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

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

I think I got it. 

bool can_load was doing a default + 60 followed by -58 for Bontech_Prusa_Upgrade_MK3S

For all other extruders it feeds 8 mm further than it pulls out.

Added balancing load to sequence. It's in my repository now, or you can manually edit your copy of mmu.cpp to read as

static bool can_load()

{

    #ifdef SLICEMAGNUM //Kuo

      current_position[E_AXIS] += 67;

    #elif defined(SKELESTRUDER)

      current_position[E_AXIS] += 50;

    #elif defined(BONDTECH_PRUSA_UPGRADE_MK3S)

      current_position[E_AXIS] += 64;

    #else

      current_position[E_AXIS] += 60;

    #endif //Kuo ===

    plan_buffer_line_curposXYZE(MMU_LOAD_FEEDRATE, active_extruder);







    #ifdef SLICEMAGNUM //Kuo

      current_position[E_AXIS] -= 59;

    #elif defined(SKELESTRUDER)

      current_position[E_AXIS] -= 42;

    #elif defined(BONDTECH_PRUSA_UPGRADE_MK3S)

      current_position[E_AXIS] -= 58;

    #else

      current_position[E_AXIS] -= 52;

    #endif //Kuo ===

    plan_buffer_line_curposXYZE(MMU_LOAD_FEEDRATE, active_extruder);

    st_synchronize();

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

Might be best if you re-downloaded from my repo because you changed some other things during your tries.

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

ooops, I can't do simple math. It should be

fixed in my repository.

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

Thanks, I would give it a try a. I always read download, I don't trust myself enough. 🙂

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

I lost my PC Internet connection so I will be doing this test later. Didn't want you waiting around for it.

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

Finished fitting my uprated PSU set to 26v output, Reverse Einsy case, heavier duty wiring.

Fitted STEPPERONLINE 0.9° OMC 17HM15-0904S motors to both X and Y axes and fitted BALITENSEN GT2 Timing Pulley 16 Teeth 5mm Bore, Width 10mm for GT2 Belt.

Now the rest of my printer is JLTX design parts, Skelestruder, Taurus X Axis, and Taurus Y axis.

The thing with Taurus Y axis is that the belt does not wrap around the pulley as much as a standard PRUSA drive, and with the BALITENSEN pulley the belt jumps the teeth during Y axis homing. I can get homing to work, but my belt tension is quite high.

Same configuration on the old LDO 1.8 motors and I never got a belt skip.

Firmware Guy-K2's as of 31/08/19

So these 0.9 OMC steppers just drive through and will cause the belt to jump hence the Y axis length errors some people are getting.

The Taurus Y axis configuration is more susceptible to jumping of the belt.

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

Just looked at the Taurus Y. Wow, that really engages a fraction of the motor drive pulley! 

You might try a lower homing Y threshold to stop on a smaller resistance change, but I would worry about an axis that is so easy to skip teeth. It's going to have the same lowered tooth skip resistance during print operation.

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

I've adjusted the belt to keep the tensioner as closed as possible whilst still being able to adjust the tension a little, this helps wrap the belt round more of the pulley.

This has allowed me to reduce the tension on the Y axis belt quite a bit, the whole thing is much smoother and quieter, but I'm not convinced I've got a good OMC motor on the Y axis as it sounds a bit buzzy, it's smooth enough to turn by hand but a bit noisy when moving at fast speeds.

Prints well, really well!, VFA's are history.

But I've got to get this replacement cover with fan for the PSU done ASAP, the noise from the fan is driving me nuts!.

The increased voltage is helping with heating times esp. the bed. 

PID values for hotend were P17.6  I1.66  D46.45  now at 26v P13.02  I1.18  D35.91

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

Chocki, two questions.

1. Did you set linearity correction to 1.130 for the OMC?

2. Were there problems with failed homing (other than belt jumping teeth) now that the firmware has more appropriate count limit for 0.9 motors?

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

Linearity set to 1.130 and no other problems except the jumping teeth.

Here is a test qube, but I have the contrast high to show the difference and a bright led torch off to one side.

I think you can tell which one is with the OMC. The picture is really exagerating any slight imperfection, in reality it looks a lot better.

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

Good to hear about no weird problems with homing. I think the latest firmware change will solve a lot of those problems. Your construction being so unusual is a nice edge case.

Nicely done so far as VFA reduction. All I see left is what looks like bearing noise. I could make those appear by increasing side pre-load on my bearings. It wasn't until I got my rod spacings to match the spacing that the bearings naturally preferred that the random stuff was minimal. Overall, I would say this is a success in improving your print quality already.

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

It's thanks to you and all the time and effort you have put into this that we can print as well as this.

It is most likely bearing noise, as I did not really check spacing of rods etc when I rebuilt the printer this time, just did not have the time, now I know it all works, I can spend the time getting alignment perfect, and hopefully my hot end upgrade will arrive soon.

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

Posted by: guy.k2

ooops, I can't do simple math. It should be

#ifdef SLICEMAGNUM //Kuo
	current_position[E_AXIS] += 67;
	#elif defined(SKELESTRUDER)
	current_position[E_AXIS] += 50;
	#elif defined(BONDTECH_PRUSA_UPGRADE_MK3S)
	current_position[E_AXIS] += 66;
	#else
	current_position[E_AXIS] += 60;
	#endif //Kuo ===
	plan_buffer_line_curposXYZE(MMU_LOAD_FEEDRATE, active_extruder);

fixed in my repository.

I downloaded the firmware again and redid the needed uncomments, etc, like normal.  Here is a picture of where the filament stops for me, just barely peeking out of the PTFE tube.

I use a pass through PC4-M10 Festo, so the tube touches the top of the sensor, ensuring the filament does not get lost trying to enter the little hole for the sensor - which it enters without any issues (sensor triggers properly).  But then when it backs up, it pushes it too far out and it is no longer near the teeth, so it never pulls it back in.

I did a factory reset before the last update, but I will do it again now just to be sure.  But here is the picture.

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

I assume this is the top one feeding into the FESTO?

We should probably reduce the distance for the retract move. BUT....

What I don't understand is the filament tip in your pict is well above the Bondtechs. If it was just the Bondtechs retracting resulting in that position is would be about 1 cm out from PTFE end. The Bondtechs themselves can't drive the filament up further by themselves. Is the MMU2S also pulling back or did the filament simply shift position when you pulled it for the pict.

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

Cybersage let's have you do some adjustments to can_load in mmu.cpp

Where it now says...

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

You should not need to do a factory reset when changing the retract distance constant. Just edit, compile and reflash.

I'm sure you did but #define SKELESTRUDER is uncommented in configuration_Prusa.h right?

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

The hard reset did not change anything.  I will make the edits, and this time I will pay attention to what the MMU does.  You are right, it is surely being moved by the MMU since it is quite a bit above the gears.

I do not have the skelestruder, I have the Bondtech MK3S full upgrade (including the new body, filament sensor, etc.).  I will make the changes to the MK3S parts instead.

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

BONDTECH_PRUSA_UPGRADE_MK3S - I can't keep straight who which extruder.

Then adjust

#ifdef SLICEMAGNUM //Kuo
current_position[E_AXIS] -= 59;
#elif defined(SKELESTRUDER)
current_position[E_AXIS] -= 42;
#elif defined(BONDTECH_PRUSA_UPGRADE_MK3S)
current_position[E_AXIS] -= 58;
#else
current_position[E_AXIS] -= 52;

to a lower distance like...

#elif defined(BONDTECH_PRUSA_UPGRADE_MK3S)
current_position[E_AXIS] -= 40; /was 58

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

My fault, I should have told you which I had.  Easy for me to remember only one, but hard for you to remember many.  My bad.

I already tried adjusting it to -30 and it still failed.  This time, I watched everything that could move.  It appears to stop being pushed by the MMU once it hits the sensor, which (by design) is a bit above the bondtech gears.  At this point, the gears should be pulling it but cannot.  The gears are on the entire time the MMU is pushing it, so it is ready to receive.

I just changed the settings for the += portion to these and am about to test (while keeping the -30, simply because I forgot to change it).

#elif defined(BONDTECH_PRUSA_UPGRADE_MK3S)
current_position[E_AXIS] += 86;  //was 66

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

I agree having it push further is the next adjust if it isnt' getting far enough down for the Bondtechs to grip.