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MisterA
(@mistera)
Eminent Member
Inconsistent printing

Hi,

I'm currently building my own 3D printed headphones and I have experienced very inconsistent printed parts.
The first 'cup' I printed turned out ok. See first picture.

When I printed the second cup (same gcode, firmware, same filament,...) I noticed parts of the cup were not printed well.
It's not complete layers that fail but more like a big spot in the print is not extruded correctly? Very weird.

A third print was even worse as you can see in the third picture.

Any idea what the problem could be? Like I mentioned before, I have adjusted no setting at all. I'm using the same gcode file, mk3 firmware, octoprint version, filament,...

Best regards,
Jan

Posted : 22/06/2018 11:03 am
robert.t17
(@robert-t17)
Eminent Member
Re: Inconsistent printing

That looks like Prusa PLA. I had similar problems and solved them with a different brand.

Posted : 22/06/2018 1:15 pm
MisterA
(@mistera)
Eminent Member
Topic starter answered:
Re: Inconsistent printing

It's indeed Prusa Silver PLA. Didn't know there were quality issues with their PLA?
Just ordered another kg of it, plus 2kg orange ngen.

Posted : 22/06/2018 2:11 pm
ClassicGOD
(@classicgod)
Eminent Member
Re: Inconsistent printing

Problem here is too localized, if it was filament issue it would be all over the print.

Looks like cooling issue to me. Is this part positioned away from the fan? Try orientating the modeli differently (rotate by 45 degrees) and or lowering temps by like 5 degrees. It also could be caused by the first layer curling in that place - is your PEI sheet clean and not damaged - you can try printing in a different spot.

PS. It also looks like your fist layer is a bit too low. Try adjusting your z offset.

If you try and take a cat apart to see how it works, the first thing you have on your hands is a nonworking cat.

Posted : 22/06/2018 3:23 pm
MisterA
(@mistera)
Eminent Member
Topic starter answered:
Re: Inconsistent printing

As suggested, I adjusted the Z offset, rotated the model and cleaned the printing sheet with rubbing alcohol.
I'll do another print and report back.

What I did notice however are 'bubbles' on the print sheet. Don't know if this is normal or not.
On the front side of the sheet I can clearly see the countour of the printing cup I printed (3 times now).
The backside is full of these 'bubbles' as you can see on the pictures.

You can't really feel them, I guess they are beneath a clear top coating of some kind.

Posted : 22/06/2018 5:44 pm
Peter L
(@peter-l)
Honorable Member
Re: Inconsistent printing



What I did notice however are 'bubbles' on the print sheet. Don't know if this is normal or not.
On the front side of the sheet I can clearly see the countour of the printing cup I printed (3 times now).
The backside is full of these 'bubbles' as you can see on the pictures.

The bubbles are normal. They will come and go; I've been using the same PEI sheet for many hundreds of hours of printing and it does not cause a problem.

Posted : 22/06/2018 8:44 pm
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