Threadless ball screw

Hey guys/girls
just wondering if you could fill me in on whether threadless ball screws work with printing at high speeds or do they just slip. Also please say any drawbacks there are cause Im interested in putting a set of these on my 3d printer.Threadless ball screw
Thank you

While it should work quite well given the large bearing angle, it would need a closed loop system. The expense of encoders and the need for special software makes this a big undertaking.

Mike

I've been eyeing these as well. It would take some OpenSCAD work to incorporate them into the X motor end and X idler end, but it should be doable. There'd be less friction than the current poor man's anti-backlash nut, and a lower TPI should let you run the Z axis slower. The combination of these two things would make it less likely to overheat the Z motor or driver and let you run it faster, but at the cost of more hardened smooth rod and a bunch of bearings. I haven't played with one, so I don't know for certain how repeatable and slip-resistant it is, but the comments and YouTube videos make it seem pretty reliable.

Leadinglights, an encoder isn't necessary. The way the device is designed, it has a prescribed turns-per-inch that is known and repeatable, so it would work like current z-axis setups do. The only difference is that the pitch is set by the angle of the bearings rather than the pitch of threads.

I have made two of those things (had to design them from scratch because the original design didn't include the bearings I had available).
At first, I was a bit sceptical - the bearings looked like they might slip on the shaft. But to my surprise, this system works really well if you angle the bearings so that only a point on the edge is in contact with the shaft (instead of a line on the side of the bearing). That way, there is some microscopic temporary deformation going on which prevents slippage. When tightened well, they withstand quite a lot of force before slipping, and that with only one row of bearings - the double stack version might withstand even higher forces.
So my verdict is: onto the Z axis of my next printer they go!
While definitely interesting also for X and Y, the Ultimaker / Tantillus design is more cost effective / lighter / more compact with cables. The Mendel design however, might greatly profit from these threadless ball screws.

How would you ensure both sides of the Z axis stayed in sync? Surely it would mean the angle of the bearings would have to be set very precisely indeed.

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I am not sure if using this on a Mendel design Z-Axis is advisable for exactly this reason, but a moving Z table like I would like to implement shouldn't be a problem. In fact, the elegance of having one shaft as guide and the other as drive and support is somewhat appealing. If implemented on the X / Y axis of a Mendel derivate, this system might be a definite step forwards (although I tend to depart from the Mendel and favor the Ultimaker / Tantillus route now).