WTDS Type Electrostriction Ceramic Micro-actuators

We have developed more than one hundred kinds of electrostriction ceramic micro-actuators since it successfully developed the electrostriction ceramic material and the type of WTDS-1A   electrostriction ceramic micro-actuators. These actuators have been used in many fields, such as precision apparatus、photoelectricity apparatus、precision machine、abc warfare engineering、earthquake forecast and so on.

Ceramic micro-actuator is monolithic lamination technics by adopting PLZT ceramic material. This kind material can take place ausform because dielectric relaxation caused by the crystal lattice orientation under the process of electric field. It is a kind of actuator having tiny straining controlled by high resolving power voltage. The displacement of the actuator lies on the number of lamination and the magnitude of the electric field. The actuator has many prominence advantages, such as low working voltage、high resolving power、quick response、small lag、good return to zero reproducibilty、without ageing phenomenon and fine stability etc. It is the ideal executing device to actualize super-precision orientation、super-precision、error compensate、phase modulation etc used in these fields on optics、mechanical working、electron、aviation、abc warfare、medicine、heredity engineering and optical fiber communication etc. Its orientation precision can reach to sub-micron and its resolving power can reach to tens of nm.

A.　WTDS Type Electrostriction Ceramic Micro-actuators Parameter Choice Reference Condition

The relation of the displacement S and the electric field is S=nME2, n is the number of lamination, nappe S is 70%～80% of the theoretical value. We can get the displacement S of the WTDS electrostriction actuator which is about 0.8%～1.1% of the total length if we suppose the value of E is 1500V/mm and M is M1,3. For example, the length is 50 mm(0.2 mm each layer ) and the driving voltage is 300VAD, according to the equation, we can get the displacement approximately from 40μm to 55μm.

 The curve of the displacement vs. voltage is as follows.

Thrusting force

The most resistance the actuator can be endured is 100N/cm2. Under this condition, WTDS actuator’s displacement is zero and the curve of resistance vs. displacement is linearity relationship. For example, the curve of resistance vs. displacement about the outline size of actuator is 10×10×25mm and the driving voltage is 300VAD is as the chart. According to trusting force value choose the effective sectional area of the actuator.

Response time

The response character of WTDS series actuators is as follows: the bigger the sectional area of the actuators, the bigger the capacitance, the bigger the displacement of the actuators; the more the lamination, the bigger the capacitance, the homologous response time is relativity defer. The response time of WTDS series actuators is from 10ms to 100μm.

The enveloping form

Epoxy pastern encapsulation. Under this form, the actuator can endure positive pressure but not resist tension.

Metal crust encapsulation. (1) The actuator just can endure positive pressure.

(2) The actuator can both endure pressure and resist tension. It is a special structure.

Fixing form

The nosetip is plane. One end impact or glue with rigidity palasome and the other contact credibility with the matter being pushed when using.

The nosetip is pillar bolt or bolt hole. Link it with the working end when using.

The instructions of the type.

W  TDS  2 Numbers  2 Numbers  3 Numbers ­—— H or J

W­——Micro-actuator;

TDS­——Electrostriction ceramic;

2 Numbers ­——The length of ceramic slice or the outside diameter of cannular wafer;

2 Numbers­——The breadth of ceramic slice or the inside diameter of cannular wafer;

3 Numbers ­——The length；

H or J——The enveloping form，H- epoxy J-metal。

For instance: WTDS0805020－H；

The electrostriction lamination L×W×H is 8×5×20mm,using epoxy pastern encapsulation。

Usually the length and width of actuators adopting epoxy pastern encapsulation is bigger 2 mm than ceramic lamination;

The circular pipe using metal crust: the outside diameter = the catercorner size of the lamination +3～5mm.

B. Technique parameter of WTDS series electrostriction Micro-actuators