[peteeng]

Hi All - The design order for a screw drive is:
1) Design for a speed range
2) Design for a force

At the end you have to design for both.

1) Design for speed first - Direct drive. Select your pitch to get to your chosen top rapid speed. Take into account the motor torque speed curve. Steppers drop off so max speed will be 500-750rpm. Some advanced drivers will run over 1000rpm I've seen curves up to 2500rpm.
2) Check you have the design force required in the cutting speed range
3) If all correct then check for whirling or whip
40 Once all correct check accelerations including rotational inertia (do search for this covered in other threads). Check you can get to design accel if you have a target. If your short you may have to go up in motor size to get your target.

If you can't get the force, speed or it whips then look at gearing. You may have to go up a screw size to prevent whip.
Go through the process again. By Round 2 or 3 you will have settled out the design that works for you...

Hiwin publish design manuals for all of these conditions. They have been physically checked in other threads especially whip.

Cheers Peter

[NIC 77]

Peter,

I can't really tell if you're trolling or not. LOL.

Once all correct check accelerations including rotational inertia (do search for this covered in other threads). Check you can get to design accel if you have a target. If your short you may have to go up in motor size to get your target.

If I do a search for this covered in other threads, I will be reading my own posts. As far as I know, I was the first person on these forums to do rotational inertia equations and graphs for both ballscrews and rack and pinion to target a desired linear acceleration.

Just looking for a couple of opinions from the OP about his design concept that is uncommon. Not looking to take over his thread or make enemies .

[peteeng]

Hi Nic - Neither me, was just trying to summaries the process. People seem to use screws and gears and end up in the same place as a direct drive would have been. Peter

[NIC 77]

If you'd like to check out my thread on this, it's here:

https://www.cnczone.com/forums/linea...ml#post2386312

I go into more specifics in that thread.