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

Do you have a list of the specific changes vs stock somewhere? If stock works for me I'd like to know what changing firmware could offer me.

Y homing works fine, and I'm not running in silent mode as I find power mode to not even be that noisy.

What are the risks/problems I might encounter from sticking with stock, assuming I have set my e-steps, ustep rate and added heatsinks to the drivers?

 

 

 

Posted : 18/07/2019 4:23 pm
Bunny Science
(@bunny-science)
Noble Member
Topic starter answered:
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

Do you have a list of the specific changes vs stock somewhere

No. Extremely low on my list of things to do. Lots of changes scattered. Easiest thing to find all the changes is to search agains "kuo" in the firmware (all tabs).

 

Posted : 18/07/2019 4:50 pm
vintagepc
(@vintagepc)
Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

No offense but I think I'll stick with stock then unless I have issues. I can see the specific code changes but it's hard to tell from a high level what each one does/affects, so without that I'm going to subscribe to the "if it ain't broke" school of thought. 

Posted : 18/07/2019 5:08 pm
Ben's 3D Prints
(@bens-3d-prints)
Eminent Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

Are there limitations (Speed, Acceleration etc.) for using Stealth mode?

Yesterday I tried stealth mode and already got a massive layer shift after the third layer. Those don't happen in spreadcycle (normal) mode.

Posted : 19/07/2019 11:01 am
Bunny Science
(@bunny-science)
Noble Member
Topic starter answered:
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

In my experience with the 0.9 motors, a layer shift issue that shows up in Stealth but not spread cycle strongly suggests a friction issue on that axis. You have less available torque with 0.9's, but with well moving bearings, you should not need to worry about special speed limitations - at least I don't.

I strongly recommend testing axes with the belt completely removed so you can feel the smallest of catches. Sometimes, it's just a bit too much torque on a bearing mount that is causing an issue.

This post was modified 5 years ago by Bunny Science
Posted : 19/07/2019 3:10 pm
Ben's 3D Prints
(@bens-3d-prints)
Eminent Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

I recently regreased all my bearings whilst installing the new Bear X axis. During the installation of the Y axis I very much looked for any resistance before tightening every bolt.  

But the thing is, the layer shift happened on the x axis. It was also no minor layer shift more like a shift of 5 cm. Those large shifts I see only when the grub screw isn't tight, or in my case the thread was damaged and it felt tight but wasn't. I replaced them all and those shifts would also occur in spread cycle (which they did) but the print result with spread cycle is spot on and never looked so good thanks to your "0.9 firmware".
 
As I can tell the extruder moves very smooth without any sudden resistance (belts off). The idler of the x axis moves also very smooth as it is not bolted like on the stock Prusa axis but spins freely on a iron pin. 

I thought about limitations of stealth because there is the possibility to set different machine limit settings in Slic3r.  I increased the feedrate for x and y to 120 mm/s because this is my PLA infill speed. Those were set to 100 mm/s by Prusa. Maybe that was too much? I'll try again with 100 mm/s and see if that helps. 

Posted : 19/07/2019 4:48 pm
Bunny Science
(@bunny-science)
Noble Member
Topic starter answered:
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

I think it would also be worth backing off the bear x-cover screws about 1/8 turn. That can be critical especially if one has a stiffer plastic or slightly high extrusion multiplier when printing the x-carriage. 

I use Prusa movement speeds or a bit slower in my profiles. I'd pay attention to the non-print move speed as well.

This post was modified 5 years ago by Bunny Science
Posted : 19/07/2019 5:00 pm
Eric Mathison
(@eric-mathison)
Active Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

After installing Moons 0.9 motors on the X & Y axis, along with flashing new firmware, my layer height is 2x normal. 0.2mm layers are measuring 0.4mm~. I'm not sure why. Here's my hardware & settings:

Extruder: Bondtech BMG with 1.8 pancake
X & Y Axis: MS17HA2P4100 0.9 steppers

M92 X100.00 Y100.00 Z400.00 E415.00
M350 X8 Y8 Z16 E16

#define X_AXIS_MOTOR_09 //kuo exper X axis
#define Y_AXIS_MOTOR_09 //kuo exper Y axis
//#define Z_AXIS_MOTOR_09 //kuo exper Z axis
//#define E_AXIS_MOTOR_09 //kuo exper EXTRUDER

#define BMG_EXTRUDER //Kuo Uncomment for BMG 3:1 extruder. This also sets BMG height for you.

Any ideas?

https://ericmathison.com/blog
Posted : 19/07/2019 5:44 pm
d_ave
(@d_ave)
New Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

I managed to fix the issues i was having (crashes on Y axis) by changing the belt, the holder under the Y carriage and the pulleys. Printer is back online and printing without any issues. however sometimes when it homes the X motor keeps pulling the carriage to the left and start skipping steps until the printer restarts. it basically hits the left end once, than moves a bit to the right, hits the left side again but the motor keeps spinning and starts skipping. i tried different belt tension but it seems that this doesn't affect the issue. what might be causing this? 

Posted : 19/07/2019 6:35 pm
Bunny Science
(@bunny-science)
Noble Member
Topic starter answered:
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

Your values look correct to me. That is weird behavior.

Every time we see weird behavior, the solution seems to need a full factory reset with data clear.

Then reissue the commands and redo printer setup.

M350 E16

M92 E415

M900 K0.15

M500

After that do a power off/on  and issue M503 to verify values were stored.

Hopefully, that will get things working normally again. 

 

Posted : 19/07/2019 6:43 pm
vintagepc
(@vintagepc)
Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

OK, with stock and an OMC stepper on Y I'm getting a step skip when the bed does the fast travel from the purge line to the start of the print; I'm assuming this is because of insufficient motor current, and if so, I suspect M907 is my friend. 

I'll tinker and see; otherwise I may indeed have to try Guy's FW... 

Posted : 20/07/2019 1:38 pm
vintagepc
(@vintagepc)
Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

PSA: Prusa's Marlin does not support M350 for anything but the extruder.

 

case 350: //! M350 - Set microstepping mode. Warning: Steps per unit remains unchanged. S code sets stepping mode for all drivers.
{
#ifdef TMC2130
if(code_seen('E'))
{
uint16_t res_new = code_value();
if ((res_new == 8) || (res_new == 16) || (res_new == 32) || (res_new == 64) || (res_new == 128))
{
st_synchronize();
uint8_t axis = E_AXIS;
uint16_t res = tmc2130_get_res(axis);
tmc2130_set_res(axis, res_new);
cs.axis_ustep_resolution[axis] = res_new;
if (res_new > res)
{
uint16_t fac = (res_new / res);
cs.axis_steps_per_unit[axis] *= fac;
position[E_AXIS] *= fac;
}
else
{
uint16_t fac = (res / res_new);
cs.axis_steps_per_unit[axis] /= fac;
position[E_AXIS] /= fac;
}
}
}

So no, it would appear stock cannot be used with 0.9 degree motors (yet).

Posted : 20/07/2019 1:49 pm
vintagepc
(@vintagepc)
Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

So this is interesting. I'm running Guy's firmware now and no more skips/issues there. 

My X now looks perfect, but I don't see any improvement in Y. (Calicat/small cube are "before", waveform correction tower is "after" install of new motors. Calicat was facing forward). I'm also seeing zero difference up the waveform correction tower, which is interesting as well. It's the same gcode I was using for 1.8 degreemotors and for those earlier prints I did see them change slightly.

Thoughts? Did I get a bum motor? Didn't feel like it was "notchy" when I spot checked it before install.

Posted : 20/07/2019 6:10 pm
--
 --
(@)
Illustrious Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

I never saw ANY effect running the tests on Y ... I did get a really weird offset, very consistent and repeatable, but no change in patterns. But then I think my Y motor is unusually 'clean' in this regard.

This post was modified 5 years ago by --
Posted : 20/07/2019 8:31 pm
vintagepc
(@vintagepc)
Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

Interesting. I wonder if I should swap my X and Y motors and see if the issue I'm seeing also moves. I'll do that after my current (4h) print finishes.

Posted : 20/07/2019 8:40 pm
Albe
 Albe
(@albe)
Eminent Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

I don't know if it is just me - the latest firmware (today) doesn't display some values. 

Quick test - do autohome and then check Z height on the home screen - displays " Z ?". Moving the axis up and down doesn't change it.

Checked with 0.9 and La1.5 and 0.9 versions.  Standard Prusa firmware 3.7.2 shows it correctly.

This post was modified 5 years ago by Albe
Posted : 20/07/2019 9:33 pm
--
 --
(@)
Illustrious Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Posted by: Albe

I don't know if it is just me - the latest firmware (today) doesn't display some values. 

Quick test - do autohome and then check Z height on the home screen - displays " Z ?". Moving the axis up and down doesn't change it.

Checked with 0.9 and La1.5 and 0.9 versions.  Standard Prusa firmware 3.7.2 shows it correctly.

There are features that change along the way - they do this to make room for new features - but I think they break things because they don't seem to go back and regression test after the fact.  So while the claim is it was a temporary removal of code - the final code when it gets reinserted is essentially untested - and it's left to the user to test.   

Posted : 20/07/2019 9:40 pm
Albe
 Albe
(@albe)
Eminent Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Posted by: Tim
Posted by: Albe

I don't know if it is just me - the latest firmware (today) doesn't display some values. 

Quick test - do autohome and then check Z height on the home screen - displays " Z ?". Moving the axis up and down doesn't change it.

Checked with 0.9 and La1.5 and 0.9 versions.  Standard Prusa firmware 3.7.2 shows it correctly.

There are features that change along the way - they do this to make room for new features - but I think they break things because they don't seem to go back and regression test after the fact.  So while the claim is it was a temporary removal of code - the final code when it gets reinserted is essentially untested - and it's left to the user to test.   

Sorry not sure I follow you - what changes are you referring to that would not report Z height values?

Posted : 20/07/2019 9:47 pm
Bunny Science
(@bunny-science)
Noble Member
Topic starter answered:
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)

You won't get Z height reported correctly after a factory reset and data clear. 

Only after repeating the setup wizard and the printer remeasuring baseline geometry will z be reported again.

Posted : 20/07/2019 10:15 pm
--
 --
(@)
Illustrious Member
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Posted by: Albe
Posted by: Tim
Posted by: Albe

I don't know if it is just me - the latest firmware (today) doesn't display some values. 

Quick test - do autohome and then check Z height on the home screen - displays " Z ?". Moving the axis up and down doesn't change it.

Checked with 0.9 and La1.5 and 0.9 versions.  Standard Prusa firmware 3.7.2 shows it correctly.

There are features that change along the way - they do this to make room for new features - but I think they break things because they don't seem to go back and regression test after the fact.  So while the claim is it was a temporary removal of code - the final code when it gets reinserted is essentially untested - and it's left to the user to test.   

Sorry not sure I follow you - what changes are you referring to that would not report Z height values?

I was referring to the fact you can no longer print (v3.7.1) without using G80; Z-offset is no longer used properly and subsequent runs will continuously change where it needs to be. v3.7.1 also broke Temp calibration: the firmware seems to no longer uses the measured PINDA vs temperature table properly, so run to run variations can't be "calibrated out" like 3.6 did.  There are other things that used to work that also seem broken, I'm not convinced magnet correction can be disabled (has no discernable effect on my printer, and I am getting worse bed meshs than when I was using a home grown build with 7x7). 

There's a remote chance it's just my printer and 3.7.1 has corrupted EEPROM data since I did my initial reset and recalibrations after installing 3.7.1 ... but I doubt it. Especially when you read the build notes on Github and see where certain features are disabled for certain builds. 

I'm almost afraid to update to 3.7.2 for all the issues 3.7.1 brought me.

This post was modified 5 years ago by --
Posted : 21/07/2019 12:32 am
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