Direct-drive non geared .9 stepper?

Wyvern

Looking for more ways to improve my FT5 R-2, the movement axes are in good order and need no further improvement, so the extruder is the next thing to improve.

I'm running a MK10 hotend on a direct drive tooth hobbed extruder, I'm not looking to complicate things with a geared assembly, will a .9 stepper handle the task of an un-geared setup?

I usually run .2 layers at around 50-75mm/s.

dc42

I generally advise against using non-geared extruders with PLA because the force they can provide tends to be only just sufficient, which may limit your print speed. However, if you want to stay with an ungeared extruder, then the important thing is that the 0.9deg stepper motor you use provides at least as much torque as the 1.8deg motor you are replacing. I suggest you look up the specifications of the original motor, and use them as a reference when looking for a suitable 0.9deg motor.

It's usual to find that a 0.9deg motor has a little less torque than a similarly-sized 1.8deg motor in the same range.

The E3D "compact yet powerful stepper motor" may be suitable.

Wyvern

@dc42 said in Direct-drive non geared .9 stepper?:

E3D "compact yet powerful stepper motor

Thanks! the stock extruder is 5Kg/cm so I will have to source something comparable.

I hit a wall at about 85mm/s if I am printing within the high temp range of PLA and a little more if I'm above the rated temps, the MK10 is good for retraction and stability, but they aren't that great for speed, in fact it's not the extruder that runs out of torque, but rather it's the hotend that fails to heat fast enough as It will start to chew a hole in the filament- I have since lowered amps to prevent that.

Belt drive extruders are intriguing and I may look into them soon.

3dmntbighker

I had the genuine E3D pancake 0.9 on my Bondtech, and that thing had to run red hot to avoid skipped steps. The BT is geared three to one. I installed a cheap crap 1.8 pancake and it uses like half the current. I'm on 24 volts too BTW. So I think that's a big no.

3DOeste

I use the Titan aero, which is 3 to 1, with the e3d pancake 0.9 deg. at 100% current, which is 1400ma. I never have a problem, but I used to print with 0.5mm nozzle at 0.1mm to 0.4mm layer at 50mm/s. I never have missed steps. Although all my assembly is full aluminium so heat is not an issue.
I used to have an mk8 I think, and at some point I calculated the torque between the two extruders (the mk8 has a more powerful 1.8deg) and it was the same but with much more resolución which greatly improved part quality.

Wyvern

My e stepper bolts to a aluminium carraige, which rests on a metal linear block, so thermal capacity is high.
I will give it a try before trying anything else crazy.

3dmntbighker

With enough thermal mass my 0.9 probably would have worked. Expect to hear from DC42 about running at 100%. He's going to tell you not to run above 80% if he holds true to form

dc42

@3dmntbighker said in Direct-drive non geared .9 stepper?:

With enough thermal mass my 0.9 probably would have worked. Expect to hear from DC42 about running at 100%. He's going to tell you not to run above 80% if he holds true to form

You can run stepper motors at 100% if your motor mounts can take the heat.

3dmntbighker

@dc42 said in Direct-drive non geared .9 stepper?:

@3dmntbighker said in Direct-drive non geared .9 stepper?:

With enough thermal mass my 0.9 probably would have worked. Expect to hear from DC42 about running at 100%. He's going to tell you not to run above 80% if he holds true to form

You can run stepper motors at 100% if your motor mounts can take the heat.

I was sure I read you tell other folks not to run over 80% as a best practice. Mine was getting way too hot for my comfort, though it didn't seem to bother the PETG. I don't think I lost much with the 1.8 and the Bondtech BMG.

You're killin me dude

dc42

@3dmntbighker said in Direct-drive non geared .9 stepper?:

I was sure I read you tell other folks not to run over 80% as a best practice.

I advise 60% to 85%. The reason I don't normally advise above 85% is because of the heat generated by the motors.

Wyvern

Finally ordered a stepper, I went with the compact E3D.
I am going to be dismantling half the printer for Z axis and bed upgrades anyway.

Maybe next I will switch to all .9 as I focus on details over speed.