24v 40watt cartridge can't keep up



  • I'm pushing the limits of the machine to see whats possible.

    Filament: 2.85mm PETG
    Temperature: 320c

    Nozzle Diameter: 2.25mm
    Layer Height: 1.0mm
    Print speed: 1200mm/min

    24v 40 watt heater cartridge

    The print goes fine for a layer or two, but eventually the machine stops and says "Temperature excursion exceeded 15 degrees" and stops printing. I think it's just having a hard time heating up that much plastic quickly.

    What is the solution?

    Can I add an additional heater cartridge by connecting a second into the same terminals one in parallel with the first?



  • What kind of part cooling?



  • Have you done a PID tune for 320c? What does your temp graph look like?

    2.85mm filament has a much greater thermal mass than 1.75. You may not be able to melt it through fast enough. Throwing more heat at it may help, but you risk scorching the outer area of plastic before it melts the center area.



  • so ~2mm^2 layers and 20mm/sec printhead speed? 40mm^3/s is about all a Volcano can manage, regardless of the heater you mount into it.

    3dmntbighker is on the right track though, if you're directing a lot of air at the heaterblock, it'll need to be insulated.

    I'd insulate the heaterblock before trying to add heaters/heater cartridges.



  • Excellent advice! I added a sleeve to the heater block and the heater is staying within 5c now

    I have two ducted fans, they do tend to blow on the block a bit, that may have been contributing to it

    I believe I did run a PID tune at this temperature at one point early on, but I will run it again to make sure I have the right values



  • @elmoret said in 24v 40watt cartridge can't keep up:

    so ~2mm^2 layers and 20mm/sec printhead speed? 40mm^3/s is about all a Volcano can manage, regardless of the heater you mount into it.

    3dmntbighker is on the right track though, if you're directing a lot of air at the heaterblock, it'll need to be insulated.

    I'd insulate the heaterblock before trying to add heaters/heater cartridges.

    I see heaters of 60 watt and higher available. But I also have a few extra 24v 40 watt cartridges unused, and I'm only running 1 nozzle.

    What is the maximum heater cartridge wattage the Duet 0.8.5 can support?

    Is it practical or even possible to use both heater cartridges on 1 extruder? The only other thing I can think of is maybe just adding more mass, making the hot-end longer, and/or changing the material from aluminum to something else.

    I appreciate your help!



  • @duetfan223 it may be easier to transition to 1.75 filament?



  • @phaedrux he has a 2.25mm nozzle don't think going to 1.75mm Filament will work 🙂



  • @starscream83 Believe it or not, you can print 1.75mm filament through nozzles bigger than 1.75mm. The filament is all melted against the walls of the hot zone before it reaches the nozzle tip, so the orifice only sees liquid and it really doesn't matter what size the filament is. But you will probably have to drill out your own nozzle to get one that big.



  • 1.75 mm filament doesn't melt well in a 2.85 mm chamber. Too much of an air gap. Not bad once you form a puddle but things get messy when you try and push the melt rate up. (At least that's what I found when I did some crazy experiments with melt chambers a little while ago).



  • I've got the 24v 60w heater in now, I'll report back with my findings



  • The 60 watt heater worked like a charm! The heater has no trouble keeping up now. The board didn't even seem warm while running the 60w cartridge heater. It's ready to print at 340 Celsius in less than 30 seconds and has no trouble maintaining temperature, even without a silicone sleeve.

    I guess I'll save the "dual 40 watt cartridge heaters wired in parallel" trick for when I get around to running 6mm filament/3mm nozzles (should be soon).



  • @duetfan223 I'd really like to see what you're printing!


 

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