Stops extruding - Wrong temperature?

[Sergantnord]

The problem:
The printer stops extruding suddenly. At first mid print and now all the time.

I have a Rostock Max V2 printer and it started to do bad prints suddenly a few weeks ago and before that i never had a problem with it with 2 months of regular use.
Layers stopped sticking together and after a while it stopped extruding completely. I suspect its the temperature that drops because when using a IR thermometer pointed at the nozzle I get a reading of about 50c lower than indicated.
It clogs the nozzle pretty quick and only clumps of filament get out every few layers. I have cleaned out the nozzle 3 times and after the first time i managed to get about 10 hours through a 15 hour print before it clogged up again and the extruder started digging through the filament. When i cleaned it again it started clogging after a few seconds.
Everything is stock on this printer.

When i try to push filament through by hand i can't and it feels like its not hot enough even though it says 230


What i have measured:
In room temperature i get 21c both from the IR thermometer and from the lcd display.
The same happens at 100c so when I point the IR thermometer towards the hotend it says 100c.
When i heat up the hotend to 200c it says 200c on the lcd but when using the IR thermometer i can't get it over 170c at all and when i put it up to 230 i get something like 180 at most with the IR temp.


Did a thermistor break down on me or is the problem something else altogether?
I dont know even know if the hotend is supposed to reath the same temperature on the outside as it does on the inside so maybe measuring with the IR thermometer is useless?

I'm really tearing my hair off here!


http://imgur.com/a/jvi8S

[IMBoring25]

IR thermometers can be less reliable when targeting something as small as a hot end. Have you added the PEEK fan and are you sure the filament is not PLA?

[Sergantnord]

Yes the peek fan is there and i have tried several different brands of ABS, its definitely ABS since i can dissolve it in acetone

[Tincho85]

It looks like a thermistor issue. Do you have a spare one? Change it and see what happens.
Or read the temperature with a thermocouple, they are more accurate.

[Tincho85]

Oh, and be careful with the ultra copper rtv silicone. Don't fill the thermister hole with it. It will act as a thermal insulator and give you bad readings.

[teoman]

If i were you i would get one of those screw in thermistors.

Also if indeed it is failing by reading too high of a temperature, you are lucky as should it be the opposite situation you would have a dead peek in your hands.