Glass injection molding | EurekAlert! Science news

PICTURE: Injection-molded structures made from the newly developed Glassomer composite. view More

Photo credit: Photo: Neptun Lab / University of Freiburg

Glass is ubiquitous, from high-tech products in the fields of optics, telecommunications, chemistry and medicine to everyday items such as bottles and windows. However, the shaping of glass is mainly based on processes such as melting, grinding or etching. These processes are decades old, technologically demanding, energy-intensive and severely limited in terms of the forms that can be realized. For the first time, a team led by Prof. Dr. Bastian E. Rapp from the Process Technology Laboratory at the Institute for Microsystems Technology at the University of Freiburg, in cooperation with the Freiburg-based start-up Glassomer, developed a process with which glass can be formed easily, quickly and in almost any shape using the injection molding process. The researchers presented their results in the journal Science.

“For decades, glass has often been the second choice when it comes to materials in manufacturing processes because its formation is too complicated, energy-intensive and unsuitable for the production of high-resolution structures,” explains Rapp. “Polymers, on the other hand, have made all of this possible, but their physical, optical, chemical and thermal properties are inferior to glass. As a result, we have combined polymer and glass processing. Our process enables us to be fast and inexpensive.” – Effectively replace both mass-produced and complex polymer structures and components with glass. “

Injection molding is the most important process in the plastics industry and enables components to be manufactured quickly and inexpensively with so-called high throughput in almost any shape and size. Until now, it has not been possible to shape transparent glass. With the newly developed Glassomer injection molding technology from a specially developed special granulate, it is now possible to shape glass with a high throughput at only 130 ° C. The injection molded components of the 3D printer are then converted into glass in a heat treatment process: the result is pure quartz glass. This process requires less energy than traditional glass melting, which leads to energy efficiency. The molded glass components have a high surface quality so that post-treatment steps such as polishing are not required.

The novel designs made possible by Glassomer’s glass injection molding technology have a wide range of applications, from data technology, optics and solar technology to so-called lab-on-a-chip and medical technology. “We see great potential, especially for small high-tech glass components with complex geometries. In addition to the transparency, the very low expansion coefficient of quartz glass also makes the technology interesting. Sensors and optics work reliably at any temperature if the key components are made of glass,” explains Dr . Frederik Kotz, group leader at the Process Technology Laboratory and Chief Scientific Officer (CSO) at Glassomer. “We were also able to show that micro-optical glass coatings can increase the efficiency of solar cells. With this technology, low-cost, high-tech coatings with high thermal stability can now be produced. There are a number of commercial possibilities for it.”

The team around Frederik Kotz and Markus Mader, PhD student at the Laboratory for Process Technology, solved existing problems in the injection molding of glass such as porosity and particle abrasion. In addition, important process steps were developed in the new method to use water as a basic material and to make the technology more environmentally friendly and sustainable.


Bastian Rapp is managing director of the Freiburg Materials Research Center FMF and a member of the Cluster of Excellence Living, Adaptive and Energy-Autonomous Material Systems (livMatS) at the University of Freiburg, which develops novel, bio-inspired material systems. Rapp is also co-founder and Chief Technical Officer (CTO) of Glassomer GmbH, which develops high-resolution 3D printing technologies for glass. For his research he received a Consolidator Grant from the European Research Council (ERC). He was nominated for the German Future Prize 2021.

Original publication

Markus Mader, Oliver Schlatter, Barbara Heck, Andreas Warmbold, Alex Dorn, Hans Zappe, Patrick Risch, Dorothea Helmer, Frederik Kotz and Bastian E. Rapp (2021): “High-throughput injection molding of transparent fused silica glass”. In: Science. DOI: 10.1126 / science.abf1537

Video: Making glass by injection molding

Laboratory for process technology / Neptun Lab

Glassomer GmbH

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