ivo.h wrote: ↑
Tue Feb 27, 2018 6:02 pm
Your setup with concrete blocks might give you harm ...
Hm... I think I don't understand what you mean by this statement because I have absolutely no problems with this setup and get perfect prints. But maybe I used the wrong word ("vibrations"). The concrete blocks are not really against vibrations. They are more an "absorber" against the noise of this printer, when putting on a normal table. And for this issue it's just perfect (inspired of this video: https://www.youtube.com/watch?v=OnfYA5QLA84&t=3s
). Or do you mean the printer "need" vibrations to be more "elastic"? Is this necessary?
By any means, i do not encourage more elasticity. The printer does not need this as it will create more amplitude to vibrations that may harm the print quality.
Increasing the mass lessens the vibrations by making the base more inert so less vibrations are transmitted to the table below which being a big flat object makes a lot of noise when it vibrates.
If however you want to dampen also the motions of the printer itself to minimize effect on print quality and risk of skipping steps, you want the printer to be as rigidly attached to the big mass of the concrete block as possible. The Prusa i3 by design is not super rigedly attached to whatever it is sitting on as the Y-axis is untriangulated rods with the support quite far from the loads on the central part caused by acceleration of the extruder assembly and of the X-axis.
Normally, I don't see this as a very big problem as the central part cannot rotate very much before the zip-ties that hold the wires underneath come in contact with the concrete block and limits movement. In your setup however, it is free to rotate as much as it might want, so you use up all the flexibility that the y-axis and the printed cornerpieces has. This will increase oscillations of the printer itself even if it is not audible when the table is not being used as a loudspeaker because the concrete blocks are there.
But if you're satisfied with your setup, then i guess the impact is less than I imagine.