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

RE:

If your running higher currents then you should fit heatsinks to the board, this is better with a new control board case with more room. 

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

Hi everyone, I am very interested in this topic and I am wondering 2 things:

A) why not apply a gearbox to the X & Y motors (with something similar in the picture) so that they run faster and, theoretically, canceling or masking the VFA.

B) why not replace the belts with lead screws?

Thank's for your replay.

RE:

Well, you certainly could build a reduction set or adapt leadscrews. This would likely interfere with the sensorless homing of a MK3.  The leadscrews give a large reduction advantage without messing with the bulk and belt tension sues of belts.  Perhaps some kind of planetary gearset could also be used?

A simpler way to accomplish this would just buy a Snapmaker which uses lead screws on all axis.  It seems like an expensive purchase but would probably end up cheaper and better than adapting a MK3 to leadscrews especially if you consider the time saved. 

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

Hi, long time no see 🙂 I finally found the time to finish the Taurus MK3 (no S/+) LGX + now with Mosquito Magnum and added the recommended changes from Gabe to the variant file on github. Everything went smoothly, homeing works so I am really happy! Thanks once again Gabe Guy and HBPrint, hope this will be the start of further usefull updates 😉

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

Very happy that it went well for you! Hope you have many an amazing print!

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

Thank you for this post!!!  If I don't go with Prorify3d, then I'll follow your advice on just the extruder motor with the 1.8 moons.

Thank you!!

RE:

@HBPrint

Glad to see this is still moving along!
I had updated KUO's 0.9 Moons firmware to 3.10 last year, and have been using it on a Skelestruder/MK3s variant with virtually no problems on single color prints (fails to calibrate the z-axis). When using the mmu, I can't get the steps low enough for fast retractions, but the print quality is great. Here's a link if you want to compare notes.

https://github.com/bartrv/prusa.9

The prints in the photo are using a .25 nozzle at a .07 layer height, no supports, Moons 0.9 motors on x/y/e

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

Hey guys, great thread!

I have a heavily modified Ultimaker Original, tuned enough that VFAs are quite noticeable.

I switched to 0.9* steppers quite a while ago, but they seem to have quite a bit of VFA ( https://www.omc-stepperonline.com/nema-17-bipolar-0-9deg-46ncm-65-1oz-in-2a-2-9v-42x42x48mm-4-wires-17hm19-2004s).

The early part of this thread seems to lean towards certain 0.9* steppers, but later in the thread I am seeing more 1.8* motors listed. Is this just because people do not want to recompile firmware, or are these better 1.8's on par with 0.9's? Without any firmware constraints, what is the current best value motor?

Does anyone know what part number Prusa is using on the new MK4?

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

I should have also mentioned that I am running a Duet Maestro controller with TMC2224 drivers.

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

Crickets in here!

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

Posted by: @hbprint

Github link for Custom v3.11.0 firmware

https://github.com/Clixster/Prusa-Firmware/tree/MK3_3.11.0_CLX

Thanks - I acquired a second hand MK3S with the MMU, BondTech extruder upgrade, 0.9 degree steppers across the board and a Slice thermistor. The printer came with the 3.8.1 Kuo firmware, but as a n00b, I heeded the firmware upgrade prompt and "upgraded" to stock Prusa firmware. This didn't work too well :).

The previous owner pointed me to this thread, and your branch saved my proverbial bacon.

As an aside, I also got a second MK3S with a bear frame and all the other upgrades (sans MMU). It occasionally resets during printing, and I wonder if there are any known crash bugs in the (Kuo) 3.8.1 firmware?

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

Posted by: @sigurdur-asgeirsson

The previous owner pointed me to this thread, and your branch saved my proverbial bacon.

I'm now struggling with the calibration of the thing. Initially, it was failing on the X axis length, detecting it as 248.75mm rather than 250mm. This was because there's interference at the far end between the wire loom from the extruder and the frame. Since I have custom firmware, I just reduced the limit to 248.5mm and moved on.

Now I'm having trouble with the XYZ axis calibration. It looks like the printer is hunting for the first calibration point in the wrong spot - slightly to the left of the first point. I've looked at the code, and it seems the firmware expects the points to be proximate to specific locations from the X/Y homing, so I don't understand how this could be off on this printer.

RE:

It looks like my problem is at the right end of the X-axis, with interference between the extruder and the ball screw support. I assume this is not the normal homing position of this printer?

RE:

If you look at the typical torque curve for a properly sized 0.9 degree motor, you'll see that maximum torque occurs at 150 rpm. If you don't have gears, your RPMs will be very low and the torque will drop dramatically, so to speak.

Oh I found a post on steppermotor where I did some work on stepper motors and torque etc, this was for a Nema17 stepper motor but might give you some clues as to what to check in your case.

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

Can someone tell me how the wiring should go on the LDO 42sth40-1684mac?

Mine go G Bl Bk R to R Bl G Bk and I'm pretty sure that's not correct.

Is this diagram correct?

https://caribou3d.com/img/cms/Motors/LDO40.webp

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

Is this a modification Prusa users are still doing? Seems really neat, especially after looking at the VFA my MK3s+ makes. 

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

Hello to all,

I was reading this topic really carefully, but despite that I was lost a lot of times. So I would like instead of searching and scratching my head ask a question.

To order Moons stepper motors, here in EU is really expensive. First one motor costs more than 100€ and than additional customs, shipping etc.

But I have home 2 LDO motors 42STH48-168MAC. In that topic was discussion about LDO but for smaller one 42STH40-168MAC. 

I would like to ask if bigger one will also work or not?

If not, there is also option to buy new ones from NanoTec ST4209M1206-A.

Some of specs:

Phase | 2

Step Angle | 0.9°

Shaft | Single

Frame Size | NEMA17(42mm)

Length | mm | 39.5 

Rated Current | A | 0.85

Voltage | VDC | 5.61

Holding Torque | Nm | 0.35

Resistance per winding | Ohm | 3.3

Inductance per winding | mH | 16

Coil Type | Bi-Polar

Detent Torque | mNm | 12

Rotor Inertia | gcm² | 54

Weight | kg | 0.28

Thank you in advance for your answers.

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

Oh my!!!...I want to give a huge thank you to guy.k2 and spacemarine for testing! You guys rock! Steppermotor propose une riche série de produits et chaque moteur possède ses propres avantages et caractéristiques uniques, qui peuvent répondre aux besoins de différents clients et de différentes applications.

RE:

Posted by: @hbprint

I will post my fork as well, which I arrived at via a different path, and at this time only provide the MK3S/MK3S+ variant file.

Original Source(s):  After running Guy's v3.8.1 firmware for a while, I wanted to update to V3.11.0 for Super PINDA support. I merged all of Guy's updates commented with 'KUO' across seven files from his v3.8.1 fork, into Prusa's official 3.11.0 release.

Guykuo - https://github.com/guykuo/Prusa-Firmware/tree/0.9-Degree-Stepper-Support

Prusa - https://github.com/prusa3d/Prusa-Firmware/tree/MK3_3.11.0

Updates/Additions: I added a few new variables to Configuration_prusa.h (Comment with CLX) for motor tuning and to support Bear X-Axis heights (passes calibration)

• 0.9 stepper type (Moons or OMC). I did this because testing showed a small variance in ideal feed rate, for Moons vs OMC.
• Trinamic QSH4218-51-049, if uncommented instead of Moons/OMC, will use all default parameters for 3.11.0, except increase current as suggested by Vojtěch. I have these running on an otherwise stock MK3S, however still having occasional Y-Axis crashes. More tuning maybe in order here.
• Option for 'Bear X-Axis' which sets Z_Max_Hop to 202, which passes calibration with a BMG extruder on Bear Frame/X-Axis.

I had looked at and tested the BMG releases, before deciding to do a full update based on Guy's earlier work. What differs from BMGs release beside sub-versions;

• Support for Skelestruder (Merged, not tested - lacking HW))
• E3D Volcano Hotend (Merged, not tested - lacking HW)
• Extruder loading and unloading process
• Guy's separation of XY settings into separate X and Y setting,
• Guy's extra M-Codes for trouble shooting and tuning (M919-M222) (Enabled in this Fork)
• Guy's TMC2130 Updates for 0.9 degree optimization
• Guy's options for Slice Magnum tuning with Prusa MMU

Github link for Custom v3.11.0 firmware

https://github.com/Clixster/Prusa-Firmware/tree/MK3_3.11.0_CLX

Github link includes a simple readme, with link to Guykuo's original v3.8.1 fork for installation and configuration details. Be sure to run a PID tune after installation, as included values Slice HT thermistor at 255 degrees.

Validation/QA Systems:

• Machine #1: MK3S+ full Bear frame, Bear X-Axis with BTMM-HT extruder, Misumi rods and bearings, 9mm Y-Axis belt, OMC X&Y Steppers, Linearity Correction @+1.130 and Einsy Heatsinks
• Machine #2: MK3S+ stock frame, Trinamic QSH4218-51-10-049 steppers on X&Y & BTM extruder, Einsy Heatsinks (Getting occasional Y-Axis crash, may need more tuning)

Given this code, includes updates for hardware that I do not have, a portion of this fork is not yet validated. I will make an effort to post any updates or minor changes needed, should need arise and receive notification.

Hello,

I want to ask for help. @hbprint

Is there any chance of updating the original firmware 3.14.1 with all the improvements?

I would do it on my own, but I don't know which file I need to update and I am afraid that I will miss something.

TNX