What to try next to reduce stringing?
I built my MK3 a couple weeks ago, and have been quite pleased with the prints. However, I decided to print the sample frog from the SD card last night with my Hatchbox orange PLA, and it's showed me how bad my stringing problem is. So much to try to remove from between the webs and legs and body...
Anyway, I decided to try to start cataloging the stringing effect on my MK3. I found a small 4 post string test print, and started changing settings.
From top to bottom, I ran prints from my default 210C, to 205C, 200C, 195C. I ran a temperature tower and it petered out at 190C and wouldn't continue printing past that point.
Left to right, I was increasing the retraction length. The 2nd - 6th rows I eliminated attempting prints that previously showed no improvement, and then I tried comparing a couple prints with same settings on Stealth and Normal modes.
The best results so far seem to be around 200C and 7mm retraction. That seems like a lot of retraction for direct drive from what I've read, and I don't want to keep pushing it that far if it's not worth it.
Here's a close up of the results I'm seeing with default settings:
Same settings, bumped to 5.0mm and 7.0mm retraction distance, looking better than defaults, but still fuzzier than I'd like:
And same settings at 205C rest-of-print temp, 5.0mm and 7.0mm examples:
And the end of my testing for today:
Right test is:
Left test is:
Very last one, increased the retract speed to 50mm/s, poor photo, but I would say it looks mostly like the last pair of tests above:
Prusa i3 MK3 kit
MK3/S Upgrade Kit
FW 3.7.0
Slic3r PE 1.41.3
Re: What to try next to reduce stringing?
try 45-55 retract speed, and get a better fan shroud. thats an awful lot of retraction for direct drive.
this should go without saying, but make sure your printer is actually printing *real* models well before going crazy over a beyond-worst-case stringing test.
Re: What to try next to reduce stringing?
Yes, I will give 45-55mm/s a try for the run of tests (210C/45-55mm, 0.8mm retract, and 195C/45-55, 5.0mm and 7.0mm retract) tomorrow.
I have printed many things on this printer so far, and have been quite happy with how things are coming out, up til the tree frog example. That one was just being so difficult to clean the stringing out of, it got me searching for improvements in that area.
Most of the other things I've been printing don't have lots of hops across empty spaces, so it hadn't been much of an issue before.
Prusa i3 MK3 kit
MK3/S Upgrade Kit
FW 3.7.0
Slic3r PE 1.41.3
Re: What to try next to reduce stringing?
Different filaments have different stringing properties, maybe try some different brand or filament color.
I have a few special PLAs (color changing, glow in the dark, particle infused) from aliexpress and amazon, and they are super stringy. Like double that of PETG.
Normal PLA from local retailer only strings a little bit.
Re: What to try next to reduce stringing?
I agree that you should try another brand of filament before going too much farther on this. That's a heck of a lot of stringing! I'm not sure I could force my MK3 to do that much stringing with PLA if I tried. I've never seen that result on my printer.
Re: What to try next to reduce stringing?
I did some experiments a while back with the winged dragon print, and I found a couple of other adjustments (besides temperature and retract distance) that helped. By default, the "stock" Prusa settings include "wipe" and "raise the z before non-printing moves"; I eliminated both of those settings and the stringing problem got much better.
On the E3D extruder, it is strongly recommended to never retract more than 0.3mm or so, because you are pulling melted hot plastic into a cold zone where the plastic can solidify and create an extruder jam.
Right now, I'm printing a set of replacement plastic parts (before I need them!) for the MK3. For small parts, I'm printing 2 - 4 parts at a time, and I see no stringing at all between the parts. The filament I'm using is Max-G from 3DXTech. My extruder is at 240C, using no wipe, no Z raise, and 0.3mm retract.
Re: What to try next to reduce stringing?
Battling this with MatterHackers Build Series PLA as well. With 1mm of retraction (and linear advance) along with a print temp of 200C I've gotten the MatterHackers stringing test cubes to print ok. I was going to try adjusting speed but before I do I was going to try using the "Use firmware retraction" setting in Slic3r PE just to see.
Of note, E3D actually recommends .8mm for retraction with the suggested range being .5-2mm: https://e3d-online.dozuki.com/Wiki/V6_Troubleshooting#Section_Misconfigured_Retraction
Re: What to try next to reduce stringing?
Here's where I'm at so far: https://forums.matterhackers.com/topic/1089/recommended-settings-for-matterhackers-build-series-and-prusa-mk3/3
(The gist of it is:
Print Settings:
First Layer Speed: 10mm/sec
Filament Settings:
First Layer: 220/65
Other Layers: 215/65
Cooling: 75-100%
Printer Settings:
Retraction: 1.4mm
Re: What to try next to reduce stringing?
@jeffrey.b22 - this is a great stringing study - thank you!
I'm trying to minimize stringing with TPU, and I figure your results would point in the right direction.
I'm curious - where did you end up? Did you find a setting that eliminated stringing?
Re: What to try next to reduce stringing?
Try disabling Z hop.
Re: What to try next to reduce stringing?
Not to get off topic with the PLA issue, but...
I'm trying to minimize stringing with TPU
If you have not already disabled retract when using TPU or TPE...give it a try.
Re: What to try next to reduce stringing?
Try disabling z-lift or dropping the value. For the filaments I use the default value of 0.6 is to high I find for pla/petg.
Re: What to try next to reduce stringing?
Were you ever able to solve the problem? I have been having the same issue as posted here https://shop.prusa3d.com/forum/how-do-i-print-this-printing-help--f63/stringing-issue-t27349.html
Re: What to try next to reduce stringing?
How old is the filament?, moisture absorption can also influence stringiness, but basically keep your non print moves as fast as you can, your temperature as low as you can and still print successfully, fast retraction but don't go over 2mm, to be honest if it is still stringing at 1mm, it will keep stringing, i bet that when you finish there is a continuous streamer from the nozzle to your printed part and even with no extrusion you can pull a cobweb thread for over 12 inches from the nozzle and unloading the filament results in a long thread of filament coming out of the extruder feed hole at the top.
It's just the filament, and probably not much can be done, just use it for less critical work where the head does not hop about too much and use GYROID infill as it has less hops.
Wait till you get onto PETG 😀
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
Re: What to try next to reduce stringing?
How old is the filament?, moisture absorption can also influence stringiness, but basically keep your non print moves as fast as you can, your temperature as low as you can and still print successfully, fast retraction but don't go over 2mm, to be honest if it is still stringing at 1mm, it will keep stringing, i bet that when you finish there is a continuous streamer from the nozzle to your printed part and even with no extrusion you can pull a cobweb thread for over 12 inches from the nozzle and unloading the filament results in a long thread of filament coming out of the extruder feed hole at the top.
It's just the filament, and probably not much can be done, just use it for less critical work where the head does not hop about too much and use GYROID infill as it has less hops.
Wait till you get onto PETG 😀
I have tried at least 15 different combinations of settings and doing the test prints and used freshly opened PLA right out of the packaging. I contacted the support chat a few days ago and tried their recommended settings and adjustment, but it still strings a lot. I then emailed support about 24 hours ago, but haven't heard back. Yesterday I printed this Silica holder https://www.thingiverse.com/thing:3164954 and between the little air vents I had lots of stringing still. I guess I will contact support again for additional assistance. I have only had this printer a month and I was hoping it would not produce this kind of stringing issue.
For the record I have tried
Re: What to try next to reduce stringing?
Have you got any access to a thermocouple thermometer or have any way of checking what your actual hot end temperature actually is, it's possible the current thermocouple is not reading correctly and you are in fact running the hot end at a much higher temperature.
Actually scrap that idea, you would never have got the cone towers so straight if you had been running too hot.
Normal people believe that if it ain’t broke, don’t fix it. Engineers believe that if it ain’t broke, it doesn’t have enough features yet.
Re: What to try next to reduce stringing?
I had the same problem. Any PLA I tried stringed excessively. This is very counterintuitive, but try REDUCING the fan speed. It worked for me. I am sorry I don't have my settings handy, but I turned off 100% fan, turned on only fan when needed, and I think set maximum fan speed at 50%. A quick test- take off your nozzle fan shroud and run your test print with the same setting to see if there are improvements.
A short history, I tried everything suggested in this thread with only marginal improvement, and eventually invested in new nozzles. After changing out my nozzle, suddenly no strings! "Eureka!" And then I noticed I neglected to replace the nozzle fan shroud. I attached it, ran the same test, strings reappeared. My hypothesis is my fan shroud is slightly defective, and routes the air in a way that induces strings. By turning down my fan speed AND no z-hop I have no appreciable stringing. (No I haven't tried replacing my shroud; I am in line to get the mmu2 and will replace my shroud with the new version, hoping that will fix everything)
Re: What to try next to reduce stringing?
I had the same problem. Any PLA I tried stringed excessively. This is very counterintuitive, but try REDUCING the fan speed. It worked for me. I am sorry I don't have my settings handy, but I turned off 100% fan, turned on only fan when needed, and I think set maximum fan speed at 50%. A quick test- take off your nozzle fan shroud and run your test print with the same setting to see if there are improvements.
A short history, I tried everything suggested in this thread with only marginal improvement, and eventually invested in new nozzles. After changing out my nozzle, suddenly no strings! "Eureka!" And then I noticed I neglected to replace the nozzle fan shroud. I attached it, ran the same test, strings reappeared. My hypothesis is my fan shroud is slightly defective, and routes the air in a way that induces strings. By turning down my fan speed AND no z-hop I have no appreciable stringing. (No I haven't tried replacing my shroud; I am in line to get the mmu2 and will replace my shroud with the new version, hoping that will fix everything)
Thanks for the suggestion. I tried turning down the fan to 40%, but the stringing still appears to be the same.
RE: What to try next to reduce stringing?
I am in the same situation when I use Prusaslicer. For some reason no matter what parameter I change I still get unacceptable levels of stringing. Taking the nozzle temperature down can only help a little but I think there is something else wrong. I still rely on Cura for slicing, with the same retraction I get horrific Prusaslicer results, for a reason I cannot point at I get clean prints with Cura even for small detailed parts with loads of gaps and related retractions. I have not tried yet the fan settings suggested somewhere in this post.