I've posted about my machine before. I do want to convert it to ball screws and linear rail bearings, along with some other upgrades. The machine is 8040 C-beam construction for all leadscrew axes. The Y axis C-beams are 1000mm long. The X axis C-beam is 620mm, but I'm pretty sure I'm going to have to adjust that when converting to the rails. I want to flip the Y axis C-beams so that the open side faces away from the work area, and putting on the rails will extend the distance between the gantry plates that hold the ends of the X axis C-beam. The X axis beam does have the open side facing the way I want to, but I'll expect I'll need to make modifications for how the Z axis is connected to the X axis. I'm also wondering if I should have an extra extrusion, maybe 4040, to help support the Z axis, especially if I'm going to be upgrading to a 1.5Kw spindle. I saw the comment from @Rob Taylor about needing DFU nuts on the ballscrews. I also want to be able to get close to 200in/min, or 5000mm/min travel if possible. I realize getting ballscrews may make that unfeasable, but I'm currently limited to 75in/min. I'm happy to replace the motors and controller if needed. Sorry, getting called away, and I don't want to lose this post. So more later.
Ok, back again. Thinking a little bit more about this, I'd also be happy to go with scrapping my current X and Z axes, and go entirely with a known build instructions, adapted for my X axis length. I'm limited to roughly my current X and Y axes size due to where I'm working and space limitations. I've got a budget of between $1.5K - $2K, and about a 4-6 week window to get it done. I'm on a working vacation now and will be home on the 9th, but can do online orders. Thanks for any help/advice/warnings you're able to give! Also, thanks to the moderator who put in the correct tag for @Rob Taylor ! Edit: I was originally looking at something like this for my Y axis for the rail bearings: https://www.amazon.com/CHUANGNENG-HGR20-1000mm-Carriage-Bearing-Rounters/dp/B08W23P41B/ Though I'm annoyed that I can't fin the one I was looking at a few weeks ago that had multiple lenghts and styles selectable. Also, can you even use the 1610 ballscrews with 8040 C-beam? It looks like the nuts are 48mm on the ones I'm checking out.
Ok, I guess I should break it down a bit more. From casual searching, I'm not seeing DFU nuts for screw diameters under 16mm. Am I missing them, or is this an accurate interpretation? Secondly, with 8040 C-beam, what is the largest size ball screws that will fit? Can you fit a 1610 with a DFU nut by cutting down the nut flange to fit, or is this a really bad idea?
I don't think an internal screw is going to work on standard C-Beam if you're graduating to "real" motion control parts. They're designed for 8mm leadscrews. I'm not sure I really even see the point in single-extrusion axes if you're looking at HGR20 rails and DFU1610 screws, either. Those are exactly what I've got on my build and I did the FEA modeling to figure out how to use them to... Not their full capacity, by a long shot, but enough strength that they're not completely wasted- or worse, cause damage to a machine insufficient to support them. This is my gantry/X-axis profile: Top and bottom structural steel, rear structural aluminum, and ends firmly locked in place to 3/4" aluminum plate columns with 1/4" aluminum plate and reinforcing C-Beam. Yes, this is so that a 14" lever doesn't move by more than 0.1mm at the tool under fairly unreasonable load expectations; going to a more sensible Z-axis length like 4" or so and reasonable load expectations like 20N (lbf? I forget) would probably allow you to dump the steel tubes, but I wouldn't expect to lose the 1/4" aluminum plates all over the place. (And yes, I love the fact that 60mm NEMA24s fit exactly inside the gap, no I'm not sure why the top steel is at an angle, I think a nut jammed somewhere but I've gotta go back and add more screws anyway) You can't consider rails and screws to be structural, either; your build has to be sufficient on its own before you attach them so that they can do their job- be precise. I cheat a little with the Z screw, but that's much shorter than the others. With single-extrusion machines, I suspect there's a non-zero chance that just adding the heavy rails and screws would cause deflection and sag by themselves, I was surprised by how much V-Slot moved when I measured it. It comes very straight, but it doesn't take much to move it. You can cut a nut flange down though. You can cut any flange down, I see used equipment of all kinds all the time with cut down flanges for custom installs- I assume they did the engineering math to make sure it was still safe (shouldn't be too complex, just operational torque/mounting pattern radius/shear strength of total number of screws, or something along those lines), but there probably isn't enough force on this machine to worry about it too much. The cylinder is ~28mm, the flange is maybe ~48mm? Might not be easy to make the actual screw holes fit inside a 40mm gap, especially trying to keep things symmetrical to avoid twisting.
@Rob Taylor , thank you! I appreciate the reply, plus looking through your build for your machine, gives me a better grasp on what my range of options are. Given my size limitations, I'm thinking of switching to maybe the Lead 1010 with the High Z mod, and reduce the X-axis from 1000mm to 700mm to fit my size limitations. I can maybe save a little cannibalizing the 2 1000mm C-Beams and 1040mm lead screws from my current setup. I don't think it is worth it to start a new thread, so some additional questions. With the Lead, black box controller, and the High Torque NEMA 23 motors, what would be a reasonable expectation for travel (not pushing for max, just reasonable torque for mainly hardwoods)? And what would be a safe upper limit for spindle weight with the High Z mod? I'm thinking getting a water-cooled spindle somewhere between 800w and 1.5Kw. I'm reasonably sure that at this point, it isn't worth trying to mod my current machine anymore. It is designed with the C-Beams on the Y axis facing into the center of the machine, and the roller wheels have no eccentric nuts to adjust. I'm also planning on using 8020 extrusions to make a table for the Lead, and putting a spoilboard on top when needed. A lot of what I want to do, I'm going to be using vises and cam clamps. Thanks again!
