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PETG bubbling due too high temperature?  

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Wojciech
(@wojciech)
New Member
PETG bubbling due too high temperature?

Hello, 

I have i3 mk3s, from the beginning when I assembled it, it was printing beautifully. Then I replaced motherboard, nozzle, thermistor and nozzle heater. Now I have terrible stringing and during the print I can hear that melted plastic is bubbling, it is visible also on the prints. It is not about humidity absorption, I tried with new reels as well. I replaced thermistor, checked wiring and fixing of heater and thermistor in the heat block. Everything seems to be fine. 
I was trying to measure the temperature using thermocouple, I observed that when temp is set to 200c I can read the same result on my tester but setting 230 results in 250C on the tester with thermocouple. 
I performed factory reset and then PID calibration using standard procedure for the menu. 

Please advise what I can do to fix this strange issue. 

best regards 

Wojciech 

Posted : 25/11/2021 2:46 am
Dan Rogers
(@dan-rogers)
Noble Member
Did you buy the correct heater

Just thinking what could go wrong - putting a 12 v heater into the 24 volt machine could do this.

Posted : 25/11/2021 5:14 am
Wojciech
(@wojciech)
New Member
Topic starter answered:
RE: PETG bubbling due too high temperature?

Hi Dan, thank you for the replay and suggestion. I have to check what I bought but always I'm looking for parts for MK3S only. 

Anyway I will check and let you know.

Posted : 25/11/2021 8:56 am
Wojciech
(@wojciech)
New Member
Topic starter answered:
RE: PETG bubbling due too high temperature?

Hello Dan, as you suggested I did a simple check with the heater - it is correct 40W 24V. Then I replaced the heater as I have spare part from Prusa store. Nothing changed at all. 

I was playing with different temepratures to find sweet spot and from now PETG prints almost without stringing at 220C. Previously it was 230 - 240 with perfect results. 

Anyway thank you for giving your thoughts.

Cheers
Wojciech

Posted : 26/11/2021 11:04 pm
3Delight
(@3delight)
Moderator
RE: PETG bubbling due too high temperature?

This can also be caused by damp filament.  Either try some brand new filament or dry what you are using.

How Do You Dry PETG?

You can dry PETG in your oven at a temperature of 65-70°C for 4-6 hours. You can also purchase the PrintDry Pro for both effective filament drying and storage. A food dehydrator works great for dying PETG, and you can also purchase a cheap filament dryer to keep PETG dry and moisture-free.

Let’s take a look at how you can dry your PETG.

Dry in an Oven PrintDry Pro Filament Drying System Food Dehydrator Filament Dryer Dry in an Oven

One of the easiest ways to dry out PETG is by using a regular home oven. This is a quick way to get rid of any moisture build-up that your filament might have if you’ve left it out in the open for some time.

The recommended PETG filament drying temperature is done best at 65-70°C for anywhere between 4-6 hours.

Posted : 26/11/2021 11:39 pm
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