RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Also, if I pull out the ptfe tube and prevent the filament from hitting the sensor, the MMU pushes it forever. If I disable the hot end sensor, it changes nothing, though - same small tip.
My test of the huge change to both the plus and minus in the MMU.cpp file has failed. Same results...
current_position[E_AXIS] += 86; //was 66
current_position[E_AXIS] -= 30; //was 58
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Wait "the sensor" and "the hot end sensor" are they different sensors (FINDA vs hot end filament sensor) or are they the same?
I think likely have ruled out can_load as the routine controlling that motion.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Wait "the sensor" and "the hot end sensor" are they different sensors (FINDA vs hot end filament sensor) or are they the same?
I think likely have ruled out can_load as the routine controlling that motion.
I always mess up names - and I meant to say extruder, not hot end. The hot end is only a little part of the extruder. I am talking about the one that now has the metal ball and magnets to move a flag into the sensor to block the light (dark on), that changed between the MK3 and MK3S versions due to it not seeing light filaments properly.
This guy:
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
yeah, those settings won't help; they only come into play after the filament has been grabbed by the extruder motor.
Your problem is earlier, I think you want "Extra loading distance" in the slicer settings. The issue here is the MMU2S setup expects the sensor to be tripped by the gears being spread, not before.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
yeah, those settings won't help; they only come into play after the filament has been grabbed by the extruder motor.
Your problem is earlier, I think you want "Extra loading distance" in the slicer settings. The issue here is the MMU2S setup expects the sensor to be tripped by the gears being spread, not before.
I can do that, but that will not help me do first layer calibration...
EDIT: I can manually guide the filament in by removing the tube, so if that is my only bad point, I will take it! 🙂
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Ah now I undertand what is going on. The BMG-Prusa MK3S upgrade extruder is using the filament sensor in single filament poistion. Is there not a chimney adpater for it?
BNBSX uses its own sensor lever for MMU2S sensing at the Bondtechs or alternatively also allows use of the Prusa chimney adapter.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Ditto for the Skele. Your only other option shy of hacking in an extra load distance after sensor trigger would be to run the Mk3 firmware and manually calibrate the bowden length.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Now that I'm looking at it.... I think the Slice Magnum move distances are wrong in my can_load. Shouldn't the distances be shorter rather than longer to reach the melt zone? Probably should go back through the CAD files and readjust based on relative Bondtech axis to melt zone distances.
That won't help with Skele or BMG MK3S. I think it would be easiest to hack in an extra move distance post initial load for those extruders. Where in the code is the initial load made? Could add the extra move there for Skelestruder and BMG MK3S that lack a Bondtech gear separation sense option.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Skele doesn't need any mods, it works fine with just the move distance tweaks as it has a gear-based IR option.
The can_load distances are the MMU jam detection, where it loads the filament a bit, then unloads it a little less; if the IR registers 0 during this time it determines there's a jam because it didn't load the whole distance.
The first distance is not to the melt zone. You'd have to measure on a stock extruder but I'd wager a successful load takes it to somewhere around the step in the heat break. You don't want it actually pushing out any filament or you'll get blobs on your purge tower that cause collisions later.
Best bet is use the stock distances, and subtract the difference between the gear->nozzle length in stock vs slice.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Had not looked at current Skelestruder. Where is the gear based IR option? I found a mod for the MK3S sensor, but that is above the Bondtech gears?
The can_load distances goes to the melt zone. Here are the default values superimposed on a Prusa MK3S extruder
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
That makes the equivalent for Skelestruder to be +55 and -47 mm
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
BNBSX is 0.4 mm shorter than Prusa MK3S. That close enough that no adjustments from stock should be needed.
Standard Mosquito (with Bunny Science Mosquito adapter) has melt zone 1 mm shorter drop. Again close enough that no change is needed from stock.
Mosquito Magnum (with Bunny Science Mosquito adapter) shortens distance by 8 mm compared to Prusa MK3S. So we shorten the distances by 8 mm.
Bondtech BMG MK3 Upgrade, I don't have a CAD file to measure.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Got the Bondtech MK3S Upgraded extruder STEP file to measure. Its equivalent can_load distances should be +72 and -64 mm
I am going to update my mmu.cpp to reflect these CAD based distances.
Note, I only take care of ONE option at time. If you put a Mosquito Magnum into a Bondtech MK3S, you have to change the distances yourself to +64 and -65 mm.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Only question I have is the negative move should leave the filament tip always 8 mm below Bondtechs or always same distance above melt zone. Above melt zone might make more sense since that would make subsequent moves the same distance for all the extruders. Always 8 mm below Bondtechs means different distances to advance to begin extrusion depending on extruder.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
https://www.thingiverse.com/thing:3255143/
My original distances were based on the Skelestruder docs noting it was 10mm shorter than the stock extruder, hence I just subtracted 10. It's worked well and there's no significant harm in being a little under because you're purging onto the tower anyway.
I think your question about where to "leave" the filament is where the single extruder MM settings may come into play on the advanced slicer settings. IIRC when unloading the filament is moved to park from the top of the region defined as the "cooling tube". I would suspect it expects the pre-load to leave the filament there as well.
You may be able to gain some insight from my reverse-engineering of the generated gcode to write my bucket processing script, see here:
https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2/bucket/tool
lines 220-355 or so. It walks through the various movements that are made as calculated from the filament settings parameters.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
... Durr, right there in plain sight:
reload_distance = printer["filament_park_position"] + printer["extra_loading_move"]
So those parameters do also need adjusting for your particular extruder, and the load/unload sequences should agree with what you've got there.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
How about this for the can_load retract distances? Leaves them pretty close to the same above melt zone. The Skele and Magnum Slice I couldn't quite do 52 mm because that would put filament tip into questionable (or non-grip) position.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Hi ! I installed the OMC 0.9 motor on my Y axis and the VFA are gone . Thanks Guy Kuo.
Now I have an issue with the motor skipping step when it move the bed to start the print . I tried to raise the voltage using M907 Y270 without success .
I will post a vid
I tried the LDO motor too but have a homing issue
Which setting should I modify in your firmware ?
Thanks
Sry for my English .
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
I can't edit my post so I post the vids in a new reply .sry
//youtu.be/C66EhGZk_N0
The motor skip steps while doing fast movement too. I tried raising current to 350 without success.
RE: Stepper Motor Upgrades to Eliminate VFA's (Vertical Fine Artifacts)
Skipping steps during printing is almost always indication of a mechanical issue with an axis, not the motor itself. The 0.9 have a bit less torque and that can cause a marginally acceptable axis to show up as a problem.
1. Is this a belt skipping a whole tooth? If yes, belt is too loose.
2. Is this pulley loose on motor shaft? Check that both set screws are correct. One must be perpendicular to motor shaft's flat. Does the motor lack a flat? Grind a flat.
3. Is this a layer shift in the midst of a print? Check that rods and bearings are completely free running and correctly lubricated.