From what I understand (based on smaller printed buildings anyway) it’s identical to FDM 3d printing pretty much, except that instead of filament, a massive onsite silo contains a liquefied cement-like mixture. The nozzle also has a valve of some sort to immediately stop flow.
Typically one operator has a computer running the printer host software, and others manually fix-up print errors (and things like blobs) while the mixture is still damp. A paperclip shaped rebar is also inserted into the walls every few layers for additional structural integrity
There are challenges with things like rainfall retention in walls during construction, but various companies have their own way of dealing with that from what I understand…
Due to the mixture it’s usually restricted to walls AFAICT. Overhangs like doorways need beam supports to be inserted into the structure beforehand
unexposedhazard@discuss.tchncs.de 8 months ago
The whole print process video is embedded in the article… www.youtube.com/watch?v=cfWryED7Zrk It really is just a big 3D printer. At first i thought the walls were like 90% air with no infill but it looks like they fill them up with rebar and cement. So really its just a thing that prints unique molds to pour concrete into so not really “a 3D printed building”
RobotToaster@mander.xyz 8 months ago
Thanks, but I more meant specifics, like what is the “cement-like mixture”, what extruder they are using. If it would be possible to DIY this basically.
Fermion@mander.xyz 8 months ago
m.startribune.com/…/273410261/
This guy DIY’d it way back in the early days of concrete extrusion. He actually let a college class i was in see it. It was definitely an involved project and the result was pretty rough around the edges.
Unfortunately I don’t remember much about the type of mix he used or the pumping system. So I can’t guide you in the right direction.
greybeard@lemmy.one 8 months ago
There are several companies doing 3D printed concrete. It generally is concrete, just formulated and mixed for being piped and coming out of a 4" nozzle. Ifyouu search YouTube you can find more detailed breakdowns, but the principles are the same as desktop FDM, just scaled way up. That said, don’t expect to be doing this in your backyard unless you have heavy equipment and large scale building tools laying around.
maiskanzler@feddit.de 8 months ago
Oh and you also need a decently sized stone crusher for all your failed attempts and speedbenchies.