Need some assistance - Ender 3 w/ Hemera stringing

Tengis

Tengis

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Jun 11, 2003
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I can't figure out what is causing this stringing and it's driving me crazy. I bought a used Ender 3 and have been printing great with a few minor defects, and then realized my settings in Prusa Slicer were wrong.

With my e3d Hemera direct drive I should have retraction set to .5 to 2mm max. My old settings were for a stock Ender 3 with BLtouch, something like 5mm retraction.

I made this one change and immediately print quality was really bad where it pulls away - tons of stringing. Ran through a bunch of troubleshooting stuff and ended up running a stringing test from teachingtechyt. The string test was overall a success and I dialed it into .8mm retraction. And then the retraction speed and 50mm was the best.

I started with a fresh profile and Prusa slicer and put the settings in and I still have insane stringing. I've messed with the temperature, zhop, and a bunch of other stuff.

Left is the stringing test, right is the same model sliced in Prusa Slicer. Also, I've also tried Cura and have the same problem.

PXL_20231121_004910022.jpg
 
NightReaver said:
Ah, so it generated a g code?

*Edit* And I assume you generated Prusa g code?
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Yes. After I did the retraction test I put those settings into the PrusaSlicer and got the tower on the right. There is a disconnect somewhere that Im overlooking.

Ive thought about setting my printers firmware/settings back to a baseline to make sure there isnt something going on there, but I dont know how it could be that if the TechningTech gcode works just fine.
 
Huh, that'd be weird.

I'm guessing you went through the section at the bottom of that page about not being able to translate test results to your actual printing?

Wish I could help with any of the actual codes, but it's been years since I've done any Marlin stuff.

*Edit* Oh. It's sliced using Simplify3D. Maybe it'd import into that correctly.
 
Looks way too hot imo. Also sometimes increasing printing speed can help.

Things I would work through:
1. PID tune the hotend
2. Check tension on extruder arm
3. print a temp tower
4. then work on retraction settings


Check you have a suitable retraction setting.
  • We recommend starting with a retraction value of 0.5mm which can be incrementally increased up to 2mm if you experience stinging or blobbing. If you still experience stringing or blobbing at 2mm reduce the printing temperature and start again.
  • If stringing and blobbing persist despite the temperature and retraction tweaking then you should look at the filament you are using, in the first instance dry out your filament, and or consider a different brand.
  • Do not exceed a retraction length of 2mm, this will cause the molten filament to be pulled into the cold section of the heatbreak and will most likely cause jams.
 
NightReaver said:
Assuming his normal profile is using the same temp as the test he generated, that shouldn't be it.

The problem is that the generated test came out clean. It won't be hardware related.
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I assume nothing. Even the outer edges of the pillars look globby. Looks hot.
 
Darunion said:
I assume nothing. Even the outer edges of the pillars look globby. Looks hot.
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Maybe a little. Could just be in need of flow rate adjustment. That doesn't explain why the left print is so much cleaner than the right.

*Edit* When you get back OP, try doing another generated test print. Verify the temp is the same and that it comes out fine again.
 
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I used the same temperatures and even calibrated my esteps for the extruder. Unfortunately I have no idea whats going on or I wouldnt be posting here lol.

I was on the edge of buying a P1S with their BlackFriday pricing... if I cant figure this out today then Im probably not going to put anymore time into it. Ive probably messed with it for 15 hours total changing settings, leveling, printing, changing settings, calibrating, printing, calibrating... -_-
 
So you went through the list at the bottom of the page?

Also see if you can import into Simplify3D to check the settings.
 
NightReaver said:
So you went through the list at the bottom of the page?

Also see if you can import into Simplify3D to check the settings.
Click to expand...
Yes I went through the list. Im going to check that when I get home.
 
ChatGPT to the rescue? I asked it to compare the gcodes. The second set of gcodes is the one that Prusa Slicer did:

Here are the key differences:

  1. Temperature Settings:
    • The first set adjusts the bed and hotend temperatures (M140, M190, M104, M109).
    • The second set has more elaborate temperature control, including warming up, waiting for stabilization, and adjusting the temperatures during the print.
  2. Acceleration and Feedrate Settings:
    • The second set includes commands (M201, M203, M204, M205) to set maximum accelerations and feedrates, which are not present in the first set.
  3. Retraction:
    • The second set explicitly commands retraction before and after layer changes (G1 E-.8 F3000, G1 E.8 F2400), while the first set has custom retraction and un-retraction commands (G1 E-.8 F2100, G1 E0 F2400).
  4. Layer Change:
    • The second set includes specific commands and comments related to layer changes, while the first set does not have such explicit indications.
  5. Prime the Nozzle:
    • The second set includes commands to prime the nozzle (G1 Y140 E10 F1500, G1 Y10 E10 F1200), while the first set does not have explicit priming commands.
Click to expand...
 
Huh. Maybe you can try adding those g codes to yours? Errrr wait, so yours has extra g codes?
 
I wonder if there is a first layer temp and top layer temp setting you have chosen. That is the only thing i could think would need adjusted mid print from the slicer side.

Acceleration can help with stringing but usually only at the small thin strings level, causes them to snap instead of tethering to the other side.
 
Possible. I might download Simplify3D and see if I can import a profile from the generated g code.
 
NightReaver said:
Huh. Maybe you can try adding those g codes to yours? Errrr wait, so yours has extra g codes?
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Prusa Slicer is adding extra gcode, while the one from the website is barebones. Im not a 3d printing wizard but Im very tech savvy - Im not deep enough into this hobby to answer questions I have in my head without extensive Googling.

Does the printer firmware store any of these types of settings or is that strictly settings for the stepper motors, extruder, etc? There are no "fall back" settings? Would it benefit me at all to reflash my machine firmware and/or upgrade and recalibrate everything?
 
You shouldn't have to touch your firmware. The g codes are just extra commands the slicer is sending directly that are built into the file.
 
Bruh...

I just absolutely baked my filament in a toaster oven and the print came out fantastic. It probably has some minor tweaking to do now, but overall, its better than the tower on the left.

Im actually kind of pissed. Spent a ton of time and even went out of my way to try to dry the filament just in case, twice. Got pissed off again after work and put it in my toaster oven for two hours at a temp that was borderline too hot.

I ordered a nice filament dryer two days ago, should be here tomorrow.
 
Hahahahahaha. Been there, don't feel too bad :D

Still odd about the difference if it was using the same filament, but whatevs. Enjoy!
 
NightReaver said:
Hahahahahaha. Been there, don't feel too bad :D

Still odd about the difference if it was using the same filament, but whatevs. Enjoy!
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Those prints were a couple hours apart. Maybe I got it just dry enough and then after sitting in my cold house it was screwed up again.
 
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