Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)  

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Active Member

Can someone please point me to the latest firmware repo please?  I know Guy has been been occupied with bigger things.

I'm still on 3.8.ish

If you are looking for 0.9 degree X/Y support on a 3.9 branch, this is your best bet right now from what I can tell:

Posted : 12/10/2020 10:02 pm
Albe liked
Active Member

Hi Everyone,

Looking this forum posting inspired me to go mad. Like MAD MAX ROAD WARRIOR MAD, Mad like with Moons MS17HA2P4150 on X and E, and MS17HA6P4150 on Y. I know that max current is 1.5A and Einsty can deliver 1.4 RMS, i'll take the bit on the loss of .1 Amps in performance. Thermal issues, lots and lots of current = lots and lots of heat. Over the driver vias on the back I have large heat sinks and I am going to be running a fan too until I figure out liquid / thermal electric cooling the board with controller. Also, I probably going to trying to put external copper heat blocks on the outside of motors with coolant flowing through the copper to chill the motors.

Looking through the github for the EinstyRambo, the sense resistors are .22 ohm , I noticed in Guy's AMAZING CODE, that he has the base value to .2 in tmc2130.cpp then in cur calc the divider value picks up the hundredths precision. Three questions; in NON stealth mode (dont care about noise) if in configuration_prusa the scaler value is set to 63, then the drivers would be supplying close to 1.4 amp RMS - correct? Second question, for crazy idiots like me, Guy dropped the hundredth precision on the initial variability for the sense to "slightly" protect the board - is this assumption correct? Third off the rail question, how does the regulation, PSSR, and DC noise from the power supply affect the TMC and their ability to build an analog wave with low noise? I know there is a bunch of by pass caps through out the board, but I am building a DC to DC power supply for a DAC, and the DC ripple noise requirements are crazy. Given that the TMC are building not the same but similar wave functions, I thought there might be a correlation. 

Also, I am changing the PWM pins for the bed heater and nozzle to external PWM controlled MOSFET for reduce massive current flows through the board. I will update if I get successful completed. 

Latest, thank you to Guy for developing the code. Thank you to everyone that has posted on this thread - absolutely amazing. Looking forward to heard back from everyone.


Posted : 20/10/2020 6:52 am
Dan Rogers
Honorable Member


This is good stuff - Hoping that drop-in = change out, plug in to same place as original.  Couple of questions - which stepper motors to upgrade?  The MS17HD2P4100 shows up as a Prusa Extruder stepper (amazon) .  So more of a how many of these to buy and which ones to target - plus is there any slicer settings I need to make to adjust for these "drop in" replacements?

Posted : 01/12/2020 6:23 pm
New Member

For what it is worth I purchased some Moon's 0.9 steppers off Amazon after reading this thread and have observed... no change at all in "VFA's" after installing the motors. Certainly not results like in OP's photos, but in fact no change at all under a magnifier / various lighting, etc. Evenly spaced vertical lines still appear e.g. across all faces of the XYZ cube, etc., identical in comparison to the 1.8 (stock) steppers I replaced with these.

I am running an Ender 3, these are the steppers I swapped in for the stock (1.8 degree) steppers:

These steppers were also noisy enough I ultimately had to put the stock ones back on (as the printer runs near my working desk here at home). Tried various / stealthchop / microsteps / adjusting the amperage (easy to change using TMC2209's + Klipper), etc., but they just seem to have a baseline level of ... whiny noise I couldn't get rid of. Printer sounded like it did with the stock Creality control board in it, despite running an SKR Mini E3 V2.0 (on which the stock motors are dead silent).

These are *not* the exact same model steppers as mentioned earlier in this thread by OP: I specifically sought out "1.5 Amp" steppers as I believed the Ender 3 required this more-or-less as the Creality motors are ... widely reported to be 1.5 Amp. I think now this is probably an error on my part, yadda yadda, but wonder if it makes any difference in terms of noise level?

Both steppers are also quite a bit larger / heavier than the stock Ender 3 steppers- the Y-Axis rather comically so, as I had to modify the bed plate to accommodate it. The X-Axis too a little wrangling so it wouldn't bump the endstop but no big deal - it does drop my X gantry a right bit quicker than stock though ;).

What I liked about the arrangement is the motors ran much cooler than stock while providing more-or-less the same overall performance - no layer shifts, etc. I had them set to 0.725 amps in Klipper / TMC2209 UART config, FWIW. This is the same amperage rating I was running with the stock motors (I don't believe the SKR board / electronics will push much more juice than this, could be wrong I guess) - the stock motors used to run pretty hot this way.

In case it is not obvious, I am somewhat new to the hobby and not opposed to trying out random parts to swap in / out of my printer.

I may even grab a couple of the original motors mentioned by OP - MS17HA2P4100 - and see how these fare in my rig.

Just my 2 cents in case it may be useful to someone stumbling upon this old(er) thread.







Posted : 11/03/2021 9:24 pm
g monkey
Trusted Member

I have put a set of the Trinamic QSH4218-51-10-049 on my X and Y axis, along with some toothed idlers.  They are drop in replacements so no firmware changes are required.  The print quality may have improved, but they are certainly very quiet - completely silent in stealth mode. 

Posted : 11/05/2021 2:29 pm
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