So I've had an interesting request,

So I’ve had an interesting request, a friend has asked me to build a printer with a 15 by 15 inch bed and 30 inch build height. I figured I would give it a shot, and am sourcing parts for it, though I’m not sure whether it would be cheaper to build my own makerslide/openrail based design or to take a design like the ultimaker or Sharebot and scale it up.

Now obviously there are a lot of problems with a machine this big, such as curling due to the shear size of the bed, and also if it were to be a rod based design the diameter of the rods would have to be large enough to prevent them from flexing enough to cause a problem.

What is your guys suggestion, for lowest cost, and easiest to source option?

For that size, I’d probably try a delta-inspired printer, like a Rostock or other more developed variant.

I back that! Rosstock printers are the only ones that can print heigher than 20.

Atleast as far as i know…

I’ll definitely look into Delta printers (definitely a Rostock variant,) I’ve never worked with a delta before.
I’m pretty sure that you could print over 20 with a normal cartesian bot, you would probably run into problems still, I think that the whole build area might need to be enclosed and maybe heated a bit.

Delta is probably the most pain-free as far as scaling goes, but make sure the longer belts don’t introduce more backlash into the system; wider than normal belts and a solidly made set of tensioners may be called for.

delta with high-pitch screws

@Sparr_Risher also a good choice

Definitely looking at deltas now, it seems like a lot of the problems with the first Rostock design have been solved with extrusion being substituted for the smooth rod. Also I had forgotten about how they have the advantage of both a low moving mass and a stable bed.

seems like a jumbo cartesian bot would be more of a novelty rather than anything else, I feel dumb for forgetting Deltas.

These guys are in the makerspace I frequent:

I believe three people have successfully replicated this 1m cube cartesian bot:

I didn’t know that LeBigRep was successful, I read about it on the wiki some time back and it didn’t have very much infomation. That is really cool, especially because it’s a Darwin.

Thanks for the link to the delta, I will check out their kickstarter when it’s up. Do you have any inkling of what they will be charging for it?

I was planning on having it have an xy gantry similar to either the Ultimaker or the Foldarap 2 hbot variant to reduce bed movement, The physics would just be terrible for anything as big as my friend wants. It would still be pretty bad even if the bed moves up and down, the motor would have to be pretty strong and I would need a bulkier lead screw, as well as support.
I plan on trying out multiple heads in the near future as well, but only once I get a mendel max built, I’m tired of having to square my Prusa every week or so.

i have started building 1 ( its about 600x600x900 (XYZ). its not finished yet, and like you, i have been thinking about how to make it sturdy.
its gantry style, i like the rostock, but i dont think 2000mm will fit in my bed room …