Building a new machine, from scratch, 24"x24" design goal

[ZorAxe]

It's a pleasure. My CNC engraver is about 900x700mm (thats around 3x2.3ft) and the 17's work for me. Remember it's not really about size it's more about what's resisting the motor. I do understand that the bigger in size the more weight it will be for the motors to move, but as long as there is as little friction as possible, then you will be ok.

Don't let me sway you from getting NEMA 23's. I'm just giving you my perspective and what I've discovered with steppers. The more torque won't hurt, but just always check the holding torque and the amperage drawn. If you do go NEMA 23 then try to find one that will give you the most torque around 2A.

[DBFIU]

It's a pleasure. My CNC engraver is about 900x700mm (thats around 3x2.3ft) and the 17's work for me. Remember it's not really about size it's more about what's resisting the motor. I do understand that the bigger in size the more weight it will be for the motors to move, but as long as there is as little friction as possible, then you will be ok.

Don't let me sway you from getting NEMA 23's. I'm just giving you my perspective and what I've discovered with steppers. The more torque won't hurt, but just always check the holding torque and the amperage drawn. If you do go NEMA 23 then try to find one that will give you the most torque around 2A.

Awesome. I was actually going to use the extra long NEMA 17s, but the SMW3D actuator package that I linked above, already comes with 23s. I will keep my eye on current though and adjust accordingly using the pots on the drivers.

Also, are you saying these motors have a a sort of dyno graph? One NEMA 23 can make more or less torque at 2 amps vs another NEMA 23? I would hate to have to try and figure out now where to find this detailed information. These chinese motors dont usually come with this information.

[ZorAxe]

...Also, are you saying these motors have a a sort of dyno graph? One NEMA 23 can make more or less torque at 2 amps vs another NEMA 23?...

In a way yes there should be a graph that will show the different torque and what the amount of current drawn is at the particular torque figure. If I remember correctly, "The torque generated a the motor is proportional to the amount of current flowing through the motor." Basically what I meant is find 23's that will give you the most for their values:

Lets make an example:
You have 2 NEMA 23's.
-----------
Motor A has 4.0Nm holding torque at 6A
Motor B has 1.6Nm holding torque at 2A
-----------
On paper it seems as Motor A is more powerful (and it is) but if your driver can only supply 2A then it's not possible to run the motor at full torque.
If I'm correct in saying torque is proportional to current then Motor A will only push out 1.33Nm torque at 2A, making it less powerful then Motor B.

I stand to be corrected in the above statement, and please do correct me if I'm wrong. It's just something I came across when I was choosing motors for my CNC engraver. So keep those calculations in mind when looking for motors. Your drivers limited to 2A and that plays a big part.

[DBFIU]

In a way yes there should be a graph that will show the different torque and what the amount of current drawn is at the particular torque figure. If I remember correctly, "The torque generated a the motor is proportional to the amount of current flowing through the motor." Basically what I meant is find 23's that will give you the most for their values:

Lets make an example:
You have 2 NEMA 23's.
-----------
Motor A has 4.0Nm holding torque at 6A
Motor B has 1.6Nm holding torque at 2A
-----------
On paper it seems as Motor A is more powerful (and it is) but if your driver can only supply 2A then it's not possible to run the motor at full torque.
If I'm correct in saying torque is proportional to current then Motor A will only push out 1.33Nm torque at 2A, making it less powerful then Motor B.

I stand to be corrected in the above statement, and please do correct me if I'm wrong. It's just something I came across when I was choosing motors for my CNC engraver. So keep those calculations in mind when looking for motors. Your drivers limited to 2A and that plays a big part.

That would be assuming the current/torque relationship is linear, and if you interpolated it linearly then yes I see what you mean. But what if the curve is not straight?

Maybe I am overthinking this part of the plan..

Either way thank you for the input, it is always appreciated.