The discussion of 3D printing and materials is ongoing, fascinating, and continually enlightening—and many still do not realize that there is a wide variety of options out there today besides ABS and PLA. I am often asked what the point of 3D printing is if we are just limited to fabricating a ‘bunch of plastic stuff.’ Well, one—thermoplastics can be incredibly strong, durable, and useful in making everything from exceptional architectural prototypes to functional automotive components, electronic assemblies, and even toys (think Legos). But those using 3D printing and additive manufacturing have certainly moved far beyond the limitations of plastics, with metal 3D printing taking its place in the forefront of manufacturing, and a range of alternative materials making their way into the mainstream, from nylon to wood or even stone.
More and more, however, we are also seeing another very exciting material being explored: ceramics. We’ve followed numerous cases where this is being used in projects by industrial artists and potters to companies developing hardware made to extrude ceramics specifically.
UK researchers from the School of Engineering at the University of Warwick are working with a different type of ceramic material that’s extremely useful, in the form of piezoceramics. Their work and goals are outlined in their paper, ‘Additively-manufactured piezoelectric devices.’ Authored by David I. Woodward, Christopher P. Purssell, Duncan R. Billson, David A. Hutchins and Simon J. Leigh, the paper was recently published in the physica status solidi journal.
While using ceramic materials–even to include porcelain—is exciting and new—piezoceramics are exponentially so in that they are a special class of ceramics that can not only create an electric response but they can actually respond to one also, in turn—changing shape. Imbued with these unique qualities, piezoceramics already play a part in many components, such as car airbag sensors or ultrasound scanners used in medical imaging. Scientists hope that with 3D printing, this material can be used more to its potential, as currently traditional manufacturing is limiting as it restricts both the shape and structure of this material as well as the data that can be extracted from ultrasound scanners.
“Having greater freedom in achievable geometry can potentially offer significant improvements in the performance of many devices, including piezocomposites, in particular the use of wider bandwidths and shorter pulse lengths, but further shaping of devices is an energy- and time-intensive processing step. Injection moulding techniques have enabled rapid production of high-volume devices and techniques such as tape-casting and gel-casting have made it possible to create devices that could not be made by conventional methods, and yet all of these techniques remain far from widespread, due in part to the high initial costs and the potential restrictions these techniques place on the build process, for example, the need to first create an accurate mold for injection molding or gel-casting,” state the researchers in their paper, as they outline the current needs to expand these materials.
“To enable AM to change the future of designing and building ceramic devices, a truly widespread technique is required; one that is low-cost but has high accuracy and resolution and can be applied to the widest possible range of piezoelectric materials.”
And…enter 3D printing, right on cue. While this study is just part of ongoing research at the University of Warwick regarding the combination of functional materials and electronics, the team has so far been able to use 3D printing for the fabrication of light-sensitive polymer/ceramic mixture which is then fired in an oven. This process actually removes the polymer, resulting in a solid ceramic object which is not only extremely dense, but also possesses the desired piezoelectric functionality.
“The AM technology chosen for this study was curing of ceramic-loaded photo-sensitive resins using micro-stereolithography (MSL). It combines low capital and operating cost with simplicity, high resolution and the potential to be applied to a wide variety of materials,” state the researchers.
The team is also able to use the benefits of 3D printing technology to their advantage here in terms of size, producing more complex and customized shapes not previously achieved through traditional processes and conventional machining. Low cost is also an extremely positive feature in 3D printing as it allows them to explore the materials and processes more fully, as well as actually make components.
“The sintered ceramics are shown to have the high densities necessary for use in applications and their physical properties are shown to be extremely close to those of ceramics prepared conventionally using uniaxial pressure. The process lends itself to flexibility in terms of shapes, sizes and changes in materials,” state the researchers.
It is hoped, according to the researchers, that these intricately shaped ceramic components could eventually find application in high-tech scanners for medical imaging and inspection of aerospace components after manufacture.
“The next step in this work is to generate a library of materials and scale-up the process for making much larger ceramic components,” said Dr. Simon Leigh, one of the team of academics.
This research team has also been responsible for other related projects such as the fabrication of miniature flow sensors which could have many uses, and can be manufactured affordably, again coupling 3D printing with innovative materials and electronics. What are your thoughts on these more complex ceramic materials? Discuss in the 3D Printed Piezoceramics forum over at 3DPB.com.