Hi, I have been trying to decide which ball screws would be good for machine that is 1500 x 1500. I am finding for diameter I can get 16,20,25 mm in overall length of 1500mm. How big of a diameter is enough for that length? Is 16 ok or should I get 20? Also what pitch is good? I see I can get 5 or 10 mm. I read people using 5 then other people say 5 is too fine and the movement would be too slow.
I'm not running metric, but I have 1/2-10 5 start (2 turns / inch) lead screws on my workbee 1510. No whip at all or that I can notice anyways.
Thanks! I guess I don't need to get metric it just seems like what I am finding is all metric. 1/2 inch would be close to the 16mm ones. Got any pictures that show the screws installed in there?
Yep. Check out the 1/17 update here (about halfway down): Shawn's Workbee 1510 And more here: Shawn's Workbee 1510 And you can check out Jacob's build here: 1510 Workbee Modified
There are length/diameter guides out there, but based on what I've seen, 1605s should be ok at 1500mm. It's definitely on the border of where 25mm might make more sense, but that's a lot of mass to be moving around and most people don't seem to have issues. I max out my 1204 and 1605s (with dovetail ways) running NEMA34s at 2500mm/min (100IPM) and 6000mm/s/s acceleration, and typically run around 1500mm/min until I can reinforce my frame some more. That's not bad in metals, but if you're looking at soft materials you might need a higher feed to cut proper chips. 1610s or 2510s are always an option, as is going to servos to get useable high-speed torque. Lower feeds are just an inherent downside of going to screws over belt/chain/rack and pinion, though.
Assuming steppers at 8x microstepping, you have 0.00625mm resolution, or about 2.5 tenths/a quarter thou. An order of magnitude more resolution than you need in soft materials, which is perfect, but they do tend to have one downside: cost. If you can find them reasonably priced somewhere, go for it, but since most people get the 1605s, they tend to run a bit higher and be harder to find from reputable sources.
My workbee from Ooznest claims a resolution of 0.1mm. Given the inevitable play & flex in the whole system that's not bad for a machine using aluminum extrusions and "ACME" leadscrews. (my measurements so far indicate it achieves this or better). If you are using ballscrews the limiting factors are going to be the rigidity of your framework. Alex.
Thanks! So if I am figuring right with the 1610's even with no microstepping I would get .05mm. So I think the 1610, 2010,2510 would be the way to go. Gotta see what they cost now.
If you use 1/2 inch ball screw, you get whip. 1/2 inch = 12.7 mm. I used 12mm ball screw on my OX. But because of the whip I upgraded mine to 20mm. Her is my OX today.
Did you use 2005 or 2010? I see everyone using the linear rails but I already bought all the v wheels so I don't want to switch now.
I use the same (or similar) lead screws as sharmstr on my 1500 mm Y axis and have not seen any noticeable whip even jogging much faster then I would ever cut with it. I bought these McMaster-Carr
