Clogging/blocking issues with PETG in right brass nozzle on j1s

J1/J1s IDEX
1

I own this printer for a while but am not really using it a lot and now that I need the IDEX I’m having issues with it. When I got it I replaced the left nozzle (both were brass) with hardened steel one as I only expected to print abrasive with left and I kept right one brass for potential support or flexible that do not require abrasive resistance.

Trying to print now both using LUBAN and latest ORCA (not snapmaker orca but regular orca 2.3.2) but while left extruder works ok with both PLA and PETG but I’m having issues with the right one (brass original) as it blocks non stop both with PLA and PETG. This morning e.g. 24C room, top removed, doors open, printing a fairly simple object, no bridges, no retractions, just a simple cylinder we could say, in PETG, from LUBAN it printed one ok, I was out for few hours (so everything cooled to room), pushed print on same gcode, it printed 70% and complained it cannot feed the filament any more, extruder was clicking, filament was blocked… removing the filament I just see a minimum of flare at the tip of the filament, nothing close to what a normal block would be… try to feed that filament, extruder clicks and do not extrude, cut the 1cm off the tip, push it back in, extrudes just fine !!!

Filament is dry (printing from dry box), nozzle is clean, never printed anything other than pla and petg through right one, petg at 255, should go through without a problem .. every time I start the print PLA or PETG it will block after 30 to 60 minutes of printing.

Left one (hardened steel) seems to work ok.

I searched the forum, I searched redit, google, wiki … I found a bunch of fairly old posts with questions but no solutions so decided to make a new one. I’m willing to test anything at this point (I have time and filament and other 5 non-snapmaker printers that I can use for testing or printing parts, but none of them is idex). I’d appreciate a good profile for modern orca too :slight_smile:

2

Did you try a cold pull or replacing the nozzle?

3

Yup, did cold pull, looking down the nozzle looks very clean. It prints great for 30-60min then just blocks. I get the filament out, cut off the tip, put it back in and it works again great.

I am not very new to this hobby, just to this particular printer, kinda came into the hobby 20 years ago with reprap, even got to be part of the reprap core team but this extruder baffles me. The tip, when extruder blocks, does not look how it normally looks on blocked extruders. There’s no 3-4mm of swollen filament, just maybe 0.5-0.8mm of swallen filament, not something extruder should have a problem pushing through?!

Trying out the snapmaker version of orca .. maybe it will behave differently

4

I had a loose piece of PTFE tube in my hotend after I got the A350. Maybe an option to take the hotend apart?

Hard to suggest anything to such an experienced maker like you :wink:, thought this already yesterday as you stated 5 other printers..

Ok, basics for someone else and doublecheck:
-Print temperature?
-Retraction length and speed?
-Cold pull? Yes.
-Standby Temperature? (maybe too hot for Pla, not enough retracted?)
-Is the filament grinded where the extrudergears are?
-Possible to push it through after printing in air?
-Preassure of the extruder gear normal?

5

Since I’m out of ideas I created the post. When out of ideas ANY idea is good as I could missed something basic. Major brain-problem here is all my machines (except bambuses) I know to a last screw and this J1s I am pretty new with, so thanks for participating in this debugging session :slight_smile:

After @xchrisd (you) originally wrote I did cold pull again just for a good measure :smiley: … didn’t help, pull was clean but… tried it again never the less.

Maybe an option to take the hotend apart?

Removed the hotend completely, didn’t disassemble the hotend but cleaned it looked with endoscope through it to check if there are some remaining pieces inside. Wanted to replace the fan that cools the coldend but all the fans I have actually have a smaller flow so left the original.

Heated it, checked if everything is tight… looks ok, also cold pull shows no joint-lines…

Inspected the extruder (light and endoscope) - it is clean for now.

-Print temperature?
-Retraction length and speed?
-Cold pull? Yes.
-Standby Temperature? (maybe too hot for Pla, not enough retracted?)
-Is the filament grinded where the extrudergears are?
-Possible to push it through after printing in air?

temp - dunno, I tried what works on other printers, could not get it to block/not-block by changing it. Even with very constant env. temp and identical start settings one time a print will go through other time it won’t.

Originally I believed the standby could be the problem so I printed with right nozzle only, so no temp changes… could not make it block on demand nor print reliably

Retraction was my first go-to so I disabled retractions completely during this hole test

Standby - again, testing “right only” to eliminate that as a problem. Also I’m having problem with PETG - testing PETG as it is more resilient to temp and can handle hotter environment and hotter cold part of the hotend

Grinded- oh yeah, I can hear it before printer push out error pausing print I can hear extruder clicking… if I remove the filament I can see it started to grind but it stops before it grinds a typical semicircle in filament… I click load and it extrudes while clicking but underextrudes a lot, I remove the filament and I can’t see the typical bulge on the tip just a minimal one, I cut that off, load again, it extrudes without a problem.. for a while, then same problem after an hour

Trough air - YES, when it blocks, I can push with my hand and it will go through (open the extruder) but then if I click “load” sometimes it extrudes ok after I push it with my hand and sometimes it start clicking after few seconds

-Preassure of the extruder gear normal?

As I’m writing you this answer, instead of talking to rubber ducky :D, this is something I’m thinking off, looks like extruder just don’t grip the filament good enough and is slipping… No idea how to test / change the gripping strength on this extruder ?!

BTW, last night I loaded 2 PLA’s in the printer and printed a small dual color test using snapmaker orca 2.3.1 and it printed fine… will start another larger test tonight … it could just be terrible profiles and not a hardware issue

6

UPDATE

I changed a bunch of things but I think it’s SW… I cleaned everything, compressed air the @5\62(%^&#! out of it, cleaned moving parts and applied new coat of lubricant on to them… disassembled and reassembled hotends… removed PETG and put PLA that is usually more prone to blocking due to thermal creep… and on top of all changed slicer (took snapmaker-orca 2.3.1 with default profile)

and after more than 12 hours of printing, both only right and using left+right at rather slow speed at .16mm layer - no issues, beautiful prints… I think the only real change here is slicer but… we’ll see

now going to change things (first switch to fatter layers) to see if the problem will come back

7

Good to hear you made a bit progress.

Missing cooling could also cause heat creep.
Broken heatsink fan or missing thermal paste.

8

Fan’s are good, I have some strong ones and wanted to replace original ones but measured CFM of the original ones and it’s even higher than ones I have so kept them. Was thinking about cutting out bigger hole (removing grill making it just a square hole) where hotend cooling air is leaving extruder .. but without seeing that the filament actually bulks up inside hotend I don’t see the point.

With snapmaker-orca and PLA no matter what I changed everything works good. Switched back to PETG so will see if that start blocking but so far it works as expected.

Looks like issue is in ORCA profile (printer or plastic). Will use snapmaker-orca now for a while and will return to regular ORCA to see if I can copy the data to see if regular ORCA will work ok now.

What’s weird is now PLA works great with 35C chamber temp so pretty hot inside…

The only other changes that I made since the blocks are

  • PETG was printing from drybox - so some additional force required to pull it from the box other than now filament being just on the holder on back.
  • I added another riser for the printer so the filament goes nicely in to the extruder, not through high angle as it does originally

We’ll see … so far I already printed the part I needed IDEX for so so far so good :smiley:

Interesting, messing with it for over a week without any progress, the day I created the account and wrote a post it started solving itself :smiley: :smiley: :smiley: so thanks for the discussion