Hi. I took a look around the site for an answer and now my wife is wanting to go out so I have 5min to ask!

I am converting my CNC router to ballscrews instead of the Festo belt linear actuators it has already. The Festo belts need maintenance and are a little loose for cutting round holes and alloy.The screws are 1605 and are so much more stable (twin on the Y) and accurate. But they are slow. If I speed up my steppers, they make a knock every once and a while which I can only account for losing steps. Also the couplers slip. So I have a machine that is extremely accurate now but very very slow to achieve the results I want.

I am using proper SFU rails and blocks that have a little bit of friction due to the seals.

What do I do here can anyone give some advice? It is easy to stop the couplers from slipping I guess by making some or keying the shafts but steppers losing steps is an issue. I am using Nema 23 approx 465" lbs torque.

Do I go for bigger Nema steppers? I do understand they lost torque with speed. Gearing up the ballscrews is possible but a lot of work.

I love my machine. It is 1800mm x 1400mm. The Y axis is about the maximum length for a ball screw but they do not whip so all is ok. It is looking amazing and is robust and tight. Just slow now if I want to keep my alloy cuts within tolerance. Timber it is not so much an issue.

A thousand apologies if I have run over an old story but my wife is waiting............. :-)

Regards
Boyd