I am using a Snapmaker J1s for about a year now. Mainly simply prints without problems. I have been testing with PLA, ABS, PETG. The last weeks I have been testing with prints in two colours, using PLA. Since then I am experiencing troubles. The nozzles are constantly clogged after printing a couple of minutes. Sometimes printing lasts for 30 minutes, sometimes 1 minute.
I am printing the exact same models as two months ago, but al of a sudden I can’t finish them anymore. Sometimes clogging happens after exact one layer, sometimes exactly after ending the printed support. While clogging (and before clogging) I hear a ticking sound and then the printing stops. After that I can (most of the times) load the filament without problems. A real clogging is not the problem, so it seems.
I have the newest firmware. I have calibrated everything. I have thoroughly cleaned the nozzles. I have printed with open doors and with closed doors. I have printed with top plate, without top plate. Tested temperature from 195 to 220. With and without a heated bed. Used new filament in different colors.
Once I switched to all metal, the small intermittent skips were gone. I recently posted a suggested solution for first layer hard clogs, letting the bed heat before the hotend. That only started for me with the all metal ones.
(Typically printed at 210 or 215 C depending on the PLA)
I use the standard hotends (bought the printer january 2024) with brass nozzles. I also have a pair of hardened steel hotends. Both type of hotends have the same problem.
I have sent an email to Snapmaker, they offered me two new pairs of hotends. I think that might be the all metal hotends. According to the Snapmaker webshop those are “optimized to reduce filament clogging”.
I have installed the new all-metal hotends, at first that seemed to work fine with some small prints. But eventually the hotends still get clogged, only after a couple layers of printing (I can only embed one photo in this post).
The cloggin happened after a couple of layers printing. I was printing (new) PLA at 200 degrees, with 2mm retraction, without extruderchange, heated bed 50 degrees, fan 100%.
I had the suspicion the retraction was the cause. I tried again without retraction. You can clearly see the stringing of course. But at about 60% the left extruder was clogged.
I have changed the gcode like described in your post. Don’t know yet if that is the solution. Also changed the temperature to 210C, I am testing it at the moment. The stringing is due to zero retraction, when I print with retraction there is less stringing (but more clogging).
I am convinced the filament is dry, the humidity in the room is about 40%.
@Michiel It’s odd that its clogging even without retraction. That shouldnt even happen with the old sucky hotends… Did you check to see if the coolingblock fans are running while printing? Maybe there is a loose connection somewhere…
You could use tape to put a tiny piece of paper where the air exits and see if its blowing while printing.
Also a couple of cold pulls wouldnt hurt.
I was not referring to the part cooling fans. Am I right to assume that you understood that?
I suppose next thing after verifying the functionality of the cooling block fans could be to investigate weather it’s necessary to put more cooling paste on the heatbreaks or not…
Yes, I thought you meant the part cooling fans. How do I check the cooling block fans? I have two brand new hotends, how could it be possible both of them ain’t working right?
When you heat up a hotend you can hear it starting at around 50 degrees. However, I suppose that if there is a loose connection somewhere, perhaps a cooling block fan could work while the toolhead is standing still but fail while moving…
You should be able to feel the airflow with your hand.
Yes, I can feel the airflow. The cooling block fans are working.
This afternoon I have finished a one hour, two colour print twice. Retraction set at 0.7mm. After that I tried to print the same model, but two at once. I sliced the two models with the exact same settings as the single print. At about 25% the left extruder was clogged again.
I think two models in one print result in more travel and more retractions. The retractiondistance is really low, 0.7mm. Retraction speed is 35mm/s.
Do you mean the “nozzle switch retraction” (I use Cura)? I use this one with the two colored models at a distance of 16mm. I don’t think that is the problem. It was before, when this setting was at 1mm.
Tonight I have tested another model in one color, but in copy mode. Each print persist of four identical elements, so in copy mode eight models (four left, four right). These models need a little support (tree). Exactly where the model touches the support (layer 222) both nozzles are clogged. That’s not the first time this print causes clogging exact at that moment.
