 20mm 3 (SML-05-28) Number of Cycles in Millions Capacitance [nF] Actuator 1 Actuator 2 Actuator 3 5 X 5 X 40mm 3 SCMAS/S1/A/005/005/0,040/020/052/01000 : 5 X 5 X 40mm 3 (SML-05-29) Number of Cycles in Millions Capacitance [uF] Actuator 1 Actuator 2 Actuator 3

Results (cont…) Free Stroke as a function of number of cycles

Results (cont…) Blocking Force as a function of number of cycles

Conclusion and Future Works Base on the preliminary results, after applying 10 8 cycles of cyclic voltage of 200V (4kV/mm), the piezo-actuators maintained its excellent characteristics with no degradation (decay characteristic) of the free stroke, blocking force and capacitance In order to observe the degradation trends, it is beneficial to evaluate the piezoelectric actuators under the higher mechanical load condition

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