[HN Gopher] New Process Allows 3-D Printing of Microscale Metall...
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       New Process Allows 3-D Printing of Microscale Metallic Parts -
       Www.caltech.edu
        
       Author : rbanffy
       Score  : 17 points
       Date   : 2022-12-05 22:16 UTC (44 minutes ago)
        
 (HTM) web link (www.caltech.edu)
 (TXT) w3m dump (www.caltech.edu)
        
       | cwkoss wrote:
       | "Then, in the "reaction" portion of the process, the researchers
       | burn away the hydrogel portion of the structure in a furnace that
       | reaches 700 to 1100 degrees Celsius, depending on the material.
       | Because the melting point of all metals is higher than the
       | combustion temperature of the hydrogel, the metal remains intact.
       | 
       | The heat not only removes the hydrogel, it also causes the
       | overall structure to shrink as the hydrogel burns off, resulting
       | in an even tinier metal structure. With this process, in addition
       | to pure metals, the team can 3-D print metal alloys and
       | multicomponent metallic systems, with feature sizes around 40
       | microns, or less than half the width of a human hair."
       | 
       | ---
       | 
       | How much does it shrink? Does the shape deform as it shrinks? I
       | would imagine certain geometries wouldn't work because the
       | outsides would shrink faster than the inside, which could
       | break/bend some features.
       | 
       | Seems like awesome tech, but I suspect there are a number of
       | limitations to this technique which the article does not discuss.
        
         | misthop wrote:
         | At those temps I believe many metals will also end up being
         | heat treated. And it sounds like the time will be dependent on
         | how much hydrogel is present, so there will be at least a lower
         | bound on what heat treatment you need apply. I wonder how that
         | works with the shrinking, along with lots of other properties
         | you may want of the end product
        
       | qwezxcrty wrote:
       | There is a older (commercialized [1]) process called two-photon
       | photo-polymerization, which can also create mind blowing
       | nanoscale 3D parts [2]. Although limited in choose of materials
       | it can print, still pretty cool and sometimes can find
       | applications in photonics.
       | 
       | [1] https://www.nanoscribe.com/en/ [2]
       | https://www.epfl.ch/research/facilities/cmi/wp-content/uploa...
        
       | hyferg wrote:
       | They seem to achieve the 'multimaterial' label by soaking
       | different parts of the polymer in exclusive precursors. If you
       | want to create advanced microelectronics using this method, you
       | would probably want to be able to control gel-differentiation
       | process as part of polymerization.
        
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