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Looking for suggestions for 0.9 Nema17 stepper

Posted by PDBeal 
Looking for suggestions for 0.9 Nema17 stepper
November 24, 2018 07:44PM
I think it’s time to replace the 1.8 Nema17 steppers on my Z axis on my CoreXY machines. Can anyone recommend a decent one that’s readily available in the USA and from a proper vendor and not an EBay store.

My Z axis uses GT20 belt with a 608Z bearing, and I believe I’d get better control of the Z resolution with a 0.9 NEMA17 stepper motor upgrade, but I’m not sure exactly how much current the motor will need compared to the 1.8 NEMA17 stepper I currently use. I’m currently using 1A on 3 of the 4 machines with the Duet 0.8.5 boards with the other larger machine using 1.4A on a Duet 0.8.5. Is there any current change if I change the 1.8 to 0.9?

And I have no interest in redesigning the Z axis with lead screws. I’ve already done some substantial redesigns debugging the GT20 belt setup and I’m very happy how it performs, apart from it doesn’t appear to be consistent with anything less than 0.2 layer heights.

2 of the machines currently use 17HS16-2004S1 and the other 2 use 17HS3001-20B if that helps.

Edited 1 time(s). Last edit at 11/24/2018 07:50PM by PDBeal.
Re: Looking for suggestions for 0.9 Nema17 stepper
November 24, 2018 09:01PM
StepperOnline sells on Amazon, Ebay, Aliexpress, and their own website. I've never had a problem with any of the stepper motors I've purchased from them.
Re: Looking for suggestions for 0.9 Nema17 stepper
November 24, 2018 10:50PM
They supplied the 17HS16-2004S1 through Amazon that I’ve been using. Looking at other motors they offer, it appears as though 17HM19-2004S would be similar to what I’m using on 2 of the printers with the only change being slightly longer motor and 0.9 degree per step change like I’m looking for. They definitely are more expensive for 0.9 degree per step, just not sure if it matters to keep the ~40ish Ncm holding torque if I move to 0.9, or if the 0.9 will require more current for the same torque. Especially since this is for the Z bed that’s cantilever design with GT20 belts.

Anyone know if there is any reason to put a 0.9 degreee per step motor on the extruder? Is there really any noticible difference in filament extrusion?
Attachments:
open | download - 17HS16-2004S1.pdf (140.2 KB)
open | download - 17HM19-2004S.pdf (133.4 KB)
open | download - 17HS3001-20B.pdf (546.4 KB)
Re: Looking for suggestions for 0.9 Nema17 stepper
November 25, 2018 02:39AM
A while back, I also thought 0.9° steppers were 'the holy grail', but for extruders they don't make sense.
It seems they not only loose some steps when the filament back-pressure exceeds a limit, but they got pushed back a lot.
On my E3D Titan, I replaced the original 0.9° pancake with it's 1.8° brother (17HS08-1004S) and my retraction setting worked much better since.

Edited 1 time(s). Last edit at 11/25/2018 02:43AM by o_lampe.
Re: Looking for suggestions for 0.9 Nema17 stepper
November 25, 2018 07:40AM
Im really interested in the whole 0.9 vs 1.8 steppers for XY and Z. Would be interested to hear peoples thoughts. It seems to me the main gain is vibration damping.
Re: Looking for suggestions for 0.9 Nema17 stepper
November 25, 2018 04:05PM
Using 0.9deg motors instead of 1.8deg on a well built delta printer gives a small but measurable improvement in print quality. The same was true of my SCARA printer because the gearing between motors and arms wasn't very high. But on a Cartesian or CoreXY printer, I doubt you would notice the difference. The noise and vibration might be a little lower, but you can also achieve that by using better stepper motor drivers that support higher microstepping.

Using 0.9deg motors on the extruders is in principle worthwhile, because high extruder resolution and linearity contributes to print quality. However, 0.9deg motors generally provide less torque than similar 1.8deg motors. So if you are using a pancake or other low torque motor, you may have insufficient torque if you switch to a 0.9deg motor of similar size.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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