Cleaning the hotend and heat block
I had a clog a few weeks ago with a gray PLA filament. I cleaned it out as much as possible using pliers and scissors, opened up the extruder and took out as much of the plastic that was on the heatblock.
After the clog, my prints still keep getting small chunks of gray in them like this and this.
After the cleaning, this is what the heat block looks like now. There are still some small parts of plastic between the "spring" and the "block", but I don't know if its possible to remove the "block" part of the hotend from the spring, and if it is even necessary.
Should I assemble the extruder back again, are the prints going to work now, or is this hotend lost and I'll need to buy a new one?
RE: Cleaning the hotend and heat block
You can use a brass wire brush to clean the block up further when its at temperature.
RE: Cleaning the hotend and heat block
It looks like you need to rebuild the hotend.
The heatbreak isn't far enough into the heater. Your nozzle is right up against the heater. That means there is a small gap between the two.
Heat it up. Remove the nozzle. Let it cool. Remove the hotend. Screw the heatbreak in until it's flush. Screw in the nozzle. It should be a full mm away from the heater block. Heat the hotend to 285, and tighten the nozzle.
There will likely be some cleaning steps you'll need to do with the hotend apart. A 6mm tap is your friend. You likely have plastic in the heater block threads.
Be careful of the wires. The thermistor wires are particularly fragile.
Good luck!
RE: Cleaning the hotend and heat block
You can use a brass wire brush to clean the block up further when its at temperature.
This is what I use.
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Chuck H
3D Printer Review Blog
RE: Cleaning the hotend and heat block
When using brass on a heater block, just be aware the heater wires are NOT insulated as they leave the casing and brass brush bristles are conductive. A blown Einsy is the outcome if you miss the mark and brush the wires.
RE: Cleaning the hotend and heat block
Heat it up. Remove the nozzle. Let it cool. Remove the hotend. Screw the heatbreak in until it's flush. Screw in the nozzle. It should be a full mm away from the heater block. Heat the hotend to 285, and tighten the nozzle.
How do you remove the heater from the "spring" part of the hotend? Is it a type of screw that I just rotate until it losens?
I was able to clean it entirely using a brass brush, so I think if I just close the gap, as you said, it should be good. What is the right way for doing this?
Also, I don't understand how did become that lose in the first place.
RE: Cleaning the hotend and heat block
You can use a brass wire brush to clean the block up further when its at temperature.
This is what I use.
There are brass brushes - then there are brass brushes.
If the filament sticks to the brass bristles and makes a gooey mess - you got the wrong kind.
I have done a lot of cleaning with mine and the bristles are still mostly clean.
RE: Cleaning the hotend and heat block
I buy the cheap brass brushes from Harbor Freight.
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Chuck H
3D Printer Review Blog
RE: Cleaning the hotend and heat block
I buy the cheap brass brushes from Harbor Freight.
Report! Does melted filament stick to them?
I have a harbor freight really close...
RE: Cleaning the hotend and heat block
I have had this problem continuously, especially on large prints. I am now tearing down the extruder as the only way to clear this last clog. Thanks to your analysis, I now understand the problem. For one thing, I have been running at 220 degrees which is apparently too hot. As I repair the unit I would like to replace the heat break with the one with no bottle neck. I guess this is the original ED3 V6 heat break as you mentioned. Can you tell me where to find one of these?
Amazon has lots of heat-breaks but does not mention these kind of details. And I am not sure what "original" refers to. I have a Prusa Original i3MK3 printer, recently purchased (my second printer so I am reasonably well versed in these machines). I assume that the term original does not refer to the Prusa Original? Also, where to find the 2.2mm diameter PTFE?
Thanks for any help.