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Discussion in 'CNC Mills/Routers' started by drxlcarfreak, Jun 15, 2017.
Very stout 2'x4' machine with a deep Z axis
drxlcarfreak published a new build:
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The dual gantry isn't something I would do initially, or probably at all. I just wanted The provisions for it in case I wanted more production out of The same footprint. The added 10" is a benefit, but the main reason I thought to do is to increase overall cutting speed. The average I have seen on this site is 50ipm, two gantries would effectively double the speed. Granted it wouldn't be fully double, since the way I see it I would break the code into 3 parts. 2 where each machine can do it's own thing and not worry about the other, and a 3rd to have one do the little interference strip in the middle. Most of the pieces I envision doing are 24x24 anyways, so I could also run 2 pieces at once with no worries.
My main concern right now it the structure of it being sound enough to cut at full depth of 6/6.5".
I actually had a thought recently while designing the 2x4 setup, to just bite the bullet and build a 1500x1500 machine. I put together a model to mimic the same allowable deflection gantry as the 750mm C-beam Xlarge. I think it was somewhere in the range of 0.028mm vertically and 0.14mm horizontally with a 10kg load. Using just MOI and assuming the pieces are rigidly bolted together this beam is right there, with 0.03mm vertically and 0.11mm horizontally.
It's a pretty overkill beam, but in reality, the overall footprint is almost the same as the C beam plus the support.
Looking quickly through the numbers, it looks like this will be about a $250 premium to double the size of my cutting area. I am trying to decide to bite to bullet and try and find room for it in my garage, or stick with a more run of the mill machine that has been tried and true. Any input is welcome!
Lol, well I am a structural engineer by education, so my expertise is in making sure that things don't move ever!
Not so good at the things moving part.
Something about structural engineering and precision machine design has never sat right with me. Probably because most structural engineers I encounter(two uncles included) only work with civilian structures. At that point it's the difference between verniers and measuring tape. The daily weather change is enough to expand and contract a structure, but it's only the fractions that matter to them. On the other hand, plus or minus a degree in a controlled precision lab is a huge deal. For the latter it seems not a lot of the oldheads remember their education.
Btw if you want to save a couple of bucks, you could probably get away with less screws in all of your end plates. Every other corner brace on your base and every other piller support in your gantry could probably be tossed too. To each his own I guess.
Your single router mount looks like a weak point and I think you can get away with less hardware if you lay the worktable extrusions out differently. Make the horizontal lengths uncut instead. Depends on extrusion lengths I guess.
I love the idea, but where I am lost is the software to make it all work. I have a build at the moment. Purchased C-beam and using it to grow into a 500 L x 1000 W which I can turn into a 500 W x 1000 L cnc for a similar build as yours. But again, am not great (AT ALL) in the software department to make it work. Absolutely clueless. What are your ideas into this?