Having problems with overhangs (?) , on every type of plastic
 
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mAtoOo
(@matooo)
Active Member
Having problems with overhangs (?) , on every type of plastic

Hello!

To start off , I rock a MK3S+ with a REVO Six hotend , and dual print fan setup. Until recently everything was working flawlessly but after , a rather hard, nozzle change (where the nozzle got stuck because of a serious clog and I had to remove it with pliers), issues started to occur on my prints, especially with overhangs.

I have tested these on both overhang test prints and benchies where I tried to adjust the print and bed temperatures, print fan speeds , print speeds (this helped a lot compared to the others), and PID and overall calibration with no , or limited success. I tried different nozzles too, but it was not the issue in them - this was just overthinking.

I had partial success after straightening the Z-axis (making sure they are even), (the picture with only one PET-G benchy)

These overhang issues are reoccuring on every filament I print with - PLA, PET-G and ASA.

Thank you, I will value your input/help ! 🙂
PET-G Benchies - same nozzle, different speedsPET-G benchy - after straightening the Z-axisPLA Benchies - same gcode two different 0.4mm nozzles

Posted : 28/07/2023 12:43 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Having problems with overhangs (?) , on every type of plastic

Could you please send a picture similar to this, of your prusa with  Revo. 

Note, this is not a prusa, but it's the only printer that I have a Revo on!

regards Joan 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 28/07/2023 1:01 pm
mAtoOo
(@matooo)
Active Member
Topic starter answered:
RE: Having problems with overhangs (?) , on every type of plastic


Note: Ignore the background , that is obviously not my main print room. It is there just for testing purposes :p

Posted : 28/07/2023 1:43 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE:

Is that an aftermarket Fan duct? often modified fan ducts perform poorly.    I was looking to see if the fan duct was low enough, and that looks ok... do you have a standard prusa Fanduct that you can try? 
Can you turn the Benchy 90 degrees so that the bows are pointing in a different direction, and see if the results change  there may be poor cooling in some areas... 

If you need to print a prusa fan duct, you can print PETG without a fan duct if necessary. petg is not as good as |ASA but for a test it should be fine

good luck, 
Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 28/07/2023 4:09 pm
mAtoOo
(@matooo)
Active Member
Topic starter answered:
RE: Having problems with overhangs (?) , on every type of plastic

Turning the benchy seems to help with the overhangs significantly.  Is this due to poor belt tension (I tried adjusting these twice before writing this post , I guess it was not enough?) or is this due to cooling? There still seems to be a very small artefact at the beginning part of the bow of the ship.

Picture:

Posted : 30/07/2023 8:33 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Having problems with overhangs (?) , on every type of plastic

I would suspect cooling. Try a standard prusa fan duct

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 30/07/2023 9:39 am
fuchsr
(@fuchsr)
Famed Member
RE: Having problems with overhangs (?) , on every type of plastic

I must say I've tried a few new and improved fan ducts and found that none of them did any better than stock, and often worse… I suspect that there's always the edge case or two were those "improved" designs may yield better results, I just never encountered one in my practice.

Posted : 30/07/2023 10:29 am
mAtoOo
(@matooo)
Active Member
Topic starter answered:
RE: Having problems with overhangs (?) , on every type of plastic

This helped, I found a standard prusa fan-duct but for two print fans, the prints are flawless now. Thank you! 🙂

Posted : 25/08/2023 7:12 am
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