Duet Wifi and nimble acceleration issue
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I did away with all the settings and interaction problems by going to Portescap P430 258 005 01 3.6 degree ultra low rotor inertia disc permanet magnet steppers for my Nimble extruders. I'll never go back to conventional steppers with a high ratio extruder after using them, they are like a sports car vs a Yugo for starting, stopping, and reversing direction in comparison to the suggested Nema 17 pancake and Nema 14. Expensive new, but they can occasionally be found used at a decent cost.
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@Alexander-Mundy said in Duet Wifi and nimble acceleration issue:
I did away with all the settings and interaction problems by going to Portescap P430 258 005 01 3.6 degree ultra low rotor inertia disc permanet magnet steppers for my Nimble extruders. I'll never go back to conventional steppers with a high ratio extruder after using them, they are like a sports car vs a Yugo for starting, stopping, and reversing direction in comparison to the suggested Nema 17 pancake and Nema 14. Expensive new, but they can occasionally be found used at a decent cost.
Where did you get yours? I cannot (so far) find a vendor in the US.
Thanks.
Frederick
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Used on ebay
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@Alexander-Mundy said in Duet Wifi and nimble acceleration issue:
Used on ebay
It seems that there are currently none there.
Too bad, I would like to try one.
Frederick
Printers: A FT-5 with the 713 upgrade bits, a custom MarkForged style, a small Utilmaker style, a small CoreXY from kit and a E3D MS/TC setup. Various hotends. Using Duets (2 and 3) running 3.4.6
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Just wanted to thank you all very much for input and sharing, don't want to be ungrateful. I had some success with 120 E acceleration and 0.03 PA. On a side not my prints look a little different since moving from direct to nimble, walls have weird "pattern". I need to test more to eliminate speed factor. Also ill be looking to get that portescap stepper it seems to be a way to go. Again Thank You!
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@svalsorim said in Duet Wifi and nimble acceleration issue:
On a side not my prints look a little different since moving from direct to nimble, walls have weird "pattern". I need to test more to eliminate speed factor.
The patterns are command and a known issue in V2 extruders. They are apparently caused by 2nd order resonance in the helical gears. (Us old farts would remember the diff howl typical in pre 70's cars)
You'll need to go to the discord channel and register to have the gears replaced when a fix is available.
My experience was that no amount of tuning would get rid of it completely.
Also be aware that the breech will soften if exposed to much heat. They advertise 60 degrees.
In my case, printing ABS generated enough ambient heat (unheated enclosure) to make the breech soften and cause under extrusion.
I like the design philosophy, so when they can sort the gears I might get it out of the draw again, but I was unable to realize the benefits that the design promised.
And I'd have to make a breech to work reliably at ABS temps.
Others seem to love them, so perhaps it comes down to the sum of the manufacturing tolerances in the particular unit you get. -
@OwenD said in Duet Wifi and nimble acceleration issue:
They are apparently caused by 2nd order resonance in the helical gears.
Why wouldn't a speed change allow avoiding the resonance?
Thanks.
Frederick
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@fcwilt 4 times what I paid but still way cheaper than retail:
https://www.ebay.com/itm/192599739125
If you look at the pics it is the same part#. In fact mine came with the "theta assembly" label pigtail also. Escap is Portescap's old name.
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The patterns were also a sometimes symptom with V1. Mine were some of the first sold and 1 printed flawless and 1 had the repeating pattern. Turned out to be the shaft undersized on the hob which Zesty replaced. Some of the original flex shafts had a defect and Zesty sent everyone new replacements. Same with the bodies. I give them kudos for customer service. Later 1 of them started the patterns and it was a worm bearing going bad. I replaced all bearings with ceramic ones and no problems since. I certainly wish I would have bought additional V1's while they were available. Too bad they have had the technical problems, when working properly (and IMO with the portscap stepper no need to go to V2 with 20:1 as I have tested retraction all the way up to 100 mm/s without skipping) they are top notch.
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@Alexander-Mundy said in Duet Wifi and nimble acceleration issue:
@fcwilt 4 times what I paid but still way cheaper than retail:
https://www.ebay.com/itm/192599739125
If you look at the pics it is the same part#. In fact mine came with the "theta assembly" label pigtail also. Escap is Portescap's old name.
Thanks much.
Frederick
