whip on lead screw

[badassdevil]

I am looking for some help i am trying to get rid of the whip on my z lead screw it is 1800 mm long and 12mm in diameter any ideas how i can lose the bad whip i am thinking of using m16 or m18 screw

[diycnc]

i would go with 25mm with 10mm lead minumum, it will still whip but at a higher rpm

look up on ebay LinearMotionBearings they have decnetly priced screws.

[BillTodd]

my z lead screw it is 1800 mm long and 12mm in diameter

That's a serious Z axis

12mm seems a little light for a screw of that length it has a core of only about 10mm.

One option (other than increasing the diameter of the screw) is to re-engineer the axis so the screw is stationary and taut between mounts, while the nut rotates (i.e. the nut is mounted, with the drive motor, on the gantry)

[Matt Adams]

How fast do you want to spin, and what is the pitch of the screw?

The 25mm diameter screw with 10mm lead recommended above is rated for 362 inches per minute. Is that enough?

1" diameter with a 1/2" lead gets you up to 468 i.p.m.

[badassdevil]

i got confused it should be the x axis lol funny considering i am a cnc machinist for a living

[badassdevil]

thanks for all the help guys i have re designed it so the nut rotates rather than the screw

[BillTodd]

Originally Posted by badassdevil thanks for all the help guys i have re designed it so the nut rotates rather than the screw

Pictures - or it didn't happen....!

[svenakela]

Originally Posted by badassdevil thanks for all the help guys i have re designed it so the nut rotates rather than the screw

Very good idea, I use rotating nuts myself and they are very well performing. I can "pre-tension" the screw and even though my screws are as long as yours (but thicker though, 16 and 20 mm) I have no problem driving my axis at 15-20 meters per minute, that's about 600-800 IPM.

Pictures not needed, I have videos.

YouTube - 20090416012

YouTube - 20090416012

YouTube - 20090416010

YouTube - 20090416010

[peter.blais]

Looks like this thread is sorted- FWIW though, all the big screw manufacturers provide equations for predicting whip in their data sheets. A quick run through of those would prevent nasty surprises, and could probably be *roughly* used with other no name brand screws as well, for hobby use.

[badassdevil]

the system in your vids is very simular to mine and it works just great length is no longer and issue so in my opinion a better system

[BillTodd]

Originally Posted by badassdevil the system in your vids is very simular to mine and it works just great length is no longer and issue so in my opinion a better system

Come on then, where are the pictures ?????

[jurban]

Are there any commercial/stock rotating nut ball screws? The examples I've found here look custom or at least partially fabricated. I'd rather spend the money on that part instead of the time.