Ultrasound Transducer Array Fabrication Based on Additive Manufacturing of Piezocomposites

Abstract

Conventional methods for fabricating ultrasound imaging transducer arrays, especially for high frequency range (>20 MHz), are expensive, time consuming and limited to relatively simple geometries. In this paper, the development of an additive manufacturing (AM) process based on digital micromirror devices (DMDs) is presented for the fabrication of piezoelectric devices such as ultrasound transducer arrays. Both green-part fabrication and the sintering of fabricated green-parts have been studied. A novel two-channel design in the bottom-up projection system is presented to address the piezo-composite fabrication challenges including a small curing depth and viscous ceramic slurry recoating. A prototype system has been developed for the fabrication of green-parts with complex shapes and small features. Based on the fabricated green-parts, the challenges in the sintering process for achieving desired functionality are discussed. Various approaches for increasing the density of sintered components are presented. Dielectric and piezoelectric properties of the fabricated samples are measured and compared with those of bulk PZT samples. Based on the identified challenges in the DMD-based AM process, future work for achieving fully functional piezoelectric ceramic components is discussed.

Advanced Synthesis on Lead‐Free KxNa(1−x)NbO3 Piezoceramics for Medical Imaging Applications

“…An ultrasonic transducer is basically composed by multilayer elements (Figure b) including i) a backing substrate which absorbs the acoustic emissions; ii) an active layer made of a piezoceramic disk; and iii) a matching layer, typically based of a piezoceramic material but possessing an acoustic impedance approaching that of the investigated tissue …”

Ceramic fabrication using Mask-Image-Projection-based Stereolithography integrated with tape-casting

“…Chabok et al [11] investigated the fabrication of PZT ceramics using the MIP-SL process. A novel two-channel bottom-up projection based system was developed to achieve the separation of cured layers from the slurry tank.…”

Finite Element Simulation of Localized Electrochemical Deposition for Maskless Electrochemical Additive Manufacturing

“…Maintaining the interelectrode gap is of prime importance in this process, since the interelectrode gap is one of the critical process parameters. An in-house built control system [2], consisting of a current-sensing closed loop feedback system was used to avoid short circuiting. When the electrodes are in close proximity, the current increases; when the current exceeds a preset threshold value, the feedback system moves the stage down from the microa node to reestablish a predetermined interelectrode gap.…”

“…The following relation describes deposit cluster size as a function of current density [21], which can give clues to the resulting grain size: d{t) = -(iJ(ri))t (2) where i0 is the current density in A/cm2, Vu is the molar volume of the deposit in cm3/mol, z is the charge number (2 for Ni2+ ions), and f(r\) is the overpotential function, which is described by a b…”

“…How ever, three-dimensional features in micromanufacturing are still a distant dream-existing micromanufacturing or nanomanufacturing techniques are mostly limited to two-dimensional (2D) or 2.5D capabilities. Additive manufacturing, a recently developing process, has the capability of producing complex 3D parts from computeraided design (CAD) models [1], from varying materials including metals, polymers [1], and even piezoceramic materials [2].…”