Bed size and XY carriage mismatch

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DLrocket89
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Bed size and XY carriage mismatch

Post by DLrocket89 »

Hi everyone,

Question for the braintrust here. I have a desire to build a larger form factor 3D printer for making large rocketry components. The biggest body tube I'd be looking at is 12" in diameter, which easily fits on a 400x400 bed. Beyond that, I'd like to have a lot larger area for fins...maybe 800x800 or so for the XY dimensions.

The big issue here is an 800x800 bed would be astronomically expensive, and likely a complete pain to work with...whereas a 400x400 is just fine.

How do people think it would work if I were to put a 400x400 bed into an 800x800 framed printer? Would keep the cost down, but let me go big where I want to.

Thanks in advance!

Dustin

DLrocket89
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Re: Bed size and XY carriage mismatch

Post by DLrocket89 »

If it helps any, here's what I'm talking about. Basically, the tubular part would fit on the 400x400 build plate, the fins would fit in the 800x800 build volume.

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firegun
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Re: Bed size and XY carriage mismatch

Post by firegun »

If I'm getting this right you would like to have the 400x400 centered on the 800x800 frame ?

I think you gonna run into some troubles to mount the things on the Z axis to begin with. Later on you would have to be careful on each and every print to make sure you using the center of the printing area, all hot end cleanup routines have to be updated and so on.

What is making your build so much more expensive at 800x800 is the bed heating only? Maybe you could have a smaller heater on the big bed?

But don't take only my opinion on this one, this is just what crossed my mind while reading your questions :D

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Re: Bed size and XY carriage mismatch

Post by RedFlash »

I would build a normal bedframe with the mountings for the 800mm bed. Then build a second, small bedframe for the 400mm bed.
Then mount the small frame in the center of the big frame somehow and mount the plate on.

As firegun mentioned you have to change some config data for that.

DLrocket89
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Re: Bed size and XY carriage mismatch

Post by DLrocket89 »

Thanks for the input...I like the idea of an 800mm2 bed (or at least an extruded frame) with the 400mm bed on it.

The two issues wit that size I have are a) heater size and b) keeping something that big flat.

No worries on the config update...I just successfully rolled my first version of Marlin for my CR-10, so while I don't yet know exactly how I'd do it, I'm comfortable that I could figure it out.

TeamADW
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Re: Bed size and XY carriage mismatch

Post by TeamADW »

You might want to look at large format laser cutters, Ive been looking at mine, it has a 900x600 bed, and uses 4 ball screws and a servo to lift the Z. Been wondering for a while if I could convert it to a printer later based on these machines. You would lose leveling if you used 4 ball screws on 1 servo, but Im thinking many of these machines would be an interesting start for a large bed machine.

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