Not enough material with the magma hotend? FIX Included

[writemecas]

Hi all,

i'm new to this forum so the first thing i want to do is introducing me. My name ist Kai, i'm 23 years old and i'm from germany. I recently got my makerfarm prusa i3 8". After some calibration i was ready to do some testprints which went fine, but then i had a problem with the magma hotend. This was originally posted on my blog but i thought some others may have this problem too so here it is:

Two weeks have passed since i got my Makerfarm Prusa i3 Kit. I bought it together with the magma hotend which allows me to print PLA and ABS parts.

It all worked fine until yesterday when i tried another calibration print to improve my setup. First everything seemed normal, but then i noticed that the nozzle pushing out the melted abs could not keep up with the movement of the extruder and the abs was sticking to the nozzle. For this testprint i lowered the temperature to 215c which i thought could be a problem. This is a picture taken after the print.

1.jpg

After adjusting the temperature the result was the same so i had to investigate further...

After letting it cool down i started by removing the hotend from the extruder. I wasn't able to just pull the filament out of the nozzle so i connected to the prusa using pronterface and tried to extrude some material so i could cut it off. If you try doing so you will soon be disappointed because you won't be able to extrude without heating it. To bypass this security setting you can send a simple "M302" using the pronterface command line.
Next i extruded some material and cut off the main line. Doing so i was able to see the whole magma nozzle with it's first problem. There is too much tension on the cables because they are not cleanly tied so the thermistor got pulled out of the tiny whole in the nozzle.

3.jpg

I decided to completely remove the kapton tape and rewire everthing.

Next, connect to your prusa using pronterface and reverse extrude the rest material so you can remount the hotend to the extruder.


All done, yes! Sadly not. I did a fresh testprint but it showed exactly the same symptoms.

I pulled out the filament, ready to disassemble the extruder again when i saw arrears in the extruder feed. I took a close look at the filament i just pulled out and saw the cut i made when i disconnected the hotend. This meant that the filament is not getting into the nozzle. I cleaned the feed using a small screwdriver and then tighten the screws on the idler.

After that the testprint went good and the throughput seems to be ok now.

Note 1: Because of forum restrictions i can not upload all the pictures to clarify the process so feel free to read the original article here.
Note 2: Maybe a FAQ-Thread would be cool?

regards
Kai