The 3D printing market is expanding and the range of 3D printed products is becoming more and more extensive: from machine components to dental products to organ transplants. The company mz Toner Technologies, together with the Technical University of Cologne, is now developing a new 3D printing process based on electrophotography, which, among other things, should enable printing in space.
Electrophotography is the process by which most printers work. A so-called photo drum is completely electrically charged inside the printer. A laser beam then images the motif to be printed on this drum by selectively erasing electrical charges. The dye adheres to the drum where charges remain. This is transferred to the paper and thus creates
the image that is visible at the end.
Building on its many years of experience with electrophotography in other applications, the Saarland-based company mz Toner Technologies GmbH & Co. KG is developing an electrophotographic 3D printing process together with a research team led by Prof. Dr Danka Katrakova-Krüger in the Materials Laboratory at the Institute for General Mechanical Engineering at the TH Köln.
For this, the component to be produced is first "cut" into several wafer-thin layers using software. Instead of dye, polymer particles, i.e. plastics, are to be used. One to ten layers, which are a few micrometres thin, can be printed one on top of the other on a carrier film and pre-consolidated by a roller. In order to completely produce the desired component, several of these previously printed layer packages are joined together in the second process step with the help of a heating press.
In the process, mz Toner is developing a prototype of the 3D printer as part of the project, while the university team is focusing on the materials suitable for this process.
Use in space
The research team of both partners is initially concentrating on plastics, as it is developing the 3D printing process with a view to its use in space stations. Plastics are particularly suitable for space travel because they weigh little and are also mechanically resilient.
The electrophotographic process is to be implemented in such a way that it can be used despite the absence of gravity. The advantage of such a 3D printer in space travel: Not all spare parts that might be needed during an expedition have to be taken onto the spaceship. They can be manufactured directly on site as needed. This saves space and weight.
The scientists at the TH Köln are in contact with the European Space Agency (ESA) regarding the use in space.
Alternative to injection moulding
Until now, common 3D printing processes could not compete with the widely used injection moulding process in terms of speed. This could change with the new process. This is because injection moulding requires expensive moulds that only pay off for larger quantities. This jeopardises a possible start of production.
The electrophotographic process, on the other hand, does not require any moulds and still enables a high number of pieces to be produced. 3D printing with electrophotography is suitable for all material groups such as plastics, metals and ceramics, saves weight, has an increased speed and offers enormous design freedom such as the more generous use of colours," says Katrakova-Krüger. This opens up another potential field of application besides space travel: the household and electrical appliance market, which has so far used injection moulding for the production of appliances and their components.
The project is funded by the Federal Ministry for Economic Affairs and Energy as part of the "Central Innovation Programme for SMEs" and will run for two years.
www.ceramictoner.com