Hi, I am planning to use a nema 23 motor in my build, using the openbuilds bracket, like in the picture I attached. My question is, how rigid will the motor plate be in this orientation? Is the connection provided by the T-nuts strong enough to hold against a typical amount of belt tension, for a 3d printer belt driven system?
More than strong enough, this is why I suggested a NEMA17 motor before, teaming it with a 14t pulley and your done. -Ronald
Hi Ronald - I decided to stick to nema 23 since models are available with 0.45 degree step angles. This is not possible using nema 17.
I see. Remember that in general your stepper driver will give you an at least 1/2 step (using a l298n only) if I'm right, but most will do even up to 1/32 if not 1/64, this makes a 0.45º motor unnecessary. I don't know if you already know that; when I started designing CNC machines I also was focused on a 0.9º motor but know now that a 1.8º motor will do just fine . -Ronald Edit: changed values, 0.45 to 0.9 and 0.9 to 1.8 º...
Yeah I did consider micro-stepping, but I think that these microsteps are not as accurate as full steps. I think ultimately a 0.45º motor with 1/32 microstepping will have better repeatability and precision than a 0.9º motor with 1/64 microstepping. Do you agree?
That would sound logic, but in practice it will give you for 99.9% the same results. I forgot that on OpenBuilds we only have the 1.8º motors, I also edited one post up that I made as I wanted to say 0.9 and 1.8º. Any way, 1/16 step with stock NEMA17 and 14t pulley will give you a resolution of 8.75 micron. You will only go to a full step to get more torque out of a motor, something that isn't needed with a 3D printer, except for the extruder although the grip of the extruder pulley is the limited factor there in most cases. -Ronald
that reminds me of another thing I wanted to talk about actually! I have been reading that a smooth idler wheel is not ideal for belt driven motion, and either a toothed idler or twisting the belt so that the smooth part of the belt rides on the idler would be better. Do you have anything to say about this?
As an aside, does openbuilds offer custom parts? I might need an aluminium L bracket with slightly different dimensions from what is available on the store
