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PI manufactures its own piezo ceramic materials at the PI Ceramic factory. The process starts with mixing and ball milling of the raw materials. Next, the mixture is heated to 75% of the sintering temperature to accelerate reaction of the components. The polycrystalline, calcinated powder is ball milled again to increase its reactivity. Granulation with the binder is next, to improve processing properties. After shaping and pressing the green ceramic is heated slowly to burn out the binder.
The next phase is sintering at temperature between 1250 °C and 1350 °C. Then the ceramic block is cut, ground, polished, lapped, etc., to the desired shape and tolerance. Electrodes are applied by sputtering or screen printing processes. The last step is the poling process which takes place in a heated oil bath at electrical fields up to several kV/mm. Multilayer PZT actuators require a different manufacturing process. After milling, a slurry is prepared. A foil casting process allows layer thickness down to 20 µm. Next, the sheets are screen printed and laminated. A compacting process increases the density of the green ceramics and removes air trapped between the layers. The final steps are the binder burnout, sintering (co-firing) at temperatures below 1100° C, wire lead termination and poling.
All processes, especially the heating and sintering cycles, must be controlled to very tight tolerances. The smallest change affects the quality and properties of the PZT material. 100% final testing of the piezo material and components at PI Ceramic guarantees the highest product quality.
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