Thermal runaway MELTED the aluminum heat block  

RE: Thermal runaway MELTED the aluminum heat block

There is no doubt about it contact support through live chat on home page way to dangerous to try fix something when getting to that hot of temps it may also be the einsy how old is printer if it's less then 1 year they will also send parts for free

RE: Thermal runaway MELTED the aluminum heat block

Posted by: @dcphoto

My question is how could this have happened and what kind of problem should I be looking for when I fix it?

More info can be found here .

RE: Thermal runaway MELTED the aluminum heat block

Well, it goes without saying that you reached a temperature of 660.32°C.

Posted by: @dcphoto

I think it goes without saying that … My question is how could this have happened? 

RE: Thermal runaway MELTED the aluminum heat block

The experts at Prusa would be needed to answer this question. However, they would need more information about what was going on when this happened. 

Was your thermistor working correctly?

The thermistor is measuring the block temperature. If the thermistor is not working correctly, you would continue to put in power and heat up the block. 

Posted by: @dcphoto

and what kind of problem should I be looking for when I fix it? 

RE: Thermal runaway MELTED the aluminum heat block

Don’t see any specs thermistor.  Found this description on Amazon.

Description

A custom made thermistor encapsulated into an easy to use cartridge package. Using our proven Semitec 104GT thermistors, which are then potted into a cylindrical copper cartridge with a high conductivity ceramic based adhesive. The legs are insulated with fibreglass sleeving, and terminated with a Molex Microfit 3.0 connector. This makes it particularly easy to disconnect your entire HotEnd without the need for re-wiring, especially when used with our high-precision heater cartridges.

RE: Thermal runaway MELTED the aluminum heat block

So it appears to be anE3D thermistor.

E3D explains their temperature measuring options here.

And E3D gives the thermistor specs here.

And theData Sheet here

So at 0C, the resistance is 354,600 Ohms.
At 25C, the resistance is 100,000 Ohms
At 100C, the resistance is 5 569 Ohms
At 200 C, the resistance is 445.2 Ohms
At 300 C, the resistance is 82.78 Ohms
And that is its official limit.

.

Prusa will definitely want to know about this, especially if you are using the most recent firmware.  Contact support with these pictures and the version number of the firmware you are using (LCD menu).

For support: Log into your Eshop account, navigate to Company, click Contact Us and 24/7 live Chat is one of the options.

Cheerio,

RE: Thermal runaway MELTED the aluminum heat block

So you can test your NTC Thermistor to see if it is working correctly.

With it still plugged in, does it read ambient temperature?

Unplug the Thermistor, check the resistance at room temperature.

Put it in hot water at a known temperature. Check the resistance again.

Repeat for another temperature.

RE: Thermal runaway MELTED the aluminum heat block

A good article onthermistor failures.