Excess stringing PETG on Mini  

RE: Excess stringing PETG on Mini

Hi, yes retractions are set higher on MINI compared to MK3S. To be honest I am using default retractions for MINI in Prusa Slicer and they work fine with filaments I use. If you get excessive stringing, there are few things you can try too, for example lowering temperature a bit and drying the filament (4 hours at 60-65 degrees Celsius should do the job). Try printing one of stringing test models and play with settings, it’s a quick model to print and this way you’ll be able to better see what works with your filament.

RE: Excess stringing PETG on Mini

Try turning on Avoid Crossing Perimeters (assuming it's not already on), I find it reduces PETG stringing a bit on my Sovol.

RE: Excess stringing PETG on Mini

Posted by: @towlerg

Try turning on Avoid Crossing Perimeters (assuming it's not already on), I find it reduces PETG stringing a bit on my Sovol.

I will include crossing perimeters in my experiment plan. Thanks for calling my attention to it. I've identified a stringing test print. I'll let you know how it turns out.

RE: Excess stringing PETG on Mini

Yes, please post. One of the most common reasons for petg stringing and uglyness is humidity, that filament is a bit hygroscopic. Drying it won’t hurt anything, only exclude one factor.

RE: Excess stringing PETG on Mini

Posted by: @crawlerin

Yes, please post. One of the most common reasons for petg stringing and uglyness is humidity, that filament is a bit hygroscopic. Drying it won’t hurt anything, only exclude one factor.

My filament should be very dry; always stored at RH less than 30%, printing in room less than 40%.

RE: Excess stringing PETG on Mini

I also think a heattower might help you see if you need to tweak your temp settings or not.

RE: Excess stringing PETG on Mini

You are not alone, also get much more stringing on the mini then on the mk3s. New Prusamen out of the box won't help against it. Mk3S with 1 month old filament and the mk3s in the ikea enclosure gets a perfekt print.

RE: Excess stringing PETG on Mini

@rolf

Same here... just got a mini. Prusamment PETG filament roll on MK3S prints fine. Excess stringing and poor strength on Mini. I'm using all the default settings. Disappointed 🙁

RE: Excess stringing PETG on Mini

same here.

"tinmorry" or "getech" petg filament works more better then prusa original petg with prusa mini original settings.

what a shame :-//

RE: Excess stringing PETG on Mini

Posted by: @widerporst

same here.

"tinmorry" or "getech" petg filament works more better then prusa original petg with prusa mini original settings.

what a shame :-//

Well, such comment is of no value ..what a shame.
I won't go into "which is better", but there's no doubt that Prusament PETG is an excellent filament -which has been proved by many experienced users and also in professional use.
If you prefer some other brand, that's fine. But to share your experience on which is better for you, you should be more specific.

RE: Excess stringing PETG on Mini

Posted by: @bogdanh

Posted by: @widerporst

same here.

"tinmorry" or "getech" petg filament works more better then prusa original petg with prusa mini original settings.

what a shame :-//

Well, such comment is of no value ..what a shame.
I won't go into "which is better", but there's no doubt that Prusament PETG is an excellent filament -which has been proved by many experienced users and also in professional use.
If you prefer some other brand, that's fine. But to share your experience on which is better for you, you should be more specific.

Well, as the original poster of this question regarding PETG stringing on the Mini, I find the recommendation both relevant & helpful. I intend to try it out. I am still a fan of Prusament PETG on the MK3S. Are you able to control stringing of Prusament PETG on the Mini? If so, please share your settings. Thanks in advance.

RE: Excess stringing PETG on Mini

hi i want to share my experience with PETG on MINI+, i find that when i change the retraction length from (default) 3.2mm to 2.0mm , it makes a difference. less stringy and great results. now i'm using eSUN PETG 230C. here is my 6 minutes boring video

RE: Excess stringing PETG on Mini

Posted by: @burtronix

 Well, as the original poster of this question regarding PETG stringing on the Mini, I find the recommendation both relevant & helpful. I intend to try it out. I am still a fan of Prusament PETG on the MK3S. Are you able to control stringing of Prusament PETG on the Mini? If so, please share your settings. Thanks in advance.

Actually I think there are no magic settings with Prusament PETG. Still, here are my values (for 0.4mm nozzle at 0.20mm QUALITY):
Hotend: 1st layer 240°C, the rest is 245°C
Bed: 80°C for all layers (textured sheet used)

And most important of all: I never assume filament is dry, even if I just opened it -I always dry filament first! And if filament is exposed for few days, I repeat drying!
I use food dehydrator for that. Simply because 99% of filament dryers on market aren't capable to dry PETG (not to mention ASA/ABS).

I never do "stringing test" prints, because I know what I can expect. If object has a lot of small (vertical) details, there will be a little stringing, of course. But that's quickly solved with a lighter. But for "normal" print objects (name any printable part on Mini, for example), no post processing is needed.
I just need to repeat again: PETG requires proper drying process before usage.

That's it... as said, no magic 😉 .

RE: Excess stringing PETG on Mini

sorry bogdanh, but as a buyer of a prusa original device (coming with a prusa slicer) and prusa original filament, it is quite a shame for me that prusa does not publish updated settings here. for me, that is also part of the quality, not only the hardware. in other words, i want to express my disappointment and frustration, the mini has not only been on sale for a few weeks!

RE: Excess stringing PETG on Mini

Posted by: @bogdanh

Posted by: @burtronix

 Well, as the original poster of this question regarding PETG stringing on the Mini, I find the recommendation both relevant & helpful. I intend to try it out. I am still a fan of Prusament PETG on the MK3S. Are you able to control stringing of Prusament PETG on the Mini? If so, please share your settings. Thanks in advance.

Actually I think there are no magic settings with Prusament PETG. Still, here are my values (for 0.4mm nozzle at 0.20mm QUALITY):
Hotend: 1st layer 240°C, the rest is 245°C
Bed: 80°C for all layers (textured sheet used)

And most important of all: I never assume filament is dry, even if I just opened it -I always dry filament first! And if filament is exposed for few days, I repeat drying!
I use food dehydrator for that. Simply because 99% of filament dryers on market aren't capable to dry PETG (not to mention ASA/ABS).

I never do "stringing test" prints, because I know what I can expect. If object has a lot of small (vertical) details, there will be a little stringing, of course. But that's quickly solved with a lighter. But for "normal" print objects (name any printable part on Mini, for example), no post processing is needed.
I just need to repeat again: PETG requires proper drying process before usage.

That's it... as said, no magic 😉 .

Thanks for the reply. Not looking for magic - just for what works. This is question is because I have a huge difference with stringing on the same model using the same dry Prusament PETG on the Mini vs the MK3S. I've used a heat gun to treat the stringing, but for production I'd really like to eliminate post-processing. My solutions so far has been to schedule all the PETG jobs on the MK3S, but as my shop gets busy, that may not be the best option.

Glad the stringing is no big deal for you. It remains somewhat of a deal for me.

RE:

@burtronix
I need to apologize for not mentioning one important thing (I believe): I use Bondtech extruder (and Bondtech heatbreak) since first day. I can't tell how much difference that makes compared to stock extruder, but I would guess that extrusion & retraction is quite more precise -I mean, that's the whole point to upgrade the extruder.

@widerporst
I don't know what you mean by "prusa does not publish updated settings". The settings I've mentioned in my previous post are not the perfect settings. They just work fine for me, for things I usually print. If I would print some small decoration figures or similar, then I would most probably need to change settings. And if I would mostly print big objects, then I would change settings again. And finally, if I use another filament brand, I change settings again. Perfect recipe doesn't exist -there are only general recommendations.

RE: Excess stringing PETG on Mini

Posted by: @burtronix

I've been printing PLA on my Mini for almost a month with no problem. Today I tried PETG on the Mini for the first time. The stringing is very excessive compared to PETG on my MK3S. Do I need to tweak the retraction and/or jerk settings in the PETG profile in Prusa Slicer? I would have thought that would be done in the default settings for the Mini. Does the Bowden extruder require more retraction to compensate for slack between the tube & filament? 

Hey! I too have a Prusa Mini and was having a hard time with stringing and blobs on my prints with PETG, not allowing me to print more than one thing at a time and even then it was iffy quality. I got on here and read a bunch of suggestions and tried about 20 different variations of changes and the best one I found that almost completely eliminated and stringing and blobs was the following settings...

Filament: Prusament Jet Black PETG
1st layer- nozzle: 242   bed: 87
other layers- nozzle: 245    bed: 87
*change retraction length to 2mm (instead of the default 3.2)
*change FLOW FACTOR on your printer to 135 (instead of the default 95) (you have to change this setting after the printing starts

ALL OTHER SETTINGS ARE STOCK SETTINGS FOR PRUSAMENT PETG

I've also been using a small metal tool that's not sharp and removing the excess filament from the nozzle while it's heating up for the next print. These settings took me from ugly AF blobs and stringing that was not usable to super fine strings that you have to almost squint to see them. Hit those tiny strings with a quick blast of a heat gun and BAM! easy peasy! This literally took me about 2 days of fudging around and tons of mini string tower prints. As soon as I discovered it worked I started typing this in here to share. Hope it helps someone!! 

Cheers!

RE: Excess stringing PETG on Mini

PETG stringing has been a problem for me on the Mini for two years now. After much reading and retraction testing, I have almost completely eliminated PETG stringing on my Mini.  There are some very, fine wispy spider web strings from time to time, but they are easily removable by hand, a small wire brush, heat gun or cigar-lighter-torch.

First, PETG printing speed is always slower than PLA. Check other articles and Prusa discussions for good PETG print speeds on the Mini.

I am in agreement with others that PETG is a stickier than PLA and ABS. On retraction the PETG wants to act like a sticky glob and does not want to move fast/far during a retraction. So slowing retraction speed way down appears to be the way to go to minimize stringing for the Prusa Mini when printing with PETG. I cannot completely get rid of stringing on every print and detailed printing remains extremely challenging, but I am very close. The worst I am getting is very fine wispy spider webs that are very easy to remove when the print is done.

It should go without saying that in Print Settings - Avoid crossing perimeters should always be a Yes (box should be checked). 

Setting ranges for various PETG filaments that appear to work very well on retraction tests and on real prints to eliminate stringing.

My nozzle temperature is set as close to the middle of the manufacturer's print temperature range. It is rare I go lower than 10 C below the middle of the suggested print range.  

Printer Settings or (Filament Settings - Filament Overrides): 

• Retraction length: 3.2 - 4.2 mm
• Z-lift: 0.5 - 0.1
• Retraction speed: 12 - 17 mm/s (yes, this slow seems to move the sticky PETG glob. It surprised me)
• Detraction speed: 12-17 mm/s
• Minimum travel after  retraction: 0.25 - 2.0 mm
• Retract on layer change: yes
• Wipe wile retracting: yes
• Retract amount before wipe: 15-25%

Filament Settings - Cooling (only enable cooling PETG when a layer prints in less than 90 seconds)

• Keep fan always on: No
• Enable auto cooling: Yes
• Fan Speed: Min: 60%  Max: 85 - 100%
• Enable fan if layer pring time is below: 50 - 100 seconds
• Slow down if layer print time is below: 20 -40 seconds
• Min print speed 10 - 15 mm/s

Please let me know if these settings help you on your Mini.

@ojohonny, your before picture shows typical wet filament stringing.

Reset to defaults and dry your filament.

Cheerio,