When it comes to 3D printers, most machines you’ll see are pretty small. The Ultimaker, Prusa, Lulzbot, and the Rostock Max are desktop devices. While they have entirely usable build volumes, you’re not printing furniture with these machines. Yes, large format 3D printers exist, like the SeeMeCNC Part Daddy (they’ll build you one for ~$90,000, IIRC), a house printer that uses concrete, and a number of very large printers from various other manufacturers with very high price tags.
There is no 3D printer designed to print large objects without spending tens of thousands of dollars on a machine. That’s the focus of this Hackaday Prize entry. [RigTig]’s Big 3D Printer is designed to be big, but also inexpensive.
A big, inexpensive 3D printer can’t use the usual machine setups seen in other large format printers. Big machines with traditional kinematics demand big pieces of aluminum, counterweights, and a design that might spiral out of control. Instead of a thousand pounds of metal, [RigTig] is using something like the Skycam system seen at every NFL game; put a few towers up at the corners of a triangle, run some string or cable through some pulleys, and you have a simple, light movement platform.
With the machine side of the problem figured out, the next question is what material to use. [RigTig] has decided plastic filament is impractical because of cost. A clay extrusion system has a lot of problems. Concrete is a good idea, but the prints would weigh several tons. Right now, [RigTig] is planning on using dirt with a polymer binder. It’s an interesting idea, and one we haven’t seen elsewhere.
Building a 3D printer from scratch is easy. Building a huge 3D printer is one of the most interesting engineering challenges out there. Not only do you need a motion platform that can make it work, but you also need to print in a material that is cheap enough and prints fast enough for the printer to make sense. We don’t know if [RigTig] is on the right track yet, but we’re glad to see him put in the effort for this excellent addition to the Hackaday Prize.
The tree conductive support lines could be used for power ans control signal to the print head as well.
Some of the concrete printers use foamed cement it weighs considerably less.
there’s “aircrete” which is typically less dense than water (!!! print BOATS!) but which requires incredibly fiddly tuning to achieve proper mixture – but is CHEEEEEEEEEEP – and then typically it’s not very viscous (the “foaming agents” are usually dish soap in DIY systems, which makes the uncured material flow like, well, soap bubbles.)
there’s the air-vitrified commercial stuff that gets used in Europe, but that stuff gets cured as whole blocks and then milled to size, so not really good as a printable material.
I’d love to see something printing large-format aircrete! I have to imagine most of the challenges there will not be in the mechanics of the movement platform, rather in mixing an aircrete that’s stiff enough while uncured to be usefully printable.
Is using a metal chain better than say, spectra finishing line? I didn’t see anything on the project page about why chain was chosen over other options
Maybe metal chains act as conductors, sending power to the extrusion head.
For larger print jobs, I’d like to see the ability to add wire to the build – as a support frame.
The FX for the TV show Westworld show printers laying down tendons on a skeleton. I will settle for a printer head spraying mud or clay on a chickenwire outline.
I wonder if the author of this considered putting a mig welder at the end. seems to be a possible solution to his problem of what medium to use.
I wonder if you could use expansion foam…
Thinking the same thing. It’d insulate, waterproof, and a single line might expand enough to provide total wall thickness. It’d be light, too- important for earthquake aftershock resistance. You’d need two lines into the print head, and mix the two components as they are extruded.
Expansion foam releases quite a bit of heat when it hardens, any bigger print would run into cooling issues…
How about something like Insulated concrete forms (ICFs) [ http://www.the-self-build-guide.co.uk/insulated-concrete-forms.html ] but the insulated lego-style bricks are manufactured on-site – curves, openings, etc ?
Then pour your chosen eco-version of concrete ?
Indeed. Instead of 3D printer, we can use a pick and place machines to lay the wall or rather a combination of both. Cranes are used on construction anyway, so this is an extension to this.
Perhaps you will imagine this as a big gantry over the house but it is not necessary. One can use a local machine that is moved around by a crane. As it has lower radius of movements and is standing on the ground then it can have much higher precision and speed. It can use magazines of building blocks that are again filled using a crane. Loading can be advised by helper codes such QR-codes and placing can use laser range finders for position. If necessary special building blocks with codes can be incorporated into a wall for a reference.