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brother_beams
Dec 01, 2021

Help getting filament shaped

in Support

Ok so now that I can successfully get the unit to push 4 colors to the extruder I need some help getting I’m the tips of the filament shaped to be able to retract or reload and not get stuck. if anyone has the unload settings in their direct drive setups would be great to see if you had to tweek the generated g code.

ender3 v2 microswiss direct drive



23 comments
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Bill
Dec 01, 2021

So... I can see the blue Capricorn tube... have tried to adjust it so that it uses that spot for the cooling? That would be the ideal position for it to constrict it and shape the tip. Basically, alternate between that point (for cooling) and the nozzle for string elimination. What do your tips look like? Also, what changes have you made to the gcode?

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brother_beams
Dec 01, 2021

@Bill so what you are saying is adjust the retract mm on the unload g code from the websites generator to get the filament into the Capricorn tube so instead of the -10mm that’s there might have to move it more to get out of the heatbreak into the tube. The gcode generator is standard at -10 then rams back in to 1.

i cut the tips to get it ready to try and print again so I will have to run another test print to snap a picture but I will adjust the retract length for the filament shaping first then try it out

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Bill
Dec 01, 2021

Yep... so, the GGode generator doesn't know about the specific design of your machine... which means it's not backing it out far enough at the start... we need to tune that so that when it retracts, it only goes all the way to the Capricorn tube. Then we can do the bounce from there to the tip. So, at the start of our code, it's only going to E-20... which isn't into that Capricorn yet... so we need to move it farther, maybe something like E-50 (but you'll need to measure where the optimal distance is). Then we need to make sure the bounce goes all the way to the tip... if it's actually needed. It should go to the tip as it is... but you might need to speed it up so it doesn't have a chance to melt again in the hot end. I've had customers report that they don't need to do anything at all with that extruder... just simply retract it into the Capricorn... let it cool... then retract it out.

Bill

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brother_beams
Dec 01, 2021

@Bill ok makes sense I will check it out in a little bit. I know 75mm is my gears to the hotend and the first initial retract is -50 then it was doing -80 but I changed that to -65 to keep it in the gears then it did the ramming and unloading phase which I will adjust and see what happens.

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brother_beams
Dec 01, 2021

@Bill I messed with the retract distance and I think it’s close picture is what it ended up as but it did get stuck trying to retract so it still needs tweaking but better than what I was getting and I don’t have any smaller tubing I measured all the stuff I had which the id is all around 2mm even the Capricorn is 2mm

next question is I don’t think it’s starting with the first color more like the 4th and the gcode is correct in cura on the machine tool settings so when it prints the brim on the tower it doesn’t print the whole thing anymore I don’t want to open the test print as a new project again because it’s getting old having to copy and paste the generated gcode to each tool every single time and I don’t know how to keep it in there (thought I did and this is what is now happening) It Should be complete but it finished the brim like this



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Bill
Dec 01, 2021

@brother_beams Ok... two issues... #1 long thin round strings indicate the temperature is too high... but looking at it... did it actually ram into the nozzle to eliminate it, or was that just backed out? #2 - When you home it, it should always go to the 1st (top outside edge) extruder. Is that not what it's doing? What does your tool change gcode look like? When you start the job, it will not try to unload the last filament, because it assumes it is loaded to 1" before the Y adapter for each color... it will then switch to whatever color the slicer indicates it is moving to... so if it's starting color is 4, then that is where it will go to. Perhaps you can email me your gcode (for the file you're trying to print) so I can examine it. (You can also look into it... the 4 extruders will be indicated in the code by T0 - T3... and the LCD of your printer will also tell you which color it is switching to.)

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Bill
Dec 02, 2021

So... the temperature I'm referring to is the temperature you're changing the colors at, not what you're printing at... they can be two different temps. And yep... if you're using Cura, it could also be not taking into account the retraction distance on color change... for some reason, they don't include that in the current position... so it could be off by 10 or 12mm depending on that setting. As for the purge tower Cura, if you're talking about the hole in the center of the purge tower, that is normal... they have a very odd logic in their system and they don't even support the purge middle for previous layers... so a lot of the time, it'll just dump the purge into the middle without it attaching to anything. Personally, I only use PrusaSlicer for it now, as they really understand the details of MMU styles machines much better. Ultimaker sticks with just two colors for Cura, and really don't support it beyond that.

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brother_beams
Dec 02, 2021

@Bill ok I will attempt this weekend the prusa slicer getting a little burnt out on it messing with it before work and after work need a small break lol. But today I am getting closer to getting the tips shaped 3mm on the ramming is too much has some come out the nozzle so I’ll try 2 but that will have to wait. Thanks for the great info. I will update you in what happens this weekend with it.

brother_beams
Dec 04, 2021

@Bill first attempt at the prusa slicer and it completely messed up my hotend so I’m not sure if I’m even going to keep trying it now. new issue is completely tear apart the microswiss hotend then reassemble and probably redo offsets

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brother_beams
Dec 06, 2021

@Bill I’m waiting a some new tube for the hotend should be here this week. As for prusa slicer there are a bunch of settings I’m not sure what all needs set. I saw one for unloading filament in a different tab not sure if that needs set also along with the prusa slicers generated g code from the website or not. I did change the gcode to match what I had for cura and got it in the color change tab of the slicer but not sure if there are more settings in prusa slicer that need changed to go along with it.

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Bill
Dec 06, 2021

If you're using PrusaSlicer, I just use the built in settings for Ender 3... then reduce the retraction since you don't have a Bowden tube. Then our generated gcode gets added to the Tool Change gcode... set the printer configuration to 4 extruders and make sure you copy all the settings from Extruder 1 to the other 3 verbatim.


That should be all you need to worry about. The out of the box settings should be great.


Bill


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brother_beams
Dec 08, 2021

@Bill thanks I’ll look into this as soon as I get a chance. I didn’t see an ender option for printer settings but I must have completely missed it. Im waiting on some stuff for the hotend and since it’s apart I can get an accurate measurement for retraction to shape the filament.

brother_beams
Dec 08, 2021

@Bill quick question on measuring for retraction do you measure from the tip of the hotend nozzle to about the middle of the tube? Last time since the hotend was all together I used my calipers and made a rough estimate on length from the tip to the middle of the tube. Just want to make sure I’m getting the correct measurement.

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brother_beams
Dec 15, 2021

@Bill are these settings I changed along with the generated g code right





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Bill
Dec 08, 2021

It really doesn't matter where in the tube it retracts to as long as it's somewhere in a cool section. It's the total distance that really matters... and even that isn't so exacting... When it is retracted out of the extruder, we always run an extra 30mm back out to make sure it's fully expelled from it.

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Michael Despault
Dec 15, 2021

I'm at this step right now as well. I'm pretty consistently able to load filament with any of the 4 gears, but the unloading is still problematic. Specifically, it tends to get stuck when the tip gets to the extruder (can't grip) and I'm guessing I need to shape the filament better.


I don't fully understand the generated g-code for unloading. ie:


G0 E-50 F2000 ; quickly retract the filament to shape it
G0 E-80 F600; slowly allow it to cool
 
G0 E1 F2000 ; blob elimination
 
G0 E-50 F2000 ; quickly retract the filament to shape it
G0 E-80 F600; slowly allow it to cool
 
G0 E1 F2000 ; blob elimination
G0 E-10 F2000 ; quickly retract the filament to shape it
G0 E1 F2000 ; quickly ram the filament to shape it
G0 E-10 F2000 ; quickly retract the filament to shape it
G0 E1 F2000 ; quickly ram the filament to shape it
 
G0 E-50 F2000 ; quickly retract the filament to shape it
G0 E-80 F100; slowly allow it to cool

My understanding of the above code is that it retracts the filament by 50mm quickly, then another 80mm slowly... then it pushes forward 1mm? to eliminate blobs? I don't yet understand why you would want to retract 50+80 and then only move it forward 1mm after it has cooled. It then does seem to repeat the same process but I guess the "G0 E1 F2000" throws me off since the filament would be only moving back such a small amount? I can fix the distances to be specific to my extruder/hot end distances (it's bowden tube, not direct drive) but what is the generator trying to accomplish so I can modify it?

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Bill
Dec 15, 2021

No... the positions are absolute... so it retracts fast to 50mm, then slowly an additional 30mm... (to the 80mm position) then it loads it all the way into the hot end (1mm from it's original position.) However, when you're saying it's not loading into the extruder... is your extruder starting up early enough? Is it spinning as the filament reaches it so that the 3D Chameleon and the extruder are pushing/pulling at the same time?

Michael Despault
Dec 15, 2021

Thanks Bill, I overlooked the transitions between relative in absolute in the g-code. It makes much more sense to me now. I've also resolved the loading and unloading as well, though I still need to test it with an active hot-end. I removed the hot-end from the equation for testing while I refined my g-code, and was able to tune it so I could load and then unload one of the extruders 3 times in a row which is great progress. Next I'll continue working on the shaping and then it will only be a matter of making slight adjustments for the other 3 extruders

Alfred Weippert
Dec 16, 2021