[Danny1978]

Could anyone tell me what would be the maximum speed I could rotate a 25mm diameter by 10mm pitch ballscrew . The length is 1600mm 63" between the bearing mounts ( bk and bf 15 mounts ) thanks. Danny

[wayneb]

G'day Danny
Back again
http://www.nookindustries.com/Engine...cCriticalSpeed
1181 rpm
Cheers Wayne

[Danny1978]

Hi again mate ,so I would think a rotating ballnut like your set up. I got my quote today from dmm 4 axis .75kw AC servo kit $3160 including shipping,I wonder how much our government will throw at it in taxes. Could you tell me why you went for a rotating nut,it doesn't seem like you we're chasing high speed. If I remember right you are using a stepper motor do you run any sort of reduction, For me to run a reduction of 2:1 or 2.5:1 I should be within the speed range of the screws max rotation speed,giving I'm using a 2510 ballscrew that should give me a max travel speed of 10,000mm a minute,what are your thoughts on this will I be trying to push the limits a bit,I've also read running a belt can help dampen resonance in the screw.thanks .Danny

[wayneb]

G'day Danny,

Mass is the biggest reason I'm running a spinning ballscrew nut. If I was to run servo motors there is virtually no rpm limit for the nut assembly. I don't think there is much of a benefit to run a reduction and 10mm pitch, the resultant torque would be the same as a 5 mm ballscrew. I bought my motors and drives from oceancontrols.com.au .They do sell a servo motors but only 400w/ 1.27NM. At present I run a thick grease in the nut assembly, which may be loading up the motor. There should be really no load on the motors using 5mm ballscrews. Don't get me wrong about speed, I'll try to get the max rpm out of my machine, but I think it's going to boil down to, if you want speed, r&p and may be 4:1 gear to maintain power.

Food for thought.

Wayne

[Danny1978]

Hi Wayne I no what you mean about no torque increase it was more to do with lowering the ballscrew speed when the servo is ran at high speed,thats why i opted for the 10mm pitch screw and also the belt to maybe help with resonance issues,I also wanted to tuck the motors out of the way so they are not seen and protected. Danny