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Failure to heat after runout
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Last Friday I started a long ~50 hour print.

Extruder 1: polymaker polydissolve
Extruder 2: polymaker pla
Cura: 3.6.8
Printer: Beta KT 7

About an hour into the print, I had a false positive runout error for extruder 2, but it resumed fine and ran normally. At 38 hours, 44 min it had a true runout error for extruder 1. I removed, cut, and replaced the polydissolve and confirmed it was extruding. I was also running low on the PLA, so I wanted to replace it with a full reel. I selected extruder 2 and set it to heat back up; however, the temp kept going down, and after a minute or so I got the error: E2 HEATING FAILED, PINTER HAULTED, Please Reset.

Yesterday I tried to print a shorter 13 hour model with the same filament setup. At 1 hour 55min, it had a false positive runout. This occurred after I left, so I didn't resume it until this morning. It heated back up resumed printing. At 3hr21min and 4hr35min it had false positive runout failures for extruder 2; both times the print was able to resume printing. Jeff suggested to turn off the runout sensor, but I wanted to keep logging the errors. At 4hr52min, it had a true positive runout error for extruder 1. I confirmed it was stripping, but also it was losing heat. I set the temp to 200C for one, then both nozzles, but neither were heating back up and after a min got the same error "E1 Heating Failed, Printer Haulted, Please Reset."

If no one else is running into these runout and heating failures it may be my machine, and it needs to be addressed before I continue printing.

Event Timeline

matth created this task.May 8 2019, 12:57 PM
matth triaged this task as High priority.
marcio added a subscriber: marcio.May 8 2019, 2:38 PM

It sounds as if you might have had a runout on extruder 1, but then changed the extruder to load filament on extruder 2. Did you return to extruder 1 before resuming the print? If you did not, there is a possibility that Marlin got confused because it was expecting you to still be on extruder 1. I suspect Marlin isn't currently smart enough to recover from this. We may have to change the UI to prevent changing the extruder while paused.

matth added a comment.May 8 2019, 2:48 PM

Both heating failures occured before returning to the print. The second one occurred while I was extruding after cutting the filament. It went like:

-printing paused, filament runout error for extruder 1
-menu -> change filament. Set to unload.
-filament removed, cut, and inserted.
-set to extrude. After ~200mm was extruded, I noticed it was stripping again and the temp was falling. I tried to manually set the temp in the temperature menu, then I tried switching nozzles and setting the temp for 2. Soon enough I got the error.

So far, these errors have only occurred in the middle of several hour long prints. Not sure if the false positive runout errors are related but I felt they should be mentioned.

marcio added a comment.May 8 2019, 3:16 PM

What may be happening is that once Marlin puts the heaters into timeout, it may not allow you to set their temperatures back up. Normally the way you clear the runout condition is resume the print, at which point Marlin will reheat the nozzles to the proper temperature. Obviously if you have a runout and the nozzle temps down, you won't be able to remove the filament, so this is a catch-22. I'll have to find out whether I can force Marlin to reheat the heaters before the user goes into the filament change screen.

west added a subscriber: west.May 9 2019, 10:12 AM

So first thing I notice when I removed the toolhead is, the heater pin on E2 isn't fully seated in the connector. That could cause intermittent connections when E@ is moved up and down and eventually not heat. Ill continue investigating the printer and post more when I have info

west added a comment.May 9 2019, 10:48 AM

Also E1's idler tension was all the way loose. I dont know if this was done intentional or not but it could be the reason of stripouts

matth added a comment.May 9 2019, 11:49 AM

The idler tension would not be intentional. That would be my bad, probably from when I had to dismantle the tool head in order to remove filament that had broken off and couldn't be extruded out. That may explain my true positives with extruder 1, but obviously not the false positives with extruder 2.

In any case, this was a beta machine, and until production has enough surplus to spare a machine I won't be testing quiver for now.

west assigned this task to marcio.EditedMay 9 2019, 1:45 PM

So this is how you replicate it .

  • cause filament runout
  • let printer sit until extruder temps down

  • go into menu and select change filament
  • click "high 220" or any other pre defined temps
  • stay on the change filament screen
  • heater error

On .118, there is a partial workaround for changing the filament if the heaters timeout:

  • Cause filament runout
  • Let the printer sit until extruder temps down
  • Click "Resume Print"
  • Marlin will reheat the heaters and show a dialog box saying "Reheat finished"
  • Before acknowledging this dialog box, you can now remove or swap filament with the hotend hot, although you will need to turn the gears by hand
  • Click the "Okay" button when you are ready to resume the print

This is sort of a kludge, but it can be used to save your print until I come up with a better solution.

One of the things that would help to know is whether this is an issue with our UI, or an issue with Marlin in general. I suggest running the following experiment on a TAZ Redgum or TAZ6:

  • Start an SD print
  • Pause the print from the LCD (this is equivalent to a runout)
  • Let the printer sit until the extruders temp down
  • Attempt to set the temperature from the LCD

If this also causes a heater error, then we know this is a problem that isn't exclusive to our UI.

A fix for this has been pushed in .119

matth added a comment.May 15 2019, 9:32 AM

Is the "Reheat finished" dialog box confirmation necessary? I would prefer if it just immediately resumed printing.

I feel if the user had to replace filament or otherwise run it out, they'd do so before hitting resume print.

Is the "Reheat finished" dialog box confirmation necessary? I would prefer if it just immediately resumed printing. I feel if the user had to replace filament or otherwise run it out, they'd do so before hitting resume print.

I agree, but this was the way it is done in upstream Marlin. I can add a workaround for it in our FW.

DaniAO added a subscriber: DaniAO.May 29 2019, 1:22 PM

@marcio Has this work around been tested at all? If so are we good to close this ticket then?

It works on my machine, but I don't know if anyone else has tested it. @matth?

matth added a comment.May 29 2019, 1:27 PM

Appears to be working as intended for me. Can close for now.

DaniAO closed this task as Resolved.May 29 2019, 1:28 PM