New process enables 3D printing of small and complex components made of
glass in just a few minutes
Scientists combine materials science invention with newly developed 3D printing technology
Date:
April 19, 2022
Source:
University of Freiburg
Summary:
Scientists combine materials science invention with newly developed
3D printing technology. Components made of highly transparent
glass can be manufactured in just a few minutes and with great
geometric freedom.
Possible applications of the new process technology are
micro-optical components of sensors, microscopes or lab-on-a-chip
systems
FULL STORY ========================================================================== Because of its outstanding transparency as well as its stability in
contact with heat or chemicals, glass is relevant for many high-tech applications.
However, conventional processes for shaping glass are often tedious,
energy- intensive and quickly reach their limits for small and complicated components.
The Freiburg materials scientists Dr. Frederik Kotz-Helmer and Prof. Dr.
Bastian E. Rapp, in cooperation with the University of California
at Berkeley in the US, have developed a novel process that can be
used to produce very small components from transparent glass quickly
and precisely using micro 3D printing. Possible applications include
components for sensors and microscopes, but also for lab-on-a-chip
systems. The researchers were able to publish their results in the
current issue of the journal Science.
========================================================================== Glass powder in plastic binder The new technology is based on so-called Glassomer materials, which Kotz-Helmer and Rapp developed at the
Department of Microsystems Engineering (IMTEK) at the University of
Freiburg. "Glassomer materials consist of glass powder in a special
plastic binder," says Kotz-Helmer, "allowing to process glass like
a plastic." The resulting components are then placed in a furnace,
which causes the plastic to burn and the glass to be sintered,
i.e. densified. "In the end, the components consist of one hundred
percent highly transparent fused silica glass," says Kotz-Helmer.
Component is created in a single step The Freiburg scientists have now
combined Glassomer materials with a new 3D printing process developed
by a research team led by Prof. Dr. Hayden Taylor from the University of California, Berkeley. Conventional 3D printers print their objects layer
by layer. However, in the new process, called Computed Axial Lithography
(CAL), the component is created in a single step. A vessel containing
liquid, light-sensitive material is exposed to two-dimensional light
images of the object to be printed from many different angles. Where the
images overlap and the amount of light absorbed thus locally exceeds
a certain threshold, the material hardens abruptly -- within a few
minutes, the component is formed. The excess, still liquid material can
be washed off.
Structures with the thickness of a single hair "In principle, this
process also works with Glassomer material," says Kotz- Helmer. For
this purpose, the Freiburg scientists developed a material made of glass
powder and plastic that is both highly transparent and hardens quickly at
a suitable threshold value. "The devil was in the chemical details here,"
says the materials scientist. Previously, moreover, the CAL process had
only been suitable for relatively coarse structures. By combining the
materials science expertise at the University of Freiburg and the project partner Glassomer GmbH, a Freiburg spin-off, as well as the further
development of the system technology at the University of California,
it has now been possible to combine and improve these technologies. "For
the first time, we were able to print glass with structures in the range
of 50 micrometers in just a few minutes, which corresponds roughly to the thickness of a hair," says Kotz-Helmer. "In addition, the surfaces of the components are smoother than with conventional 3D printing processes."
Glass as a substitute for vulnerable plastic Kotz-Helmer sees possible applications for the innovative manufacturing process, for example,
in micro-optical components of sensors, virtual reality headsets and
modern microscopes: "The ability to manufacture such components at high
speed and with great geometric freedom will enable new functions and
more cost-effective products in the future." Microfluidic channels are
also needed for so-called lab-on-a-chip systems for research and medical diagnostics. Until now, these have mostly been made of plastics, but they
often cannot withstand high temperatures and aggressive chemicals. Thanks
to the new process technology, complex channel systems can now be
manufactured in glass, says Kotz-Helmer: "Thanks to the thermal and
chemical stability of glass, many new fields of application are opening
up, especially in the area of chemistry on-a-chip synthesis."
========================================================================== Story Source: Materials provided by University_of_Freiburg. Note:
Content may be edited for style and length.
========================================================================== Journal Reference:
1. Joseph T. Toombs, Manuel Luitz, Caitlyn C. Cook, Sophie Jenne,
Chi Chung
Li, Bastian E. Rapp, Frederik Kotz-Helmer, Hayden
K. Taylor. Volumetric additive manufacturing of silica glass with
microscale computed axial lithography. Science, 2022; 376 (6590):
308 DOI: 10.1126/science.abm6459 ==========================================================================
Link to news story:
https://www.sciencedaily.com/releases/2022/04/220419112422.htm
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