Solved Clogged hot end

After two hours of running I realized no PLA was coming out. I have removed the hot end according to the instructions. But even at 240° the filament seems to be really stuck. So as not to make things worse, what do I do next?

 

When you say "remove the wires", you must mean unplug the cables. But the wires will still be attached to the heater and the thermistor, right?

I wonder if this happened because my nozzle is running too close to the bed, and the filament has trouble getting out.

The tiny little fan on the side of the heater always runs, but it's not very big, and it doesn't move much air.

 

Never underestimate how little a greenhorn knows, or how much "sense" may not be common. ;-)

Since I don't want to do MORE damage, I'm going really slowly. I assume I can remove the heater by loosening the 1/16" hex screw, but should not try this when it's cold. I loosened the screw and heated the fins with a hot air gun. It will twist now, but does not easily pull off. Do I just need to heat it up good and pull hard enough to separate the heater from the cooling fins?

 

Should I first remove the thermistor capsule and heater block from the hot end, before I try to separate the hot end from the cooling fins?

 

After much careful fiddling and finagling I have disassembled the entire hot end. One thing that was not clear is that the cooling fins UNSCREW from the heater block. The setscrew tricked me into thinking it was a slip fit. And, evidently, this screwed connection was jammed up against the nozzle, preventing it from unscrewing. Once the heater block unscrewed a little, the nozzle came loose.

With heat and MEK I have cleaned all the PLA from the nozzle and cooling fins (still don't know the correct term).

But I have another question before I assemble this again. At the top of my cooling fins there is some brown sealer. I thought this was melted PLA, but now I'm thinking it's some kind of high temperature RTV gasket material. Does this need to be removed and reapplied to reinstall the hot end? It seems likely that this old material will prevent a proper seal if I try to insert it as-is.

 

What about the old sealer on top of the cool end?

 

So, no need to scrape off the old stuff?

 

Actually, the sealer on top of the cold end had to be scraped off. Left in place, the module could not be inserted high enough to close the latch. For future reference......

 

I got everything back together. Before I test the heater, I want to adjust the bed. I'm pretty sure my clog was caused by scraping the bed with a nozzle set too low. When I can get the Z axis to go home, the nozzle is touching the bed. I can manually turn the lead screws to raise the head, but it resets on the next home command. I looked up an old thread about this, and Mark said:

They have screws that hold them clamped to the nuts so .. loosen those and make sure the nut is seated into the X carriage fully (all the way) then slide the switch up so that with the nozzle off of the bed the switch is pressed up tp the carriage and closed. Retighten the screws that hold the switch to the nut.​

I see two screws that hold the limit switches in place, but loosening them does not seem to allow me to adjust the position of the switch. Are these the screws you were talking about?

Also, MatterControl 2.0 mostly doesn't respond to a request to home the Z axis. It only works sometimes.

Everything is a struggle.....