Picking a motor?

[kim50usc]

I am trying to create a mechanism that uses a rack and pinion mechanism that pushes an object upwards sort of like this one here.

I plan on making it with a stepper motor instead of a servo and with some off-the-shelf gear racks. We need a motor with sufficient speed (the mechanism needs to move 3-4" a second) and power (needs to lift 10-12 lbs)

I guess I have more than one question, but in regards to the motor, which would you recommend?
I've been looking into the NEMA 23's because they seem to have sufficient torque. Please let me know if you have any other recommendations!

 

[flexoprinting]

Hello kim50

I am thinking you might want to produce your entire assembly first and then measure how much torque it requires and go from there. A lot
comes in to play lifting X amount of lbs with for example one gear or four gears, leverage can also be a factor. I am interested in the comments
from other members such as the proper steps for something like this.

Chuck

 

[SceneryDriver]

Stepper motors must be significantly over-sized in applications like this. "Sufficient" torque may not account for real world effects such as occasional binding due to dirt, imperfect assembly, etc...

If the motor isn't over-sized, it can start missing steps, and accuracy will suffer. A good starting point is to use a motor with twice the torque needed to move the load.


SceneryDriver