layer adhesion problem after hours of printing
Hi!
First : sorry for my english...
I build my MK3 in May 2018 and since then, I have used it a lot (around 5000 hours). Three months ago I have upgraded it for a MK3S. Recently I have observed layer adhesion troubleshootings with some PLA.
It generally happens after hours of printing on model with a lot of retractions. I read the different posts about this problem and I have decided to change the heatbreak for E3D stock V6 heatbreak (so 2mm all along the tube).
Yestersay I launched a long print (17 hours) with light grey Filamemtum PLA (print at 205 degres, a bit low). This model doesn't require a lot of retraction. This is a simple model and the stl file is great. The first layer was nice and the first 10 hours ran nicely. But the problem arrived as you can see on the pictures. I could see some PLA dust around the bondtech, so I tried to release a bit the tension but it doesn't change.
What I did on the machine the last 3 months : change the bearings (grease them), change the belt, replace the heatbreak, install a E3D nozzleX, change the heatblock...and of course clean fan frequently, oil the axes... I also install the last firmware and launch a complete Wizard without any problem.
Now I don't see how to fix it
... If someone as an idea or can show me a link to another topic that would be really helpful! Thank !
RE: layer adhesion problem after hours of printing
Have you modified your print profiles to use higher nozzle temperatures? The steel nozzle doesn't conduct heat as well and lowers the overall flow capability of the printer. Most hardened steel nozzle users report needing to print as much as 15c-25c hotter to get proper flow and interlayer adhesion.
RE: layer adhesion problem after hours of printing
Thanks for the information!
I didn't change the temperature so I will raise it up until 220 degres and have another trial.
RE: layer adhesion problem after hours of printing
A quick search of the forums for HARDENED STEEL NOZZLE : only 623 pages of posts that discuss using one in place of the stock brass.
RE: layer adhesion problem after hours of printing
Hi,
Thanks for the links, they recommend to increase by 5 degres. So I changed the extrusion temperature, 10 degres more (I was too low before), so it was 215 degres this time.
Unfortunetaly it doesn't change anything, it is worst... Once again the first layer is perfectly fine. I really don't see where the problem comes from.
RE: layer adhesion problem after hours of printing
Simple thing to check. Can you try a different roll of filament?
Referring back to your first pictures and the horizontal dark lines close to the top, it looks like you might have a moist filament problem.
RE: layer adhesion problem after hours of printing
Hi,
I don't have this issue with PETG. For PLA I didn't try other filament since I have changed the heatbreak.
I doubt there is a moisture problem cause the roll is only 2 months old and is stored in a dry place. But you are right, I will try other PLA to be sure.
Before changing the heatbreak, I had problems with PLA semi-matte black and white from Colorfabb (these PLA don't have fiber inside) and Filamemtum electric grey. But Polymax from polymaker prints perfectly fine (really good filament! But crazy expensive).
RE: layer adhesion problem after hours of printing
Your first layer looks really good - to me. Your bed adhesion looks really good - to me.
That about exhausts my expertise. Higher layer problems (belts, extruder, steppers) will take a higher authority.
I am sure one will comment.
RE: layer adhesion problem after hours of printing
Is it only that part giving problems?
If yes, does it tend to fail in that same spot on that part? Like problems begin when printing the bridges over doorways. Are you using Detect Bridging Perimeters?
The fact is seems to be printing the right shape offset from the part, hints at a crash... and this section looks like you are printing a rather difficult overhang without any support, and the first images hint at bridging problems.
Post your STL or export and post a .3MF (zipped) so folks can see what the part looks like in three dimensions and what your settings are.
RE: layer adhesion problem after hours of printing
Hi,
You are right, the problem usually occurs at a specific spot, like bridge. On this model, I don't use support and there are some overhangs (they are a bit tricky cause they are not perfectly straight). I don't use Detect bridging perimeter. For this print, I use the stock setting from Prusa : PLA Speed 0,15 mm. I just changed the temperature according to the fact that I use a hardened nozzle.
I try the exact same settings but with Filamemtum Extrafill Vertigo Grey. The print is nice, without any bad adhesion between layers.
So the problems happens with Filamemtum Electric grey, Black Pla semi-matte, White PLA semi-matte. With Extrafill vertigo grey and Polymax I don't see any problem. It is a bit strange cause I never had theses problems before (even with theses filaments) and I have printed much more complicated model without support and tons of retraction.
I have attached the stl file. It would be really interesting for me to know how you would set up the slicer for this kind of print.
thank for your help!
RE: layer adhesion problem after hours of printing
This arched window header will be difficult to print unless supported. It's just begging for curl and bridge related fails. I'll play with it and get back to you.
RE: layer adhesion problem after hours of printing
I suspect you are fighting a nozzle crash at the windows. The PLA is curling and presenting a good place to snag the nozzle.
And, that arch is a pain. FDM doesn't print in free air very well, and doing a horizontal loop in free air is, well impossible: unless you allow supports. The closet? area should print okay, but make sure you're using [X] Detect Bridging Perimeters and have the bridge infill alignment correct (default angle worked for me).
But if it isn't the nozzle colliding - the steel nozzle (or how it was installed) can add to the print complexity. Do some more reading, pretty sure 5c is NOT enough to compensate for the different conductivity. And you haven't mentioned reducing your flow rates as needed, either.
You might look into a Tungsten Carbide nozzle: they are reported to work as well as brass, and wear better than steel.
RE: layer adhesion problem after hours of printing
Thank you!
Your recommendations are really helpful. I have already changed the flow, so I will change some others settings and have a look on this tungsten nozzle. I doubt my nozzle isn't well installed but I will check it too, sometimes it is easy to forget to screw half a turn.
I believe my problem is a combination of many 'small' things: temperature, filament, bridging settings, support...
And when everything arrive at the same time : the problem occurs.
So now I will take time to check everything step by step cause you gave me some good informations.
Regards,