Additive Manufacturing of High-Resolution PZT Components: Slurry development, Characterization, Design, and Fabrication

Vat-photopolymerization Additive Manufacturing (VPP-AM) is a technology that allows the manufacturing of objects with complex and specific geometries at a high resolution using ultraviolet radiation to cure liquid photopolymer selectively in a layer-by-layer fashion. The combination of precise optical control and fast reaction chemistry enables VPP-AM to build complex 3D objects with microscale resolution at speeds unmatched by other AM technologies. A promising method to enable functionality in VPP-AM components is by adding small particulates into the photopolymer resin to manufacture a polymer matrix composite (PMC). The combination of geometrical resolution from the photopolymer and the functionality of the additive particulate can lead to desirable material properties of the PMC. Furthermore, the PMC can be treated as a green body that is debound and sintered to produce a component only consisting of the particulate material and having piezoelectric properties [1].

Piezoelectric materials are a class of ceramics that produce electricity under the influence of mechanical stress and vice-versa. These materials are widely used in transducers/sensors, underwater acoustics, medical ultrasound, actuators, and other industrial applications [2]. Conventional manufacturing technologies of piezoelectric components limit geometries to discs, plates, tubes, or other 2½D shapes. Therefore, in this area, progress is possible in the field of design and the development of a new formula, which together can lead to improvements in physical and mechanical properties.

The project aimed to develop a lead zirconate titanate (PZT) slurry with a minimum of a 30% vol (real density) PZT powder loading in order to avoid excessive shrinkage and delamination during the debinding and sintering processes [3 -5], capable of creating high-resolution complex parts using a state-of-the-art vat photopolymerization AM machine. Experiments also included mechanical, chemical, and thermal characterization of the slurry and design and fabrication of lattice structures. The first step was to study the effect of various dispersants on slurry development and suitability for manufacturing, which is presented in this paper. Three promising dispersants were chosen for further research as well as the manufacturing process was optimized for fabricated slurries. The important slurry properties including viscosity and fabrication were analyzed and the correlations to process parameters were benchmarked.

This research has an impact on the study of the possibility of VPP-AM of high-resolution (on a microscale) components of a complex geometry that contain ceramic particles.