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30 Oct 2015 06:08 #64494 by bill516
Worm drive was created by bill516
I have a worm drive gear box that I am playing with as a possible 4th axis on my machine but the stepper config has me baffled. What do I need to enter for the pulley/gear settings and the leadscrew pitch in the step config

Pulled the drive apart and the worm is a 2 start thread with a 5mm pitch, the gear is 88 tooth. Physically rotated the drive shaft 44 times and got 1 rev of the output shaft

200 step stepper with 1/8th microstep (although that is adjustable)

Bill

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30 Oct 2015 08:21 - 30 Oct 2015 08:21 #64495 by LearningLinuxCNC
Replied by LearningLinuxCNC on topic Worm drive
Bill,

You will need to set the gear ratio as 1 : 44 if the stepper motor is direct coupled to the worm gear input shaft.
Then put the value of leadscrew pitch to be 360 degrees per revolution.

I think I would go down to a microstep of 1/2 instead of 1/8.
Last edit: 30 Oct 2015 08:21 by LearningLinuxCNC.
The following user(s) said Thank You: bill516

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30 Oct 2015 17:21 #64508 by bill516
Replied by bill516 on topic Worm drive
Thanks Nitro, thinking about it its logical that the pitch is 360.

Bill

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30 Oct 2015 20:29 #64516 by andypugh
Replied by andypugh on topic Worm drive

What do I need to enter for the pulley/gear settings and the leadscrew pitch in the step config


Stepconf tries to be too helpful, and asks questions that can not always be answered.
Perhaps here should be a box to directly enter the step scale.

The final result of the multiple boxes in Stepconf is a single number in the INI file, the number of step pulses per machine unit.

In your case 1 degree is 44 / 360 turns per degree
If you are at 1/8 microstep then that is 200 x 8 steps per turn.

The number of steps per degree is thus 200 x 8 x 44 / 360 = 195.5555556

And that should be the number that you see in the INI file.

This also shows that you have a resolution of 1/200th of a degree but that you need 1170 Hz for 1 rpm. You might find that you can't make steps fast enough to turn at the rate you want, and that reduced microstepping will be needed.

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31 Oct 2015 03:10 #64529 by bill516
Replied by bill516 on topic Worm drive
Thanks Andy it was the pitch box that threw me.

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