A tiny bead of clear silicone around the intersection with the frame on the outside would seal just fine. Getting baked/dry sand isn’t a big challenge (play sand is fine, screened so it flows well, and usually still dry if you can get it from an inside source). Sand doesn’t “attract” moisture, it’s just very good at moving it around, so if it’s dry when it goes in, it’ll be fine. Trace amounts of moisture aren’t going to make any difference (the beams are anodized). Don’t overthink this.
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ha, me overthink something…never…(always)
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I’ve been following this thread fairly close and while interesting I’m not sure what the actual outcome is supposed to be. Is it sound suppression, better accuracy? I’m not trying to be difficult (my wife may say I am, haha!!!). I understand the idea that mass is “good”, but what is the expected outcome, or is it more of an experiment of “What would happen if?”? My thoughts on a lightweight belt driven machine is that mass would hurt acceleration and possibly add to deflection. So where are we headed? Again I’m I’m not trying to be difficult, just curious.
Dan
The increase in mass should reduce chatter (lower resonant frequency). The rails really are quite sturdy - I have yet to see a case where the rails were the source of movement, it’s almost always been slack somewhere in the Z gantry assemby for me (mine has some from the anti-backlash nut on the acme thread Z I have - a ballscrew would be a lot better).
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Yea, basically what @mikep said; the frame is pretty stiff already (but can always be stiffer…thats what she said), but a hollow metal body allows for a LOT of vibration (so both chatter, noise, and eventually resonance and inaccuracies), so just playing around with ways to mitigate it.
The stationary Y-axis frame rails dont move, so there is really no reason not to fill those with sand, or some sort of heavy, vibrationally inert material. The X/Z axis (moving) gantry filled with sand may be too heavy for a belt driven system, and this is where my original question of expanding foam insulation or something like it would at least reduce vibration and noise.
so i think something to try is a flat, heavy table (i am going to build a torsion top and bottom shelf and fill both with sand), possibly with rubber isolators, but maybe not, combined with a sand-filled stationary frame and a foam filled x/z frame, for an extra $20 could net you some sound deadening and increased cut quality on something like aluminum.
Totally an experiment in “why not” and it may not make any noticeable difference, but for $20…why not!?
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I could give a good “why not” reason…
Its not the weak point. In fact, its one of the strongest points on the machine. The wheels and mounts are the weak points. If you want to change that, get some good linear actuator rails and carriages. It will be overkill, but then setting the tension wont be a matter of “I think its tight” it will be a matter of setting tension to a defined measurement (my preferred rail is 7 inch pounds).
When I converted my 40w laser to real rails (no plastic on aluminum) after wearing out 2 in a year, I used these:
http://www.mcmaster.com/#catalog/121/1138/=10g6a9o
The parts ordered for this:
Side-Mount Track Roller Carriage, 87 mm Length - 6738K221
Guide Rail, 720mm Long, for 87mm Long Side-Mount Track Roller Carriage - 6738K74This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.