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Discussion in 'CNC Mills/Routers' started by Mike Campbell, Nov 29, 2020.
This is a custom gear rack drive machine with a 4'x8' cut capacity.
Mike Campbell published a new build:
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Tried to make this build a little bit bigger this week and hit a snag. I've re-worked the OB spindle mount specs to accept a full size router and even cut one on the machines at work to test. The good news is the mount works great. The bad news is this frame design, as it is, won't handle a big router. There is just too much deflection on the gantry beam to be usable. I don't see why this mount wont work on the new "LEAD1515" gantry setup, so I'll clean it up and share the file here soon.
I did manage to get the X axis motor mount made and installed though. All that's left is to make is the custom swing arms for the rack and pinion drive on the XY and start wiring.
Try making another motor mount and put the mounts at top and bottom of the carriage, holding the motor at top and bottom. I think that the router motor may be too heavy.
I think I follow what you're saying here, a second spindle mount wouldn't hurt. And the weight of the router can be overcome by adding a spring loaded return without much trouble which is pretty common.
The real problem here is the lateral flex in the "C-beam" gantry rail. The OpenBuilds team has addressed this issue pretty well on the LEAD series by stacking the C-Beam extrusions and doubling up on the axis plates. Since I'm cobbling this machine together with off the shelf parts and plates from older builds, it has certain limits.
Good thing I can use it to improve itself though.
Interesting.. for something that wide... I would go with a much taller setup on the x axis. quad c beams.. maybe that is overkill.. but 2 butted up edge to edge and double that up.. lose the wheels and go with linear rail. I think even with a regular spindle you are going to see torsional flex due to the width.. You could also try balancing it.. place a counterweight to offset the router and the weight of the Z axis...
I like where your head's at, but this build is kind of a Frankenstein's monster using parts and resources already on hand versus buying and designing all new. It will be fine, as is, to dial in the new drive system and even fabricate parts for it's own replacement down the line.
Just about got her all wired up and ready to test over the holiday. Had to drop back and order some other wire and a few bits of hardware to complete everything, so another week in limbo.
Machine is 100%. Here's a quick vid of the first motion test. Full speed/random jogging by way of the game pad. More to come...