Part 3: AFM Based 3D Printing
13 June, 2018
The third and last part of the series “3D Printing in Sub-Micron Scale” is about direct metal printing, which uses an atomic force microscope (AFM) setup and a unique fluid-delivering micro-cantilever. Atomic force microscopy was my weapon-of-choice during my PhD research and you could read more about its principles in my previous post – this would help a lot understanding the direct metal 3D printing approach if you are not familiar to AFM.
In direct metal printing, an aqueous solution of a metal salt is injected onto a gold substrate. Metal ion (usually copper) is positively charged and it is soluble in water. The gold substrate, however, is electrified and acts as a cathode. Once in contact with the metal ions in water, it turns these ions into insoluble solid metal.
The introduction of the metal salt solution onto the gold substrate is achieved by a micron-scale channel, which is embedded in an AFM cantilever (a technology called “fluid force microscopy“, developed in ETH Zurich). The AFM cantilever therefore does two things: first, it transfers the fluid metal salt solution to the desired position on the gold substrate so that the metal can be deposited there in solid form and second, the cantilever detects the height of the deposited metal and stops the fluid transfer once the desired height is reached. It can then be moved to the next point, based on the digital 3D design e.g. an .stl file. Seeing it is worth a thousand words so here is the promotional video from Cytosurge – the startup company that commercialized this technology:
This approach is truly amazing. Complex microstructures that can be built this way were out of question only a few years ago. And in general, as the resolution of these methods push sub-micron and even nanoscale resolution in addition to decreasing operation costs, we should all be ready for another industrial revolution.
Disclaimer: This is a personal blog. I write about things that I find exciting and think are worth sharing. The content was not influenced by advertising or sponsorship. There may be other great products from other companies that I am not aware of (actually I would appreciate if you could write to me if you know any).
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