Session: 16-01-01: Government Agency Student Poster Competition

Paper Number: 149728

149728 - 3d Printing Ceramics With Vascular Channels for Thermal Management and Self-Healing Structures 

As the power density of electronic systems continues to increase year over year, there is a growing demand for effective thermal management that can withstand high operating temperatures. Ceramic cold plates are a promising candidate. This need for vascular ceramics extends beyond cooling. Metallic molding requires ceramics with engineered interior cavities, many fuel cell designs incorporate ceramic anodes with channels for flowing fuel, and self-healing metallic structures benefit from ceramic channels that facilitate electrolyte flow. However, designing such parts often involves highly complex vascular networks that cannot be machined. Therefore, exploiting the unique benefits of 3D printing is essential. Specifically, Digital Light Processing (DLP) 3D printing has proven to be a quick and reliable way to manufacture ceramic components with complex internal geometries. Despite the proliferation of this manufacturing technique, little work has been done to analyze its ability to create accurate and functional negative volumes within a part. This work investigates the accuracy of DLP printing for creating alumina ceramic geometries with vascular channels and examines the effect on fluid flow and mechanical strength.

This work advances the possibility of applying ceramic additive manufacturing to several fields where it has so far been neglected. Thermal management still largely relies on metals, despite the existence of ceramic materials with thermal conductivities that rival copper. This reliance stems largely from the increased difficulty that traditional ceramic manufacturing presents. If 3D printing can reliably create suitable ceramics, the operating temperature of electronic systems could increase significantly. Molds intended for molten metal currently require a lengthy process called investment casting to create; 3D printing the ceramic shell would streamline the process. Fuel cell anodes could more effectively transport gaseous fuel if the internal structure of the anode could be prepared with computer-aided design and 3D printed. Self-healing structures could operate more effectively by controlling exactly where electrolyte gets deposited along a ceramic channel.

This work outlines three key areas of interest: the geometric accuracy of the channel, resultant mechanical strength, and the expected effect on fluid flow. These are the three chief concerns when a vascular ceramic part is being put into application. Geometric accuracy is investigated through 2D optical microscopy and X-ray computed tomography (XCT) scans. Any deviation from the intended shape is reported as it would be in machining – cylindricity and total runout. Mechanical testing compares the strength of beams with and without channels present under 4-point bending. Influence on fluid flow is studied by scanning the interior of the channels with optical profilometry, providing a measure of the channel’s roughness. This measurement, as well as the previously observed shape of the channels, provides a comprehensive idea of the pressure drop that fluids experience, how fluids with higher surface tension interact with the channels, and how the channels affect turbulence in the fluid.

Preliminary results show that the smallest diameter channel that is printable while maintaining structural integrity during sintering is 1mm. XCT scans of the geometry reveal microcracks that form around the channel’s perimeter, likely to inhibit fluid flow and mechanical strength. Nevertheless, the presence of the channel is beneficial during the debinding stage of manufacturing, allowing gas to pass through the green body more freely. This point is of interest when comparing the mechanics of solid and vascular beams, as the solid beam generates more defects due to a more strenuous debinding process. Early results have shown that, despite some difficulties, there is potential that DLP can reliably print vascular ceramics with applications ranging from microfluidics to bulk casting.

Presenting Author: Zachary Alsup University of Texas at Dallas

Presenting Author Biography: Zachary is a junior at The University of Texas at Dallas. He has been conducting undergraduate research with his advisor, Dr. Majid Minary, for two years. He initially worked with piezoelectric polymers - electrospinning nanofibers and characterizing woven smart fabrics. Recently, his focus has been on ceramic additive manufacturing - developing and characterizing ceramics manufactured via digital light processing. Zachary also spent a summer at Oak Ridge National Laboratory where he worked on additive manufacturing of magnets - creating bonded permanent magnets via fused deposition modeling. Besides research, Zachary is an avid member of an aviation club that builds RC airplanes, participating in the annual international Design, Build, Fly competition.

Authors:

Zachary Alsup University of Texas at Dallas
Moein Khakzad University of Texas at Dallas
Sudip Kumar Sarkar University of North Texas
Narendra Dahotre University of North Texas
Majid Minary University of Texas at Dallas