Unable to stop stringing  

RE: Unable to stop stringing

Hi Nanotone, 

the prusa shouldn't string badly.

If memory serves me well the ender3 has a bowden drive extruder, and the prusa has a direct drive extruder, so the retraction settings will be significantly different

Are you using Prusa Slicer for the Prusa, or are you using your previous slicer?

the Prusa slicer settings have been pre configured to work well with the prusa printer,   other slicers can be made to work well, but you have to work out the settings that suit your combination of slicer and printer...  
regards Joan

RE: Unable to stop stringing

I tried both PrusaSlicer 2.0 and Simplify3D (with settings from the Prusa site). First I used the default values, however both slicer delivered the same result - stinging.

Here a some prints from PrusaSlicer 2.0 (default settings) with the Prusa PLA (coming with the printer)

RE: Unable to stop stringing

Hi Nanotone, when you add pictures to the forum, could you please 

enable, link to media file

and the image should enlarge when clicked

regards Joan

RE: Unable to stop stringing

how do the pre sliced models print? 

regards Joan

RE: Unable to stop stringing

Posted by: nanotone

I have got some 3d printing experience with an Creality Ender 3 Pro and with this printer and the Simply3D slicer I'm able to get very nice prints, however I spend in the last couple of days endless hours to get something similar out of my new Prusa i3 MK3S. 

They are very different printers. Be sure you're not trying to use the same techniques on the Mk3 as on the Ender 3. The direct drive mechanism needs to be set to counter stringing very differently.

No chance - every print shows very hard signs of stringing. I tried different PLAs with different temperatures and also different retraction settings, but no success. 

It would be much easier to help if you would provide specific settings that you tried.

Once as I had some stringing on my Ender 3 I changed the retraction length and speed and from now on every print was stringless.

The time has come to regret my Prusa i3 MK3S purchase 😭 

I had issues with stringing, and spent a lot of time trying to narrow down the issue. I found that -- counterintuitively -- I got better settings with less retraction and particularly less z-hop. Here are my current settings for PLA with a 0.40mm nozzle:

I arrived at these settings after doing extensive testing. Here's one run with retraction set to 0 at bottom-left, then increasing in 0.1mm increments from left-to-right on each row using PETG (normally known for being very stringy):

What I found was that:

1. You can waste a lot of time chasing "stringing" using small test prints that have no bearing on what you'll actually be printing. Try to reduce it to reasonable levels, but don't go bonkers.
2. Reducing retraction to 0 produces very poor results. Just about any other level improves it significantly. I saw little improvement using more than 0.30mm.
3. I try to keep z-hop as high as possible to reduce surface scarring, but again, low levels produce very little stringing.
4. Calibrating for your filament is almost as important as any other settings. Prusa has a blog entry on the topic, although I use a different process. Getting the extrusion multiplier right is important.

As a result,  I always calibrate for a new filament type, then start with very low retraction values. I adjust when and if I actually need to during a print. If I have large flat top surfaces, I will try to increase z-hop to reduce scarring.

If you're happier with your 1st layer calibration, print surface and bowden setup on the Ender, by all means, stick with them. This isn't a religion, and nobody's going to get bent out of shape if you decide to go somewhere else. Just watch your hands using the scraper! If instead you'd like to share your settings and some pics of your results, we can try to help you if you do decide to keep your Prusa. 

RE: Unable to stop stringing

Hi Captainkiwii

I guess that the one you linked to, will probably work... but I have no direct experience.... 

the E3D standard thermistor has a connector a short distance from the extruder heat block, on Original Prusa i3 printers, this tends to get in the way of good cable management

Prusa addressed this by replacing the connector with crimp tubes and heat shrink tubing. making the cable management much easier. 

Early in the development Prusa did use the plug and socket version, but they discontinued that option because they were getting failures due to the connector and lack of space behind the extruder assembley

regards Joan

RE: Unable to stop stringing

Posted by: joan.t

how do the pre sliced models print? 

regards Joan

 

Hi Joan, the Benchy was just printed from the GCODE from the SD card and the Retraction test was sliced in PrusaSlicer 2.0 with the 2.0 Quality profile. Both were print with Prusa PLA comming with the printer.

RE: Unable to stop stringing

@bobstro: This is the result with your settings (other setting where default 0.2 Quality profile) 🤔 

Meanwhile I have the feeling regardless what I tune, the output is always the same 

RE: Unable to stop stringing

I print almost exclusively with PETG.  I found that I could reduce stringing to an acceptable level - usually none at all - by using zero retraction, no "wipe" and no Z hop.

As to Bobstro's concern about top surface scarring, I just finished a print with a beautiful top surface. I think scarring comes from slightly over-extruding so the plastic squishes out slightly above the level of the printhead.

For me, the key is to actually measure the diameter of the filament on every spool.  I cut off three samples about 15mm long, and using the knife-edge jaws of my digital caliper I measure each sample in the orientation that gives the smallest diameter and the orientation that gives the largest diameter (filament is almost always slightly oval).  I take the average of the six readings and I write that on a label on the spool.  Then when I slice, I use that specific diameter for the filament size.  This process has worked great for me; I don't have to do experimental prints searching for the ideal Extrusion Multiplier.  (I've never even checked the default Prusa Extrusion Calibration of steps per mm; it has be perfect from day 1.)  I would never, ever, consider using a "generic" G-code file that's been generated on the assumption that the filament is exactly 1.75mm.  It never is.

RE: Unable to stop stringing

Posted by: nanotone

@bobstro: This is the result with your settings (other setting where default 0.2 Quality profile) 🤔 

 

Meanwhile I have the feeling regardless what I tune, the output is always the same 

Yummy!  Hot gun fodder.  I love the way spider webs melt away under attack by 500f air streams.

RE: Unable to stop stringing

I should have said that depending on the filament and the print I do use retraction.  Usually 0.3mm.  Larger than that for printing TPU.  But definitely zero Z hop, zero wipe.

RE: Unable to stop stringing

Posted by: nanotone

Posted by: joan.t

how do the pre sliced models print? 

regards Joan

 

".....Both were print with Prusa PLA comming with the printer....."...the Prusa filament that came with your printer is the issue. I had horrible stringing with that stuff as well, no matter what I did to compensate.

I had the exact same problem with the gray pla that came with my MK3S as well. Out of frustration, I tried generic Sainsmart pla I had on hand, used the generic pla settings in prusaslicer 2.0, and got an excellent non-stringy print. I print stuff for my quads using petg and tpu with no issues. 

I could not believe how crappy the included pla spool was....

Try something else

RE: Unable to stop stringing

Posted by: nanotone

@bobstro: This is the result with your settings (other setting where default 0.2 Quality profile) 🤔 

I suggest trying the following:

1. Try another PLA filament. Sometimes settings need to be tweaked for specific filaments. Sometimes you need to calibrate for specific filaments. This is the easiest test. If this works, it's possible that your original spool simply absorbed moisture along the way. You can try drying it. PLA doesn't absorb moisture as badly as other types, but it can under certain conditions. It costs nothing to try. If that yields bad results, you've just got a bum spool.
2. Calibrate for your filament by knocking back the extrusion multiplier a few percent. If this helps, you can use a more precise method for getting the best value.
3. If you have a spare, try another nozzle (being sure to follow E3D's nozzle swapping guidelines.) If the tip of your nozzle is damaged (or sometimes just dirty) it can aggravate stringing. (If you don't have a spare, try stroping the tip of the nozzle with a bit of cardboard.
4. Try a cold pull or 3. This doesn't look like a partial clog, but it can't hurt to be sure everything is clear.

I had very nearly the same level of stringing and it was driving me mad. That's what led me down the path of troubleshooting. Somewhere along the way, I swapped nozzles and started calibrating filaments for each new brand per type, and it mostly cleared up.

Meanwhile I have the feeling regardless what I tune, the output is always the same 

If you really just want to complain, please say so. Reading these sorts of complaints about Prusas, the superiority of Enders and whatever else you care to grouse about it really not motivating anyone to help. I'll go hang out in the Creality subreddits if I want to read how much better they are.

RE: Unable to stop stringing

Something no one seems to have mentioned: I have found reducing the hot end temp to the minimum printed on the filament spool helps - a lot - with reducing stringing.

In my case, for the Prusa Silver, that comes out to 200 C.

YMMV.

RE: RE：无法停止穿线

Posted by: @nanotone

I have got some 3d printing experience with an Creality Ender 3 Pro and with this printer and the Simply3D slicer I'm able to get very nice prints, however I spend in the last couple of days endless hours to get something similar out of my new Prusa i3 MK3S. 

No chance - every print shows very hard signs of stringing. I tried different PLAs with different temperatures and also different retraction settings, but no success. 

Once as I had some stringing on my Ender 3 I changed the retraction length and speed and from now on every print was stringless.

The time has come to regret my Prusa i3 MK3S purchase 😭 

 

 

stringless

This is a matter of choice.
1. The stringless and relatively weak structure of Ender3.
2. i3 had stringing and relatively strong structure and perfect first layer.

RE: Unable to stop stringing

@bobstro

I'm trying to work through this stringing issue on my Mk3s. I see there are 2 places to set retraction settings - in the Printer Settings/Extruder and in the Filament Settings/Filament Overrides. Does it always use the ones in the printer settings unless there is something in the Filament Overrides? Your screen clip shows the Printer settings. Not sure which to use.

RE: Unable to stop stringing

Strange - I'm finding a benchy printed on my newly built MK3S has a few wisps of "stringiness", where my old and trusted MK1 (1.75) is rock solid.

I'm sure there's lots of potential reasons  (e.g. setup/teething problems) but I didn't expect the MK1 to hold up so well. 

I was going to sell the Mk1 , but I'm now conflicted - There appears to be little printing improvement (other than a bendy plate)

just saying

RE: Unable to stop stringing

Posted by: @dlp

[...] I see there are 2 places to set retraction settings - in the Printer Settings/Extruder and in the Filament Settings/Filament Overrides. Does it always use the ones in the printer settings unless there is something in the Filament Overrides? Your screen clip shows the Printer settings. Not sure which to use.

Think of the Printer Settings group as your system-wide defaults. Unless explicitly directed otherwise, these values will be used for every print.

Think of the Filament Settings overrides as those explicit instructions to do otherwise. Most of the time, you'll leave them blank and the system-wide Printer Settings values will be applied. When using filaments with specific requirements unlike other types, you can use the overrides.