Best Choice of Motor for a Delta Printer
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After a lot of trial and errors, I have finally convinced myself that 0.9 deg/step, Stealthchop and High Speed are mutually excluding concepts....I would like to ask for your advice about the best 1.8º deg/step motors that I can use on my Predator Delta. I am using Duet3 Mini5+ so they are going to be driven by TMC2209 (max 2 A) and a 24V PSU.
I am trying to decide between:
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OMC 17HS19-1684S1
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LDO-42STH48-2504AC
The latter may seem overkill with its rated current of 2.5 A, but the figures I obtain in the EMF Calculator seem better than the OMC ones.
What do you think?
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@ignacmc I' argue that StealthChop and high speed are mutually exclusive. No matter 1.8 or 0.9deg steppers.
I've had Wantai 0.9° steppers and now Moon's 0.9° steppers in my frankensteined Predator. I would recommend the Wantai as they're way more silent, have less inductance, rotor inertia and cost about 1/3rd or less. Next time I tear apart my towers I'll revert to the Wantai and use the Moon's for another project.
I'd highly recommend 0.9 steppers over 1.8 steppers on a Delta.
As you don't seem to care too much about precision as you do for noise I'd also say add 3 stepper dampers and you'll have a virtually silent printer (depending on fans and the rails used).
Not sure what your speed target is but I can do a 10 minute speed benchy just fine on my 0.9° moon's and a ~23 minute benchy that actually looks quality without flaws.
I usually print at 500mm/s travel, 8k accel and 200/400 (perimeter/infill) just fine. 500@10k is about the limit though on the outer edges of the bed. Anything near the center of the bed can probably do twice the quoted values.
You can always try to feed less current to your motors to make them more quiet which also helps back EMF.
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@bberger Could you please give me the reference number of the Wantai and Moons you are using?
Also, using 1.8 deg steppers should allow for higher speeds…Is there a noticeable difference in print quality between using 0.9 and 1.8? I do care about quality, but i have tried 0.9 LDO and OMC, and something does not seem right (even in Spreadcycle) comparing them to the stock Anycubic motors
Dampers were useful with good old A4988 but should not be needed with modern TMC. They also introduce some degree of imprecision since the motor is allowed to “sway” a little no?
Vorons are built for speed without compromising quality and usually have 1.8 deg motors…
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Wantai 42BYGHM810
Moon's MS17HA6P4200You'll want to get as much mechanical precision as you can get from a delta. It's a completely different kinematic than a cartesian/corexy and errors/inaccuracies in the motion system get multiplied across the cartesian plane.
If you're still slinging around that massive aluminium effector with massive carriages rolling on non-flat and potentially bumpy extrusions you'll be much better off with improving there compared to new motors. Deltas (actually almost all printers) work best when they don't have sling around massive chunks of weight.
As for your problems: what exactly are you experiencing problems with? Could it be that you overtightened the belts when re-assembling? Maybe your carriages aren't properly tight or too tight after reassembly. Maybe a pulley got loose. Or maybe you just chose a motor that's too weak throwing around the ginormous weight of the stock effector and carriages (in that case 1.8deg motors with more oomph might actually help, but then you could just reinstall the stock motors) and improve in other areas for the same budget with better results. Even the dirt cheapest linear rails you get from china are potentially and exponentially bigger improvement than new motors.
And for the Voron reference: they aren't. They're built to be enclosed for ABS printing first and to be stylish second. They sling around too much unnecessary weight and plastic for them to be speed monsters. (they are interesting machines though!) Have a look at VzBot, Hevort for coreXY woth speed in mind. Or at the Annex printers if we're talking quadrep kinematics.
//Edit: just saw in your signature that you're using the smart effector already, so that's down a ton of weight. Please explain your issues so we (or at least I) can do a better job at helping
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@bberger
Well, I felt in love with delta kinematics 10 years ago with a Rostock Max v2 ( man, that was expensive and noisy) then I had a Kossel and now a Predator.I dont like the magballs way so I am using MPJET very tight ball joints and a smarteffector over a pc printed effector. I am pretty confident there is no backlash there.. I am using an Orbiter Direct Extruder.
After an odissey here in Spain I managed to buy some very genuine HIWIN linear rails that I have installed recently.
Still the motors dont run smooth specially on the X tower which I believe I overtightened and damaged the bearings. I was using stealthchop on the Marlin Kossel, but I realise this is never going to be the case in the Predator.
I can’t recall how much money I invested on the Predator and Kossel but i still want to have a Delta which performs.
I am ready to give 0.9 deg steppers one more chance if you tell me this is still worthy.
Can I abuse of your kindness to ask you to share your config.g and your slicer configuration with me?
Best Regards
Ignacio
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@ignacmc haha, looks like a similar love story to delta kinematics like mine.
Btw. I'm running an Orbiter direct drive extruder too, but on magballs and an 80mm rod spacing adapter.. Was experimenting a LOT lately and also thought about trying out the MPJet as I'm slowly collecting enough parts to build a second delta from all my experimentation iver the past 2 years..
I don't have my RRF config anymore as I switched to another FW recently for experimentation's sake but I think I have most values still memorized - so ask away if you want to know specifics.
I do have to say that I am on 20T pulleys as I didn't get any toothed 16T idlers with bearings back then - so that's potentially a 25% load and speed difference. I suspect that with 16T pulleys my speeds would be more limited as I'm not sure the need for 25% higher revs could be offset by lowering the current enough to compensate for back-EMF.. I suspect that the Wantai would be fine and possibly also the smaller Moon's (P4100/P4150 opposed to the P4200) but I'm also pretty sure I'd have to sacrifice top speed with the P4200.
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@bberger I have a predator with a flying orbiter and remote cooling, linear rails, Kevlar belts, with moons p4200 0.9° and duet2.
I’ve bought them without knowing anything about back emf or knowing about the stepper calculator tool.
They are about 1.5 years in use.I was trying to fight VFA’s and while they got slightly better they are still there.
So my reliable travel speeds are max 350mm/s if I go higher I risk layer shifts if the nozzle bumps slightly in to the print. Still fighting with ringing if I go higher then 600mm/s on jerk.
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@bberger Looking at the Wantai and Moons datasheet and introducing their values in the EMF Calculator, the Wantai seems a better choice with much lower inductance (1.8 vs 4 mH) which results in lower Back EMF. Also the speed at which torque starts to drop is also much higher on the Wantai (277 vs 150 mm/s). I do have some LDO 42STH48-1684MAC at hand whose performance seems in the middle between Wantai and Moons (1.65 Ohm / 2.8 mH)...should I use them or ordering the Wantai will worth the money and time?
Predator with Duet3 Mini 5+, Smarteffector v4 and LGX Lite Extruder
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LDO-42STH48-2504AC. Swap duet board with a mellow super 8 on rrf and 48v stepper drivers.
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@ignacmc said in Best Choice of Motor for a Delta Printer:
... I do have some LDO 42STH48-1684MAC at hand whose performance seems in the middle between Wantai and Moons (1.65 Ohm / 2.8 mH)...should I use them or ordering the Wantai will worth the money and time?
Keep the LDO. Should be good enough.
What exactly is the problem you're experiencing though? Noise? Layer shifts? Artefacts?
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@bberger Originally I had the LDO42STH48-1684MAC installed, but they were impossible to put in StealthChop mode, giving very loud noise and layer shifts. In Spreadcycle they behaved much better but still found them noisy, although print quality was acceptable. Then I changed to OMC 17HM19-2004S1 and everything get worse specially during high speed movements. Stealthchop which was always used in my Marlin powered Kossel seems out of place in Duet.
So I don't know if going back to 1.8 steppers (LDO-42STH48-2504AC perhaps?) should make life easier for me and not have a noticeable impact on quality (as some people in other forums say) or remain at all costs with 0,9 steppers like you say that would have to be my current LDO42STH48-1684MAC or bite the bullet and purchasing some Wantai 42BYGHM810.
I know it is crazy to think about changing motors for the 3rd time, but I am really a perfectionist regarding motors performance.... Poor myself !
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@ignacmc just disable stealthchop and make sure you have enabled interpolation.
Would you mind maybe recording a small video clip of those noises? It would help us judge if that's something to be expected or if it's out of the ordinary.
If you're travelling from one edge of the bed to the other edge of the bed with 300+ mm/s then sure, they'll whine. But they should be near silent on anything in a radius of ~10cm in the middle of the bed and practically dead silent near the center.
What really (really) helps the noise on the Predator are stepper dampers. Especially of you have rigidly mounted rails. And to be honest I didn't really notice a difference in quality then I removed them some weeks ago, but that was before I was able to go for crazy accelerations and speed thanks to Input Shaping.
What also contributed to a LOT of nasty noise was the top electronics panel. Make sure you've got that strapped down snuggly without overtightening it. That thing has a tendency to rattle.
Also, should you happen to have an enclosure (maybe the famous one from CarstenD) - that's a bad (BAD) idea for noise. Those curved panels at 120deg angle are basically reflectors throwing sound waves from all directions to the middle of the chamber where they basically "explode").
Maybe the noise alternatively comes from bad bearings at the idlers or the belt rubbing against something? Millions of possible reasons and I still doubt the motors are the main contributor.
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@bberger Sorry for not answering earlier. Yes, I have accepted to never try to use Stealthchop again.
I have ordered the third set of motors for this machine. First LDO, then OMC and now the Wantai you suggested me, that seem to be the best in the category according to the results obtained in the EMF Calculator. Hope I will give the older motors good use in another project.
I will report my findings when I install the Wantai in the next weeks.
I am opposed to use the dampers with TMC drivers. They were needed in the old times (A4988) but now I think they are obsolete and they introduce a elastic joint which can lead to lack of precision. The noise came from motors and does not seem to resonate in the frame.
I plan to build an enclosure in the near future but I am designing one of my own that can be easily attached via magnets and removed when not needed or for doing maintenance.
I will have a look again at pulleys for sure.
Thank you for your help. I will keep posting here when I have updates to share
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@ignacmc don't forget to share you enclosure please
Still trying to get away from the parabolic resonance hell the CarstenD enclosure gives me (it also is too narrow for my cooling solution).I know Chris W. in the Advanced Predator group has designed a flat enclosure with more spacing from the same panel sizes that Carsten used, but haven't gotten around to print the parts yet..
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@bberger My idea is something like this:
I can send you the Fusion360 files if you want. I intend to place some steel tape on the towers and some embedded magnets or magnetic tape on the enclosure panels
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@ignacmc I'd happily take the F360 files
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@bberger Here you have them...still a work in progress, but can be printed so far...I tried to avoid all collissions with bolt heads and so on. You have on FRONTAL part and TWO sides...If you develop them further, please share
Change extension from STL to F3D
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@bberger said in Best Choice of Motor for a Delta Printer:
Wantai 42BYGHM810
I use the Wantai 42BYGHM810 on my delta. I don't use dampers and the motors are basically silent. I have gone through 3 different sets of dampers and after chasing every other mechanical issue I could and tuning the drivers, they very much were unnecessary and only added to ghosting. Whatever your choice if you don't have a pillow block (most printers don't) then I highly recommend putting a roller bearing between the pulley and the motor case (my current preference is the needle bearings). You have to measure the space available and account for possibly adding some washers to keep your pulley centered. What this does it reduce the tension on the motor shaft, the tension on the pulley instead is applied to the thrust bearing and motor to the motor case saving your internal motor bearings. Before I started doing this my previous motors needed replacement every 2-3 years because of bearing issues on my deltas, and I feel like it helps on ghosting and tension too (that's just an added bonus so wasn't worth testing for me).
uxcell TC512 Thrust Needle Roller Bearings with Washers 5/16" Bore 3/4" OD 5/64" Width 5pcs
https://www.amazon.com/gp/product/B07VZXWSG6/uxcell F5-10M Thrust Ball Bearings 5mm x 10mm x 4mm Chrome Steel Single Direction 4pcs
https://www.amazon.com/gp/product/B07QKKYKR8/ -
@lord-binky I am afraid there is not enough space to fit a Bearing here....
Predator with Duet3 Mini 5+, Smarteffector v4 and LGX Lite Extruder
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@ignacmc the needle bearings suggested here are super thin though.
But yes, with the suggested tension of Gates for their belts in linear positioning applications we're at the upper end of what Nema 17 bearings usually are rated for. On my Moon's it just barely within "extended" spec (they're in the rated "can be up to this load, but expect reduced bearing life).
Haven't looked up the Wantai specs though. I don't think that they'll be a problem in our application. At least not for the lifetime of the printer unless it's maybe running 24/7 in a farm.
The thing with pillow blocks / bracings is: they need to be accurate or they will introduce crooked sideload themselves on the motor bearings.
Has anyone been able to find the Wantai with a D-Shaft and connectors? That's the primary reason why I have been to lazy to switch back to them.. I know they exist as they can be ordered to spec that way, but haven't seen any retailer carrying them
