freaky printhead jam

This is for general discussions. Also FAQ can be found here.

Moderator: speedake95

Post Reply
Geertjan
Posts: 62
Joined: Thu Aug 23, 2012 6:22 pm
Location: maastricht, NL
Contact:

freaky printhead jam

Post by Geertjan »

extruderjam.jpg
During an overnight lengthy print session something went horribly wrong. But I am not sure what caused this. The base of the printhead and the door mechanism melted, the filament was still feeding and ended up like a clew between the feeder and the extruder.
Any Idea's on why this happened ? Perhaps the thermistor failed?

Saamec
Posts: 157
Joined: Fri Jun 21, 2013 9:28 am

Post by Saamec »

Obviously insufficient input data. What plastic printed? No pictures of the extruder. I honestly have not seen this. Sympathize with you. I think thermistor nothing to do with. Rather was the place to print at high temperatures. Maybe cooling fan extruder not worked. On my printer was the failure of thermistor, so extruder just cool and everything, respectively cut off the plastic and thread bored, and all. I am inclined to believe that you have typed ABS plastic at high temperatures. Platform led from the heat and the fan on the role played by submitting this heat, as пеплый air rises. There was a huge temperature table and extruder. I am concerned as plastic so twisted. At what expense? Comes to mind, that on extruder is not fluoropolymer coupling, say aluminum. Fluoroplast prevents the rapid transfer of heat in the upper part. In General, you need details of printing , and more. From what you wrote, it is difficult to make any presumptions to determine the cause of all this. Describe everything in detail.

Geertjan
Posts: 62
Joined: Thu Aug 23, 2012 6:22 pm
Location: maastricht, NL
Contact:

Post by Geertjan »

I was printing PLA at 205 degr.
I have not tested if the fan is still working nor that it failed during printing. But the fact that the PLA was crumpled as it did is an indication to me that the temperature went up above the intended 205 degr.
I still have the old extruder parts from my 1.5 felix. I'll try to use the old parts and run some tests. I certainly keep an eye on the printer while printing. No overnight printing for me.

Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

Sorry to see this.

You should inform Guillaume, if not already done.

Important for everyone to understand what happened and to fix it .

Potential fire hazard here maybe ? Can the heating element become hot enough to ignite PLA ?
Hugues
Regards from Switzerland

satoer
Posts: 436
Joined: Mon Oct 01, 2012 8:00 pm
Location: Netherlands

Post by satoer »

According to this PLA Material Safety Data Sheet:
http://bitsfrombytes.com/sites/bitsfrom ... 20MSDS.zip

Flammability:
Autoignition temperature: 388°C

Never tried it, but if the controller board keeps heating it 100%, without cooling (and also no cooling from the melted filament cooler)... I think it's possible the hot end can reach that temperature. But I don't think the aluminum top block can reach that because of the PEEK insulation between them.

So, the PLA will not auto ignite?

My theory: The melting point of Polyether ether ketone (PEEK) is 343 degrees That's way lower than the autoignition temperature of PLA. So before the PLA will autoignite, the PEEK is melted. Resulting falling of the X Carriage on the printed PLA object... if it goes beyond the 388 it probably autoignites and burning the X carriage above it. That's not a happy forecast.

Maybe a solution: implement a second thermistor. If the temperature difference between them is more than 30 degrees the firmware will disable the heater. this shouldn't be hard to implement I think.
My Felix 1.5 printed designs on Thingiverse
E3D V6 Hot end upgrade for your Felix
Tweezer bracket for your Felix
Led bar upgrade for your Felix

Geertjan
Posts: 62
Joined: Thu Aug 23, 2012 6:22 pm
Location: maastricht, NL
Contact:

Post by Geertjan »

I indeed was thinking about a safety mechanism and two sensors measuring temperature difference make sense . I don't think the printer software has an option for this? The Filament in the top part above the peek insulation was melted but not overheated. (no bubbles formed) I had to heat up the aluminium top part to get the filament out.
I wish I did know what finally stopped the printer. I did not make enough noise to wake me up:-(

Hugues
Posts: 270
Joined: Thu Apr 04, 2013 5:36 pm

Post by Hugues »

satoer wrote:...

Maybe a solution: implement a second thermistor. If the temperature difference between them is more than 30 degrees the firmware will disable the heater. this shouldn't be hard to implement I think.
Good idea, and probably simple to implement, and cheap.

Guillaume ?
Hugues
Regards from Switzerland

gobi
Posts: 52
Joined: Sun Sep 09, 2012 1:05 pm
Location: Hungary

Post by gobi »

check this out. filament broke at the top and the rest just followed

Image

Image

Image

Bachgassenbande
Posts: 132
Joined: Sat Jul 20, 2013 12:50 pm
Location: Würzburg

Post by Bachgassenbande »

What happend with your hotend? seems like it disangled? Was the fan running?
Felix 2.0
E3D Kraken Hotend
3mm Glas bed
LED light bar upgrade

gobi
Posts: 52
Joined: Sun Sep 09, 2012 1:05 pm
Location: Hungary

Post by gobi »

the filament pushed it away and as a result the little 'door' melted as the head moved -

Post Reply