Prusa I3 MK2 Z-Axis support and sound dampening  

Re: Prusa I3 MK2 Z-Axis support and sound dampening

Gorgeous photo Stephan, but I think I'd go a different route. The key flaw I see is part access. I know from experience that you sometimes need a lot of force and multiple attack angles to get a piece off the bed. Anything in the way will be...irritating to put it lightly. A moot issue with MK2.5 though. I also am not a fan of offloading frame planarity to a permanent plate, this is a frame to support a frame which is ridiculous, no? If you're going to give the structural duty to the plate, give all to the plate, an excellent low cost if very heavy solution to nearly all i3 series frame problems.

So, this is great idea not yet complete. Go ALL THE WAY!

As for my design, I use the conventional extended front lateral rod with union knuckle to gusset strut to keep printer light and still looking steampunk of current Mendel design ethos. But that is a religious choice (church of Mendel) rather than a good expedient engineering choice as your design.

Re: Prusa I3 MK2 Z-Axis support and sound dampening

I don't think that access for removal would ever be a problem, because there is more than enough space to work with a spatula between the printing plate and the diagonal rods. If parts stick that much, you're in danger of ripping your PEI sheet anyway (and I ripped mine removing parts printed out of E3D Flex65). But that seems indeed to be a religious question.

And structurally - the diagonal rods are specifically called "hinged pier" in stuctural engineering and this is a very reasonable solution. And stucturally, the base plate is forming a lattice structure together with the frame of rods, thus increasing the height of the beam, which is going into the formulas by cube. So, there is a sense to that particular solution. The plate made out of 16 mm material is a compomise between weight and stiffness, as machines go, more weight is always better. There is a reason why professional milling machines - even small ones - weighing a ton. But everyone should do what he thinks is the best solution.

Re: Prusa I3 MK2 Z-Axis support and sound dampening

Stephan, I do like your approach. It does not add that much to the machine foot print, but appears to add a lot of stiffness where the original structure needs it.
By any chance, do you have a large, tall print, like a vase, that was done before your added structure and the same item after the addition? I would expect an overall better surface after the added support.
The only addition I would do would be to put the entire structure, printer, struts and base plate on the floor mat. This, I hope, would prevent or lessen the transition of vibrations to the room.
Again, great job.

Re: Prusa I3 MK2 Z-Axis support and sound dampening

Unfortunately, I don't have before and after samples, because my prints weren't that large. I did the change because i felt the vibrations on the Z frame and thought that that cannot be positive.

Instead of a floor mat, i used these, printed out of NinjaFlex:

Re: Prusa I3 MK2 Z-Axis support and sound dampening

Probably best isolation between stone plate and desk: Bike tube.
https://shop.prusa3d.com/forum/improvements-f14/best-usd7-buck-improvement-you-can-make-t3051-s20.html#p46134
And let's hope the MK3 frame is stiff enough so you can lift the printer up without having to recalibrate it afterwards.

- Martin, expecting MK3 in March

Re: Prusa I3 MK2 Z-Axis support and sound dampening

Damn, that is brilliant! I already used halved handballs as feet but both these ideas are much better.

These solid halved and glued handballs were too tough though they are supporting nearly 25 kg. The paving stone was a red brick variety on sale clashed with printer so sealed with truck bed liner spray, which turned out to be a bad idea because it is dissolved by Acetone, a common bed cleaning agent when ABS printing.

Pretty though. Sigh.

Re: Prusa I3 MK2 Z-Axis support and sound dampening

A use a 1/4" sorbothane sheet between the paver and desk. It was expensive ($35 on Amazon) but She Who Must Be Obeyed was getting annoyed at the noise, so you can't put a price on that 😛 I'm impressed, it works very well (this is upgrading from a foam floor mat).

Re: Prusa I3 MK2 Z-Axis support and sound dampening

@Tom
Sorbothane huh. Was tempted to line my enclosure with Dynamat (much cheaper, more size selection)...but installed dampers everywhere because it was even cheaper. Worked but took a hit in print quality, no regrets though except you know, MK3 and it's Trinamic drivers tho.
@Martin
You won't need any of this junk (so they say).
@Stephan
Line with Dynamat then footpad with Sorbothane isolators. +2 silent running points.

Re: Prusa I3 MK2 Z-Axis support and sound dampening

@Tom
Sorbothane huh. Was tempted to line my enclosure with Dynamat (much cheaper, more size selection)...but installed dampers everywhere because it was even cheaper. Worked but took a hit in print quality, no regrets though except you know, MK3 and it's Trinamic drivers tho.
@Martin
You won't need any of this junk (so they say).
@Stephan
Line with Dynamat then footpad with Sorbothane isolators. +2 silent running points.

The one I used: https://www.amazon.com/gp/product/B006YJ9AOS/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 sliced into quarters because it's a bit smaller than the paver.

There are sorbothane feet which might work as well. I wasnt up for experimenting 😀 The smaller feet also might let it induce some wobble and take a print quality hit. I'm sure dymamat world work too, just messy when you want to remove it.