MK4 PLA Stringing  

RE: MK4 PLA Stringing

I might have missed it, but did you try to increase the tension of the Nextruder? It might be that the filament slips due to the fast retraction.
At least, this was it in my case.

RE: MK4 PLA Stringing

I also tried to play around with the tension. And also performed 3 cold pulls in a row. 

Still no change. 

RE: MK4 PLA Stringing

Same observation: no stringing on my old MK3, bad stringing on MK4, with otherwise very good results on any other features.

Some trials: 1/ printing with layer 0.15 gives better results then 0.1 

2/ Without having the means to measure, I have the feeling that "190°on MK3" is not the same as "190° on MK4". I made several test prints with the usual PolymaxPLA and lowered temp from 195° to 190° and now 185°. It is going better.

RE: MK4 PLA Stringing

What also causes stringing is over extrusion, as the distance and speed of the retraction aren't correct. Did you try to lower the extrusion?

Posted by: @soccermaster

I also tried to play around with the tension. And also performed 3 cold pulls in a row. 

Still no change. 

RE: MK4 PLA Stringing

I managed to get rid of nearly all the stringing (after tweaking just everything, mostly unsuccessful)

1/ Lift Z set to 0.1, "Whipe while retracting" desactivated

2/ Lowering the temp down to 185° (PolymaxPLA), except first layer

Also: Perimeter generator reset to "Classic" , "Thick bridges" on

RE:

Posted by: @3designsch

What also causes stringing is over extrusion, as the distance and speed of the retraction aren't correct. Did you try to lower the extrusion?

As I stated in my beginning post I already adjusted the extrusion to the correct value. Had to raise the value in M92 to E412 instead of E380 as the extrusion was too much, indeed. But, sadly, the effect was just of a small improvement. However, what makes me wonder, is that this value wont be stored with M500 (what is working on the MK3S). After a power cycle the value gets lost and resetted to E380. Any tips, how I can store the M92 (of the M503 printout) value on the MK4? 

Posted by: @volkmar-meier

I managed to get rid of nearly all the stringing (after tweaking just everything, mostly unsuccessful)

1/ Lift Z set to 0.1, "Whipe while retracting" desactivated

2/ Lowering the temp down to 185° (PolymaxPLA), except first layer

Also: Perimeter generator reset to "Classic" , "Thick bridges" on

I tried that as well without any improvement. My MK4 doesnt seem to perform in a correct way.

RE:

>> Any tips, how I can store the E92 (of the M503 printout) value on the MK4? 

You can't (M500 is not supported).  But you can customize the start Gcode in your slicer to include the proper E92 command, so the adjustment is made before each print starts.

RE: MK4 PLA Stringing

My MK4 is also very stringy, but the MK3s+ sitting beside it is pretty much free of strings.

It's extremely annoying... I tweaked a bunch of the usual things, but didn't solve anything, and then I gave up. 

I'm just going to print string-prone prints with the MK3s+. Really disappointed with the MK4.

RE: MK4 PLA Stringing

I wonder if it's a nozzle issue.

Anyone who's using the nozzle adapter with an old school V6 nozzle also have stringing issues?

RE:

I'm only in 3D-printing for a couple of months now and only printed large objects .

Yesterday i had to print a very small object with 3 small towers inside.
I noticed that i had a lot of stringing and was very surprised by that.

So today i found this interesting thread and tried the g-code from Rainer.
I noticed that he was printing the towers at 200° while i print the PLA (Prusament) at 215°.
So i lowered the temperature to 200) and it came out almost perfect with just a little bit of stringing.
I lowered the temperature to 195.

Just take a look at the pictures.....

Printed at 215° (prusament default settings)

Printed at 195°

RE: MK4 PLA Stringing

Also noticed this in my mk4, heavy stringing, at least they are really fine but so annoying. Never had that on my mk3s+

Quite disappointing that the printing quality in the new product is worse compared to their own mk3.

RE: MK4 PLA Stringing

For anyone still having stringing issues, I'm curious as to which nozzle you are using, and whether you've attempted re-tightening the nozzle in the heater block.

RE: MK4 PLA Stringing

yes, I tried all things physical with the nozzle/heater block, and even ordered a brand new nozzle. 0.4mm. Nothing made any difference.

Posted by: @carlmmii

For anyone still having stringing issues, I'm curious as to which nozzle you are using, and whether you've attempted re-tightening the nozzle in the heater block.

RE: MK4 PLA Stringing

I tried a lot of combinations. More than 15 impressions. In none have I achieved the expected result. The best I've gotten, and it's 70% Stringless was:40 mm/ 0.4m Retraction / 190°.It is really worrying that such an EXPENSIVE printer has these problems.I'm testing with Firmware Input Shaper RC and Prusa Slicer 2.6.1 RC. Every day I think that I should have bought a Bamboo

RE: MK4 PLA Stringing

Every day I think that I should have bought a Bamboo

You can still do it. I'm sure you can sell the MK4 well. If you take the P1S you might even save money.

But I would advise you to visit the bambulab forum first. Just in case you don't think there are any problems there.

And if you really do, unplug the bamboo when you're not at home. Not that he starts printing alone again and your house burned down.

I read here in the forum of someone who had a Bambu and is now happy with his MK4. So it also works the other way around.

The important thing is that you are satisfied.

RE: MK4 PLA Stringing

No friend, I live in an underdeveloped country. You have no idea how difficult it was to buy the MK4. There are no second chances in this case. Thanks for the recommendation

RE: MK4 PLA Stringing

In the end I found that lower print temps, down to 180 for PLA, more or less solved the issue. I do have to wonder if the temp is reading low causing the actual temperature to be higher than expected. Overall though I am very happy with the printer. The quality at the alpha firmware input shaping speeds is great, I'm building the Ikea Lack enclosure and have ordered the MMU3. Whatever is the ultimate cause of the stringing, I am remaining hopeful that it will be fixed.

RE: MK4 PLA Stringing

the mk3 series have a low extrusion temperature  threshold of 170C set in firmware, (COLD EXTRUDE  M302)  below that, the extruder, simply stops working(NO Warning, No error messages) , I expect that the mk4 is similar. 

If this becomes a problem, you can lower the Cold extrude setting can be revised 
See 
https://marlinfw.org/docs/gcode/M302.html

regards Joan

RE: MK4 PLA Stringing

Well, if I could get the free roll of galaxy black to stick ...     I have had good retraction tests  with FL form 220-225 and OL 215-220  (I am using a /25 nozzle x in the adapter.  On the prusament GB my retraction is .8 and  .1 @ 40 mms  on Poly Terra Charcoal Black, same nozzle  .2 and .1   @40 mms  FL 220 others 212 no strings unless I jack around with the temp and speed to finish up a print too fast =D

RE: MK4 PLA Stringing

Interesting... so u increased the temperatures to get less stringing?

I get less stringing when I use the input shaper profile which also is much higher temps.

Posted by: @paul-harbin

Well, if I could get the free roll of galaxy black to stick ...     I have had good retraction tests  with FL form 220-225 and OL 215-220  (I am using a /25 nozzle x in the adapter.  On the prusament GB my retraction is .8 and  .1 @ 40 mms  on Poly Terra Charcoal Black, same nozzle  .2 and .1   @40 mms  FL 220 others 212 no strings unless I jack around with the temp and speed to finish up a print too fast =D