Extruder stopping intermittently
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@t3p3tony I sent the M122, added the M308 to the config, started the gcode but shortly after I got real fast dips in the hotend temp and heater faults. The program stays running and only the extruder stops when the temperature dips too low. Where the extruder stops for a long period match's up with the dip in temp. I ran the same program twice and the places where the dips happen match up.
Is the issue then caused by a bad conductor or thermistor?
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@3dprintingworld said in Extruder stopping intermittently:
I got real fast dips in the hotend temp and heater faults
heater faults should pause the print, so that is definitely not expected behaviour. How much was the temperature dropping by and did the heater actually say "fault" in DWC?
It could be the heater or thermistor with an intermittent fault, possibly just in certain positions on the bed if its repeatable with the same print, with the hotend at temperature, but not printing, can you move the hotend around to similar positions to see if you get the dips? Depending on how much its dipping I suppose it could also be a very aggressive fan cooling the hotend but you did not mention a change to the fan setup you were using.
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@t3p3tony
I am now getting a heater fault message in the console at the first dip and a bunch near the end before I stop it. I didn't think I was getting these previously, I don't know how I could have missed them. The graph is similar when I run the same first layer in the g-code multiple times, the print does not stop automatically after receiving the fault. Is it because the dip is so quick?I only see a couple degree temperature swing when I move the carriage around by hand. I tried moving the wiring around by hand as much as I can but everything is well constrained in wire chain. It was all new wire and I haven't have tons of hours on this printer yet.
No change in fan setup. This g-code is on the first layer so the part cooling fan is not on, if you think it may be cooling the hotend.
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@3dprintingworld My twopence worth.....The temperature excursions are much too fast for it to be a faulty heater cartridge. I've seen that behaviour with both a temperature sensor wiring issue (bad crimp) and with faulty thermistor cartridge. The amplitude of the temperature excursion and the time it needs to have exceeded that limit before a heater fault is triggered are configured using M570. I didn't notice an M570 command in the config.g that is posted so I guess default values would apply. These are 15 deg C and 5 seconds so the heater excursion will need to exceed 15 deg C for 5 seconds before a fault is flagged. hence the reason why some excursions trigger the fault but not others.
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@3dprintingworld yes, definitely not cooling fan related. As @deckingman has pointed out, this is this is a temperature sensing issue. I would investigate wires/connectors/crimps breaking contact intermittently because all the spikes are going down we know its a break in connection not a short between thermistor wires. Also as @decking man has mentioned it could be a intermittent fault inside the thermistor cartridge itself.
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Does M122 report extrusion-skipped-due-to-cold-nozzle events? That could be useful.
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@zapta no i don't think M122 reports that but it will be reported in the console in normal use, unless M302 P1 is in use.
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I've been busy printing and designing too much cool shit so didn't have the time to look into this until just now.
@T3P3Tony is going to say I got what I deserve for not going CAN and he's probably right... It turned out to be a defect in the stock thermistor wire. There was a small internal bulge in the wire with a short that was located in the middle of the x-axis wire chain, I don't think it could have been caused by the wire management. Fixed now, thanks for the help! -
@3dprintingworld said in Extruder stopping intermittently:
It turned out to be a defect in the stock thermistor wire.
Did your duet give you any warning (e.g. console messages) about the anomalies in the thermistor signal?
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@zapta In the beginning I started to get heater faults only when preheating when starting g-code, maybe every 20 prints. I was not sure, I thought maybe it was from environmental conditions. Over time I started to see under extrusion in my prints but no error. During the troubleshooting in this thread I started to finally get heater faults while printing. I think its because previously the dips were not long enough and over time the short in the wire got worse causing their duration to increase.
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@3dprintingworld thanks for reporting back what the issue was. Glad you pinned it down.
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