Hi Guys, @Griffin_Paquette
My friends (1 of whom is the techie) and me are building a SmartRap.
Our design uses NEMA 14 stepper motors, non-heated bed, single extruder.
We’ve read that NEMA 14’s torque could possibly be not high enough and we are also concerned about over heating of the NEMA 14.
Q1: Is it still advisable to build a SmartRap, using NEMA 14s (perhaps one with hi-torque and better current/temp ratings or simply go with NEMA17?
Thank you
@Mark_Moissette_ckaos , I know you have plenty of time working with Nema 14’s on that little mini prusa mendel, thing. – would you recommend them?
What’s your reason for wanting to use NEMA 14s?
Stepper torque is roughly proportional to motor volume/weight, it’s hard to get around that. What you CAN do is configure the drivetrain to run at higher RPMs (24v PSU, low inductance motor) and then gear down the motor to move up the power curve.
@ThantiK , thanks for @Mark_Moissette_ckaos .
@Ryan_Carlyle , thanks for your information.
Nema 14 was chosen mainly > smaller footprint compared to using Nema 17.
I would never ever use Nema 14s: the torque is low but not catastrophic, but they overheat like hell: even with 2 huge heatsinks and a big fan per motor they reached temperatures > 110 °C after 20 mins of printing.
So please @Ivan_Hoe save yourself the trouble and use a Nema17 
they are not that much bigger but they are way more useable ( and easier to source)
@Mark_Moissette_ckaos , thank you. Done, your advice has been accepted : )
@Mark_Moissette_ckaos pretty sure you must have been over-driving them. Stepper current ratings are literally determined by the amount of motor heating that is produced.
@Ivan_Hoe no problem, glad if my own mistakes can help.
@Ryan_Carlyle I spent month adjusting current for steppers and they either skipped steps or overheated 
I found there was very little tobe done either way.
But the stepper drivers are better these days so you might have more luck…but not much point risking it, unless you really need the extra few cms.
@Nathan_Walkner yeah, seems like that’s what’s going on here.
Now, a triple-stack NEMA 14 can be higher torus entrant a short-stack NEMA 17, but you have to ask why bother at that point since there’s no real weight advantage.
I have a portable printer design in mind where I might end up using NEMA 14s or even 11s just to prove it’s feasible, but I’m not going to try to drive it particularly fast.
I honestly would look at some smaller nema 17. The torque loss going from 17 to 14 is significant in my opinion. @Brook_Drumm uses some nice small nema 17 steppers in I believe the play (correct me if I’m wrong) and I have many and really like them. Nema 14 also tend to cost more… Interested to see the design either way though!
I loved my smartrap when I had it but I wouldnt build another. It just lacked rigidity that was needed to give it consistent and good quality prints. I fought with mine a lot to get it to print right. My current Frankenbot has crazy stiff rods that I think help with the rigidity a lot. Have had almost zero tuning to it since day one of printing.
If you are going to have a small build area, you might be able to get away with a smartrap but also look at the design from @Diego_Trapero . Similar but braced which I think would make a world of difference.
Hi @Nathan_Walkner , @Griffin_Paquette , thank you all for your advice. Appreciate it : )