Rotating Ballnut - design ideas

[richienz]

Impressive nuts! I just took a look at your e-moto webpage quickly too , wicked. Great project and racing at Isle of Man wow respect that place is nuts.

Hey I have a large router that is running well but I want to upgrade the main screw to a fixed screw rotating nut design. The screw is 40mm dia 10mm pitch and 3m long so its heavy. Running a 940W AC servo and a Grantite Devices VSD-XE servo drive, and 80VDC supply, I'm getting good response now with 8m/min velocity and about 400mm/s/s acceleration. This took a long time for me to work out the servo tuning but I got there in the end. I'd like to remove the rotating mass to improve my accelerations. The gantry it moves weighs around 150KG I estimate.

So I am wondering are you interested in building me a ball nut for this? Happy to pay market rates of course and if it helps fund any of your emoto projects then all the better. Please contact me if this is interest to you.

Below is my final servo response I got recently which I am really stoked about it, but to speed up my jobs I really want to up the accelerations.

cheers
Richard

Is that just the pulleys you're after, or bearings and pulleys? For the bearings, I got the last lot from here:

https://www.aliexpress.com/store/pro...053270817.html

[It may help to order 2 at a time to avoid customs charges. Not sure how it works in the USA, but I ordered two with no charges, then got taxed a lot when I bought 10 :(]

Regarding the pulleys, I can get 30t 5m HTD for about £6.30 each. Boring them accurately then drilling/tapping the setscrew holes takes maybe half an hour, so I'd be happy to sell them for £10 each plus postage.

This weekend, I made some progress on the six mounts I'm making:



I'm away racing next weekend, but after that I should have time to finish these ... at last.