Q&A: 3D Metal Printing at the Microscale
Part One: Print Materials and Substrates
Learn more about the CERES print system and its capabilities in this Q&A series; held in conjunction with QD USA, our distributor in North America.
Part one covers possible print materials, substrates, and material properties.
Can you print other materials than copper?
Do the printed voxels have voids or pores, or are they completely solid?
That is a very good question. As we print voxels, one might assume that there are voids inside, but in fact, there are not; it is a very dense material. We have made many cross-section analyses, and we have a 99.5% density (or even greater) pure copper metal. When you consider it, in the semiconductor industry they are using an electroplating process which is widely used, and they have high-quality copper as well. So basically we are producing the same but in 3D shapes.
We have made many cross-section analyses, and we have 99.5% density (or even greater) pure copper metal
Can one print aluminium?
Aluminium is not possible. Basically, if a metal can be electroplated, it can be 3D printed with our technology. However, aluminium cannot be electroplated and therefore we cannot print it.
Does the substrate have to be made of the same material as the printed object?
No it doesn't; we can print with our inks on different materials/carriers. Of course, copper - copper is a great match. Copper - gold is a great match. Copper - ITO (a transparent conductive oxide) works very well. PEDOT (conductive polymer) we can also print on.
Not all metals can be combined; as we are using an electroplating process, it could happen that we dissolve the other metal. For example, aluminium and copper will not work because if you would print on aluminium, the copper will be reduced, but the aluminium will also be reduced; it will disappear. So, you cannot combine everything. But what we did with aluminium was to make a very thin protective layer of only 200 nm above this surface. And then it works. So, there sits a layer, it can be very, very thin, and we can still print on it with different materials.
How do you connect these printed objects to other devices like electronics?
We usually print where we need the parts, so normally we do not print and remove the parts. However, we have a customer (a university in Japan) that wanted to have metal parts and handle them separately. So, what we did was to print on a polymer foil (PEDOT), which can be removed, and has a different elastic behavior to the printed metal part. Then you can take off the metal products with a micromanipulator. So yes, it is a little bit of a complex process, but if you want to have specific shapes of pure metal objects without any connection to a carrier, there are possibilities to remove them.
Can the system print oxide materials?
In a certain way we could, but we do not want to - our system is not designed to print oxides. As the electrolytic bath that we are using is water-based, there is the possibility of oxides when printing certain metals, but this is not the case for copper or gold.
Our print process relies on the previous voxels to be conductive in order to print the next one in line. As such, our system is not optimized to print oxides, which are far less conductive.
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