DIY 3d Printer Frame from steel

Hi,

I currently have a hictop prusa i3 clone and I am considering making my own larger printer with a steel frame with fully supported linear rails, nema 24 stepper motors and drivers from a left over project.

I have a mig and tig welder, a Bridgeport milling machine and a CNC milling machine that I made from scratch so fabrication isn't a problem.

So basically what i am asking is of anyone has done similar and some pros and cons of my ideas

I was thinking of making something similar to a ender 5 box frame but with welded steel and powder coated so it would be as solid and heavy as ever needed.

I would try and make the moving carriage part at the top with the hot end etc as light as possible (possibly machined aluminium parts) to help acceleration and deceleration as much as possible with the same dual belts to move the y axis.

Would nema 24 be to large? Will the motor inertia be a problem?

By increasing ridigity would it increase printing speeds or does it not work that way?

Thanks
Dave.

increased rigidity and weight - will help increase print speed.
Nema 24 for moving things around should be fine.
wouldn't use it for the extruder though, unless you're planning on a bowden setup (why would you ????).
Although for actual print speed the classic I3 design is a lot faster than standard cartesian box setup. That's pretty much the slowest setup.

I've got a rep pro clone, i3 clone and a delta. Speed wise the delta is the fastest, the i3 is pretty close behind and the rep clone runs at about half the speed of the others - flat out.

Get it right with a delta and they'll blow everything else away for speed and qualiy.
A good I3 (NOT ender range) will also print at speed with excellent quality.

Good i3; dua bed side rails, direct drive extruder and dual z screw - basically as Josef prusa designed it. Not as it has bee crippled by cheap chinese manufacturers like creality.

With linear rails for side supports and the nema 24's with 10mm belts an a super rigid frame you could really rack up the speed.

Have you started this yet? It's interesting as rigidity is mostly missing from ally framed printers.
(though I just received an Ender5 to mess about with)
But it seems to me that once you've welded your framework, you may have to machine any mounting positions for the rails etc, otherwise they won't be square to the bed or each other.
I'm a CNC mill setter/operator.

Hey Dave. I have a GEEETech i3 which is extremely close to yours. I actually have a fistful of different printers and have reworked each one many times just because I get my jollies off on it. From all of my reworking and experience here let me tell you for our i3's the best we can do is to make this reinforcement for the front section of the frame. The back half is already pretty robust. But this is what I have done with my i3 to make it strong: https://3dprintboard.com/showthread....3-32bit-Rework .
This bracing is every bit as good as anything else you will do that will re use those 8mm smooth rods. The 10mm rods will have a little less deflection but really what makes these machine precise in their movements is the expensive CNC parts. Like the linear rails. I have converted one of my machines to good quality linear rails and guides for just and I do mean just under a grand for the rods and rails. Bang for buck it is not worth it. These printed parts make the frame rigid enough to pick it up and carry it around one handed by the top of the frame only and still have the bed be level. This way is cheap and brings real results. For strength in your stepper motors you could look to a 32 bit control board like the SKR 1.4 Turbo and a set of TMC 2208 or TMC2209 drivers and maybe invest in a 24v power supply.

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Originally Posted by cheapo

Have you started this yet? It's interesting as rigidity is mostly missing from ally framed printers.
(though I just received an Ender5 to mess about with)
But it seems to me that once you've welded your framework, you may have to machine any mounting positions for the rails etc, otherwise they won't be square to the bed or each other.
I'm a CNC mill setter/operator.

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I havent got round to it yet due to work and other commitments but my idea was to fabricate and weld the 4 sides separately. Then once it was all completely welded mill them flat and the mating surfaces for each side square and the bolt them together either threaded or nuts whatever works.

Then once all 4 sides where bolted together make an aluminium carriage frame for the extruder to run on trying to keep it as light weight as possible without losing ridgitidy. Maybe even cnc mill a honeycomb pattern into a solid aluminium bar?!

The options are endless and I think the rigidity would allow faster printing to a certain level without inducing vibrations to the print. I would expect the print quality to be far superior to any budget made frame?

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Originally Posted by Davemorl

I havent got round to it yet due to work and other commitments but my idea was to fabricate and weld the 4 sides separately. Then once it was all completely welded mill them flat and the mating surfaces for each side square and the bolt them together either threaded or nuts whatever works.Then once all 4 sides where bolted together make an aluminium carriage frame for the extruder to run on trying to keep it as light weight as possible without losing ridgitidy. Maybe even cnc mill a honeycomb pattern into a solid aluminium bar?! The options are endless and I think the rigidity would allow faster printing to a certain level without inducing vibrations to the print. I would expect the print quality to be far superior to any budget made frame?

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Except for how noise and vibrations just love to travel through metal. Plastic has a dampening affect akin to rubber in the world of NVH. And a metal frame needs to have a medium between the rods/rails and the frame and also as feet under the frame. Or even with the silent drivers running in the most advanced form of stealthchop available will still be noisy. Because as rigid as metal can be, it also loves to carry vibrations. Just a thought for some of you young'n builders to consider. I personally love a quiet machine. However because the linear rails bolt directly to my aluminum extrusion, my Multi Widow is still louder than it was with the rubber v wheels on the aluminum extrusion. Metal is great. But it is far from the be all - end all of building materials especially for something as light duty as these 3d printers. Let us all always remember, metal structures that aren't dampened suck. They make noise and in most applications live a shortened life. For CNC we want all metal because we need strength and also because CNC equipment doesn't live in a person's home. And noise levels in a shop are always a secondary concern. I am just saying the best things in life are purpose built and thought through. All metal construction just sounds like an uncontrollable noisy mess to me.

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Originally Posted by AutoWiz

Except for how noise and vibrations just love to travel through metal. Plastic has a dampening affect akin to rubber in the world of NVH. And a metal frame needs to have a medium between the rods/rails and the frame and also as feet under the frame. Or even with the silent drivers running in the most advanced form of stealthchop available will still be noisy. Because as rigid as metal can be, it also loves to carry vibrations. Just a thought for some of you young'n builders to consider. I personally love a quiet machine. However because the linear rails bolt directly to my aluminum extrusion, my Multi Widow is still louder than it was with the rubber v wheels on the aluminum extrusion. Metal is great. But it is far from the be all - end all of building materials especially for something as light duty as these 3d printers. Let us all always remember, metal structures that aren't dampened suck. They make noise and in most applications live a shortened life. For CNC we want all metal because we need strength and also because CNC equipment doesn't live in a person's home. And noise levels in a shop are always a secondary concern. I am just saying the best things in life are purpose built and thought through. All metal construction just sounds like an uncontrollable noisy mess to me.

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I agree it could end up ringing like a bell but I think this would be reduced by your advice of rubber feet. As for print quality I dont think the vibrations and resonance would be large enough to leave any marks within the print itself as the mass and rigidity is a lot larger than the head moving around as it would be so light weight in comparison to the frame.

You could even put plastic or rubber isolation/ dampening mounting plates between the motor and the frame if this was needed to reduce the noise.