Is there a way to tighten the gantry. I know I made a giant Micmac but thought seens there was going to be no z axis pressure it might be fine. It doesn’t appear to be the x and y giving me problems just the gantry on the movements that require x and y to move together straight and curves seem to be fine.
This is why the Lowrider exists…
At a minimum, you’ll need supports in your X and Y spans.
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As above.
The MPCNC was never designed to go that big. You might get away with adding supports along the X and Y rails but if I were you I’d be looking at the Lowrider as an alternative.
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Yea, lowrider with an acrylic carriage so you can see the cut would be the way to go.
The advice like, “you should have built a low rider” is right. But I imagine that is pretty frustrating feedback. It is clear there was a lot of effort, energy, and expense in this build. It looks good, but it is very very large.
There are a couple of things you could do to make this work better:
- Make a good test pattern. Something like a few different sized squares and arcs. Something where you can measure a few mm of error as the machine whips around a corner.
- Drop the Z height. I would be curious how much that helps on its own. You have a laser, which is zero load, but there is still a lot of weight in that huge gantry moving around.
- add midspan supports. You might be able to test how effective that would be by just doing a pattern in the middle vs. at a corner.
- make sure you are very square, your motors are moving smoothly, and the bearings are touching. If something is snagging, it will stutter and that will make everything shake.
- reduce the top acceleration and speeds. You have the heaviest gantry on here, even with a laser.
Ultimately, building this out of 1" tubing instead of 3/4" pipe would have been a little help, but this build should have been a low rider. You can still salvage this by cutting this down to 24"x24"x3" and I bet everything will be fine. Fine enough to start building a low rider for this big table. Probably not the news you want to hear, but I guess that going from 1-5 above, you will still end up with sloppy results with a build this big.
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I actually have the pieces to make it a low rider. The table use to be a lowrider but I could never get the z axis to work and didn’t use the router portion of it and was converting it to a laser thought mpcnc format might work.
Man, i thought a 2x4 mpcnc was big!
Still, for a laser i don’t think it’s so bad. Like Jeff said, though, try to shorten the z. That laser is WAY below the gantry, and that’s gonna cause it to whip around a little at corners. You might alleviate some of that by turning the acceleration down, too.
Also, hard to tell what the zip ties are holding. Looks like a tool plate mounted behind the laser, so if the laser is screwed to that, good. If it’s the zipties holding it on, well, that can’t be helpful.
After some experimentation I can run it at 8 mm a sec and get good results
The sheer size of this is amazing! 