tag:blogger.com,1999:blog-2191333127541714803.post4169747920219550655..comments2023-04-02T05:55:04.314-07:00Comments on Metal 3D printing project: Brain Storm sessionEtienne Lhttp://www.blogger.com/profile/16917430509975175038noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-2191333127541714803.post-10298306751672887282013-01-21T05:31:26.166-08:002013-01-21T05:31:26.166-08:00We have made some experiments with the metal paste...We have made some experiments with the metal paste extrusion process. But the problem that we found is that the paste must be liquid enough when extruded, but hard enough, when released, to hold it's shape. Sadly those two properties doesn't match. Copper powder mixed with water actually behaves the opposite way (like corn starch) it solidifies when pressed but liquify when released. This can be attenuated by adding a small amount of Carboxymethyl cellulose (a non toxic chemical normally use to thicken cream). The stuff burns when heated in the kiln. Putting too much trap the water inside the paste and the evaporating water make the structure grow a bit like popcorn.<br /><br />Right now the project is on standby since the original team dissolved. I joined a new maker space recently, so the project might get back on track soon.Etienne Lhttps://www.blogger.com/profile/16917430509975175038noreply@blogger.comtag:blogger.com,1999:blog-2191333127541714803.post-4472554203202417412013-01-20T16:26:55.451-08:002013-01-20T16:26:55.451-08:00Hi Etienne,
I find your project super interesting...Hi Etienne,<br /><br />I find your project super interesting - I am also looking for a safe and affordable method for 3D printing with metal and am curious to know if you have made any progress with your research.<br /><br />Thanks!<br /><br />MichaelAnonymoushttps://www.blogger.com/profile/10381217043821175987noreply@blogger.comtag:blogger.com,1999:blog-2191333127541714803.post-92058518097583275592012-12-03T10:36:12.781-08:002012-12-03T10:36:12.781-08:00I see two ways to "pressurize" the part....I see two ways to "pressurize" the part. One way, usually used in sintering, is to apply pressure using a press inside a negative mold of the part. The pressure crushes the particles and forces the air between the particles out of the part. This can effectively increase the density of the part. However, in the case of a 3D printed part, one doesn't have a negative mold of the part and applying such pressure will most likely result in crushing the part.<br /><br />The other idea is to pressurize the whole enclosure. To be able to crush metal particles to the point of welding them together, we are talking of 10 to 100's of atmospheres (1000's of PSI). The other thing is that the pressurized fluid inside the chamber is very likely to infiltrate in the part by the fine channels between the grains thus balancing the pressure all around the grains. This results in no net force on the grains and therefore no forces to crush the grains against each other.<br /><br />I believe that the best way to get a full part is to soak the finished part with another lower melting point metal. Like a sponge, the spaces between the original metal particles will wick the molten metal, filling those spaces. Etienne Lhttps://www.blogger.com/profile/16917430509975175038noreply@blogger.comtag:blogger.com,1999:blog-2191333127541714803.post-13146728432795132982012-12-03T08:12:10.980-08:002012-12-03T08:12:10.980-08:00Could you achieve a higher density and possibly no...Could you achieve a higher density and possibly not require a kiln by placing the 3d printer in a pressurized enclosure.Anonymousg64https://www.blogger.com/profile/02181690842629047025noreply@blogger.com