Print quality degrades near the edges of the print surface
 
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doctorg
(@doctorg)
Eminent Member
Print quality degrades near the edges of the print surface

I am wondering if anyone else has run into the issue of perfect prints in the center, but substandard prints when printing close to the edges of the print surface.

I am printing in PETG on a MK3S+ with MMU2S, nozzle is at 235c (hardened steel), bed at 85c, first layer speed is 15mm/s. This prints a beautiful first layer test in the center, but will not stick to the print surface if I push it out near one of the print surface edges. When I increase the nozzle temp to 245c, the problem is solved, and the prints on the edge look amazing. So, I am just curious if anyone else has experienced something similar.It seems odd that temps would affect one side more than another. I use the 27 point calibration before each print with no problems. It also seems to affect the right and rear edges of the print surface more that the left or front.

Any thoughts?

 

Posted : 18/02/2024 10:47 pm
JP Guitars
(@jp-guitars)
Estimable Member
RE: Print quality degrades near the edges of the print surface

Sounds like uneven bed heating to me.

Posted : 19/02/2024 12:38 am
doctorg
(@doctorg)
Eminent Member
Topic starter answered:
RE: Print quality degrades near the edges of the print surface

Could be, my next test will be to check the temps with my thermometer gun. But, I increased the bed temps during my test prints and that did not make any difference, so I temporarily ruled it out.

Posted : 19/02/2024 12:49 am
Diem
 Diem
(@diem)
Illustrious Member

Two possibilities:  Poor adhesion close to the edges *might* be a bed cleaning issue; the edges collect more fingerprints than the centre so need more cleaning.

Or drafts/air currents affecting the cooling, a variant happens when room heating switches off overnight and parts of a long print are impacted by air temparatures outside the acceptable range.

Cheerio,

Posted : 19/02/2024 6:57 am
doctorg
(@doctorg)
Eminent Member
Topic starter answered:
RE: Print quality degrades near the edges of the print surface

Thank you for your thoughts. No drafts in this area and my tests were on a freshly cleaned surface (soap and water, followed by an alcohol scrub). I eliminated (I think) all the "usual" problems, the increased heat is the current solution. That's what doesn't make sense to me.

Posted : 19/02/2024 11:02 am
_KaszpiR_
(@_kaszpir_)
Reputable Member
RE: Print quality degrades near the edges of the print surface

You don't need a draft per se but sometimes even minimal flow from the cold window pane pouring on the printer can have a negative effect, especially if you need to increase temperature just a bit.

What is your ambient temperature? What is the outside temperature?

Does the printer stands close to the window or wall? May be worth to even try with cheap carton shield to see if it helps for test.

Another thought is uneven bed but calibration should in theory help with that unless the differences are noticeably higher than the first layer.

See my GitHub and printables.com for some 3d stuff that you may like.

Posted : 20/02/2024 6:58 am
doctorg
(@doctorg)
Eminent Member
Topic starter answered:
RE: Print quality degrades near the edges of the print surface

Thank you for those thoughts. The printer is not located anywhere near a window or air vent. I have a friend who had that problem with a vent directly above the printer, so I knew to avoid that situation. The room temperature stays between 72F and 74F and the humidity during this time of year is about 25%. I keep a digital display next to the printer to track those metrics.

I don't really need an answer or solution, printing is great. Mostly I was just curious if anyone had a similar experience. It seems the answer is no, and that is OK. Thanks everyone for contributing to the conversation.

Posted : 21/02/2024 3:19 pm
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