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Keri
 Keri
(@keri)
Member
Thermal Runaway

Hello,
I have been getting thermal runaway in the middle of prints. The first time it was 3/4 through a print, second time 1/2 through a print, third time 1/4 through a print and now it goes within a few layers.

The odd thing is that the temperature goes up and down depending on where on the X axis the extruder is. If the extruder is in the middle of the axis it cools rapidly, if it is on the side it works fine.

Why would that happen?

The ambient temperature varies between 60-75 degrees F. The issue happens no matter what the temperature.

Thermistor looks in good condition. I checked the wires and reseated it in the electronics area.

Fan power settings are still at the default. I use the filament that came with the printer and use the standard Slic3r settings

The fan shroud doesn't look damaged.

http://help.prusa3d.com/mk2-electronics/thermal-runaway-and-temperature-drops

Posted : 20/12/2016 1:52 am
Soynuts
(@soynuts)
Active Member
Re: Thermal Runaway

I had a similar issue with constant random thermal runaway. Ended up being the wiring to the heater was damaged, so depending on how much it was moving, it could cause the wires to not make a solid connection and not provide enough power/heat. I ended up having to replace the e3d heater and my problem has gone away completely.

You can test this by heating up the nozzle and then just wiggling the heater wires near the nozzle and see if the temperature suddenly starts to drop as you move the wires.

If you do replace it, make sure you get the 12v 30w heater.

Posted : 23/12/2016 7:36 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Thermal Runaway

I increased the Power Supply Unit voltage a little 12.8Volts
And
Reduced the Cooling to 60%

Others fitted the silicone sock that E3D make for the later heater block. or wrapped the heater block in Kapton Tape. to reduce the cooling effect of the fan.

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 : 23/12/2016 10:31 am
Keri
 Keri
(@keri)
Member
Topic starter answered:
Re: Thermal Runaway

Good ideas! Thank you. I will try them and reply

Posted : 24/12/2016 3:28 pm
simon.p
(@simon-p)
Trusted Member
Re: Thermal Runaway

A simple search would bring you to this http://help.prusa3d.com/mk2-electronics/thermal-runaway-and-temperature-drops

You possibly have a faulty thermistor connector.

Posted : 24/12/2016 4:17 pm
Keri
 Keri
(@keri)
Member
Topic starter answered:
Re: Thermal Runaway

Hi,
I have been away from my printer and haven't been able to troubleshoot yet. I do want to order any spare parts I might need so when I get home I can troubleshoot and replace parts without needing to wait for shipping. Right now I have everything stock and it was a pain to get everything calibrated so I want to keep everything as stock as possible.

Where do you buy spare parts?

If it is wiring to the heater, would I get a new hot end? What is a Bowden add on?
Is this the one? https://www.amazon.com/E3D-All-metal-HotEnd-Full-Kit/dp/B00NAK9JFO

If my issue is with the thermistor. What is the correct replacement? I like the idea of these cartridge things. Would this work? http://e3d-online.com/E3D-v6/Spares/Thermistor-Cartridge

These things look cool. I do have gunk built up from failed prints and this might help. Ideas? Is there anywhere that sells this to the US?
http://e3d-online.com/V6-Sock-Kit-3-Pack

Now if my problem is with fan speed, or voltage, why would it have suddenly gone bad? One day it was working fine and the next it was not, using the same files.

Thanks!

Posted : 01/01/2017 3:29 am
Keri
 Keri
(@keri)
Member
Topic starter answered:
Re: Thermal Runaway

Here is a video of my hot end in its current state. It doesn't look like there are any issues.
https://goo.gl/photos/e8z6VuYYH5neo1rg8

I also realized the difference between Bowden and Direct.

Posted : 02/01/2017 2:13 pm
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