Most consumer fused-filament fabrication (FFF) 3D printers have a maximum build volume of less than 10 x 10 x 10 inches (about 250 x 250 x 250 mm). That’s perfectly reasonable, because few people need to print parts larger than that. The square-cube law tells us that the volume of a scaled-up part is proportional to the cube of the multiplier from the original size. In layman’s terms, that means that if you triple the size of a part, you are increasing its volume by a whopping 27 times, which effectively means you’re increasing the print time by 27 times. But sometimes you just need a large part. That’s why Ivan Miranda originally built his giant 3D printer, and now he has made it even larger.
We covered Miranda’s original giant 3D printer build back in 2019 and were blown away by just how large its print volume was. It had a bed that measured an incredibly 800 x 500 mm, which is roughly eight times the size of a standard Prusa i3 MK3 bed. To compensate for the realities of the square-cube law, that printer was equipped with an E3D Hemera extruder and a SuperVolcano hot end with an extremely wide 1.2mm nozzle. That nozzle can’t produce the level of detail we see from 0.4mm nozzles, but the much higher volume output dramatically decreases the time it takes to print a part. The new printer design uses a Bondtech QR extruder and a Slice Engineering Mosquito Magnum hot end with a 1.8mm nozzle. Miranda doesn’t specify exactly how large the new bed is, but it is clearly enormous.
Many of the conventional 3D printer building techniques have to get thrown out of the window at this size for economical and practical reasons. For instance, standard hardened steel rods would have been very expensive at the required length and would need to be very thick to account for flex. So Miranda ditched them altogether in favor of having each axis ride on wheels that sit on the aluminum extrusion that was used to construct the frame. The heated bed was also an issue, because nobody manufactures them at this size. That forced Miranda to use two large 1.3kW silicone heaters in order to cover the entire bed. Fortunately, Miranda was able to use a standard controller board: the Duet3D Duet 3 6HC. That has beefed-up stepper motor drivers that can handle motors strong enough to move that huge bed. Miranda is planning on using this new design to 3D-print some fenders for a vintage Mini, but he has also made the design available so you can build your own gargantuan 3D printer if you’re lucky enough to have the space for it.