Building a MEGA PRINTER, what do I need?

Think aluminum stage trusses

 

I think you would have to start with your concrete mix to come up with something that is fluid enough to pump but stiff enough to maintain a shape when extruded....and can be mixed on demand and is fast setting. The mix design will dictate much of the equipment design. In other words, I think your "concrete" is going to need to behave much more like a 2-part fast-set epoxy (with filler?) where you utilize a mixing nozzle for placement.

 

It’s technically not concrete it’s Portland cement mixed with sand and 100% polypropylene concrete and cement mortar fiber. If you use white Portland cement then you can add dye to the mix to make just about any color you want.

 

The polypropylene fiber is used for anti cracking then get a concrete mixing station with a built in pump and start playing with mixtures I’d guess 50/25/25 mix 50% Portland cement 25% sand 25% fiber would be a good place to start the viscosity of the cement would all boils down to how much water you’re using in the mix.

 

Also axis speeds of 7.00 inches per minute and use stepper motors to drive your axis’s on a gantry style machine built out of aluminum trusses

 

I’m a CNC machinist working for a shop that builds automated machines. NEMA 34 12nm stepper motors are about perfect for the application until you upgrade to printing houses because of the weight of you printer itself.