Filiment stuck at hotend

[Vulchikova]

Greetings everyone!

My son and I finally finished the Rostock Max 3.2 build last night. After updating firmware, calibrating, and rechecking everything I can possibly recheck, the filiment was loaded and I printed the demo steam boat print. I was stoked that it worked so well! There was a little stringing, but that was on the trivial side of things.

So I then used Cura to slice the Due case (Adjusted temp to 200 as the demo print at 210 caused some stringing). Uploaded the file, and started printing. Everything seemed ok at first, but then I noticed a LOT of stringing. So I canceled the print thinking the hotend cooling fans were not on. Tweaked some fan settings, reuploaded, and started again.

This time, the print quality was really bad. I was seeing a lot of glumping, but let it proceed. I soon noticed it was skipping, then eventually just stopped laying down PLA at all. The head was moving about, but the surface was clean. Stopped the print again and started inspecting. I tried to use the filiment extraction macro, but it did nothing but grind on the PLA. I found that the filiment melted slightly and swelled inside the PTFE tube at the hot end. It took me about an hour of tugging and milking the filiment out.

Which leaves the question: Why would the filiment do this? I could not find a user manual or maintenance manual anywhere. After a print (or a cancel) should you immediately use the filiment extraction macro?

Also, should I run a calibration prior to each print? If so, which one?

Looking through the Cura setup instructions, I did discover that I did not import the profiles. So, I created a new file based on the PLA Default profile and will try again tonight. Any advice yall got to help correct/prevent this would be greatly beneficial.

[Vulchikova]

Another topic, I sometimes get "Z prove value is not consistent" during the double taps. Because these messages are not consistent, meaning: sometimes I get a few messages, other times I get just one, I have been generally ignoring them. Is this something to be concerned about?

[Vulchikova]

Well it did it again. Using Cura and the SeeMeCNC Pla Default profile, I printed the mounting bracket for the Due Interface. Worked beautifully!

Went to print the back case and things started going weird. It only actually printed two layers. Then I noticed that crumbs were being left on the print and the surface was very rough. So I started watching closely and noticed that the print was not getting any thicker though I was supposed to be on payer 10. I watched the print head from the side and noticed a gap between the tip and the print. The head was simply dragging pla across the surface. I also noticed a clicking at the cold end. So I stopped the print and inspected

Tried to use the extract macro but it didn’t extract. So I had to manually extract the filament. Again the Filament was stuck in the hot end and the last half inch or so was a little melted and gunky. Tonight I am going to take it apart and see what’s going on in there.

Suggestions are welcome.

[geneb]

Make sure that the bed clips are holding down the bed firmly. I tighten them with a screwdriver a little bit after I've moved the lever over the glass. This will help with the z probe retries. You also need to make sure that you've got the latest macro files from the git repo - the bed MUST be turned off during probing because the electromagnetic field it produces will scramble the output of the probe. Keep an eye on the blue sensor LED - it should only come on when the nozzle taps the glass.

Check your filament to make sure it's within spec - it shouldn't be greater than about 1.79mm. Spool off about 2 meters and spot check it in 10 spots using a digital caliper. You can punch that average diameter into your filament diameter in Cura as well as make sure it's not wildly out of spec.

g.

[Vulchikova]

Geneb,

Thanks for the response. My bed is down quite firmly. I will check wires underneath to ensure they are not in a position to cause any springyness. The printer is currently on my dining room table, which is glass and not really the most stable surface, so there may be some inherent shimmy. I will move it to a more stable surface and try again.

As for the jams, I will check as you instruct. But, I am going to disassemble the hotend along the filiment feed path to ensure nothing in clogged/dirty, crimped, bent, or otherwise not 100%. Given the filiment end once extracted is rather messy, I would not be shocked if there is some residue left in there thay may be contributing.

[geneb]

It's also possible that the hot end is blocked by foreign debris - I've seen instances where metal particles, tiny ball bearings, etc. have been found in some of the cheaper filament brands.

g.

[rootboy]

Or, as in my case, I managed to not notice that I had my fan leads swapped on the Duet board until PLA started getting stuck in the cold end of the hot end. It was pretty obvious what the problem was when I pulled the filament out and saw the it had gobbed up in the cold end.

So, check your fan, it should be on continuously. And I would recommend an all-metal hotend. The one time that my Prometheus got seriously stuck I took it to work and asked one of our brazers to torch it. Fixed it right up.